EFFICIENT NETWORKS INC
S-1, 2000-01-10
COMMUNICATIONS SERVICES, NEC
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<PAGE>

   As filed with the Securities and Exchange Commission on January 10, 2000
                                                     Registration No. 333-
- -------------------------------------------------------------------------------
- -------------------------------------------------------------------------------
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549
                               ----------------
                                   FORM S-1
                            REGISTRATION STATEMENT
                                     Under
                          The Securities Act of 1933
                               ----------------
                           EFFICIENT NETWORKS, INC.
            (Exact name of Registrant as specified in its charter)

<TABLE>
 <S>                              <C>                           <C>
            Delaware                          3661                       75-2486865
 (State or other jurisdiction of  (Primary Standard Industrial        (I.R.S. Employer
 incorporation or organization)    Classification Code Number)     Identification Number)
</TABLE>

                               ----------------

                      4201 Spring Valley Road, Suite 1200
                           Dallas, Texas 75244-3666
                                (972) 991-3884
  (Address, including zip code, and telephone number, including area code, of
                   Registrant's principal executive offices)

                               ----------------

                                 MARK A. FLOYD
                            Chief Executive Officer
                      4201 Spring Valley Road, Suite 1200
                           Dallas, Texas 75244-3666
                                (972) 991-3884
(Name, address, including zip code, and telephone number, including area code,
                             of agent for service)

                               ----------------

                                  Copies to:
           KENNETH M. SIEGEL                    S. MICHAEL DUNN, P.C.
            ADAM R. DOLINKO                     MICHELLE KWAN MONTOYA
            HELEN E. QUINN                 Brobeck, Phleger & Harrison LLP
   Wilson Sonsini Goodrich & Rosati        301 Congress Avenue, Suite 1200
       Professional Corporation                  Austin, Texas 78701
          650 Page Mill Road                       (512) 477-5495
      Palo Alto, California 94304
            (650) 493-9300

                               ----------------

Approximate date of commencement of proposed sale to the public: As soon as
practicable after the effective date of this Registration Statement.
   If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, check the following box. [_]
   If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, check the following box and
list the Securities Act registration statement number of the earlier effective
registration statement for the same offering. [_]
   If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [_]
   If this Form is a post-effective amendment filed pursuant to Rule 462(d)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [_]
   If delivery of the prospectus is expected to be made pursuant to Rule 434,
check the following box. [_]

                               ----------------

                        CALCULATION OF REGISTRATION FEE
<TABLE>
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<CAPTION>
                                                         Proposed
                                           Proposed      Maximum
 Title of Each Class of      Amount        Maximum      Aggregate    Amount of
    Securities to be          To Be     Offering Price   Offering   Registration
       Registered         Registered(1)  Per Share(2)    Price(2)       Fee
- --------------------------------------------------------------------------------
<S>                       <C>           <C>            <C>          <C>
Common Stock, $0.001 par
 value.................     5,750,000      $58.875     $338,531,250  $89,372.25
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
</TABLE>
(1) Includes 750,000 shares that the Underwriters have the option to purchase
    from the Company to cover over-allotments, if any.
(2) The price is estimated solely for the purpose of calculating the
    registration fee pursuant to Rule 457(c) promulgated under the Securities
    Act of 1933, as amended, and represents the average of the high and low
    market prices of a share of the Company's Common Stock on January 6, 2000
    as reported on the Nasdaq National Market.

                               ----------------

   The Registrant hereby amends this Registration Statement on such date or
dates as may be necessary to delay its effective date until the Registrant
shall file a further amendment which specifically states that this
Registration Statement shall hereafter become effective in accordance with
Section 8(a) of the Securities Act of 1933 or until the Registration Statement
shall become effective on such date as the Commission, acting pursuant to such
Section 8(a), may determine.

- -------------------------------------------------------------------------------
- -------------------------------------------------------------------------------
<PAGE>

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+This information in this prospectus is not complete and may be changed. We    +
+may not sell these securities until the registration statement filed with the +
+Securities and Exchange Commission is effective. This prospectus is not an    +
+offer to sell these securities and it is not soliciting an offer to buy these +
+securities in any state where the offer or sale is not permitted.             +
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                 SUBJECT TO COMPLETION, DATED JANUARY 10, 2000.

                                5,000,000 Shares

                [LOGO OF EFFICIENT NETWORKS, INC. APPEARS HERE]

                                  Common Stock

                                   ---------

  We are selling 2,000,000 shares of common stock and the selling stockholders
are selling 3,000,000 shares of common stock. We will not receive any of the
proceeds from the sale of the shares being sold by the selling stockholders.

  The underwriters have an option to purchase a maximum of 750,000 additional
shares from us to cover over-allotments of shares.

  Our common stock is quoted on The Nasdaq Stock Market's National Market under
the symbol "EFNT". The last reported sale price of the common stock on January
6, 2000 was $60.25 per share.

  Investing in our common stock involves risks. See "Risk Factors" on page 7.

<TABLE>
<CAPTION>
                                              Underwriting                  Proceeds to
                                  Price      Discounts and   Proceeds to      Selling
                                to Public     Commissions     Efficient     Stockholders
                              -------------- -------------- -------------- --------------
<S>                           <C>            <C>            <C>            <C>
Per Share...................      $              $              $              $
Total.......................     $              $              $              $
</TABLE>

  Delivery of the shares of common stock will be made on or about       , 2000.

  Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if
this prospectus is truthful or complete. Any representation to the contrary is
a criminal offense.

Credit Suisse First Boston

         Robertson Stephens

                   Prudential Volpe Technology
                       a unit of Prudential Securities

                                                      Dain Rauscher Incorporated

                   The date of this prospectus is    , 2000.
<PAGE>

                                 ------------

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                      Page
                                      ----
<S>                                   <C>
Prospectus Summary..................    3
Risk Factors........................    7
Special Note Regarding Forward-
 Looking Statements.................   19
Use Of Proceeds.....................   20
Price Range of Common Stock.........   20
Dividend Policy.....................   20
Capitalization......................   21
Selected Consolidated Financial
 Data...............................   22
Management's Discussion and Analysis
 Of Financial Condition and Results
 Of Operations......................   23
</TABLE>
<TABLE>
<CAPTION>
                                      Page
                                      ----
<S>                                   <C>
Business............................   35
Management..........................   52
Certain Transactions................   61
Principal and Selling Stockholders..   63
Description Of Capital Stock........   66
Shares Eligible For Future Sale.....   70
Underwriting........................   72
Notice To Canadian Residents........   74
Legal Matters.......................   75
Experts.............................   75
Additional Efficient Information....   75
Index To Consolidated Financial
 Statements.........................  F-1
</TABLE>

                                 ------------

   You should rely only on the information contained in this document or to
which we have referred you. We have not authorized anyone to provide you with
information that is different. This document may only be used where it is legal
to sell these securities. The information in this document may only be accurate
on the date of this document.
<PAGE>

                               PROSPECTUS SUMMARY

   This summary highlights information contained elsewhere in this prospectus.
You should read the entire prospectus carefully.

                            Efficient Networks, Inc.

                                ----------------

   Efficient Networks is a worldwide developer and supplier of high-speed
digital subscriber line customer premises equipment for the high-speed, high-
volume digital communication, or broadband, access market. Digital subscriber
line, or DSL, solutions enable telecommunications and other communication
network service providers to provide high-speed, cost-effective broadband
access services over the existing copper wire telephone infrastructure. We
believe there is significant demand for broadband access, especially among
business users and consumers who have found current solutions to be inadequate
or too expensive. DSL networks generally consist of two core components, one
installed at the network operator's facility--typically referred to as the
central office--and one installed at the customer's home or business. The DSL
equipment installed at the customer premises is generally referred to as
customer premises equipment. We develop and produce DSL customer premises
equipment, and in particular single- and multiple-user DSL customer premises
equipment for small- to medium-size businesses, branch offices of large
corporations and consumers. Our DSL products enable applications such as high-
speed Internet access, electronic commerce, access to computer networks from
remote locations, telecommuting and extensions of corporate networks to branch
offices.

   Business-critical Internet-based applications, such as electronic commerce,
Web browsing and access to computer networks from remote locations for
telecommuters, generate enormous data traffic over the existing communications
infrastructure. The growth in Internet use, increased competition resulting
from domestic and international deregulation, and pressure from alternative
means of providing high-speed, high-volume access services have led both
traditional and new operators of the existing copper telephone wire-based
networks to deploy DSL. DSL technology enables these network service providers
to rely upon the existing copper telephone wire infrastructure to cost-
effectively provide broadband access to most businesses and homes currently
connected by telephone lines.

   In order to offer cost-effective DSL services to end users, network service
providers are actively seeking DSL customer premises equipment solutions that
offer interoperability from the end user's personal computer through the
service provider's networks and which provide for simple and low-cost
installation and maintenance. The products that make up our SpeedStream family
of customer premises equipment satisfy the requirements of network service
providers as they:

 . Enable DSL Deployments. We enable network service providers to rapidly deploy
  DSL services, thereby allowing them to quickly capture market share in
  today's intensely competitive broadband services market. By offering a broad
  product line we can support DSL services targeted at both businesses and
  consumers.

 . Ensure End-To-End Interoperability. Our technology expertise and ongoing
  product development coordination with network equipment vendors, such as ADC
  Telecommunications, Advanced Fibre Communications, Alcatel, Copper Mountain
  Networks, Ericsson, Lucent Technologies, Newbridge Networks, Nokia, Nortel
  Networks and Siemens, and network service providers enable us to ensure
  interoperability between the end user's personal computer and the service
  provider's network.

 . Provide for Efficient and Cost-Effective Installation. The software included
  with many of our products allows a network service provider to pre-configure
  the customer premises equipment to the parameters of a particular network,
  reducing the costs associated with having installers perform these activities
  during each end-user installation. As demand for DSL service grows, pre-
  configuration helps network operators meet their customers' expectations for
  rapid service activation.

                                       3
<PAGE>


 . Provide for Cost-Effective Maintenance. Our Advanced Status software allows a
  network service provider to easily monitor, diagnose and often remotely fix
  the customer's problems quickly, which can substantially reduce the network
  service provider's customer support costs.

   Our objective is to be the leading worldwide provider of high-performance
DSL broadband access customer premises equipment for businesses, remote
offices, telecommuters and consumers. To achieve this goal, we intend to
capitalize on our early market acceptance by network service providers and to
leverage our relationships with network equipment vendors. In addition, we will
continue developing enhancements to our current DSL products and expect to
develop products that are capable of processing both voice and data
communications through the same DSL equipment and network. Also, we intend to
continue to target strategic partnerships and acquisitions to augment our
product offerings, sales channels and worldwide operations. Finally, we plan to
extend our distribution channels to meet the growing demand for broadband
access solutions and increase our brand awareness.

   We sell our products to network equipment vendors and DSL network service
providers. As of December 31, 1999, our products have been deployed by
Ameritech, Bell Atlantic, BellSouth, Covad Communications, Hanaro Telecom, Hong
Kong Telecom, Pacific Bell, Singapore Telecom, Southwestern Bell, and
TeleDanmark, among others, and purchased by several network equipment vendors.
A number of other network service providers have begun to test our customer
premises equipment solutions.

   We were incorporated in Delaware in 1993. Our principal executive offices
are located at 4201 Spring Valley Road, Suite 1200, Dallas, Texas 75244-3666
and our telephone number is (972) 991-3884. Our Website is located at
http://www.efficient.com. Information contained on our Website does not
constitute part of this prospectus.

                              Recent Developments

   On December 17, 1999 we completed the acquisition of FlowPoint Corporation,
a wholly-owned subsidiary of Cabletron Systems, Inc., based in Santa Clara,
California, in exchange for a combination of common stock and convertible
preferred stock equal to an aggregate of 13,500,000 shares of our common stock
on an as-converted basis. FlowPoint's primary business is the design,
manufacture and sale of a comprehensive line of advanced broadband routers for
deployment at customer premises. FlowPoint's product line consists of routing
products for use in business-class DSL services. According to the Dell'Oro
Group's November 1999 study of market performance for the first three quarters
of 1999, FlowPoint was the market leader in SDSL and IDSL customer premises
equipment. We now provide the industry's most comprehensive line of DSL
customer premises equipment, including internal and universal serial bus modems
for personal computers, DSL local area network modems, small office and
telecommuter DSL routers, and DSL routers for small businesses and branch
offices. FlowPoint's customers include major incumbent and competitive local
exchange carriers, including Ameritech, Covad and NorthPoint, and several
European incumbent carriers such as British Telecom. FlowPoint also works
closely with a number of Internet service providers offering DSL services to
businesses. FlowPoint recently announced the availability of an integrated
access device that supports both voice and data service delivery over a single
DSL line. The acquisition of FlowPoint is expected to increase our revenue and
market share, it expands our product line and customer base, adds key
personnel, and establishes a presence for Efficient Networks in Silicon Valley.

                                       4
<PAGE>


                                  The Offering

<TABLE>
<S>                                <C>
Common stock offered by            2,000,000 shares
 Efficient........................
Common stock offered by the        3,000,000 shares
 selling stockholders.............
Common stock outstanding after     53,156,248 shares
 this offering....................
Use of proceeds................... For general corporate purposes, principally
                                   working capital, additional sales and
                                   marketing efforts, and potential
                                   acquisitions.
Nasdaq National Market symbol..... EFNT
</TABLE>
- --------
The above table is based on shares outstanding as of December 31, 1999. See
"Capitalization." This table includes 6,300,000 shares of common stock issuable
to Cabletron Systems, Inc. upon conversion of preferred stock held by
Cabletron. For a description of the preferred stock held by Cabletron, see
"Management's Discussion and Analysis of Financial Condition and Results of
Operations--Recent Developments" and "Description of Capital Stock." This table
excludes:

  . options outstanding to purchase a total of 8,164,384 shares of common
    stock at a weighted average exercise price of $10.73 per share and
    2,778,750 shares reserved for grant of future options under our stock
    option plans;

  . 184,889 shares reserved for future grants under our 1999 Employee Stock
    Purchase Plan; and

  . 34,246 shares issuable upon exercise of outstanding warrants.

                                ----------------

   You should be aware that our fiscal year ends on June 30; thus, a reference
to "fiscal 1999," for example, is to the fiscal year ended June 30, 1999. In
addition, except as otherwise indicated, information in this prospectus assumes
that the underwriters' over-allotment option will not be exercised.


                                       5
<PAGE>

                   Summary Consolidated Financial Information
                     (in thousands, except per share data)

<TABLE>
<CAPTION>
                                                         Three Months Ended
                          Fiscal Year Ended June 30,        September 30,
                          -----------------------------  --------------------
                            1997      1998      1999       1998       1999
                          --------  --------  ---------  ---------  ---------
<S>                       <C>       <C>       <C>        <C>        <C>
Statement of Operations
 Data:
Net revenues............. $  4,122  $  3,370  $  14,828  $   1,174  $  12,171
Cost of revenues.........    2,386     2,160     14,344        863     11,706
                          --------  --------  ---------  ---------  ---------
Gross profit.............    1,736     1,210        484        311        465
Loss from operations.....   (6,760)   (9,421)   (18,505)    (3,455)    (7,677)
Net loss................. $ (6,635) $ (9,291) $ (26,405) $  (3,375) $  (7,754)
                          ========  ========  =========  =========  =========
Net loss per share:
  Basic and diluted...... $  (2.19) $  (2.86) $   (6.87) $   (0.93) $   (0.25)
                          ========  ========  =========  =========  =========
  Weighted average
   shares................    3,027     3,254      3,893      3,713     30,496
                          ========  ========  =========  =========  =========
Pro forma net loss per
 share:
  Basic and diluted......                     $   (0.97)
                                              =========
  Weighted average
   shares................                        28,342
                                              =========
</TABLE>

<TABLE>
<CAPTION>
                                                             September 30, 1999
                                                            --------------------
                                                             Actual  As Adjusted
                                                            -------- -----------
<S>                                                         <C>      <C>
Balance Sheet Data:
Cash and cash equivalents.................................. $ 47,456  $160,931
Working capital............................................   69,051   182,526
Total assets...............................................   88,680   202,155
Total stockholders' equity.................................   72,252   185,727
</TABLE>

                                ----------------

   See Note 2 of Notes to Consolidated Financial Statements for an explanation
of the determination of the number of shares used in computing per share data.
The as adjusted numbers give effect to our receipt of the estimated net
proceeds from the sale of the 2,000,000 shares of common stock offered by
Efficient hereby at an assumed public offering price of $60.25 per share, after
deducting underwriting discounts and commissions and estimated offering
expenses payable by us. See "Use of Proceeds" and "Capitalization."

                                       6
<PAGE>

                                 RISK FACTORS

   You should carefully consider the risks described below before making a
decision to invest in Efficient.

Risks Associated With the Digital Subscriber Line Industry

   Sales of our products depend on the widespread adoption of broadband access
services and if the demand for broadband access services does not develop,
then our results of operations and financial condition would be adversely
affected.

   Our business would be harmed, and our results of operations and financial
condition would be adversely affected, if the use of broadband access services
does not increase as anticipated, or if our customers' broadband access
services are not well received in the marketplace. Certain critical factors
will likely continue to affect the development of the broadband access
services market. These factors include:

  . inconsistent quality and reliability of service;

  . lack of availability of cost-effective, high-speed service;

  . inability to integrate business applications on the Internet;

  . lack of interoperability among multiple vendors' network equipment;

  . congestion in service providers' networks;

  . inadequate security; and

  . inability to meet growing demands for increasing bandwidth.

   Even if these factors are adequately addressed, the market for broadband
access services to the Internet and corporate networks may fail to develop or
may develop more slowly than anticipated. If this market fails to develop or
develops more slowly than anticipated, our business would be harmed, and our
results of operations and financial condition would be adversely affected.

Many competing technologies may serve our target market, and if the DSL
technology upon which our products is based does not succeed as a
technological solution for broadband access, we would not be able to sustain
or grow our business.

   The market for high-speed data transmission services has several competing
technologies which offer alternative solutions, and the demand for DSL
services is uncertain in light of this competition. The introduction of new
products by competitors, market acceptance of products based on new or
alternative technologies or the emergence of new industry standards could
render our products less competitive or obsolete. If any of these events
occur, we would be unable to sustain or grow our business. Technologies which
compete with DSL are:

  . other access solutions provided by telephone network service providers
    such as dial-up analog modems, integrated services digital networks and
    T1 services;

  . broadband wireless technologies; and

  . broadband cable technologies.

   If these alternatives gain market share at the expense of DSL technologies,
demand for our products would be reduced, and we would be unable to sustain or
grow our business. Additionally, wireless and cable network service providers
are well funded, and cable network service providers have large existing
customer bases. As a result, competition from these companies is intense and
expected to increase.


                                       7
<PAGE>

We depend upon network service providers to deploy DSL technologies and
services in a broad and timely manner, and if they do not, we would be unable
to sell our products.

   If network service providers do not increase their deployment of DSL
services rapidly, we would be unable to sell our products as anticipated, if at
all. Factors that impact deployments include:

  . the demand from end users;

  . a prolonged approval process, including laboratory tests, technical
    trials, marketing trials, initial commercial deployment and full
    commercial deployment;

  . the development of a viable business model for DSL services, including
    the capability to market, sell, install and maintain DSL services;

  . cost constraints, such as installation costs and space and power
    requirements at the network service providers' central offices;

  . varying and uncertain conditions of the installed copper wire, including
    size and length, electrical interference, and crossover interference with
    voice and data telecommunications services;

  . problems of interoperability among DSL network equipment vendors'
    products;

  . evolving industry standards for DSL technologies; and

  . domestic and foreign government regulation.

Risks Within the DSL Industry

Competition within the DSL market is intense and includes numerous established
competitors, and if we are unable to compete effectively, our business would be
harmed.

   Competition in the DSL customer premises equipment market is intense, and we
expect competition to increase. Many of our competitors and potential
competitors have substantially greater name recognition and technical,
financial and marketing resources than we have. If we are unable to compete
successfully, our business will be harmed and our results of operations and
financial condition would be adversely affected. We cannot assure you that we
will have the financial resources, technical expertise or marketing,
distribution and support capabilities to compete successfully. See "Business--
Industry Background" and "--Competition."

   Competitive pressures could adversely affect us in the following ways:

  . reduce demand for our products;

  . cause delays or cancellations of customer orders;

  . cause us to reduce prices on our existing products; or

  . increase our expenses.

Our failure to enhance our existing products or to develop and introduce new
products that meet changing customer requirements and emerging industry
standards would adversely impact our ability to sell our products.

   The market for high-speed broadband access is characterized by rapidly
changing customer demands and short product life cycles. If our product
development and enhancements take longer than planned, the availability of our
products would be delayed. Any such delay would adversely impact our ability to
sell our products and our results of operations and financial condition would
be adversely affected. Our future success will depend in large part upon our
ability to:

  . identify and respond to emerging technological trends in the market;


                                       8
<PAGE>

  . develop and maintain competitive products that meet changing customer
    demands;

  . enhance our products by adding innovative features that differentiate our
    products from those of our competitors;

  . bring products to market on a timely basis;

  . introduce products that have competitive prices; and

  . respond effectively to new technological changes or new product
    announcements by others.

   The technical innovations required for us to remain competitive in the DSL
industry are inherently complex, require long development cycles and sometimes
depend on sole-source suppliers. We will be required to continue to invest in
research and development in order to maintain and enhance our existing
technologies and products, but we may not have sufficient funds available to do
so. Even if we have sufficient funds, these investments may not serve the needs
of customers or be interoperable with changing technological requirements or
standards. We will have to incur most research and development expenses before
the technical feasibility or commercial viability of enhanced or new products
can be ascertained. Our revenues from future or enhanced products may not be
sufficient to recover our associated development costs.

Our current products are not interoperable with certain products offered by
suppliers to our customers and are subject to evolving industry standards. If
our products do not interoperate with our target customers' networks or an
industry standard that achieves market acceptance, customers may refuse to
purchase our products.

   In some cases, network equipment vendors, such as Cisco Systems, Inc., sell
to our target customers proprietary or non-interoperable systems with which our
products will not function. In these cases, potential customers who wish to
purchase DSL customer premises equipment and who have purchased other network
equipment which does not function with our DSL customer premises equipment may
not purchase our products.

   Also, the emergence of new industry standards, whether through adoption by
official standards committees or widespread use by our target customers, could
require us to redesign our products. If such standards become widespread and
our products do not meet these standards, our customers and potential customers
would not purchase our products. In this case, our business would be harmed,
and our financial condition and results of operations would be adversely
affected. The rapid development of new standards increases the risk that
competitors could develop products that would reduce the competitiveness of our
products or could result in greater competition and additional pricing
pressure. If we fail to develop and introduce new products or enhancements in
the face of new industry standards, our product sales would decrease, and our
business would be harmed. See "Business--Competition."

We may not be able to produce sufficient quantities of our DSL products because
we depend on third-party manufacturers. If these manufacturers fail to produce
our products in a timely manner, our ability to fulfill our customer orders
would be adversely impacted.

   Any manufacturing disruption could impair our ability to fulfill orders, and
if this occurs, our revenues would be adversely affected. Although we work with
more than one third-party manufacturer, many of our products are presently
manufactured for us by only one party. Since third parties manufacture our
products and we expect this to continue in the future, our success will depend,
in significant part, on our ability to have third parties manufacture our
products cost effectively and in sufficient quantities to meet our customer
demand. There are a number of risks associated with our dependence on third-
party manufacturers, including the following:

  . reduced control over delivery schedules;

  . quality assurance;


                                       9
<PAGE>

  . manufacturing yields and costs;

  . the potential lack of adequate capacity during periods of excess demand;

  . limited warranties on products supplied to us;

  . increases in prices; and

  . the potential misappropriation of our intellectual property.

   Any of these risks, if not adequately addressed by our third-party
manufacturers, would harm our business.

   We have no long-term contracts or arrangements with any of our vendors that
guarantee product availability, the continuation of particular payment terms or
the extension of credit limits. The competitive dynamics of our market require
us to obtain components at favorable prices, but we may not be able to obtain
additional volume purchase or manufacturing arrangements on terms that we
consider acceptable, if at all. If we enter into a high-volume or long-term
supply arrangement and subsequently decide that we cannot use the products or
services provided for in the agreement, our business would also be harmed.

We may not be able to produce sufficient quantities of our products because we
obtain certain key components from, and depend on, certain sole-source
suppliers. If we are unable to obtain these sole-source components, we would
not be able to ship our products in a timely manner and our strategic
relationships with our customers would be detrimentally affected.

   We obtain certain parts, components and equipment used in our products from
sole sources of supply. For example, we obtain certain semiconductor chipsets
from Alcatel Microelectronics, Analog Devices, Inc., Texas Instruments
Incorporated, and Conexant Systems, Inc. If we fail to obtain components in
sufficient quantities when required, and are unable to meet customer demand,
our business could be harmed, as our customers would consider purchasing
products from our competitors. We also rely on Texas Instruments Incorporated,
Samsung Semiconductor Inc., and VLSI Technology, Inc. to manufacture our
application specific integrated circuits. Developing and maintaining these
strategic relationships is critical in order for us to be successful. If our
relationships with our equipment vendor and network service provider customers
are harmed as a result of a failure to obtain sole-source components for our
products on a timely basis, our business would be harmed.

   Any of our sole-source suppliers may:

  . enter into exclusive arrangements with our competitors;

  . stop selling their products or components to us at commercially
    reasonable prices; or

  . refuse to sell their products or components to us at any price.

   If we are unable to obtain sufficient quantities of sole-source components
or to develop alternative sources for components for any reason, our business
would be harmed. Furthermore, additional sole-source components may be
incorporated into our future products, thereby increasing our sole-source
supplier risks. If any of our sole-source manufacturers delay or halt
production of any of their components, our business would be harmed, and our
results of operations and financial condition would be adversely affected.

We may be subject to product returns and product liability claims resulting
from defects in our products. Product returns and product liability claims
could result in the failure to attain market acceptance of our products and
harm our business.

   Our products are complex and may contain undetected defects, errors or
failures. The occurrence of any defects, errors or failures could result in
delays in installation, product returns and other losses to us or to our
customers or end users. Any of these occurrences could also result in the loss
of or delay in market acceptance

                                       10
<PAGE>

of our products, either of which would harm our business and adversely affect
our operating results and financial condition. We will likely have limited
experience with any problems that may arise with new products that we
introduce.

   Although we have not experienced any product liability claims to date, the
sale and support of our products entail the risk of these claims. A successful
product liability claim brought against us could be expensive, divert the
attention of management from ordinary business activities and, correspondingly,
harm our business.

Risks That May Cause Financial Fluctuations

We have incurred net losses since our inception and expect future losses.
Accordingly, we may not be able to achieve profitability, and even if we do
become profitable, we may not be able to sustain profitability.

   We have incurred net losses in every fiscal quarter and annual period since
inception and expect to continue to operate at a loss for the foreseeable
future. In addition, we had negative cash flow from operations of $6.6 million
in fiscal 1998, $23.4 million in fiscal 1999, and $9.5 million for the first
three months of fiscal 2000. As of September 30, 1999, we had an accumulated
deficit of approximately $61.9 million. Due to our limited operating history
and our history of losses, we may never be able to achieve profitability, and
even if we do, we may not be able to remain profitable. To achieve profitable
operations on a continuing basis, we must successfully design, develop, test,
manufacture, introduce, market and distribute our products on a broad
commercial basis.

   Our ability to generate future revenues will depend on a number of factors,
many of which are beyond our control. These factors include:

  . the rate of market acceptance of DSL broadband access;

  . the level of demand for DSL systems that incorporate our products;

  . changes in industry standards governing DSL technology solutions;

  . the extent and timing of new customer transactions;

  . changes in our development schedules and those of system companies that
    provide complementary DSL products, or changes in their levels of
    expenditure on research and development;

  . personnel changes, particularly those involving engineering and technical
    personnel;

  . the costs associated with protecting our intellectual property;

  . regulatory developments; and

  . general economic trends.

   Due to these factors, we cannot forecast with any degree of accuracy what
our revenues will be in future periods or how quickly network service providers
will select our products for use in their systems. In view of these factors, we
may not be able to achieve or sustain profitability.

We have a short operating history and, as a result, it is difficult to predict
our future results of operations.

   We have a short operating history upon which to base your investment
decision. We first commenced product shipments in August 1994 and did not
introduce DSL products until March 1998. Due to our limited operating history,
it is difficult or impossible for us to predict future results of operations
and you should not expect future revenue growth to be comparable to our recent
revenue growth. In addition, we believe that comparing different periods of our
operating results is not meaningful, and you should not rely on the results

                                       11
<PAGE>

for any period as an indication of our future performance. Investors in our
common stock must consider our business and prospects in light of the risks and
difficulties typically encountered by companies in their early stages of
development, particularly those in rapidly evolving markets such as ours.

If sales forecasted for a particular period are not realized in that period due
to the lengthy sales cycle of our products, our operating results for that
period would be adversely affected.

   If we fail to realize forecasted sales for a particular period, our
operating results would be adversely affected and our stock price would likely
decline and could decline significantly. The sales cycle of our products is
typically lengthy and involves:

  . a significant technical evaluation;

  . delays associated with network service providers' internal procedures to
    commit to a particular product line offering and approve large capital
    expenditures;

  . time required to deploy new technologies within service providers'
    networks; and

  . testing and acceptance of new technologies.

   For these and other reasons, a sale of our products generally requires six
to 12 months to complete. Furthermore, the announcement and projected
implementation of new standards may affect sales cycles, as network service
providers may choose to delay large-scale deployment of DSL services until
compliant products are available.

Our product cycles tend to be short, and we may incur substantial non-
recoverable expenses or devote significant resources to sales that do not occur
when anticipated.

   In the rapidly changing technology environment in which we operate, product
cycles tend to be short. Therefore, the resources we devote to product sales
and marketing may not generate material revenues for us, and from time to time
we may need to write off excess and obsolete inventory. If we incur substantial
sales, marketing and inventory expenses in the future that we are not able to
recover, and we are not able to compensate for such expenses, our operating
results would be adversely affected. In addition, if we sell our products at
reduced prices in anticipation of cost reductions and we still have higher cost
products in inventory, our business would be harmed, and our results of
operations and financial condition would be adversely affected.

Our operating results in one or more future periods are likely to fluctuate
significantly and may fail to meet or exceed the expectations of securities
analysts or investors, causing our stock price to decline.

   Our operating results are likely to fluctuate significantly in the future on
a quarterly and an annual basis due to a number of factors, many of which are
outside our control. If our operating results do not meet the expectations of
securities analysts or investors, our stock price may decline. We cannot assure
you that this will not occur because of the numerous factors that could cause
our revenues and costs to fluctuate. These factors include the following:

  . the timing and size of sales of our products and services;

  . announcements of new products and product enhancements by competitors;

  . the entry of new competitors into our market, including by acquisition;

  . unexpected delays in introducing new or enhanced products, including
    manufacturing delays;

  . our ability to control expenses;

  . our ability to ship products on a timely basis and at a reasonable cost;


                                       12
<PAGE>

  . the mix of our products sold;

  . the volume and average cost of products manufactured;

  . the type of distribution channel through which we sell our products;

  . the average selling prices of our products; and

  . the effectiveness of our product cost reduction efforts.

   The amount and timing of our operating expenses generally will vary from
quarter to quarter depending on the level of actual and anticipated business
activities. Research and development expenses will vary as we develop new
products. Due to competitive factors in our market, in the past we have
experienced, and we anticipate that we will continue to experience, decreases
in the average selling prices of our products which could adversely affect
gross margins. Due to these and other factors, our quarterly revenues, expenses
and results of operations could vary significantly in the future, and you
should not rely upon period-to-period comparisons as indications of future
performance. See "Management's Discussion and Analysis of Financial Condition
and Results of Operations."

Our customer base is concentrated, and the loss of one or more of our customers
could harm our business.

   Because DSL service relies upon existing telephone lines to reach end users,
a substantial majority of potential DSL end-user accounts in the U.S. and in
other countries are controlled by a relatively small number of network service
providers. If we are not successful in maintaining relationships with these few
network service providers and the network equipment vendors that supply them,
our business will be harmed.

   Although deregulation and increasing competition are expanding our potential
customer base, a small number of customers has accounted for a large portion of
our revenues to date. We sell our DSL products primarily to network service
providers, network equipment vendors and telephone company-aligned
distributors. For the three months ended September 30, 1999, sales to four
customers, American Communications Supply, Inc., a distributor for Southwestern
Bell, America Online, Inc., Innotrac Corporation, a distributor for BellSouth,
and Lucent Technologies each represented more than 10% of our net revenues. Our
top ten customers for the three months ended September 30, 1999 accounted for
94.8% of our net revenues. For the fiscal year ended June 30, 1999, Covad
Communications Group, Inc. represented 29.6% of our net revenues, and Soon
Cabling Pte, Ltd., a distributor for Daewoo Telecom, represented 17.5% of our
net revenues. Our top ten customers in fiscal 1999 accounted for 82.3% of our
net revenues. For the fiscal year ended June 30, 1998, Victron, Inc., a
manufacturer for Xylan Corporation, represented 19.6% of our net revenues, and
Telecom Equipment, a distributor for Singapore Telecom, represented 12.6% of
our net revenues. We expect to continue to be dependent upon a relatively small
number of large customers in future periods, although the specific customers
may vary from period to period. If we are not successful in maintaining
relationships with key customers, and winning new customers, our business would
be harmed.

We derive a substantial amount of our revenues from international sources, and
difficulties associated with international operations could harm our business.

   Since inception, a substantial portion of our revenues has been derived from
customers located outside of the United States, and we expect this trend to
continue. Revenues derived from customers located outside of the United States
represented 52% of our net revenues in fiscal 1998, 41% of our net revenues in
fiscal 1999 and 20% of our net revenues for the first quarter of fiscal 2000.
We believe that our continued growth and ability to attain profitability will
require us to continue to penetrate international markets. If we are unable to
successfully overcome the difficulties associated with international operations
and maintain and expand our international operations, our business would be
harmed. These difficulties include:

  . difficulties staffing and managing foreign operations in our highly
    technical industry;

  . changes in regulatory requirements which are common in the
    telecommunications industry;


                                       13
<PAGE>

  . licenses, tariffs and other trade barriers imposed on products such as
    ours;

  . political and economic instability especially in Asia and the Pacific;

  . potentially adverse tax consequences;

  . difficulties obtaining approvals for products from foreign governmental
    agencies which regulate networks;

  . compliance with a wide variety of complex foreign laws and treaties
    relating to telecommunications equipment; and

  . delays or difficulties collecting accounts receivable from foreign
    entities that are not subject to suit in the United States.

   To date, our international sales and component purchases have been
denominated solely in U.S. dollars and, accordingly, we have not been exposed
to fluctuations in non-U.S. currency exchange rates. In the future, a portion
of our international sales may be denominated in currencies other than U.S.
dollars, which would expose us to gains and losses based upon exchange rate
fluctuations. Such gains and losses may contribute to fluctuations in our
operating results.

Risks That May Affect Our Ability to Execute Our Business Plans

Our business could be adversely affected if we do not adequately address the
risks associated with our recent acquisition of FlowPoint Corporation.

   In December 1999, we completed the acquisition of FlowPoint Corporation.
This transaction is accompanied by a number of risks, any of which could
adversely affect our business or stock price, including:

  . the difficulty of assimilating the operations and personnel of FlowPoint;

  . the potential disruption of our and FlowPoint's ongoing business and
    distraction of management;

  . possible unanticipated expenses related to technology and business
    integration;

  . the potential impairment of relationships with employees and customers as
    a result of the integration of management; and

  . potential liabilities associated with FlowPoint.

   In addition, the market price of our common stock could decline as a result
of the acquisition if:

  . Efficient does not achieve the perceived benefits of the acquisition as
    rapidly or to the extent anticipated by financial analysts; or

  . the effect of the acquisition on the combined financial results is not
    consistent with the expectations of financial analysts.

We rely on indirect distribution channels and strategic relationships to sell
and manufacture our products, and if we are not able to maintain existing and
develop additional strategic relationships and indirect distribution channels,
our business would be harmed.

   Our business strategy relies on our strategic relationships with network
equipment vendors, network service providers, and suppliers of DSL technology.
If our existing relationships are not successful or our competitors are better
able to develop these relationships, our business would be harmed. End users
typically purchase DSL customer premises equipment from network service
providers, and network service providers may purchase DSL customer premises
equipment from independent network equipment vendors and distributors. We
typically work closely with our potential customers and suppliers to ensure
interoperability of products with customer networks and of components with our
DSL customer premises equipment. In addition,

                                       14
<PAGE>

we rely on our strategic relationships with telephone company-aligned
distributors in order to broaden our distribution network. Also, larger vendors
of DSL customer premises equipment may be able to leverage their size and
established distribution channels to gain a significant competitive advantage
over us. We cannot assure you that we will be able to maintain or expand our
existing strategic relationships or that we will be able to establish new
relationships in the future. See "Business--Strategic Relationships."

We continue to rapidly and significantly expand our operations, and our failure
to manage growth could harm our business and adversely affect our results of
operations and financial condition.

   We have rapidly and significantly expanded our operations, including the
number of our employees, the geographic scope of our activities and our product
offerings. We expect that further significant expansion will be required to
address potential growth in our customer base and market opportunities. Any
failure to manage growth effectively could harm our business and adversely
affect our operating results and financial condition. We cannot assure you that
we will be able to do any of the following, which we believe are essential to
successfully manage the anticipated growth of our operations:

  . improve our existing and implement new operational, financial and
    management information controls, reporting systems and procedures;

  . hire, train and manage additional qualified personnel;

  . expand and upgrade our core technologies; and

  . effectively manage multiple relationships with our customers, suppliers
    and other third parties.

   In the future, we may also experience difficulties meeting the demand for
our products. The installation and use of our products require training. If we
are unable to provide training and support for our products, more time may be
necessary to complete the implementation process and customer satisfaction may
be adversely affected. In addition, our suppliers may not be able to meet
increased demand for our products. We cannot assure you that our systems,
procedures or controls will be adequate to support the anticipated growth in
our operations.

Competition for qualified personnel in the networking equipment and
telecommunications industries is intense, and if we are not successful in
attracting and retaining these personnel, our business would be harmed.

   Our future success will depend on the ability of our management to operate
effectively, both individually and as a group. Therefore, the future success of
our business will also depend on our ability to attract and retain high-caliber
personnel. The loss of the services of any of our key personnel, the inability
to attract or retain qualified personnel in the future or delays in hiring
required personnel, particularly engineers, could harm our business.

   Because competition for qualified personnel in the networking equipment and
telecommunications industries is intense, we may not be successful in
attracting and retaining such personnel. During 1999, we added 160 employees to
our total work force, representing an increase of 133% from December 31, 1998.
During 1998, we added 36 employees to our total work force, representing an
increase of approximately 61% from December 31, 1997. We expect to hire
additional personnel in the near future, including direct sales and marketing
personnel. There may be only a limited number of people with the requisite
skills to serve in those positions, and it may become increasingly difficult to
hire these people. In addition, we are actively searching for research and
development engineers, who also are in short supply. Our business will be
harmed if we encounter delays in hiring additional engineers. Furthermore,
competitors and others have in the past and may in the future attempt to
recruit our employees. We do not have employment contracts with any of our key
personnel.

The loss of the services of one or more of our executive officers or key
employees could harm our business.

   Our executive officers and certain key sales, engineering and management
personnel may not remain with us in the future. Our executive officers and key
personnel and in particular Mark A. Floyd, our Chief Executive

                                       15
<PAGE>

Officer, and Patricia W. Hosek, our Vice President of Engineering, are critical
to our business and its future success. If we lost the services of one or more
of our executive officers or key employees, we would need to devote substantial
resources to finding replacements, and until replacements were found, Efficient
would be operating without the skills or leadership of such personnel, either
of which could have a significant adverse effect on our business. None of our
officers or key employees is bound by agreements for any specific employment
term or covenants not to compete.

Our future success will depend in part on our ability to protect our
proprietary rights and the technologies used in our principal products, and if
we do not enforce and protect our intellectual property or if others bring
infringement claims against us, our business would be harmed.

   We rely on a combination of patent, copyright and trademark laws, trade
secrets, confidentiality provisions and other contractual provisions to protect
our proprietary rights. However, these measures afford only limited protection.
Our failure to adequately protect our proprietary rights may adversely affect
us. Despite our efforts to protect our proprietary rights, unauthorized parties
may attempt to copy aspects of our products or to obtain and use trade secrets
or other information that we regard as proprietary.

   Our means of protecting our proprietary rights in the U.S. or abroad may not
be adequate, and competitors may independently develop similar technologies. In
addition, the laws of some foreign countries do not protect our proprietary
rights as fully as do the laws of the U.S. Issued patents may not preserve our
proprietary position. Even if they do, competitors or others may develop
technologies similar to or superior to our own.

   We may become involved in litigation over proprietary rights. In the event
of an adverse result in any future litigation with third parties relating to
proprietary rights, we could be required:

  . to pay substantial damages, including treble damages if we are held to
    have willfully infringed;

  . to halt the manufacture, use and sale of infringing products;

  . to expend significant resources to develop non-infringing technology; or

  . to obtain licenses to the infringing technology.

   Licenses may not be available from any third party that asserts intellectual
property claims against us, on commercially reasonable terms, or at all. In
addition, litigation frequently involves substantial expenditures and can
require significant management attention, even if we ultimately prevail.
However, there can be no assurance that we would be able to successfully
resolve such disputes in the future.

   From time to time, third parties, including our competitors, have asserted
patent, copyright and other intellectual property rights to technologies that
are important to us. For example, we have received a letter from Bell Atlantic
indicating that they hold a patent on certain DSL technology, and urging us to
begin negotiating a license to the patent. We are aware that Bell Atlantic has
sued at least one other company alleging that such other company's DSL services
infringe Bell Atlantic's patent. We are evaluating the Bell Atlantic patent,
and have not yet determined whether to seek a license. Although there are
multiple indications from Bell Atlantic that licenses to the patent are or will
be available, there can be no assurances we would find the license terms
acceptable. We expect that we will increasingly be subject to infringement
claims as the number of products and competitors in the high-speed data access
market grows and the functionality of products overlaps. See "Business--
Intellectual Property."

Our products and those of our customers are subject to government regulations,
and changes in current or future laws or regulations that negatively impact our
products and technologies could harm our business.

   The jurisdiction of the Federal Communications Commission, or the FCC,
extends to the entire communications industry including our customers and their
products and services that incorporate our products.

                                       16
<PAGE>

Future FCC regulations affecting the broadband access services industry, our
customers or our products may harm our business. For example, FCC regulatory
policies that affect the availability of data and Internet services may impede
our customers' penetration into certain markets or affect the prices that they
are able to charge. In addition, international regulatory bodies are beginning
to adopt standards for the communications industry. Delays caused by our
compliance with regulatory requirements may result in order cancellations or
postponements of product purchases by our customers, which would harm our
business and adversely affect our results of operations and financial
condition.

Additional Risks That May Affect Our Stock Price

We may need additional capital in the future, and if we are unable to secure
adequate funds on terms acceptable to us, we may be unable to execute our
business plan.

   If the proceeds of this offering, together with the proceeds generated from
our initial public offering which closed in July 1999, our existing cash
balances and cash flow expected from future operations, are not sufficient to
meet our liquidity needs, we will need to raise additional funds. If adequate
funds are not available on acceptable terms or at all, we may not be able to
take advantage of market opportunities, to develop new products or to otherwise
respond to competitive pressures. This inability would harm our business.

We have broad discretion to use the offering proceeds, and we cannot assure you
that how we invest these proceeds will yield a favorable return.

   Substantially all of the net proceeds of this offering are not allocated for
specific uses other than working capital and general corporate purposes. Thus,
our management will have broad discretion over how these proceeds are used and
could spend most of these proceeds in ways with which the stockholders may not
agree. We cannot assure you that the proceeds will be invested to yield a
favorable return. See "Use of Proceeds."

We may engage in future acquisitions that dilute our stockholders, cause us to
incur debt and assume contingent liabilities.

   As part of business strategy, we expect to continue to review potential
acquisitions that could complement our current product offerings, augment our
market coverage or enhance our technical capabilities, or that may otherwise
offer growth opportunities. While we have no current agreements or negotiations
underway with respect to any such acquisitions, we may acquire businesses,
products or technologies in the future. In the event of such future
acquisitions, we could issue equity securities that would dilute our current
stockholders' percentage ownership, incur substantial debt, or assume
contingent liabilities. Such actions by us could seriously harm our results of
operations and/or the price of our common stock. Acquisitions also entail
numerous other risks which could adversely affect our business, results of
operations and financial condition, including:

  . difficulties in assimilating acquired operations, technologies or
    products;

  . unticipated costs or capital expenditures associated with the
    acquisition;

  . acquisition related charges and amortization of acquired technology and
    other intangibles that could negatively affect our reported results of
    operations;

  . diversion of management's attention from our business;

  . adversely affect existing business relationships with suppliers and
    customers; and

  . failure to successfully integrate these businesses, products,
    technologies and personnel.

                                       17
<PAGE>

There are substantial shares of common stock eligible for future sale, and such
sales may depress our stock price.

   After this offering, we will have outstanding approximately 53.2 million
shares of common stock after giving pro forma effect to the conversion of all
outstanding shares of Series A non-voting convertible redeemable preferred
stock issued to Cabletron, of which approximately 14.6 million shares,
including the 5,000,000 sold in this offering, plus any shares issued upon
exercise of the underwriters' over-allotment option, will be freely tradeable.
See "Capitalization" for a discussion of the shares included in and excluded
from this number. The remaining approximately 38.6 million shares of common
stock outstanding after this offering will become available for sale in the
public market as follows:

<TABLE>
<CAPTION>
      Number of Shares  Date of Availability for Sale
      ----------------  -----------------------------
     <S>                <C>
        3.1 million     April 3, 2000
       23.6 million     May 3, 2000
       11.9 million     At various times thereafter, upon the expiration of
                        respective one-year holding periods.
</TABLE>

   If our stockholders sell substantial amounts of common stock in the public
market, including shares issuable upon the exercise of outstanding options, the
market price of our common stock could fall. See "Shares Eligible for Future
Sale" and "Underwriting."

Certain provisions of our charter documents may make acquiring control of our
company more difficult for a third party, which could adversely affect our
stock's market price or lessen any premium over market price that an acquiror
might otherwise pay.

   Our charter documents contain provisions providing for a classified board of
directors, eliminating cumulative voting in the election of directors and
restricting our stockholders from acting without a meeting. These provisions
may make certain corporate actions more difficult and might delay or prevent a
change in control and therefore limit the price that new investors will pay for
our stock. Further, the board of directors may issue up to 9,993,700 new shares
of preferred stock with certain rights, preferences, privileges and
restrictions, including voting rights, without any vote by our stockholders.
Our existing stockholders may be adversely affected by the rights of this
preferred stock. New preferred stock might also be used to make acquiring
control more difficult. We have no current plans to issue shares of preferred
stock. We will also indemnify officers and directors against losses incurred in
legal proceedings to the broadest extent permitted by Delaware law.

Our failure or the failure of our key suppliers and customers to be Year 2000
compliant would harm our business.

   Many currently installed computer systems are not capable of distinguishing
21st century dates from 20th century dates. Although we cannot predict with any
certainty what adverse effects we may suffer from Year 2000 compliance issues,
possible effects include:

  . disruptions in the supply of components and manufactured goods from our
    component suppliers and contract manufacturers if they experience
    disruptions;

  . disruptions in our ability to ship and receive goods if third-party
    transportation and delivery providers experience disruptions in their
    operations; and

  . delays in receiving accurate management information from our internal
    accounting and management systems.

   We currently have no contingency plan to address potential interruptions in
the operation of our internal systems or those of third parties upon whom we
depend as a result of Year 2000 noncompliance.


                                       18
<PAGE>

   We may face claims based on Year 2000 issues arising from the integration of
multiple products within an overall network. We may also experience reduced
sales of our products as potential customers reduce their budgets for network
equipment and network services due to increased expenditures on their own Year
2000 compliance efforts. See "Management's Discussion and Analysis of Financial
Condition and Results of Operations--Year 2000 Issues."

               SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

   This prospectus, including the sections entitled "Prospectus Summary," "Risk
Factors," "Management's Discussion and Analysis of Financial Condition and
Results of Operations," and "Business," contains forward-looking statements.
These statements relate to future events or our future financial performance,
and involve known and unknown risks, uncertainties, and other factors that may
cause our actual results, levels of activity, performance or achievements to be
materially different from any future results, levels of activity, performance
or achievements expressed or implied by these forward-looking statements. These
risks and other factors include, among other things, those listed under "Risk
Factors" and elsewhere in this prospectus. In some cases, you can identify
forward-looking statements by terminology such as "may," "will," "should,"
"expects," "intends," "plans," "anticipates," "believes," "estimates,"
"predicts," "potential," "continue," or the negative of these terms or other
comparable terminology. These statements are only predictions. Actual events or
results may differ materially. In evaluating these statements, you should
specifically consider various factors, including the risks outlined under "Risk
Factors." These factors may cause our actual results to differ materially from
any forward-looking statement.

   Although we believe that the expectations reflected in the forward-looking
statements are reasonable, we cannot guarantee future results, levels of
activity, performance or achievements. We are under no duty to update any of
the forward-looking statements after the date of this prospectus to conform
these statements to actual results.

                                       19
<PAGE>

                                USE OF PROCEEDS

   The net proceeds to us from the sale of the 2,000,000 shares of common stock
offered by us are estimated to be $113.5 million, or approximately $156.4
million if the underwriters' over-allotment option is exercised in full, at an
assumed public offering price of $60.25 per share, after deducting underwriting
discounts and commissions and the estimated offering expenses. We will not
receive any proceeds from the sale of shares by the selling stockholders.

   We intend to use the net proceeds of this offering primarily for general
corporate purposes including working capital and sales and marketing efforts.
We may also use a portion of the net proceeds to acquire complementary
products, technologies or businesses. Pending use of the net proceeds of this
offering, we intend to invest the net proceeds in interest-bearing, investment-
grade securities.

                          PRICE RANGE OF COMMON STOCK

   Our Common Stock began trading on the NASDAQ National Market System under
the symbol "EFNT" effective July 15, 1999. Prior to that date, there was no
public market for our Common Stock. The following table sets forth for the
periods indicated the high and low closing prices for the Common Stock, as
reported by NASDAQ:

<TABLE>
<CAPTION>
                                                                   High   Low
                                                                  ------ ------
   <S>                                                            <C>    <C>
   Fiscal Year Ending June 30, 2000
     First Quarter............................................... $68.00 $29.35
     Second Quarter.............................................. $82.50 $33.65
     Third Quarter (through January 6, 2000)..................... $63.85 $58.75
</TABLE>

   The last reported sale price for our common stock on The Nasdaq Stock Market
was $60.25 per share on January 6, 2000. As of December 31, 1999, there were
approximately 156 holders of record of our common stock.

                                DIVIDEND POLICY

   We have never declared or paid any dividends on our capital stock. We
currently expect to retain future earnings, if any, for use in the operation
and expansion of our business and do not anticipate paying any cash dividends
in the foreseeable future.

                                       20
<PAGE>

                                 CAPITALIZATION

   The table below sets forth the following information:

  .the actual capitalization of Efficient as of September 30, 1999; and

  . the as adjusted capitalization giving effect to the sale of 2,000,000
    shares of common stock at an assumed public offering price of $60.25 per
    share, less estimated underwriting discounts and commissions and the
    estimated offering expenses payable by Efficient.

<TABLE>
<CAPTION>
                                                       September 30, 1999
                                                  -------------------------------
                                                     Actual        As Adjusted
                                                  -------------  ----------------
                                                  (in thousands, except share
                                                      and per share data)
<S>                                               <C>            <C>
Stockholders' equity:
Common stock, $0.001 par value; 100,000,000
 shares authorized; 37,482,465 shares issued and
 outstanding, actual; 39,482,465 shares issued
 and outstanding, as adjusted...................  $          37   $          39
Additional paid-in capital......................        150,320         263,793
Deferred stock option compensation..............        (16,162)        (16,162)
Accumulated deficit.............................        (61,943)        (61,943)
                                                  -------------   -------------
Total stockholders' equity......................         72,252         185,727
                                                  -------------   -------------
Total capitalization............................  $      72,252   $     185,727
                                                  =============   =============
</TABLE>

   This table excludes the following shares:

  . 7,200,000 shares of common stock and 6,300 shares of preferred stock
    (convertible into an aggregate of 6,300,000 shares of common stock)
    issued to Cabletron in December 1999;

  . options outstanding to purchase a total of 6,954,329 shares of common
    stock at a weighted average exercise price of $2.81 per share and
    3,325,000 shares reserved for grant of future options under our stock
    option plans;

  . 200,000 shares reserved for future grants under our 1999 Employee Stock
    Purchase Plan; and

  . 34,246 shares issuable upon exercise of outstanding warrants.

   See "Management--Benefit Plans," "Description of Capital Stock" and Notes to
Consolidated Financial Statements.

                                       21
<PAGE>

                      SELECTED CONSOLIDATED FINANCIAL DATA

   The following selected consolidated financial data should be read in
conjunction with "Management's Discussion and Analysis of Financial Condition
and Results of Operations," and are qualified by reference to the Consolidated
Financial Statements and Notes thereto appearing elsewhere in this prospectus.
The consolidated statement of operations data set forth below for the years
ended June 30, 1997, 1998 and 1999, and the consolidated balance sheet data at
June 30, 1998 and 1999, are derived from, and are qualified by reference to,
the audited Consolidated Financial Statements of Efficient included elsewhere
in this prospectus. The statement of operations data set forth below for the
years ended June 30, 1995 and 1996 and the balance sheet data at June 30, 1995,
1996 and 1997 are derived from audited Consolidated Financial Statements of
Efficient not included in this prospectus. The consolidated statement of
operations data for the three months ended September 30, 1998 and 1999 and the
consolidated balance sheet data at September 30, 1999 are derived from, and are
qualified by reference to, the unaudited condensed consolidated financial
statements included elsewhere in this prospectus. In the opinion of management,
the unaudited statement of operations data shown for the three month periods
ended September 30, 1998 and 1999 and the unaudited balance sheet data as of
September 30, 1999 have been prepared on the same basis as the audited
consolidated financial statements and include all adjustments, consisting only
of normal recurring adjustments, necessary for a fair presentation of the
financial position and results of operations for such periods.

<TABLE>
<CAPTION>
                                                                           Three Months Ended
                                  Fiscal Year Ended June 30,                  September 30,
                          -----------------------------------------------  --------------------
                           1995      1996      1997      1998      1999      1998       1999
                          -------  --------  --------  --------  --------  ---------  ---------
                                       (in thousands, except per share data)
<S>                       <C>      <C>       <C>       <C>       <C>       <C>        <C>
Consolidated Statement
 of Operations Data:
Net revenues............  $ 2,314  $  3,687  $  4,122  $  3,370  $ 14,828  $   1,174  $  12,171
Cost of revenues........    1,125     2,209     2,386     2,160    14,344        863     11,706
                          -------  --------  --------  --------  --------  ---------  ---------
Gross profit............    1,189     1,478     1,736     1,210       484        311        465
                          -------  --------  --------  --------  --------  ---------  ---------
Operating expenses:
  Sales and marketing...    1,505     2,366     2,409     3,436     6,133      1,168      2,652
  Research and
   development..........    3,405     3,853     4,183     4,389     7,747      1,826      3,053
  General and
   administrative.......      822     1,082     1,245     1,641     1,993        339      1,048
  Stock option
   compensation.........       --       198       659     1,165     3,116        433      1,389
                          -------  --------  --------  --------  --------  ---------  ---------
   Total operating
    expenses............    5,732     7,499     8,496    10,631    18,989      3,766      8,142
                          -------  --------  --------  --------  --------  ---------  ---------
Loss from operations....   (4,543)   (6,021)   (6,760)   (9,421)  (18,505)    (3,455)    (7,677)
Interest and other
 income (expense), net..      248       177       125       130    (7,900)        80        (77)
                          -------  --------  --------  --------  --------  ---------  ---------
Net loss................  $(4,295) $ (5,844) $ (6,635) $ (9,291) $(26,405) $  (3,375) $  (7,754)
                          =======  ========  ========  ========  ========  =========  =========
Basic and diluted net
 loss per share(1)......  $ (1.56) $  (2.06) $  (2.19) $  (2.86) $  (6.87) $   (0.93) $   (0.25)
                          =======  ========  ========  ========  ========  =========  =========
Weighted average
 shares(1)..............    2,750     2,838     3,027     3,254     3,893      3,713     30,496
                          =======  ========  ========  ========  ========  =========  =========
Unaudited pro forma
 basic and diluted net
 loss per share(1)......                                         $  (0.97)
                                                                 ========
Weighted average shares
 used to compute
 unaudited pro forma
 basic and diluted net
 loss per share(1)......                                           28,342
                                                                 ========
Consolidated Balance
 Sheet Data:
Cash and cash
 equivalents............  $ 2,650  $  1,303  $  3,413  $  7,607  $  3,604             $  47,456
Working capital.........    3,400     2,619     4,370     7,870    12,585                69,051
Total assets............    6,357     5,150     6,454    10,667    23,965                88,680
Redeemable convertible
 preferred stock........   11,155    16,155    23,635    34,743    40,495                    --
Total stockholders'
 equity (deficit).......   (6,008)  (11,643)  (17,610)  (25,374)  (39,014)               72,252
</TABLE>
- --------
(1) Note 2 of Notes to Consolidated Financial Statements provides an
    explanation of the determination of the weighted average shares used to
    compute basic and diluted net loss per share and unaudited pro forma basic
    and diluted net loss per share.

                                       22
<PAGE>

                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS

   The following discussion should be read in conjunction with the Consolidated
Financial Statements and Notes thereto, as well as the other information
included elsewhere in this prospectus.

Overview

   We are a worldwide independent developer and supplier of high-speed DSL
customer premises equipment for the broadband access market. Our DSL solutions
enable telecommunications and other network service providers to provide high-
speed, cost-effective broadband access services over the existing copper wire
telephone infrastructure to both business and residential markets. We therefore
focus on developing and producing single- and multiple-user DSL customer
premises equipment for small- to medium-size businesses, branch offices of
large corporations and consumers. Our DSL products enable applications such as
high-speed Internet access, electronic commerce, remote access, telecommuting
and extensions of corporate networks to branch offices.

   We were incorporated in June 1993. From inception through fiscal 1997, we
primarily focused on developing and selling ATM-based products for local area
network, or LAN, applications. ATM, or asynchronous transfer mode, is a widely-
used transmission technology that breaks data down into individual packets with
unique identification and destination addresses and may be used to transmit
data, voice and video within a network. During fiscal 1997 we began to leverage
our ATM, personal computing environment and networking expertise to develop DSL
modem products for high-speed Internet access. Although we continue to sell ATM
LAN products, we have largely discontinued further development efforts on such
products and are currently focusing on our DSL products. We shipped our first
DSL products in the third quarter of fiscal 1998. Our DSL products, which
accounted for less than 3% of net revenues in fiscal 1998, represented 87.1% of
our net revenues in fiscal 1999 and 98.1% of our net revenues in the first
quarter of fiscal 2000. We expect sales of our ATM LAN products to continue to
gradually decrease in absolute amount over the next one to two years, and to
decrease substantially as a percentage of net revenues during that time.

   We derive our revenues from sales of our SpeedStream family of DSL products
and, to a lesser extent, our ATM LAN products. We sell our DSL products
primarily to network service providers, network equipment vendors and telephone
company-aligned distributors. For the three months ended September 30, 1999,
sales to four customers, American Communications Supply, Inc., a distributor
for Southwestern Bell, America Online, Inc., Innotrac Corporation, a
distributor for BellSouth, and Lucent Technologies each represented more than
10% of our net revenues. For the fiscal year ended June 30, 1999, Covad
Communications represented 29.6% of our net revenues, and Soon Cabling Pte,
Ltd., a distributor for Daewoo Telecom represented 17.5% of our net revenues.
For the fiscal year ended June 30, 1998, Victron, a manufacturer for Xylan,
represented 19.6% of our net revenues, and Telecom Equipment, a distributor for
Singapore Telecom, represented 12.6% of our net revenues. Our top ten customers
for the three months ended September 30, 1999 accounted for 94.8% of our net
revenues. We expect to continue to be dependent upon a relatively small number
of large customers in future periods, although the specific customers may vary
from period to period.

   Since inception, a substantial portion of our revenues has been derived from
customers located outside of the United States and we expect this trend to
continue. Revenues derived from customers outside the United States represented
52% of our net revenues in fiscal 1998, 41% of our net revenues for fiscal 1999
and 20% of our net revenues for the three months ended September 30, 1999. We
currently maintain a European sales office in Amsterdam and an Asian sales
office in Singapore. We believe that in order to continue growing and attain
profitability, we must continue to penetrate international markets.
Accordingly, we will need to expand our international operations and hire
qualified personnel for these operations.

   To date, international sales have been denominated solely in U.S. dollars
and, accordingly, we have not been exposed to fluctuations in non-U.S. currency
exchange rates. In the future, a portion of our international

                                       23
<PAGE>

sales may be denominated in currencies other than U.S. dollars, which would
then expose us to gains and losses based upon exchange rate fluctuations.

   The gross margins on our DSL products have been below the levels that our
business has historically achieved. The lower gross margins on our DSL products
have been a result of manufacturing start-up costs and volume discounts given
to quickly introduce products into the market. Other factors that will affect
our gross margin include the product mix sold in any particular period,
distribution channels, competitive pressures and levels of volume discounts.

   Our limited operating history in the DSL market makes it difficult to
forecast our future operating results. To date, we have not achieved
profitability in any quarter or annual period, and as of September 30, 1999, we
had an accumulated deficit of $61.9 million. Although our net revenues have
grown in recent quarters, we cannot be certain that our net revenues will
increase at a rate sufficient to achieve and maintain profitability.

   For the fiscal years 1997, 1998 and 1999 and for the three months ended
September 30, 1999, we recorded an aggregate of $21.7 million in deferred stock
option compensation. This amount represents the difference between the exercise
price of certain stock options granted during such periods and the deemed fair
market value of our common stock at the time of such option grants. We are
amortizing the deferred stock option compensation over the vesting periods of
the applicable options, which is generally four years. We amortized deferred
stock option compensation in the amounts of $659,000, $1.2 million, $3.1
million and $1.4 million in fiscal years 1997, 1998, 1999 and the three months
ended September 30, 1999, respectively. We expect to amortize the remaining
deferred stock option compensation at the rate of approximately $1.3 million
per quarter until fully amortized.

Recent Development--FlowPoint Acquisition

   On November 21, 1999, we entered into an agreement with Cabletron Systems,
Inc. to acquire its wholly-owned subsidiary FlowPoint Corporation from
Cabletron. The acquisition was completed on December 17, 1999, and is being
accounted for under the purchase method of accounting.

   We paid for the acquisition of FlowPoint through the issuance of 7,200,000
shares of our common stock and 6,300 shares of our Series A non-voting
convertible preferred stock. The Series A preferred stock is convertible into
an aggregate of 6,300,000 shares of our common stock. See "Description of
Capital Stock" for a more complete description of the Series A preferred stock.

   The shares issued to Cabletron for FlowPoint were worth $924.8 million based
upon the market price of $68.50, which represents Efficient's average closing
sale price for two trading days before and two trading days after the terms of
the acquisition were agreed to.

                                       24
<PAGE>

Results of Operations

   The following table sets forth, for the periods presented, certain data from
Efficient's consolidated statement of operations expressed as a percentage of
net revenues.

<TABLE>
<CAPTION>
                                                             Three Months
                                  Fiscal Year Ended             Ended
                                       June 30,             September 30,
                                 ------------------------   ----------------
                                  1997     1998     1999     1998      1999
                                 ------   ------   ------   -------   ------
<S>                              <C>      <C>      <C>      <C>       <C>
Net revenues....................  100.0 %  100.0 %  100.0 %   100.0 %  100.0 %
Cost of revenues................   57.9     64.1     96.7      73.5     96.2
                                 ------   ------   ------   -------   ------
Gross profit....................   42.1     35.9      3.3      26.5      3.8
                                 ------   ------   ------   -------   ------
Operating expenses:
Sales and marketing.............   58.4    102.0     41.4      99.5     21.8
Research and development........  101.5    130.2     52.2     155.5     25.1
General and administrative......   30.2     48.7     13.4      28.9      8.6
Stock option compensation.......   16.0     34.6     21.0      36.9     11.4
                                 ------   ------   ------   -------   ------
  Total operating expenses......  206.1    315.5    128.1     320.8     66.9
                                 ------   ------   ------   -------   ------
Loss from operations............ (164.0)  (279.6)  (124.8)   (294.3)   (63.1)
Interest and other income
 (expense), net.................    3.0      3.9     53.3       6.8     (0.6)
                                 ------   ------   ------   -------   ------
Net loss........................ (161.0)% (275.7)% (178.1)%  (287.5)%  (63.7)%
                                 ======   ======   ======   =======   ======
</TABLE>

Three Months Ended September 30, 1998 and 1999

Net Revenues

   Net revenues consist of product sales, net of allowances for returns. Net
revenues increased 936.7%, from $1.2 million for the three months ended
September 30, 1998 to $12.2 million for the three months ended September 30,
1999. DSL product revenues increased from $410,000 for the three months ended
September 30, 1998 to $11.9 million for the three months ended September 30,
1999. The period-over-period increases in DSL product revenues reflect the
beginning market adoption of our DSL products, which first became available in
the quarter ended March 31, 1998, as well as the addition of new products to
our DSL product line. During fiscal 1997, we made the strategic decision to
focus on developing our DSL products, and, as a result, significantly reduced
the level of development and support activities associated with our ATM LAN
products. We expect ATM LAN product revenues to continue to decrease over time.

Cost of Revenues

   Cost of revenues consists of amounts paid to third-party contract
manufacturers, manufacturing start-up expenses and the personnel and related
costs of our manufacturing operation. Cost of revenues increased 1,256.4% from
$863,000 or 73.5% of net revenues for the three months ended September 30, 1998
to $11.7 million or 96.2% of net revenues for the three months ended September
30, 1999, reflecting the substantial increase in DSL product sales. Gross
margin represented 26.5% of net revenues for the three months ended September
30, 1998, compared to 3.8% for the three months ended September 30, 1999. These
amounts are not comparable due to our shift from ATM LAN products to DSL
products. Included in cost of revenues for the three months ended September 30,
1999 are $1.0 million of one-time costs associated with the change in our

                                       25
<PAGE>

contract manufacturer. Excluding these one time costs, the gross margin for the
three months ended September 30, 1999 would have been 12.0%. Our gross margin
increased in the current period as a result of a change in our contract
manufacturer and other cost efficiencies associated with higher production
volumes. We took a number of actions that were designed to bring our DSL
products to market quickly but which also partially offset the improvement in
our gross margins. These actions included initial volume price discounts for
key customers and incremental costs such as manufacturing start-up, expedite
and other incremental shipping and handling charges associated with initial low
volume manufacturing. We expect that we will continue to incur higher than
normal costs associated with the actions to bring our DSL products to market
quickly.

Sales and Marketing Expenses

   Sales and marketing expenses consist primarily of employee salaries,
commissions and benefits, and advertising, promotional materials and trade show
exhibit expenses. Sales and marketing expenses increased 127.1% from $1.2
million for the three months ended September 30, 1998 to $2.7 million for the
three months ended September 30, 1999. The increase in sales and marketing
expenses resulted from expanded sales and marketing activities associated with
our DSL products. These costs included significant personnel-related expenses
associated with increasing the size of our sales and marketing organization,
and increased trade show activities and related travel expenses. Sales and
marketing expenses represented 99.5% of net revenues for the three months ended
September 30, 1998, and 21.8% of net revenues for the three months ended
September 30, 1999. The decrease in sales and marketing expenses as a
percentage of net revenues for the three months ended September 30, 1999
compared to the same period in 1998 was a result of the increase in revenues.
We expect sales and marketing expenses to increase in dollar amount in future
periods as we continue to expand our domestic and international sales and
marketing organization.

Research and Development Expenses

   Research and development expenses consist primarily of personnel and related
costs associated with our product development efforts, including third-party
consulting and prototyping costs. Research and development expenses increased
67.2% from $1.8 million for the three months ended September 30, 1998 to $3.1
million for the three months ended September 30, 1999. The substantial increase
in research and development spending was primarily a result of increased
personnel and related costs associated with an expanded research and
development organization in connection with our DSL products. Research and
development expenses represented 155.5% of net revenues for the three months
ended September 30, 1998 compared to 25.1% of net revenues for the three months
ended September 30, 1999. The decrease in research and development expenses as
a percentage of net revenues for the three months ended September 30, 1999
compared to the same period in 1998 was a result of the rapid increase in
revenues. We expect research and development expenses to increase in dollar
amount in future periods as we continue to expand our research and development
organization to develop new products and technologies.

General and Administrative Expenses

   General and administrative expenses consist primarily of employee salaries
and related expenses for executive, administrative and accounting personnel,
facility costs, insurance costs and professional fees. General and
administrative expenses increased 209.1% from $339,000 for the three months
ended September 30, 1998 to $1.1 million for the three months ended September
30, 1999. The increases in general and administrative spending were primarily a
result of increases in headcount associated with building our infrastructure.
General and administrative expenses represented 28.9% of net revenues for the
three months ended September 30, 1998, compared to 8.6% of net revenues for the
three months ended September 30, 1998. The decrease in general and
administrative expenses as a percentage of net revenues for the three months
ended September 30, 1999 compared to the same period in 1998 was a result of
the increase in revenues. We expect general and administrative expenses to
increase in dollar amount in future periods as we continue to build our
infrastructure and as a result of operating as a publicly-held company.


                                       26
<PAGE>

Stock Option Compensation

   Stock option compensation reflects the difference between the exercise price
of stock options granted and the deemed fair market value of our common stock
on the dates of grant. A charge of $3.1 million of deferred stock option
compensation was recorded in the quarter ended September 30, 1999 in connection
with stock option grants made prior to the completion of our initial public
offering on July 15, 1999. Amortization of deferred stock option compensation
was $433,000 for the three months ended September 30, 1998 compared to $1.4
million for the three months ended September 30, 1999. We expect to amortize
the deferred stock option compensation at the rate of approximately $1.3
million per quarter until fully amortized. Prior to our initial public offering
on July 15, 1999, there was no market for our common stock, and option prices
were determined by the Board of Directors based upon numerous factors. Upon
review in connection with our initial public offering, it was determined that
the fair market value on the date of grant of certain options was higher than
originally determined by the Board of Directors. Beginning with our initial
public offering, we began pricing options based upon the public market price of
our common stock, and do not anticipate accruing additional deferred stock
option compensation in future periods.

Interest and Other Income (Expense), Net

   Interest income consists primarily of interest earned on cash and cash
equivalents. Interest income increased for the three months ended September 30,
1999 from the three months ended September 30, 1998 as a result of interest
earned on the net cash proceeds received in connection with the completion of
our initial public offering on July 15, 1999. Interest expense and other income
(expense), net primarily represents the current period accretion of the
discount on subordinated promissory notes through the date of their conversion
into preferred stock. In future periods we expect interest income and interest
expense and other, net to vary depending upon changes in the amount and mix of
interest-bearing investments and short and long-term debt outstanding during
each period.

Income Taxes

   From inception through September 30, 1999, we incurred net losses for
federal and state tax purposes and have not recognized any tax provision or
benefit. We had significant federal net operating loss carryforwards to offset
future taxable income which will begin to expire in varying amounts beginning
in 2008. Given our limited operating history, losses incurred to date and the
difficulty in accurately forecasting our future results, management does not
believe that the recognition of the related deferred income tax asset meets the
criteria required by generally accepted accounting principles. Accordingly, a
100% valuation allowance has been recorded. Furthermore, as a result of changes
in Efficient's equity ownership from Efficient's redeemable convertible
preferred stock financings, note financings, initial public offering and this
offering, utilization of the net operating losses and tax credits may be
subject to substantial annual limitations due to the ownership change
limitations provided by the Internal Revenue Code of 1986, as amended, and
similar state provisions. The annual limitation may result in the expiration of
net operating losses and tax credits before utilization.

Fiscal Years Ended June 30, 1997, 1998 and 1999

Net Revenues

   Net revenues consist of product sales, net of allowances for returns. Net
revenues increased 340.0% to $14.8 million in fiscal 1999 from $3.4 million in
fiscal 1998. Net revenues in fiscal 1998 reflected a 18.2% decrease from the
$4.1 million realized in fiscal 1997. DSL product revenues, which didn't exist
in fiscal 1997, increased from $84,000 in fiscal 1998 to $12.9 million in
fiscal 1999. The increases in DSL product revenues from fiscal 1998 to fiscal
1999 reflect the beginning market adoption of our DSL products, which first
became available in the quarter ended March 31, 1998. The increase in DSL
product revenues was partially offset by a

                                       27
<PAGE>

decrease in revenues from our ATM LAN products. During fiscal 1997, we made the
strategic decision to begin focusing on developing our DSL products and, as a
result, significantly reduced the level of development and support activities
associated with our ATM LAN products. As a result of this change in focus, ATM
LAN product revenues declined from $4.1 million in fiscal 1997 to $3.3 million
in fiscal 1998, and further declined to $1.9 million in fiscal 1999. From
fiscal 1997 to fiscal 1998, this decrease was only slightly offset by sales of
prototype DSL products that began in the second half of fiscal 1998. We expect
ATM LAN product revenues to continue to decrease over time.

Cost of Revenues

   Cost of revenues consists of amounts paid to third-party contract
manufacturers, manufacturing start-up expenses and the personnel and related
costs of our manufacturing operation. Cost of revenues increased 564.1% to
$14.3 million in fiscal 1999 from $2.2 million in fiscal 1998. This compares to
a decrease of 9.5% for fiscal 1998 as compared to the $2.4 million in cost of
sales incurred in fiscal 1997. The increase from fiscal 1998 to fiscal 1999
reflected the substantial increase in DSL product sales. The decrease from 1997
to 1998 reflected the declining sales of our ATM LAN products.

   Gross margin represented 3.3% of net revenues in fiscal 1999, compared to
35.9% of net revenues in fiscal 1998 and 42.1% of net revenues in fiscal 1997.
Gross margin on our DSL products increased from a gross loss of 22.6% of the
related revenues in fiscal 1998 to a gross loss of 3.6% of the related revenues
for fiscal 1999. Our gross margin was lower in the current period as we focused
on bringing our DSL products to market quickly and as we began to add personnel
to our manufacturing operations in anticipation of higher levels of business
going forward. We took a number of actions that were designed to bring our DSL
products to market quickly but which also adversely affected our gross margins.
These actions included initial volume price discounts for key customers and
incremental costs such as manufacturing start-up, expedite and other
incremental shipping and handling charges associated with initial low volume
manufacturing. We expect that we will continue to incur higher than normal
costs associated with the actions to bring our DSL products to market quickly
through at least the end of calendar 1999. The higher costs incurred on our DSL
products were partially offset by improved gross margins realized on our ATM
LAN products. Gross margin on our ATM LAN products improved from 42.1% of
related revenues in fiscal 1997 to 37.4% in fiscal 1998 and to 49.5% in fiscal
1999. The period-to-period increase in gross margins on our ATM LAN products
was a result of manufacturing efficiencies achieved with these more mature
products. As sales of our ATM LAN products continue to decline as a percentage
of our total net revenues, any benefit of manufacturing efficiencies, cost
reduction or other gross margin improvements in those products will have a
diminishing beneficial effect on our overall gross margins.

Sales and Marketing Expense

   Sales and marketing expenses consist primarily of employee salaries,
commissions and benefits, and advertising, promotional materials and trade show
exhibit expenses. Sales and marketing expenses increased 78.5% from $3.4
million in fiscal 1998 to $6.1 million in fiscal 1999. This compares to an
increase of 42.6% in fiscal 1998 over the $2.4 million recorded in fiscal 1997.
The increases in sales and marketing expenses in absolute amount from fiscal
1997 through fiscal 1999 resulted primarily from sales and marketing activities
associated with the launch of our DSL products. These launch costs included
significant personnel-related expenses associated with increasing the size of
our sales and marketing organization, and increased trade show activities and
related travel expenses. Sales and marketing expenses represented 58.4% of net
revenues in fiscal 1997, 102.0% in fiscal 1998 and 41.4% in fiscal 1999. The
increase in sales and marketing expenses as a percentage of net revenues from
fiscal 1997 to 1998 was primarily a result of the up-front spending required to
launch our DSL products, which only began to constitute a significant portion
of our revenues in fiscal 1999. The decrease in such expenses as a percentage
of net revenues from fiscal 1998 to fiscal 1999 was a result of the rapid
increase in revenues.

                                       28
<PAGE>

Research and Development Expenses

   Research and development expenses consist primarily of personnel and related
costs associated with our product development efforts, including third-party
consulting and prototyping costs. Research and development expenses increased
76.5% from $4.4 million in fiscal 1998 to $7.7 million in fiscal 1999. This
compares to an increase of 4.9% in fiscal 1998 over the $4.2 million recorded
in fiscal 1997. The substantial increase in research and development spending
from period to period was primarily a result of increased personnel and related
costs associated with a larger research and development organization, as well
as design and prototype expenses incurred in connection with the roll-out of
our DSL products. Additionally, research and development spending in fiscal
1998 was partially offset by $850,000 of nonrecurring engineering expenses
reimbursed by third parties. These amounts are treated as an offset to the
related research and development spending. Accordingly, while the net amount of
research and development spending in fiscal 1998 was relatively consistent with
the fiscal 1997 level, our gross research and development spending increased
25.2% from fiscal 1997 to 1998. We received no such reimbursements in the
fiscal 1999 period. Research and development expenses represented 101.5% of net
revenues in fiscal 1997, 130.2% in fiscal 1998 and 52.2% in fiscal 1999. The
substantial increases in research and development expenses as a percentage of
net revenues from fiscal 1997 to 1998 reflected our early investment in
developing our DSL products. The decrease from 1998 to 1999 in such expenses as
a percentage of net revenues was a result of the rapid increase in revenues.

General and Administrative Expenses

   General and administrative expenses consist primarily of employee salaries
and related expenses for executive, administrative and accounting personnel,
facility costs, insurance costs and professional fees. General and
administrative expenses increased 21.5% from $1.6 million in fiscal 1998 to
$2.0 million in fiscal 1999. This compares to an increase of 31.8% in fiscal
1998 over the $1.2 million recorded in fiscal 1997. The increases in absolute
amount of general and administrative spending from period to period were
primarily a result of increases in headcount associated with building our
infrastructure. General and administrative expenses represented 30.2% of net
revenues in fiscal 1997, 48.7% in fiscal 1998 and 13.4% in fiscal 1999. The
substantial increase in general and administrative expenses as a percentage of
net revenues in fiscal 1998 primarily reflected lower revenues in that year,
while the decrease from fiscal 1998 to fiscal 1999 reflected the rapid increase
in revenues in fiscal 1999.

Stock Option Compensation

   Stock option compensation reflects the difference between the exercise price
of stock options granted and the deemed fair market value of our common stock
on the dates of grant. For the years ended June 30, 1997, 1998 and 1999 we
recorded aggregate deferred stock option compensation of $2.3 million, $3.1
million and $13.1 million, respectively in connection with stock option grants.
Amortization of deferred stock option compensation was $659,000 in fiscal 1997,
$1.2 million in fiscal 1998 and $3.1 million in fiscal 1999. We expect to
amortize the deferred stock option compensation at the rate of approximately
$1.3 million per quarter until fully amortized. See Note 8 of Notes to
Consolidated Financial Statements for a discussion of our deferred stock option
compensation. Prior to our initial public offering in July 1999, there was no
market for our common stock, and option prices were determined by the Board of
Directors based upon numerous factors. Upon review in connection with our
initial public offering, it was determined that the fair market value on the
date of grant of certain options was higher than originally determined by the
Board of Directors. Beginning with our initial public offering, we began
pricing options based upon the public market price of our common stock, and do
not anticipate accruing additional deferred stock option compensation in
periods after the first quarter of fiscal 2000.

Interest and Other Income (Expense), Net

   Interest and other income (expense), net consists primarily of interest
earned on cash and cash equivalents offset by miscellaneous non-operating
expenses. Interest and other income (expense), net went from income of

                                       29
<PAGE>

$125,000 in fiscal 1997 to $130,000 in fiscal 1998 and to an expense of $7.9
million in fiscal 1999. In the second half of fiscal 1999, we borrowed $9.0
million from certain investors. These notes carried an interest rate of 10% per
year, and were payable on the earlier of January 2002 or the completion of an
initial public offering. In connection with these notes, we issued the
investors warrants to purchase 3,082,191 shares of Series H preferred stock at
an exercise price of $2.92 per share. The proceeds were allocated between the
notes and the warrants based on their pro rata fair values resulting in a
discount. The discount was amortized as interest expense over six months, which
represented the expected terms of the promissory notes. In addition, in June
1999, we borrowed an additional $5.0 million from Covad Communications Group,
Inc. The Covad note carried an interest rate of 8% per year, and the principal
amount and interest on the note converted into an aggregate of 497,663 shares
of common stock upon completion of our initial public offering in July 1999.
Upon the issuance of the Covad note we recorded $2.1 million of interest
expense which represented the intrinsic value of the beneficial conversion
feature of the Covad note. In future periods we expect interest and other
income (expense), net to vary depending upon changes in the amount and mix of
interest-bearing investments outstanding during each period.

Income Taxes

   From inception through June 30, 1999, we incurred net losses for federal and
state tax purposes and have not recognized any tax provision or benefit. As of
June 30, 1999, we had approximately $48.0 million of federal net operating loss
carryforwards to offset future taxable income which will begin to expire in
varying amounts beginning in 2008. Given our limited operating history, losses
incurred to date and the difficulty in accurately forecasting our future
results, management does not believe that the recognition of the related
deferred income tax asset meets the criteria required by generally accepted
accounting principles. Accordingly, a 100% valuation allowance has been
recorded. Furthermore, as a result of changes in Efficient's equity ownership
resulting from Efficient's redeemable convertible preferred stock and note
financings and Efficient's initial public offering, utilization of the net
operating losses and tax credits may be subject to substantial annual
limitations due to the ownership change limitations provided by the Internal
Revenue Code of 1986, as amended, and similar state provisions. The annual
limitation may result in the expiration of net operating losses and tax credits
before utilization. See Note 11 of Notes to Consolidated Financial Statements.

                                       30
<PAGE>

Quarterly Results of Operations

   The following table sets forth, for the periods presented, certain data from
Efficient's consolidated statement of operations and such data as a percentage
of net revenues. The consolidated statement of operations data have been
derived from our unaudited consolidated financial statements. In the opinion of
management, these statements have been prepared on substantially the same basis
as the audited consolidated financial statements and include all adjustments,
consisting only of normal recurring adjustments, necessary for a fair
presentation of the financial information for the periods presented. This
information should be read in conjunction with the Consolidated Financial
Statements and Notes thereto included elsewhere in this prospectus. The
operating results in any quarter are not necessarily indicative of the results
that may be expected for any future period. We have incurred net losses in each
quarter since inception, and we expect to continue to incur losses for the
foreseeable future.

<TABLE>
<CAPTION>
                                                             Quarter Ended
                          ----------------------------------------------------------------------------------------------------
                          Sept. 30,   Dec. 31,   Mar. 31,   June 30,   Sept. 30,   Dec. 31,   Mar. 31,   June 30,    Sept. 30,
                            1997        1997       1998       1998       1998        1998       1999       1999        1999
                          ---------   --------   --------   --------   ---------   --------   --------   ---------   ---------
                                                             (in thousands)
<S>                       <C>         <C>        <C>        <C>        <C>         <C>        <C>        <C>         <C>
Statement of Operations
 Data:
Net revenues............  $    676    $    833   $  1,194   $    667   $  1,174    $  1,850   $  4,115   $   7,689   $ 12,171
Cost of revenues........       396         413        744        607        863       1,647      4,189       7,645     11,706
                          --------    --------   --------   --------   --------    --------   --------   ---------   --------
Gross profit (loss).....       280         420        450         60        311         203        (74)         44        465
Operating expenses:
Sales and marketing.....       643         694        895      1,204      1,168       1,303      1,385       2,277      2,652
Research and
 development............     1,044         737      1,064      1,544      1,826       1,790      1,930       2,201      3,053
General and
 administrative.........       305         346        546        444        339         411        484         759      1,048
Stock option
 compensation...........       233         241        275        416        433         475        991       1,217      1,389
                          --------    --------   --------   --------   --------    --------   --------   ---------   --------
Total operating
 expenses...............     2,225       2,018      2,780      3,608      3,766       3,979      4,790       6,454      8,142
                          --------    --------   --------   --------   --------    --------   --------   ---------   --------
Loss from operations....    (1,945)     (1,598)    (2,330)    (3,548)    (3,455)     (3,776)    (4,864)     (6,410)    (7,677)
Interest and other
 income (expense), net..        34          12         35         49         80          30     (2,090)     (5,920)       (77)
                          --------    --------   --------   --------   --------    --------   --------   ---------   --------
Net loss................  $ (1,911)   $ (1,586)  $ (2,295)  $ (3,499)  $ (3,375)   $ (3,746)  $ (6,954)  $ (12,330)  $ (7,754)
                          ========    ========   ========   ========   ========    ========   ========   =========   ========
As a Percentage of Net
 Revenues:
Net revenues............     100.0 %     100.0 %    100.0 %    100.0 %    100.0 %     100.0 %    100.0 %     100.0 %    100.0 %
Cost of revenues........      58.6        49.6       62.3       91.0       73.5        89.0      101.8        99.4       96.2
                          --------    --------   --------   --------   --------    --------   --------   ---------   --------
Gross profit (loss).....      41.4        50.4       37.7        9.0       26.5        11.0       (1.8)        0.6        3.8
Operating expenses:
Sales and marketing.....      95.1        83.3       75.0      180.5       99.5        70.4       33.6        29.6       21.8
Research and
 development............     154.5        88.5       89.1      231.5      155.5        96.8       46.9        28.6       25.1
General and
 administrative.........      45.1        41.5       45.7       66.6       28.9        22.2       11.8         9.9        8.6
Stock option
 compensation...........      34.5        28.9       23.0       62.4       36.9        25.7       24.1        15.8       11.4
                          --------    --------   --------   --------   --------    --------   --------   ---------   --------
Total operating
 expenses...............     329.2       242.2      232.8      541.0      320.8       215.1      116.4        83.9       66.9
                          --------    --------   --------   --------   --------    --------   --------   ---------   --------
Loss from operations....    (287.8)     (191.8)    (195.1)    (532.0)    (294.3)     (204.1)    (118.2)      (83.3)     (63.1)
Interest and other
 income (expense), net..       5.0         1.4        2.9        7.3        6.8         1.6      (50.8)      (77.0)      (0.6)
                          --------    --------   --------   --------   --------    --------   --------   ---------   --------
Net loss................    (282.8)%    (190.4)%   (192.2)%   (524.7)%   (287.5)%    (202.5)%   (169.0)%    (160.3)%    (63.7)%
                          ========    ========   ========   ========   ========    ========   ========   =========   ========
</TABLE>

   Our net revenues and results of operations have fluctuated significantly
from quarter to quarter in the past, and we expect these fluctuations to
continue in the future. The following discussion highlights significant events
that have impacted our net revenues and financial results for the nine quarters
in the period ended September 30, 1999.

Net Revenues

   Net revenues increased each quarter beginning in the quarter ended June 30,
1998 due to increased sales of our new DSL products, partially offset in two
quarters by decreased revenues from our ATM LAN products.

                                       31
<PAGE>

Sales of our DSL products have increased significantly quarter to quarter since
we introduced them in the third quarter of fiscal 1998. Net revenues increased
in the first three quarters of fiscal 1998 as demand for our ATM LAN products
was increasing. With the decision to focus on DSL products, we greatly reduced
our sales, marketing and development efforts for our ATM LAN products. As a
result, sales of these products began to decline in the fourth quarter of
fiscal 1998. We expect sales of our ATM LAN products to continue to gradually
decrease in absolute amount over the next one to two years, although sales of
such products may fluctuate from quarter to quarter.

Cost of Revenues

   Cost of revenues has increased in absolute dollars in most quarterly
periods. Gross margins have fluctuated from a high of 50.4% in the second
quarter of fiscal 1998 to a gross loss of 1.8% for the quarter ended March 31,
1999. Gross margins have been adversely affected by volume price discounts for
customers in order to get our DSL products quickly into the marketplace as well
as manufacturing start-up costs and inefficiencies related to the relatively
low manufacturing levels for some of our DSL products.

Operating Expenses

   Operating expenses generally increased in absolute amount from quarter to
quarter during fiscal 1998 and 1999. As a percentage of net revenues, these
expenses fluctuated, in some periods significantly, as a result of the
fluctuations in revenues.

Interest and Other Income (Expense), Net

   Interest and other income (expense), net has varied from quarter to quarter,
based primarily upon changes in the amount and mix of interest-bearing
investments outstanding during each period. In the quarter ended September 30,
1999, interest and other income (expense), net was an expense of $77,000. As
indicated above, this was a result of the note and warrant transaction
consummated in that quarter. After the interest expense associated with that
transaction is fully amortized, we expect interest and other income (expense),
net to increase from historical levels as we invest the proceeds of this
offering pending use in our business.

Liquidity and Capital Resources

   Since inception, we have financed our operations primarily through the sale
of preferred equity securities and, in the second half of fiscal 1999, through
borrowings from our investors and others. Since inception through June 30,
1999, we raised an aggregate of $40.4 million (net of transaction expenses)
from the sale of equity securities and an additional $14.0 million through loan
transactions.

   On July 15, 1999, we completed our initial public offering. We issued 4.6
million shares of common stock and raised $63.1 million in net proceeds. Upon
the completion of the initial public offering, our promissory notes converted
into redeemable convertible preferred stock, and all outstanding redeemable
convertible preferred stock then converted into 28,300,067 shares of common
stock.

   At September 30, 1999, we had cash and cash equivalents and highly liquid
short-term investments of $56.1 million. At September 30, 1999, we did not have
a line of credit or other borrowing facility available, nor did we have any
material capital commitments.

   Cash used in operating activities for the quarter ended September 30, 1999
was $9.5 million. Cash used in operating activities has primarily represented
net investments in working capital and funding of our net losses.

   Cash used in investing activities for the quarter ended September 30, 1999
was $9.8 million. Of this amount, $8.7 million of cash was used to purchase
highly liquid short-term investments. In each period, purchases of furniture
and equipment related primarily to the purchase of computers and other
equipment used in our development activities and other equipment and furniture
used in our operations.

                                       32
<PAGE>

   Cash provided by financing activities for the three months ended September
30, 1999 was $63.1 million, consisting primarily of funds raised from our
initial public offering of common stock on July 15, 1999.

   Our future capital requirements will depend upon a number of factors,
including the rate of growth of our sales, the timing and level of research and
development activities and sales and marketing campaigns. We believe that our
cash, cash equivalents and short-term investments will provide sufficient
capital to fund our operations at least through the end of fiscal 2000.
Thereafter, we may require additional capital to fund our business. In
addition, from time to time we may evaluate opportunities to acquire
complementary technologies or companies. Should we identify any such
opportunities, we may need to raise additional capital to fund the
acquisitions. There can be no assurance that financing will be available to us
when we need it on favorable terms or at all.

Year 2000 Issues

   Many currently installed computer systems, software products and other
control devices are unable to accept four digit entries to distinguish 21st
century dates from 20th century dates. As a result, many companies' computer
systems, software products and control devices may need to be upgraded or
replaced in order to operate properly in the current calendar year and beyond.

   We have designed our products to be year 2000 compliant. However, although
we are not aware of any errors or defects associated with our products' date
functions in the year 2000, there can be no assurance that undetected errors or
defects may become evident. If such errors or defects occur, we may incur
material costs to resolve them.

   The internal systems used to deliver our services utilize third-party
hardware and software. We have completed our assessment of year 2000 risks, and
all identified instances of noncompliance have been repaired and tested. We
have contacted the vendors of these products in order to gauge their year 2000
compliance. Based on these vendors' representations, we believe that the third-
party hardware and software will remain year 2000 compliant. There can be no
assurance, however, that we will not experience unanticipated negative
consequences, including material costs, caused by undetected errors or defects
in the technology used in our internal systems.

   We have no specific contingency plan to address the effect of year 2000
noncompliance. If, in the future, it comes to our attention that certain of our
products need modification, or certain of our third-party hardware and software
are not in fact year 2000 compliant, then we will seek to make modifications.
In such cases, we expect such modifications to be made on a timely basis and we
do not believe that the cost of such modifications will have a material effect
on our operating results.

Recent Accounting Pronouncements

   In June 1998, the Financial Accounting Standards Board issued Statement of
Financial Accounting Standards No. 133, "Accounting for Derivatives and Hedging
Activities," ("SFAS No. 133") as amended by Statement of Financial Accounting
Standards No. 137, "Accounting for Derivative Instruments and Hedging
Activities--Deferral of the Effective Date of FASB Statement No. 133," which
establishes accounting and reporting standards of derivative instruments,
including certain derivative instruments embedded in other contracts, and for
hedging activities. SFAS No. 133, as amended, is effective for fiscal years
beginning after June 15, 2000. The adoption of Statement of Financial
Accounting Standards No. 133 is not expected to have a material effect on our
results of operations, financial position or cash flows as we do not currently
hold derivative instruments or engage in hedging activities.

Disclosures About Market Risk

   The following discusses our exposure to market risk related to changes in
interest rates, equity prices and foreign currency exchange rates. This
discussion contains forward-looking statements that are subject to risks and
uncertainties. Actual results could vary materially as a result of a number of
factors including those set forth in the Risk Factors section.

                                       33
<PAGE>

   As of September 30, 1999, we had short-term investments of $8.7 million. All
of these short-term investments consisted of highly liquid investments with
remaining maturities at the date of purchase of less than 90 days. These
investments are subject to interest rate risk and will decrease in value if
market interest rates increase. A hypothetical increase or decrease in market
interest rates by 10% from the September 30, 1999 rates would cause the fair
value of these short-term investments to change by an insignificant amount. We
have the ability to hold these investments until maturity, and therefore we do
not expect the value of these investments to be affected to any significant
degree by the effect of a sudden change in market interest rates. Declines in
interest rates over time will, however, reduce our interest income.

   As of September 30, 1999, we did not own any equity investments. Therefore,
we did not have any direct equity price risk.

   Substantially all of our revenues are currently realized in U.S. dollars. In
addition, we do not maintain significant asset or cash account balances in
currencies other than the United States dollar. Therefore, we do not believe
that we currently have any significant direct foreign currency exchange rate
risk.

                                       34
<PAGE>

                                    BUSINESS

   Efficient Networks is a worldwide developer and supplier of high-speed
digital subscriber line customer premises equipment, or CPE, for the broadband
access market. Our DSL solutions enable telecommunications and other
communication network service providers to provide high-speed, cost-effective
broadband access services over the existing copper wire telephone
infrastructure. On December 17, 1999 Efficient completed the acquisition of
FlowPoint Corporation, a provider of advanced broadband routers for deployment
at customer premises. We believe there is significant demand for high-speed
broadband access, especially among business users and consumers who have found
current solutions to be inadequate or too expensive. We therefore focus on
developing and producing single- and multiple-user DSL customer premises
equipment for small- to medium-size businesses, branch offices of large
corporations and consumers. Our DSL products enable applications such as high-
speed Internet access, electronic commerce, remote access, telecommuting and
extensions of corporate networks to branch offices.

Industry Background

The Growing Need for High-Speed Broadband Communications

   The amount of data being carried over the Internet and private
communications networks has grown dramatically and is expected to continue to
grow as the number of users accessing these networks increases. The increase in
the quantity of data being carried over the Internet and private networks also
is being driven by the broadening range of activities for which these networks
are being used. In order to enhance their reach to customers and suppliers,
businesses are increasingly engaging in mission-critical Internet-based
applications, such as electronic commerce, supply chain management, Web
hosting, and global marketing and customer support. Businesses also
increasingly use the Internet to create secure data networks known as virtual
private networks among corporate sites, remote offices and telecommuters.
International Data Corporation estimates that there were approximately ten
million telecommuters in 1998, of which 72 percent used online services at
least once a day. By utilizing the Internet, businesses can streamline internal
operations by facilitating employee communications, e-mail, file sharing, and
research and analysis. Consumers are also increasingly accessing the Internet
to communicate, collect and publish bandwidth intensive information, conduct
retail purchases, and access online entertainment. These growing network-
dependent activities require the transmission of large amounts of data, which
in turn, requires high-speed broadband data access services for end users to
obtain the data reliably and within practical time constraints.

Traditional Access Solutions are Inadequate

   To meet the growing demand for high-speed, high-bandwidth data transmission,
network service providers have installed high-bandwidth fiber optic
transmission equipment, high-speed switches and core routers in the Internet
backbone and in interoffice networks. While this network backbone is capable of
delivering data at very high speeds, an access bottleneck exists between the
ends of these fiber optic networks at telephone companies' central offices and
the end users' premises. The copper line connections between the central office
and the end user are commonly known as the "last mile." Last mile connections
are typically made via dial-up analog or integrated services digital network,
commonly known as ISDN, modems over the copper infrastructure that was
originally built to transmit analog voice signals. Data transmission speed,
otherwise known as bandwidth, is typically expressed in bits per second. Along
the fiber optic network backbone, data moves at speeds up to 2.5 billion bits
per second, or 2.5 Gbps, while analog modems transmit data at rates up to 56.6
thousand bits per second, or 56.6 Kbps, and most ISDN modems transmit at rates
up to 128 Kbps. Even at ISDN speeds, several minutes are often required to
access a media rich Website, and several hours may be required to transfer or
download large files. During this time, the telephone line cannot be used for
any other purpose. This bottleneck frustrates end users and limits the
capability of network service providers to deliver applications such as
efficient Internet access, multimedia entertainment, real-time telecommuting
and branch office internetworking.


                                       35
<PAGE>

   In an effort to provide greater bandwidth, telecommunications network
service providers have traditionally deployed T1 services. A T1 line is a high-
capacity, dedicated telecommunications line which can support data
transmissions rates of up to 1.5 million bits per second, or 1.5 Mbps, which is
roughly 25 times the speed of analog modems. Although T1 services have helped
fill the need for broadband access for large businesses, network service
providers have generally been unable to offer T1 services to small businesses,
remote offices, telecommuters and consumers as a result of the complexity and
high costs of deployment. Because analog and ISDN modem technology fails to
satisfy the bandwidth needs of end users, and T1 access is prohibitively
expensive, network service providers continue to seek alternatives for
providing cost-effective broadband access to both businesses and consumers.
Additionally, the continued growth in both the number of analog modem users and
their time spent connected to the Internet congests many network service
providers' networks while providing them with little or no additional revenue.

Competition is Driving Rapid DSL Deployment

   Until recently, the incumbent local exchange carriers such as Ameritech,
Bell Atlantic, BellSouth, GTE, Pacific Bell, SBC Communications and US West,
were the exclusive operators of the last mile. Since analog dialup modems, ISDN
and T1 services offered over the incumbent local exchange carriers' networks
did not adequately satisfy the demand for cost-effective broadband access for a
majority of users, alternative solutions were developed such as broadband
wireless and cable access. The deployment of these alternative broadband
solutions is now pressuring incumbent local exchange carriers to deliver cost-
effective broadband access to their customers.

   In addition, the Federal Telecommunications Act of 1996 intensified the
competitive environment because that Act requires incumbent local exchange
carriers to lease portions of their networks, including the last mile, to
competitive local exchange carriers. As a result, many new companies, long
distance telephone companies and Internet service providers have applied for
and been granted regulatory approval for competitive local exchange carrier
status. Leading competitive local exchange carriers, including Covad
Communications, MCI WorldCom, NorthPoint Communications, Rhythms NetConnections
and Sprint, are now deploying high-speed services over the copper
infrastructure owned by the incumbent local exchange carriers. In response to
these competitive pressures and in an effort to increase revenues and maintain
their existing customer base, incumbent local exchange carriers are now
beginning to commit the resources necessary to deploy cost-effective, high-
speed data services over their existing copper infrastructure.

   Similar dynamics are occurring internationally. The growth in Internet use,
telecommunications deregulation and competition from alternative broadband
access technologies have caused foreign telephone network service providers to
commit similar resources to broadband access deployment.

   Incumbent local exchange carriers, competitive local exchange carriers and
foreign telephone network service providers are deploying DSL technology as the
cost-effective broadband access solution. DSL technology utilizes sophisticated
data modulation techniques to achieve high-speed data transmission 100 times
faster than analog modems over existing copper telephone wires. The equipment
needed to enable a DSL link generally consists of two pieces, one in the
network operator's central office and one at the premises of the business or
consumer. The central office equipment is often called a DSL access
multiplexer, commonly known as a DSLAM, which aggregates data traffic from
multiple DSL links into a common link to a fiber optic network backbone. The
CPE and the DSLAM must also interoperate with the rest of the equipment in a
given network. DSL can enable cost-effective, high-speed data transmission from
the premises of a business or consumer into a DSL network operator's central
office where existing high-capacity networks can then carry data to a
destination across an Internet or other service provider's network.

   The market for DSL services is expanding rapidly. All major U.S. incumbent
local exchange carriers have begun to offer DSL services to their customers
directly and through Internet service providers. For example, in October 1999,
SBC Communications announced a $6 billion initiative to make DSL service
available to an

                                       36
<PAGE>

estimated 77 million Americans by the end of 2002. In addition, competitive
local exchange carriers are aggressively deploying DSL service. For instance,
Covad Communications first announced the availability of its DSL services in
the San Francisco Bay area in December 1997. By May 1998, Covad's service was
available to over one million potential customers. By the end of 1998, Covad
extended its DSL offerings to over 6 million businesses and homes in five major
metropolitan areas, and by October 1999, Covad had deployed DSL capability to
over 25 million homes and businesses in 51 metropolitan areas.

Existing Customer Premises Solutions are Constraining DSL Deployment

   As these and other network service providers are deploying DSL services,
they are encountering several challenges. In particular, interoperability still
presents substantial technical challenges despite recent industry efforts to
standardize the various implementations of DSL. Service providers are actively
seeking DSL CPE solutions that offer seamless end-to-end interoperability
within their networks. End-to-end interoperability requires that DSL solutions
be compatible with the customer's computer hardware, operating systems,
networking equipment and software, the CPE and DSLAM, and the switching and
routing equipment in the service providers' network. Network service providers
face additional challenges in deployment and maintenance, because DSL services
are typically targeted at branch offices, small businesses or individuals where
no particular level of networking expertise can be assumed. Therefore, to
implement rapid and widespread DSL deployment, it is of primary importance that
DSL CPE provides for simple and cost-effective installation and maintenance.

The Efficient Solution

   Efficient designs and manufactures the SpeedStream family of DSL CPE and
related software as part of an overall solution for high-speed remote access
and data transmission. Through our recent acquisition of Flowpoint, we also
provide a comprehensive line of broadband access routers. Our solutions enable
DSL deployment, ensure end-to-end interoperability and provide for efficient
and cost-effective installation and maintenance.

   Enable DSL Deployments. Efficient enables network service providers to
rapidly and cost-effectively deploy DSL services, thereby allowing them to
quickly capture market share in today's intensely competitive environment.
Efficient's products are specifically targeted to small- to medium-size
companies and consumers for applications such as high-speed Internet access,
and to large corporations for applications such as remote access, telecommuting
and extensions of corporate networks to branch offices. By offering a variety
of DSL CPE categories that support DSL types compatible with a diverse set of
DSL services, we can provide network service providers with a wide range of
options. We can also reduce operational complexity for network service
providers by offering a single point of contact for training and support for
their DSL CPE.

   Ensure End-To-End Interoperability. Efficient's DSL solutions offer seamless
interoperability from the customer's computer through the service providers'
network. To ensure this interoperability, Efficient leverages our core
technology expertise in combination with our relationships with network service
providers, such as Ameritech, Bell Atlantic, BellSouth, Covad Communications,
Hong Kong Telecom, Singapore Telecom and TeleDanmark, and network equipment
vendors, such as ADC Telecommunications, Advanced Fibre Communications,
Alcatel, Copper Mountain Networks, Ericsson, Lucent Technologies, Newbridge
Networks, Nokia, Nortel Networks and Siemens. Since these industry leaders
recognize that end-to-end interoperability is a necessary requirement for full
scale DSL deployment, network equipment vendors have provided us with early
releases of their systems and technologies so that we can ensure that our
products will seamlessly interoperate with their systems. Our relationships
with network service providers and network equipment vendors enable us to
maintain and use one of the most complete DSL interoperability test labs in the
industry. In addition, Efficient actively participates in developing industry-
wide standards to continue to facilitate end-to-end interoperability.

   Provide for Efficient and Cost-Effective Installation. Efficient offers a
full suite of easily installable DSL solutions, including DSL CPE that provides
routing and bridging capabilities which connect seamlessly into

                                       37
<PAGE>

multiple user environments using a standard networking architecture called
Ethernet. For single user environments, Efficient provides internal DSL CPE
installed directly into the end user's computer and external CPE that connect
to the end user's computer by simply plugging into the computer's universal
serial bus, or USB, port. Efficient's internal and universal serial bus modems
are supported by Efficient's pre-configurable software which allows the network
service provider to configure the CPE for a particular network before the CPE
is sent out into the field. Pre-configuration of the CPE obviates the cost and
time associated with having installers perform these configuration activities
with each end-user installation.

   Provide for Cost-Effective Maintenance. Efficient offers network service
providers our Advanced Status software, a troubleshooting and diagnostic tool.
With Advanced Status software, a network service provider's customer support
technician can walk an end user through the diagnostic process over the
telephone. This allows the network service provider to easily monitor, diagnose
and often remotely fix the customer's problems quickly, which can substantially
reduce the network service provider's customer support costs. In the event that
a technician needs to be dispatched, Advanced Status provides easy diagnosis
and facilitates on-site repair.

The Efficient Strategy

   Our objective is to be the leading worldwide provider of high-performance
DSL broadband access customer premises equipment for businesses, remote
offices, telecommuters and consumers. Key elements of our strategy include the
following:

   Capitalize upon our Early Market Acceptance by Network Service Providers. We
intend to leverage our products' early market acceptance to extend our market
share. We have been focused on the high-speed network connectivity market for
six years and specifically on the DSL market for three years. Our DSL CPE
products have been deployed by Ameritech, Bell Atlantic, BellSouth, Covad
Communications, Hong Kong Telecom, Pacific Bell, Singapore Telecom,
Southwestern Bell, TeleDanmark and several other network service providers. We
work closely with each network service provider, in most cases providing
customized software or product packages, as well as dedicated training and
support services. A number of other network service providers have begun to
test our CPE solutions. We intend to build upon this early acceptance of our
products to become the primary provider of DSL CPE to these and other network
service providers as they deploy their DSL networks.

   Leverage Strategic Relationships with Network Equipment Vendors. We intend
to leverage both current and future relationships to continue to promote
Efficient in the industry, extend our sales capabilities, increase our volume
distribution, and build brand awareness. We believe successful deployment of
DSL necessitates close working relationships with network equipment vendors.
Since most network equipment vendors do not have complete DSL CPE solutions,
they typically bundle and sell their network equipment with third-party CPE
solutions. We have established relationships with ADC Telecommunications,
Alcatel, Copper Mountain Networks, Ericsson, Lucent, Nokia, Nortel Networks and
Siemens, among others.

   Continued Development of Broadband Access CPE. We intend to continue
developing DSL CPE products that enhance the features of our current line as
well as create new bundled voice and data access products. We are developing
advanced functionality, enhanced routing and bridging capabilities, additional
software, and new products based on different physical interfaces. We are
continually pursuing techniques to reduce product costs. In developing new
technologies and products, we benefit from our relationships with key industry
leaders that offer early visibility into market requirements and deployment
trends.

   Broaden Distribution Channels. We plan to extend our distribution channels
to meet the growing demand for broadband access solutions. When we first
deployed our current generation DSL products, we initially targeted incumbent
local exchange carriers and network equipment providers in order to secure
large contracts, establish credibility in the marketplace and strengthen key
network service provider relationships. We have since built a direct sales
force to target competitive local exchange carriers, foreign telephone network
service providers and Internet service providers as well. Moreover, we are
developing alternative distribution

                                       38
<PAGE>

channels such as telephone company-aligned distributors, traditional two-tier
distribution partners, third-party integrators, and retail partners. To this
end, we have recently signed agreements with Innotrac, Nortel Supply and Sprint
North Supply, three leading telephone company-aligned distributors. We are also
expanding our global presence by extending our international direct sales
force, securing additional international value-added resellers and establishing
retail sales abroad.

   Build the Efficient Brand Name. In addition to increasing brand awareness
with network service providers and network equipment vendors, we believe it is
critical to establish brand awareness and differentiation from our competitors
with end customers through superior performance, ease of use and customer
service. We plan to continue building brand awareness of Efficient and
SpeedStream to identify us as the leading provider of DSL CPE solutions. All of
our DSL products, even when deployed by network service providers, carry the
Efficient and SpeedStream brand names. In some instances, we co-brand our
products with prominent network equipment vendors such as Alcatel in order to
build this name recognition. In addition, we plan to increase our investments
in a broad range of marketing programs, including active trade show
participation, advertising in print publications, direct marketing and Web-
based marketing.

   Leverage Strategic Acquisitions to Complement Product & Technology
Offerings. We recently acquired FlowPoint Corporation to add advanced broadband
routers to our product line for the customer premises equipment market. Our
FlowPoint products incorporate a broad range of DSL technologies, including
ADSL, SDSL and IDSL. FlowPoint also brings expertise in frame-based customer
premises equipment as well in the emerging voice-over-DSL market, and has
provided us with several new customer relationships. We intend to pursue
strategic acquisitions in the future as we identify companies or products that
will complement our current product offerings and expand our addressable
customer base.

Products

   Efficient has developed the SpeedStream family of DSL products that enables
broadband access for businesses and consumers. Our products are designed to
support a number of computer environments, DSL implementations, and network
architectures. Our asymmetric DSL, or ADSL, products provide transmission
speeds of up to 8 Mbps in the downstream direction from the network to the end
user, and up to 1 Mbps in the upstream direction. Our symmetric DSL, or SDSL,
products provide equal upstream and downstream speeds of up to 2.3 Mbps. Our
SpeedStream products are separated into these product categories:

  . 3000 Series--Designed for the single user and installable into a
    peripheral component interface, or PCI, bus slot within a personal
    computer.

  . 4000 Series--Designed for the single user and connected to a personal
    computer through a universal serial bus port.

  . 5200 Series--Designed to provide simple, zero-setup DSL access for
    multiple users through an Ethernet port.

  . 5600 Series--Designed to provide basic routing capabilities for a
    telecommuter or a small office or home office environment.

  . FlowPoint routers and Integrated Access Device--Designed to provide a
    comprehensive routing feature set for a small business or a corporate
    branch office, or to provide routing plus multiple voice lines over DSL.

   Efficient also provides a full suite of pre-configuration and diagnostic
software tools. Our pre-configuration software enables network service
providers to architect scalable DSL services and ensures rapid and reliable
installation while reducing or eliminating the need for on-site configuration.
Our diagnostic and troubleshooting software, Advanced Status, is designed to
reduce a network service provider's expense associated with ongoing maintenance
and repair. We believe that these software capabilities can reduce the overall
expense for DSL service deployment and maintenance.

                                       39
<PAGE>

The SpeedStream 3000 Series

   The SpeedStream 3000 Series consists of internal modems that provide high-
speed asymmetric DSL connectivity for a personal computer. This product family
comprises four distinct products, each designed for compatability with specific
DSLAMs from various network equipment vendors. The SpeedStream 3000 Series
incorporates the following features:

  . Installs into any peripheral component interface bus slot;

  . Supports pre-configuration using Efficient software for easy setup;

  . Includes Efficient Advanced Status diagnostic software tools for rapid
    error diagnosis and correction;

  . Supports prevalent data encapsulation standards to ensure network
    interoperability with Internet Protocol and ATM networking equipment;

  . Provides ATM functionality that enables reliable data transmission;

  . Offers remote management capability;

  . Supports Microsoft Windows 95, Windows 98 and Windows NT operating
    systems; and

  . Has list prices ranging from $129 to $269.

The SpeedStream 4000 Series

   The SpeedStream 4000 Series consists of external modems that provide high-
speed asymmetric DSL connectivity through a personal computer's universal
serial bus port. This product family comprises four distinct products, each
designed for compatability with specific DSLAMs from various network equipment
vendors. The SpeedStream 4000 Series incorporates the following features:

  . Attaches externally via a personal computer's universal serial bus port;

  . Supports pre-configuration using Efficient software for easy setup;

  . Includes Efficient Advanced Status diagnostic software tools for rapid
    error diagnosis and correction;

  . Supports prevalent data encapsulation standards to ensure network
    interoperability with Internet Protocol and ATM networking equipment;

  . Provides ATM functionality that enables reliable data transmission;

  . Offers remote management capability;

  . Supports Microsoft Windows 98 operating system; and

  . Has a list price of $299.

The SpeedStream 5200 Series

   The SpeedStream 5200 Series provides high-speed remote ADSL or SDSL
connectivity for one or more personal computers, workstations or other network
devices over a standard networking architecture called Ethernet. This product
family is currently comprised of two products designed to interoperate with
DSLAMs from various network equipment vendors. The SpeedStream 5200 Series
incorporates the following features:

  . Facilitates cost-effective DSL connectivity for multiple users via a
    standard Ethernet port;

  . Provides zero setup installation, reducing the time required for
    installation;

  . Pre-configures for rapid network deployment;

  . Supports prevalent data encapsulation standards to ensure network
    interoperability with Internet Protocol and ATM networking equipment;

  . Provides ATM functionality that enables reliable data transmission; and

  . Has a list price of $349.

                                       40
<PAGE>

The SpeedStream 5600 Series

   The SpeedStream 5600 Series provides high-speed remote ADSL or SDSL
connectivity for one or more personal computers, workstations or other network
devices over a standard networking architecture called Ethernet. This product
family is currently comprised of three products designed to interoperate with
DSLAMs from various network equipment vendors. Routing features help provide
security, and make more effective use of network bandwidth. The SpeedStream
5600 Series incorporates the following features:

  . Facilitates DSL connectivity for multiple users via a standard Ethernet
    port;

  . Provides routing or bridging capabilities for a telecommuting or small
    office/home office environment;

  . Pre-configures for rapid network deployment;

  . Supports prevalent data encapsulation standards to ensure network
    interoperability with Internet Protocol and ATM networking equipment;

  . Provides ATM functionality that enables reliable data transmission;

  . Offers remote management capabilities; and

  . Has a list price of $595.

FlowPoint Routers and Integrated Access Devices

   Routers developed by FlowPoint Corporation provide high-speed remote
connectivity for one or more personal computers, workstations or other network
devices over a standard networking architecture called Ethernet. FlowPoint
routers support three different types of DSL, plus several non-DSL interfaces
that can enhance existing DSL modems. The FlowPoint Integrated Access Devices
add support for multiple voice lines over DSL, in addition to the routing
capabilities. Our FlowPoint routers incorporate the following features:

  . Facilitate DSL connectivity for multiple users via a standard, integrated
    Ethernet hub;

  . Provide routing and bridging capabilities for a small business or branch
    office environment;

  . Pre-configureable for rapid network deployment;

  . Support prevalent data encapsulation standards to ensure network
    interoperability with Internet Protocol and ATM or packet-based
    networking equipment;

  . Support enhanced security and virtual private network capabilities;

  . Provide ATM or packet-based functionality that enables reliable data
    transmission; and

  . Offer remote management capabilities.

   The following table demonstrates some of the features of our routers and
integrated access devices:

                 --------------------------------------------------------------

<TABLE>
<CAPTION>
                                FlowPoint Routers, Integrated Access Devices
                 -----------------------------------------------------------------------
                         2200            255           144      245/2025    2200V--IAD
<S>                  <C>           <C>              <C>       <C>          <C>
       DSLAM         Nokia, Copper Alcatel, Lucent,  Copper    Any--with   Nokia, Copper
  Interoperability     Mountain         Copper      Mountain, external DSL   Mountain
                                      Mountain,      Nokia,      modem
                                       Pulsecom     Pulsecom
- ----------------------------------------------------------------------------------------
 Wide Area Network       SDSL            ADSL         IDSL     Ethernet/       SDSL
     Interface                                                   ATM25
- ----------------------------------------------------------------------------------------
  Suggested Retail       $599            $649         $499     $649/$649       $995
       Price
</TABLE>


                                       41
<PAGE>

Pre-configurable Software

   All of our SpeedStream DSL products for single personal computer
environments support the ability to be pre-configured for specific DSL
networks. SpeedStream Software allows a network service provider to select
configuration settings for the CPE that match its specific network. This CPE
pre-configuration allows a network operator the flexibility to choose network
settings unique to the network's service offerings, without requiring an end
user or an installation technician to individually configure each unit. Thus,
by setting the attributes for DSL, ATM and data encapsulation prior to
installation of the CPE, the speed of DSL equipment installation is increased.
We believe that this ability to pre-configure DSL CPE provides cost savings for
network service providers and allows them to scale their DSL service offerings
rapidly and reliably.

Advanced Status Software

   All SpeedStream DSL products for single-user environments include embedded
diagnostic and troubleshooting software called Advanced Status. During normal
network conditions, the end user is unaware that this software is operating.
However, if network degradation or failure occurs, a customer service
representative can work with the end user to diagnose and isolate problems with
the DSL link, the CPE or the network itself. Advanced Status software provides
information such as status indications and performance statistics for DSL, ATM
and packet communication layers. This information helps identify problems and
determine whether they must be solved at the central office or the customer
premises. Advanced Status software minimizes the need to send a technician to
the customer premises and speeds troubleshooting and repair. We believe that
our Advanced Status software reduces the overall expense of DSL service.

Products under Development

   Efficient is developing a new family of business class products that will
integrate voice and data traffic through a single platform. This family of
products is intended to enable service providers to offer bundled voice and
data services over a single copper connection. These integrated access products
will take advantage of the cost-effective nature of DSL access, but will
ultimately expand to support other high-speed access technologies as well. We
intend to release the first of these new products in the first half of calendar
2000. We believe that as competition among network service providers
intensifies, the ability to provide bundled voice and data services will
provide competitive differentiation among network service providers. In
addition, Efficient is presently working to add new features, enhance existing
features and reduce the cost of our SpeedStream products. Specifically, we are
working to integrate advanced filtering technology, routing capabilities,
advanced management tools and new hardware interfaces into SpeedStream
products.


Technology

   Efficient designs and manufactures DSL CPE as part of an overall solution
for high-speed remote access and data transmission. Efficient's SpeedStream
family of DSL CPE includes products intended for a single user such as a
telecommuter, as well as for multiple users within branch offices or small
businesses. Efficient integrates a diverse set of technologies and expertise,
primarily in the following areas:

  . DSL System Architecture

  . Asynchronous Transfer Mode and Data Encapsulation Techniques

  . Software

  . Application Specific Integrated Circuit Design

  . Routing and Bridging

DSL System Architecture Expertise

   We structure our product architectures to consist of highly modular blocks
of hardware and software. By utilizing our expertise in developing multiple
products with diverse types of DSL technology, we have developed a core set of
hardware and software designs. Consequently, it is a relatively straightforward
activity

                                       42
<PAGE>

to restructure the components and develop a new SpeedStream product. Similarly,
as new features are developed, they can be made available across a number of
products all based upon common components. This design modularity helps
Efficient respond quickly to new market requirements.

   Our product architectures use Efficient's proprietary application specific
integrated circuits, or ASICs, as well as chipsets from third-party suppliers.
We believe that the use of our application specific integrated circuits in
conjunction with these third-party chipsets has advantages for CPE performance
and cost. Because DSL signals operate across a broad frequency range, circuits
must be carefully designed to ensure that high performance is achieved without
disrupting other equipment in the end user's home or office (such as
televisions). We believe that our techniques for DSL circuit design, component
selection and layout, emissions shielding and certification testing result in
high-performance products that meet a broad range of emissions and safety
certifications mandated by the Federal Communications Commission, international
regulatory bodies, consumer safety laboratories and network operators.

Asynchronous Transfer Mode and Data Encapsulation Techniques Expertise

   All of our SpeedStream CPE products employ our own ATM hardware and software
technology. ATM technology enables multiple communication sessions to occur
simultaneously and bursty packet traffic to co-exist with delay-sensitive
traffic such as voice or video information. In order to allow this data to be
carried across an ATM network, it must be formatted into fixed-size ATM cells,
a technique known as data encapsulation. ATM and data encapsulation permit a
common network infrastructure to offer diverse services. There are numerous
data encapsulation techniques which network service providers, Internet service
providers or other network operators may implement.

   We have been able to implement these numerous ATM and data encapsulation
techniques because of our prior experience in designing, manufacturing, and
commercializing ATM LAN equipment. Key pieces of silicon and software
technology were re-used from these products to enable rapid development of our
SpeedStream CPE. We believe that this intellectual property, as well as the ATM
networking expertise associated with it, represents one of our key competitive
advantages.

Software Expertise

   Our software engineers have expertise in developing code that addresses the
needs of network service providers. Our modular software architecture enables
re-use of much of our software code across products. This modularity also
enables rapid development of new products. Our knowledge of network operation
and architectures and data encapsulation techniques allows us to write software
that ensures that our products are interoperable with other network equipment
vendors' products. In addition, our understanding of various operating systems
and personal computer environments allows us to create software that provides
for trouble-free installation and network maintenance. Our software engineers
also design, build and operate comprehensive testing environments to ensure not
only that our products are interoperable, but also offer high performance.

   Efficient has developed a suite of software for our single-user SpeedStream
products that enables communication in a personal computer environment. This
software is commonly called a "driver" and allows application software, such as
e-mail or a Web browser, to send and receive data over the DSL network link,
just as it would over a modem or a LAN connection. By building upon software
source code and skills developed for ATM LAN products, Efficient is able to
support a number of diverse personal computer environments. To date, Efficient
has leveraged our software expertise to develop and release high-performance,
rapidly installing drivers for our SpeedStream 3000 and 4000 Series products.
This software is interoperable with numerous brands and models of personal
computers, operating system environments such as Windows 95, Windows 98 and
Windows NT version 4, and upcoming environments such as Windows 2000.

   Efficient has also developed and released our ProfileBuilder and Advanced
Status software tools. In addition, Efficient works closely with network
service providers to create software specific to their networks, which allows
them to rapidly and reliably deploy and maintain DSL service.

                                       43
<PAGE>

Application Specific Integrated Circuit Design Expertise

   Efficient has developed custom application specific integrated circuits that
enable high-speed ATM networking using peripheral component interface or
universal serial bus attachments. Our application specific integrated circuits
provide high-speed interfaces to the personal computer and also perform several
ATM functions, including segmentation and reassembly functions whereby variable
length packets are converted into fixed size ATM cells. They also perform
traffic shaping functions that control the flow of data from the end user's
equipment into the service provider's network. The use of custom application
specific integrated circuits allows us to better control the cost of our
products and helps ensure their performance and interoperability with diverse
brands of personal computers and network equipment.

Routing and Bridging Expertise

   Efficient's multi-user products offer a shared Ethernet port for local
attachment to a computer network and an ATM DSL port for transmission and
receipt of data across a DSL interface. A bridging device forwards Ethernet
packets between the product's Ethernet port and its ATM DSL port based on
addresses contained in the Ethernet packets. Efficient's Ethernet bridging
products examine addressing information in each packet to determine whether it
should be forwarded between the local Ethernet port and the ATM DSL port. Our
bridging CPE requires little or no configuration, thereby reducing the network
service provider's installation expense. Because all packet forwarding
decisions are made independently of the network protocol carried by the
Ethernet packets, our bridging CPE can support numerous network types,
including older LAN environments such as Novell's IPX or Apple's AppleTalk, as
well as networks based on the Internet Protocol.

   Routers are able to perform much more complex functions than those performed
by bridges including restricting certain types of data from entering the
network and directing data flow based on dynamically assigned Internet protocol
addresses. Efficient's routing products forward Internet Protocol packets based
upon addressing information contained in the packet header. Support for several
different methods of ATM data encapsulation helps ensure network
interoperability. Efficient's routing products provide features that enhance
security and ease network administration for end users, such as packet
filtering, which prevents unwanted access to local servers or other private
resources, and a technique known as network address translation, which masks
the presence of local computers from other computers on the Internet. Our
routing products also implement an address management technique called the
dynamic host configuration protocol that automates the assignment of Internet
protocol addresses to computers attached locally to the router. The network
address translation and dynamic host configuration protocol features of our
routing products can help minimize address interoperability issues, and may be
able to accelerate deployment of DSL services.

   Efficient's routing products include a complete suite of management
capabilities that enable local and remote troubleshooting as well as upgrades
to system configuration or software. This is important as DSL is a complex
technology typically intended for a technologically unsophisticated user base.
We believe that our products' combination of management capabilities which can
be accessed either locally or remotely can help reduce the cost of network
administration for DSL network service providers.

Customers

   Sales of our CPE have been to two main classes of customers: network
equipment vendors who supply DSL central office equipment and DSL network
service providers. Network equipment vendors include our products as an element
of a complete solution offered to their network service provider customers. In
many cases, several different network equipment vendors specify our products as
the preferred or bundled CPE in response to bid requests issued by a network
service provider for complete DSL access solutions. Network service providers
will then provide the CPE to end users for access to their DSL network. In some
cases, we sell CPE to the network equipment vendor for resale as part of a
bundled solution to the network service provider. In other cases, we sell
directly to the network service provider.

                                       44
<PAGE>

   The following table sets forth the top 20 customers for our DSL products in
the fiscal year ended June 30, 1999, categorized by customer type. These
customers accounted for an aggregate of 22.6% of our total revenues in fiscal
1998, 85.9% of our total revenues in fiscal 1999, and 95% of our total revenues
for the first quarter of fiscal 2000.


<TABLE>
<CAPTION>
   Network Equipment Vendors    Network Service Providers      Telephone Company-Aligned
                                                                 and Other Distributors
- ---------------------------------------------------------------------------------------------

  <S>                          <C>                         <C>
  ADC Telecommunications       Ameritech                   Daehan Information Service Corp.
  Alcatel                      Covad Communications*       Global Technology Integrator
  Diamond Lane Communications  Flashcom                    Innotrac for BellSouth's network
  Ericsson                     Hong Kong Telecom           Soon Cabling Pte, Ltd.* for Daewoo
  Lucent Technologies          Panhandle Telecommunication  Telecom's network
  Nokia                         Services                   Telecom Equipment for Singapore
  Nortel Networks              Southwestern Bell            Telecom's network
  Siemens                                                  Universe Computers
</TABLE>


* The customers indicated accounted for 10% or more of our net revenues in
 fiscal 1999. For the first quarter of fiscal 2000, sales to four customers,
 American Communications Supply, Inc., a distributor for Southwestern Bell,
 America Online, Inc., Innotrac Corporation, a distributor for BellSouth, and
 Lucent Technologies each represented more than 10% of our net revenues.

Strategic Relationships

   We believe that establishing relationships with leaders in DSL technology
and services is critical to our success. Accordingly, we have formed strategic
relationships and, in some cases, entered into joint development agreements
with network service providers, network equipment vendors and developers of DSL
semiconductor technology. We are also pursuing strategic relationships to
ensure that high-volume distribution channels are in place for our products.

Network Service Providers

   Ameritech. Efficient has entered into an agreement to provide DSL CPE to
Ameritech. We have worked closely with the technical and product management
staff responsible for DSL service deployment at Ameritech. We have also
provided early software releases of new products to Ameritech, and have
provided Ameritech with training for both customer service and field support.

   Bell Atlantic. Efficient has entered into an agreement to provide DSL CPE to
Bell Atlantic. Two of our SpeedStream products are offered by Bell Atlantic as
CPE options for their Infospeed DSL service. Efficient has developed custom
hardware and software to help enable Bell Atlantic's DSL deployment, and we
have provided them with training for both customer service and field support.

   BellSouth. Efficient has entered into a joint promotion agreement with
BellSouth for DSL CPE. BellSouth provides a financial incentive for Internet
service providers that bring customers into the BellSouth DSL service. For the
term of the program, subscribing Internet service providers are offered
SpeedStream CPE at a reduced cost. Efficient has also entered into a supply
agreement with BellSouth. We believe that the joint promotion agreement in
conjunction with the supply agreement with BellSouth will create significant
demand for our products.

   Covad Communications. Efficient has worked closely with Covad to tune the
feature set of our SpeedStream 5250 symmetric DSL bridging modem to their
network requirements. We are working with Covad to develop new products
intended specifically for its network and also are involved in discussions with
Covad about our next-generation products. In addition, on June 28, 1999, we
issued a $5.0 million convertible promissory note to Covad which converted into
497,663 shares of common stock upon completion of our initial public offering
in July 1999.

                                       45
<PAGE>

   Hanaro Telecom. Hanaro is a competitive network service provider in Korea
actively engaged in DSL deployment. Hanaro offers DSL services for consumer,
academic and business applications. Efficient has worked closely with Hanaro to
enable rapid deployment of its DSL service using our SpeedStream CPE.

   SBC Communications. Efficient provides our SpeedStream CPE for DSL services
offered through SBC's Southwestern Bell and Pacific Bell subsidiaries. We have
provided training for their installation and customer service personnel, and
have worked with their certification and test staff to demonstrate new
SpeedStream DSL products.

   Singapore Telecom. Efficient has worked closely with SingTel to provide
customized software with our CPE that is unique to SingTel's advanced Magix DSL
service. We are involved in discussions with SingTel with respect to the
evolution of SingTel's network architecture and service offerings. SingTel has
consistently volunteered to work with us to test our new products.

Network Equipment Vendors

   Alcatel. Efficient and Alcatel have established a joint development and
marketing agreement for CPE that is interoperable with Alcatel's DSLAM as well
as their Litespan digital loop carrier. We are working together to develop two
successive generations of DSL CPE based around our universal serial bus, ATM
and software technology, and employing Alcatel's DSL chipsets and software. In
certain cases, we co-brand products which are sold by both Efficient and
Alcatel.

   Ericsson. Efficient and Ericsson have entered into a long term agreement
whereby we supply our SpeedStream 3000 PCI and 4000 USB products. We have
developed DSL products intended to ensure ongoing compatibility with their DSL
equipment.

   Nokia. Efficient and Nokia have entered into a purchase and distribution
agreement whereby we supply our SpeedStream 3000 PCI and 4000 USB products.
Under the provisions of this agreement, Nokia resells our products along with
its EKSOS family of DSL equipment and their SpeedLink DSLAM.

   Nortel Networks. Efficient has an agreement to supply Nortel with DSL CPE
that is interoperable with Nortel's Universal Edge 9000 access product. Nortel
offers the Universal Edge 9000 to both new and existing customers as an upgrade
for both Nortel's DMS voice switches and its access node digital loop carriers.
Based on this relationship, we are working with Nortel on next-generation
products.

   Siemens. Siemens is an investor in Efficient. We have worked with Siemens to
specifically design and produce certain DSL CPE that is interoperable with both
Siemens' XpressLink D DSLAM and with DSL interfaces for Siemens' installed base
of voice switches. Anthony T. Maher, who is a member of the board of Siemens AG
Information and Communication Networks, joined our board of directors in April
1999.

Developers of DSL Semiconductor Technology

   Analog Devices. Many of our products use asymmetric DSL technology from ADI.
Efficient was one of two CPE vendors to engage in an early availability program
with ADI for G.lite, a splitterless DSL technology. G.lite is expected to
enable deployment of DSL service without requiring a network service provider
technician to perform on-site wiring changes or installation of CPE.

   Texas Instruments Incorporated. Texas Instruments is an investor in
Efficient. Some SpeedStream products under development use asymmetric DSL
technology from Texas Instruments. We have licensed pieces of our ATM silicon
and software to Texas Instruments, and have assisted in the development of
reference designs for application of Texas Instruments' asymmetric DSL
components. Texas Instruments has provided us with access to its asymmetric DSL
components at most favored prices. Texas Instruments also fabricates one of our
ATM application specific integrated circuits and has provided introductions for
Efficient to personal computer manufacturers who are searching for sources of
DSL CPE.

                                       46
<PAGE>

Telephone Company-Aligned Distributors

   Sprint North Supply. Sprint North Supply is a primary supplier of
telecommunications equipment to Sprint. Many other network service providers
also source networking products from Sprint North Supply. Efficient has entered
into a distribution agreement with Sprint North Supply that enables it to carry
selected members of our SpeedStream product family.

   Nortel Supply. Nortel Supply is a distributor of Nortel and other network
equipment vendors' products. Through our agreement with Nortel Supply,
Efficient leverages Nortel Supply's worldwide distribution capabilities.

   Innotrac. Innotrac is a distributor of consumer telecommunications equipment
for several incumbent local exchange carriers, including BellSouth. Efficient,
Innotrac and BellSouth jointly promote BellSouth's DSL services with
Efficient's SpeedStream CPE. Efficient and Innotrac also work together to
create customized product packages and documentation for major network service
providers. We believe that we can leverage Innotrac's relationship with several
incumbent local exchange carriers, as well as Innotrac's experience in
distributing products in high volume.

Manufacturing

   We outsource the assembly and testing of products and printed circuit boards
to turnkey contract manufacturers. Currently, ACT Manufacturing, Inc.
manufactures the majority of our products at its facility in Hermasillo,
Mexico. Our FlowPoint products are manufactured by PEMSTAR, Inc. at its San
Jose, California facility. Efficient also contracts with Xetel, Inc. for the
manufacturing of its ATM LAN products and a portion of our DSL products at its
facility in Dallas, Texas. Each of these manufacturers are certified by the
International Standards Organization for manufacturing and design processes.
Efficient plans to engage an additional contract manufacturer to meet our
anticipated manufacturing requirements and to continue reducing the cost of our
products.

   Efficient has a limited in-house manufacturing capability. We have complete
capabilities for final test, packaging and shipping of our products. We perform
comprehensive inspection tests and use statistical process controls to assure
the reliability and quality of our products. Our manufacturing engineers design
and build all test procedures and fixtures for our products. We integrate these
manufacturing tests with the contract manufacturers' build processes. Our
manufacturing personnel work with our design engineers to ensure that the test
environment remains current as DSL technology evolves. We also perform warranty
and repair work at our Dallas facility.

   Efficient's engineers design custom application specific integrated circuits
that are incorporated into the majority of our products. Efficient contracts
with silicon manufacturers to fabricate the application specific integrated
circuits for prototype testing. We perform design verification and simulation
testing at our facilities. After successful completion of these tests, Texas
Instruments, Samsung Semiconductor and VLSI Technology manufacture our
application specific integrated circuits in volume on a turnkey basis. We
purchase only packaged and tested application specific integrated circuits.

   Other than our application specific integrated circuits, we try to use
standard parts and components whenever possible. We currently purchase certain
key parts and components from sole-source suppliers such as Alcatel
Microelectronics, Analog Devices, Conexant Systems and Texas Instruments.

Sales and Marketing

   Since 1996, Efficient has worked closely with network equipment vendors that
supply DSL-based central office equipment. These vendors offer our SpeedStream
products to network service providers as part of a complete, interoperable DSL
solution. We engage in joint sales activities with our partners and regularly

                                       47
<PAGE>

provide them with collateral materials to enable their sales forces to promote
our products. Our relationships with network equipment vendors result in
introductions to large network service providers. In many cases, with DSL
interoperability assured by Efficient and our partners, network service
providers choose to purchase CPE directly from Efficient.

   Efficient also works closely with network service providers to ensure that
our CPE is matched to their DSL service offerings. Initial discussions with
network service providers generally involve our sales, marketing and business
development personnel who work to communicate the strengths of our company and
our products. Detailed responses to request for purchase documents are
submitted to network service providers, often by both Efficient and one or more
network equipment vendors.

   Next, at the network service provider's request, we engage in a technical
certification process involving our system engineers who work in a lab
environment, in some cases for days or weeks, with their counterparts from the
network service provider. We frequently provide informal consultation on
network deployment and testing as well as customized training for network
service providers. In some cases, we create special software releases or
product combinations for major network service providers. Efficient typically
creates and delivers customized training courses and curricula for our largest
customers, to ensure that their installation and support personnel are
effective in satisfying end users' needs. While the actual sale and
distribution of CPE varies network by network, this initial relationship-
building stage is critical in every case. We believe that it is difficult to
provide CPE into DSL service offerings without these close relationships with
network service providers.

   We engage in a variety of marketing activities to build brand awareness. We
issue press releases concerning significant product releases, partnerships and
network design wins. We also conduct briefings for analysts and members of the
press. We participate in a number of industry trade shows and pursue speaking
engagements at related events. Efficient uses direct mail campaigns to increase
awareness of our company and our products among Internet service providers, who
are increasingly active in introducing customers to DSL services. We also
engage in joint marketing programs with selected Internet service providers
whose DSL services employ our CPE. Our broad goals are to continue to increase
the awareness of Efficient as a company, and of our DSL CPE product line brand,
SpeedStream.

   As the scope of our marketing efforts expands, our Website continues to be a
strategic resource in disseminating information to interested parties. Our
Website also plays an active role in collecting sales leads, working remotely
with partners and key customers, and performing customer support. In the
future, we believe that our Website may become an important tool for direct
sales of our products.

Research and Development

   We believe that our future success depends on our ability to adapt to the
rapidly changing communications environment, maintain our significant expertise
in core technologies, and continue meeting and anticipating our customers'
needs. We continually review and evaluate technological changes affecting the
telecommunications market and invest substantially in applications-based
research and development. We are committed to an ongoing program of new product
development that combines internal development efforts with joint ventures and
licensing or marketing arrangements relating to new products and technologies
from outside sources.

   Efficient's core research and development activities are focused on both
hardware and software technologies. In our hardware development activities, we
possess significant expertise in application specific integrated circuits
development, analog and mixed signal hardware design, ATM architecture and bus
architectures, such as peripheral component interface and universal serial bus.
In software development, Efficient has particular strengths in data networking
protocols and operating systems, device driver development and traffic
management, and techniques for advanced routing and systems management. We have
significant expertise with hardware and software technology for analog and
digital voice transmission and switching techniques as well.

                                       48
<PAGE>

   To enable successful deployment of DSL services, our CPE must be
interoperable with the DSLAM, ATM switching equipment and other networking
equipment from multiple vendors. In our development efforts, we leverage our
relationships with prominent DSLAM vendors to ensure DSL interoperability. The
continued development and use of our own industry-tested application specific
integrated circuits and software ensure ATM switching interoperability. In
addition, our support for a number of protocol stacks provides data
encapsulation interoperability with routers at Internet service providers or
within corporate networks. Efficient has a solid understanding of the end-to-
end technologies in use, and we actively work to ensure interoperability while
using technology that we control. Our design verification procedures include
testing in complex network environments created in our laboratories that
simulate end-to-end network architectures used in DSL service deployments. We
believe that our stringent design verification and test procedures allow us to
provide cost-effective, high-performance DSL CPE that minimizes the technology
risk for network operators.

   Most of the technology associated with Efficient's SpeedStream products
continues to evolve. Asymmetric DSL supports high frequency digital data
transmission simultaneously with analog voice signals on a single copper phone
line, but digital data and analog voice have the capability to disrupt one
another. One common method of minimizing this disruption is to electrically
separate the voice signals from the data signals using a circuit known as a
filter or a "splitter." At present, the use of a splitter often requires a
network technician or the end user to install the device using hand tools and
to modify phone wiring inside a home or business. We are currently researching
analog filtering circuit technology and are working with other companies to
enable filter designs that can be installed without tools or changes to
interior wiring.

   Another future technology involves ATM switched virtual circuits. Switched
virtual circuits create a dedicated connection between two points of a network.
Current ATM/DSL deployments typically use permanent virtual circuits to create
these dedicated connections. Permanent virtual circuits must be created
manually, while switched virtual circuits employ software to automatically
create a circuit across the ATM network without manual intervention. Some
network operators have expressed a concern that DSL deployments may not scale
rapidly if permanent virtual circuits are employed. Switched virtual circuit
implementations are complex and may represent a technology barrier for
competitors. Efficient has sold ATM LAN products supporting switched virtual
circuits for several years. We believe we are well suited to help enable large-
scale DSL deployments as network operators demand support for switched virtual
circuits.

Competition

   The network equipment industry is highly competitive, and we believe that
competition may increase substantially as the introduction of new technologies,
deployment of broadband networks and potential regulatory changes create new
opportunities for established and emerging companies. In addition, a number of
our competitors and potential competitors have significantly greater financial
and other resources than us which may enable them to more aptly meet new
competitive opportunities. We compete directly with other providers of DSL CPE
including 3Com Corporation, Alcatel, Cisco Systems, Netopia, Westell Technology
and Xpeed among others. Other vendors with whom we compete also have
proprietary systems with which our products are not interoperable. Included
among these vendors are Cisco Systems, Intel Corporation, Nortel Networks,
Orckit Communications and PairGain Technologies. Furthermore, DSL as a
technology for deploying broadband connections is competing with alternative
technologies including ISDN, T1, broadband wireless and cable solutions.

   The rapid technological developments within the network equipment industry
results in frequent changes to our group of competitors. The principal
competitive factors in our market include:

  . Industry relationships with network service providers and network
    equipment vendors;

  . product reliability, performance and interoperability;

  . product features;

  . product availability;

                                       49
<PAGE>

  . price;

  . ability to distribute products;

  . ease of installation and use;

  . technical support and customer service; and

  . brand recognition.

   We believe we are successfully addressing each of these competitive factors.
Nonetheless, we expect to face increasing competitive pressures from both
current and future competitors in the markets we serve.

Intellectual Property

   We rely on a combination of copyright, patent, trademark, trade secret and
other intellectual property laws, nondisclosure agreements and other protective
measures to protect our proprietary rights. We also utilize unpatented
proprietary know-how and trade secrets and employ various methods to protect
our trade secrets and know-how. To date, we have been granted two U.S. patents
with counterpart patents pending in three international jurisdictions and have
an additional 10 U.S. patent applications pending.

   Although we employ a variety of intellectual property in the development and
manufacturing of our products, we believe that none of our intellectual
property is individually critical to our current operations. However, taken as
a whole, we believe our intellectual property rights are significant and that
the loss of all or a substantial portion of such rights could have a material
adverse effect on our results of operations. There can be no assurance that our
intellectual property protection measures will be sufficient to prevent
misappropriation of our technology. In addition, the laws of many foreign
countries do not protect our intellectual properties to the same extent as the
laws of the United States. From time to time, we may desire or be required to
renew or to obtain licenses from others in order to further develop and market
commercially viable products effectively. There can be no assurance that any
necessary licenses will be available on reasonable terms.

   We have registered the trademarks "Efficient Networks" and "SpeedStream."
"Advanced Status" and "ProfileBuilder" are also our trademarks. All other
trademarks or service marks appearing in this prospectus are trademarks or
service marks of the respective companies that use them.

Employees

   As of September 30, 1999, we employed approximately 163 full-time employees,
including 41 in sales and marketing, 18 in manufacturing, 83 in engineering, 17
in finance and administration and four in customer service. Most of our
employees are located in the United States with seven sales and sales
engineering employees located in The Netherlands and three sales and
engineering employees located in Singapore. None of our employees is
represented by collective bargaining agreements, and management considers
relations with our employees to be good.

Properties

   We lease an approximately 26,000 square foot facility in Dallas, Texas for
executive offices and for administrative, sales and marketing, and research and
development purposes. The lease for this facility expires in 2001. In February
2000 we intend to relocate our executive, sales and marketing, and research and
development personnel and activities into a 125,000 square foot facility in
Dallas, Texas. We lease this new facility under a lease expiring in 2010. We
plan to sublease our current space until the expiration of the lease. We lease
two facilities in Dallas, Texas for manufacturing, shipping and receiving of
product. One facility is 11,000 square feet for which the lease expires in
2001. The other facility is 10,000 square feet for which the lease expires at
the end of March 2000. In connection with the acquisition of FlowPoint, we
entered into an agreement with Cabletron to permit us to retain, for a
transitional period, the space being used by the

                                       50
<PAGE>

FlowPoint employees at a Cabletron facility in Santa Clara, California. We
expect to lease space to relocate the Flowpoint operations to another facility
in the Silicon Valley in the first half of calendar 2000. We lease an
approximately 2,500 square foot facility in Amsterdam, The Netherlands for our
European operations. This lease expires in 2004. For our Asian operations, we
lease an approximately 1,450 square foot facility in Singapore. This lease
expires in 2002.

Legal Proceedings

   Efficient is not a party to any material legal proceedings.

                                       51
<PAGE>

                                   MANAGEMENT

Executive Officers and Directors

   The following table sets forth certain information with respect to the
executive officers and directors of Efficient as of December 31, 1999.

<TABLE>
<CAPTION>
          Name           Age                       Position
          ----           ---                       --------
<S>                      <C> <C>
Mark A. Floyd (1).......  44 Chairman of the Board, Chief Executive Officer and
                             President
Peter Bourne............  31 Vice President of Integrated Access (Business Unit)
Paul E. Couturier.......  37 Vice President of International Operations
James Hamilton..........  36 Vice President of Small and Medium Business
                             (Business Unit)
Patricia W. Hosek.......  38 Vice President of Engineering
Gregory L. Langdon......  39 Vice President of Product Strategy
Jill S. Manning.........  37 Vice President and Chief Financial Officer
James N. Nadeau.........  39 Vice President of Residential Access (Business Unit)
Brian M. Ronald.........  41 Vice President of Operations
David B. Stefan.........  37 Vice President of Sales
Dano Ybarra.............  42 Vice President of Corporate Marketing
Charles Waggoner........  60 President, Flowpoint
Bruce W. Brown (2)......  49 Director
James P. Gauer (2)......  47 Director
Robert Hawk.............  59 Director
Robert A. Hoff (3)......  46 Director
Anthony T. Maher........  53 Director
William L. Martin III     52 Director
 (3)....................
Thomas H. Peterson......  43 Director
</TABLE>
- --------
(1) Member of the Employee Option Committee.
(2) Member of the Compensation Committee.
(3) Member of the Audit Committee.

   Mark A. Floyd co-founded Efficient in June 1993 and has served as President,
Chief Executive Officer and a director of Efficient since its inception. Prior
to founding Efficient, from June 1991 to July 1993, Mr. Floyd was Chief
Operating Officer and a director of Networth, Inc., a provider of LAN products
including Ethernet hubs, switches and network interface cards. From May 1984 to
June 1991, Mr. Floyd held the positions of Executive Vice President, Chief
Financial Officer and director of Interphase Corporation, a provider of
enterprise server connectivity solutions for high-speed LAN, high capacity
storage and remote access applications. Mr. Floyd holds a B.B.A. in Finance
from the University of Texas at Austin.

   Peter Bourne joined Efficient in April, 1994 and has served as Vice
President of Integrated Access Business Unit since October 1999. From September
1997 to September 1999, Mr. Bourne served as Efficient's director of product
marketing. From October 1995 to August 1997, Mr. Bourne served as a systems
engineer for us. Prior to serving in such capacity, Mr. Bourne worked as a
software engineer. Mr. Bourne attended the University of California at Santa
Barbara.

   Paul E. Couturier has served as Efficient's Vice President of International
Operations since February 1997. From March 1995 to February 1997, he served as
Efficient's Managing Director, Europe. From June 1993 to January 1995, he was
Pan-European Business Development Manager at SynOptics, a manufacturer of
synthetic crystals and optical products. Prior to that, Mr. Couturier held the
position of Director of Sales and Marketing at Gandalf Benelux, a division of
Mitel Corporation dedicated to the corporate access segment of the remote
access market. Mr. Couturier has a bachelors degree in Marketing and in Foreign
Languages from the University of Amsterdam.

                                       52
<PAGE>

   James Hamilton joined Efficient in November 1999 as Vice President of Small
and Medium Business-Business Unit. From August 1998 to October 1999, Mr.
Hamilton served as Vice President of World Wide Sales and Services at Picazo
Communications, a provider of computer telephony solutions. From January 1996
to August 1998, Mr. Hamilton was Director of Business Development for the
Communication Products Group of Compaq Computer Corporation, a global supplier
of personal computers. From January 1992 to January 1996, he served as Vice
President of International Sales at Networth, Inc., a developer and
manufacturer of ethernet hubs, switches and related products that was acquired
by Compaq in December 1995. Mr. Hamilton holds a B.S. in Business
Administration from Lawrence Technical University.

   Patricia W. Hosek has served as Vice President of Engineering of Efficient
since February 1997. From October 1995 to February 1997, she served as
Efficient's Director of Software Engineering. From December 1990 to October
1995, she worked as a senior manager and developer at DSC Communications
Corporation, a global provider of telecommunications products. Ms. Hosek holds
a B.S. in Computer Science from Texas A&M University.

   Gregory L. Langdon has served as Vice President of Product Strategy of
Efficient since October 1999. From February 1997 to October 1999, Mr. Langdon
served as Vice President of Marketing, and from February 1996 to February 1997,
he served as Efficient's Director of Product Management. From January 1990 to
February 1996, he worked as an engineer at DSC Communications Corporation. Mr.
Langdon holds a B.S. in Electrical Engineering from Vanderbilt University.

   Jill S. Manning has served as Vice President and Chief Financial Officer of
Efficient since February 1997. From November 1994 to February 1997, she served
as Efficient's Controller. From July 1984 to November 1994, Ms. Manning was a
senior manager at KPMG LLP, an international accounting firm. Ms. Manning holds
a B.B.A. in Accounting and in Computer Information Systems from Baylor
University.

   James F. Nadeau has served as Vice President of Residential Access Business
Unit since October 1999. From February 1997 to October 1999, Mr. Nadeau served
as Vice President of Business Development, and from January 1995 to February
1997, he served as a director of sales for Efficient. From May 1993 to January
1995, he worked as North American Channel Sales Manager for Madge Networks.
Prior to that, Mr. Nadeau was a co-founder of CWS Inc., a networking
integration company. Mr. Nadeau attended Northeastern University in Boston, MA.

   Brian M. Ronald joined Efficient in July 1999 as Vice President of
Operations. From March 1996 to July 1999, Mr. Ronald had been Manager,
Manufacturing Program Management at 3Com Corporation, a computer networking
products company. Prior to joining 3Com, Mr. Ronald had been Manager, Global
Electronic Manufacturing at General Electric Lighting since September 1992. Mr.
Ronald holds a B.S. in Industrial Technology from Southern Illinois University
at Carbondale.

   David B. Stefan has served as Vice President of Sales of Efficient since
October 1997. From March 1997 to October 1997, Mr. Stefan worked as Vice
President of Sales of Dagaz Technologies, a manufacturer of telecommunications
equipment that was acquired by Cisco Systems in September 1997. From May 1996
to March 1997, Mr. Stefan held the position of Director of Sales of Sourcecom
Corporation, a computer networking equipment and software reseller. From
November 1992 to May 1996, he worked as a territory manager and system engineer
for Primary Access, a division of 3Com Corporation. Mr. Stefan holds an
M.S.E.E. from George Washington University and a B.S. in Electrical Engineering
from Michigan State University.

   Chuck Waggoner joined Efficient in December 1999 upon the acquisition of
FlowPoint Corporation. Mr. Waggoner has more than 26 years of technology and
management experience in the development and manufacturing of computer and
communications systems. Prior to joining FlowPoint, Mr. Waggoner held various
management positions, including Vice President of Engineering, at LIR
Corporation where he managed the design and development of wide area network
portable software protocols, Senior Vice President of Operations at GRiD
Systems, where he was responsible for the development and manufacture of all
portable computer products, and Vice President of Development at Packet
Technologies, Inc. Mr. Waggoner received a B.S.E.E. from South Dakota State
University.

                                       53
<PAGE>

   Dano Ybarra joined Efficient in the capacity of Vice President of Corporate
Marketing in December 1999 upon the acquisition of FlowPoint Corporation. At
FlowPoint, Mr. Ybarra served as Vice President of Sales and Marketing where he
was responsible for the management of FlowPoint's sales strategies, product
strategy and marketing programs. Prior to joining FlowPoint, Mr. Ybarra was
Vice President of Sales and Marketing at Information Presentation Technologies,
Inc., a provider of integrated server solutions for the multimedia and
publishing markets. Previously, he was Business Manager for Adobe Systems,
where he was responsible for OEM relationships and sales channel management.
Mr. Ybarra received a B.S. in Computer Science from Portland State University.

   Bruce W. Brown has served as a director of Efficient since October 1995.
Since August 1995, he has served as President, Chief Executive Officer and a
director of Vertel Corp., a provider of telecommunications network management
software and services. From July 1993 to August 1995, Mr. Brown held the
positions of President and Chief Executive Officer of ADC Fibermax Corporation,
a supplier of fiber optic networking products. Mr. Brown holds an M.P.A. from
Drake University and a B.S. in Psychology from Iowa State University.

   James P. Gauer has served as a director of Efficient since July 1993. Since
April 1999, he has been a General Partner of Palomar Ventures and Ocean Park
Ventures, and from December 1992 to November 1997, he was a General Partner of
Enterprise Partners, all of which are venture capital firms and investors in
Efficient. Mr. Gauer holds a B.A. in Mathematics from the University of
California, Los Angeles.

   Robert C. Hawk joined Efficient's board of directors in July 1999. Mr. Hawk
is President of Hawk Communications and recently retired as President and Chief
Executive Officer of US West Multimedia Communications, Inc., where he headed
the cable, data and telephony communications business from May 1996 to April
1997. He was president of the Carrier Division of US West Communications, a
regional telecommunications service provider, from September 1990 to May 1996.
Prior to that time, Mr. Hawk was Vice President of Marketing and Strategic
Planning for CXC Corporation. Prior to joining CXC Corporation, Mr. Hawk was
director of Advanced Systems Development for AT&T/American Bell. He currently
serves on the boards of Com21, Concord Communications, Covad Communications
Group, Inc., PairGain Technologies, Inc. and Radcom.

   Robert A. Hoff has served as a director of Efficient since July 1993. Since
1983, he has been a General Partner of Crosspoint Venture Partners, a venture
capital firm and investor in Efficient. Mr. Hoff also serves as a director of
Com21, Inc., Onyx Acceptance Corp., PairGain Technologies, Inc., and U.S.
Web/CKS Corporation. Mr. Hoff holds an M.B.A. from Harvard University and a
B.S. in Business Administration from Bucknell University.

   Anthony T. Maher was appointed to Efficient's board of directors in April
1999. Mr. Maher is a member of the board of Siemens AG Information and
Communication Networks. Siemens, a network equipment vendor, is an investor in
Efficient. Since May 1978, Mr. Maher has held various positions with Siemens,
including the following positions within the Siemens Public Communication
Networks Group: October 1997 to September 1998, member of the board of
directors; October 1995 to September 1997, Executive Director; and January 1993
to September 1995, Executive Director of Worldwide Product Planning. Prior to
his positions within the Public Communication Networks Group, Mr. Maher was
manager and then deputy director of system engineering for EWSD architecture
and processor technology. Mr. Maher holds a M.S. in Electrical Engineering and
Solid State Physics from the University of Illinois.

   William L. Martin III has served as a director of Efficient since January
1997. From September 1994 to November 1999, Mr. Martin served as Senior Vice
President of ADC Telecommunications, Inc. and President of the Business
Broadband Group of ADC Telecommunications, Inc., a provider of communications
networks systems and solutions and an investor in Efficient. Mr. Martin holds
an M.B.A. from Harvard University, an M.S. of Aerospace Engineering and a B.S.
in Engineering from the California Institute of Technology.

                                       54
<PAGE>

   Thomas H. Peterson has served as a director of Efficient since July 1993.
Since May 1991, Mr. Peterson has been a General Partner of El Dorado Ventures,
a venture capital firm and investor in Efficient. Mr. Peterson holds an M.B.A.
from the University of California, Los Angeles and a B.S. in Electrical
Engineering from Iowa State University.

Classified Board

   Our board of directors is currently composed of eight members. Our
certificate of incorporation provides for a classified board of directors
consisting of three classes of directors, each serving staggered three-year
terms. As a result, a portion of our board of directors will be elected each
year. To implement the classified structure, prior to the consummation of our
initial public offering, three of our directors were elected to one-year terms,
two were elected to two-year terms and three were elected to three-year terms.
On a going forward basis, each of our directors will be elected for three-year
terms. Messrs. Maher, Martin and Hawk have been designated Class I directors
whose term expires at the upcoming annual meeting of stockholders. Messrs.
Floyd and Peterson have been designated Class II directors whose term expires
at the 2000 annual meeting of stockholders. Messrs. Brown, Gauer and Hoff have
been designated Class III directors whose term expires at the 2001 annual
meeting of stockholders. See "Description of Capital Stock--Delaware Anti-
Takeover Law and Certain Charter and Bylaw Provisions."

   Executive officers are appointed by the board of directors on an annual
basis and serve until their successors have been duly elected and qualified.
There are no family relationships among any of our directors, officers or key
employees.

Board Committees

   We established an audit committee and a compensation committee in April
1999.

   Our audit committee consists of Messrs. Martin and Hoff. The audit committee
reviews our internal accounting procedures and consults with and reviews the
services provided by our independent accountants.

   Our compensation committee consists of Messrs. Brown and Gauer. The
compensation committee reviews and recommends to the board of directors the
compensation and benefits of our employees. The compensation committee also
administers our stock-based employee benefit plans.

   In October 1999, the board of directors established an employee option
committee. The function of this committee is to determine stock option grants
for employees who are not executive officers. Mark Floyd is currently the only
member of the employee option committee.

Compensation Committee Interlocks and Insider Participation

   Prior to establishing the compensation committee, the board of directors as
a whole performed the functions delegated to the compensation committee. No
member of the board of directors or the compensation committee serves as a
member of the board of directors or compensation committee of any entity that
has one or more executive officers serving as a member of our board of
directors or compensation committee.

Director Compensation

   Directors do not currently receive any cash compensation from us for their
service as members of the board of directors. In December 1996, the board
granted options to Mr. Brown to purchase 100,000 shares of common stock with an
exercise price of $0.25 per share. During fiscal 1999, the board granted to
each of Messrs. Gauer, Hoff, Martin and Peterson options to purchase 50,000
shares of common stock with an exercise price of $1.50 per share. During May
1999, the board granted to Messrs. Maher and Hawk options to purchase 15,000
and 150,000 shares of common stock, respectively, at an exercise price of
$10.50 per share.

                                       55
<PAGE>

Executive Compensation

Summary Compensation Table

   The table below sets forth the compensation earned for services rendered to
Efficient in all capacities for the fiscal years ended June 30, 1998 and 1999
by our Chief Executive Officer and our next four most highly compensated
executive officers who earned more than $100,000 during fiscal 1999. These
executives are referred to as the "named executive officers" elsewhere in this
prospectus.

<TABLE>
<CAPTION>
                                                       Long-Term
                                                      Compensation
                                                         Awards
                                                      ------------
                                  Annual Compensation  Securities
    Name and Principal     Fiscal -------------------  Underlying   All Other
         Position           Year   Salary     Bonus    Options(#)  Compensation
    ------------------     ------ ------------------- ------------ ------------
<S>                        <C>    <C>       <C>       <C>          <C>
Mark A. Floyd.............  1999  $ 200,000 $  80,000   350,000      $    --
 President and Chief
  Executive Officer         1998    178,127    20,000   350,000       16,667(1)

David B. Stefan...........  1999    125,000   112,608   100,000           --
 Vice President of Sales    1998     92,391    36,563   125,000       23,140(2)

Patricia W. Hosek.........  1999    117,000    51,479   225,000           --
 Vice President of
  Engineering               1998    107,625    21,313    50,000           --

Gregory L. Langdon........  1999    117,000    50,716   200,000           --
 Vice President of Product
  Strategy                  1998    103,290    21,051    50,000           --

Paul E. Couturier.........  1999     90,000    76,410   137,500       27,426(3)
 Vice President of
  International Operations  1998     85,709    42,742    37,500       27,634(3)
</TABLE>
- --------
(1) Represents amount paid in lieu of accrued sabbatical benefit.
(2) Represents a moving allowance.
(3) Represents an annual car and vacation allowance.

   Option Grants During Last Fiscal Year. The following table sets forth
certain information with respect to stock options granted to each of the named
executive officers in fiscal 1999, including the potential realizable value
over the ten-year term of the options, based on assumed, annually compounded
rates of stock value appreciation. These assumed rates of appreciation comply
with the rules of the Securities and Exchange Commission and do not represent
our estimate of future stock price. Actual gains, if any, on stock option
exercises will be dependent on the future performance of our common stock.

   In fiscal 1999, we granted options to purchase up to an aggregate of
2,638,500 shares to employees, directors and consultants. All options were
granted at exercise prices which the board of directors believed to be equal to
the fair market value of our common stock on the date of grant. All options
have a term of ten years. Optionees may pay the exercise price by cash, check
or delivery of already-owned shares of our common stock. All option shares vest
over four years, with 25% of the option shares vesting one year after the
option grant date and the remaining option shares vesting ratably on a monthly
basis over the succeeding 36 months.

                                       56
<PAGE>

<TABLE>
<CAPTION>
                                                                                   Potential Realizable
                                                                                     Value at Assumed
                                                                               Annual Rates of Stock Price
                                          Individual Grants                    Appreciation for Option Term
                         --------------------------------------------------- --------------------------------
                                    Percent of
                                       Total
                         Number of    Options             Market
                         Securities Granted to            Value
                         Underlying  Employees              at
                          Options     In Last   Exercise Date of  Expiration
          Name            Granted   Fiscal Year  Price   Grant(1)    Date      0%(1)        5%        10%
          ----           ---------- ----------- -------- -------- ---------- ---------- ---------- ----------
<S>                      <C>        <C>         <C>      <C>      <C>        <C>        <C>        <C>
Mark A. Floyd...........  250,000      9.48%     $1.50    $2.63    8/27/08   $  282,500 $  695,998 $1,330,386
                          100,000      3.79%     $2.50    $9.00    1/28/09   $  650,000 $1,216,005 $2,084,368
David B. Stefan.........  100,000      3.79%     $2.50    $9.00    1/28/09   $  650,000 $1,216,005 $2,084,368
Patricia W. Hosek.......  225,000      8.53%     $2.50    $9.00    1/28/09   $1,462,500 $2,736,012 $4,689,828
Gregory L. Langdon......  200,000      7.58%     $2.50    $9.00    1/28/09   $1,300,000 $2,432,010 $4,168,736
Paul E. Couturier.......  137,500      5.21%     $2.50    $9.00    1/28/09   $  893,750 $1,672,007 $2,866,006
</TABLE>
- --------
(1) Based upon a subsequent review of the fair value of our common stock at the
    option grant dates, we determined the value of the common stock to be as
    reflected in the "Market Value at Date of Grant" column. The amount shown
    in the "0%" column reflects the difference between the exercise price and
    the deemed fair market value as of the date of option grant.

   Aggregate Option Exercises During the Last Fiscal Year and Fiscal Year-End
Option Values. The following table sets forth information with respect to the
named executive officers concerning the exercisable and unexercisable options
held by them as of June 30, 1999. None of the named executive officers
exercised options during fiscal 1999. The "Value of Unexercised In-the-Money
Options at June 30, 1999" is based on a value of $12.00 per share, the fair
market value of our common stock as of June 30, 1999 as determined in a
subsequent review of fair market values, less the per share exercise price,
multiplied by the number of shares issuable upon exercise of the options.

<TABLE>
<CAPTION>
                                                Number of Securities
                                               Underlying Unexercised     Value of Unexercised
                                               Options at Fiscal Year-   In-the-Money Options at
                           Shares                        End                 Fiscal Year-End
                          Acquired    Value   ------------------------- -------------------------
          Name           on Exercise Realized Exercisable Unexercisable Exercisable Unexercisable
          ----           ----------- -------- ----------- ------------- ----------- -------------
<S>                      <C>         <C>      <C>         <C>           <C>         <C>
Mark A. Floyd...........          --       --   272,917      577,083    $ 3,165,938  $ 6,386,563
David B. Stefan.........          --       --    45,313      179,688    $   519,531  $ 1,862,969
Patricia W. Hosek.......                         61,979      280,729    $   724,033  $ 2,780,807
Gregory L. Langdon......          --       --    84,375      265,625    $   989,792  $ 2,660,208
Paul E. Couturier.......          --       --    78,802      171,198    $   927,047  $ 1,696,703
</TABLE>

   The value realized by Ms. Hosek upon the exercise of her options represents
the aggregate amount of the difference between $2.63 per share, the deemed fair
market value of the common stock on the date the option was exercised, and the
$0.15 exercise price of such options.

Benefit Plans

1999 Stock Plan

   Our 1999 stock plan provides for the granting to employees of incentive
stock options within the meaning of Section 422 of the Internal Revenue Code of
1986, as amended, and for the granting to employees and consultants of
nonstatutory stock options and stock purchase rights. The stock plan was
approved by the board of directors in April 1999 and by our stockholders in May
1999. Unless terminated sooner, the stock plan will terminate automatically in
2009. A total of 3,500,000 shares of our common stock is reserved for issuance,
plus annual increases equal to the lesser of:

  . 1,000,000 shares;

  . 3% of the outstanding shares on such date; or

                                       57
<PAGE>

  . a lesser amount determined by the board of directors.

   The stock plan may be administered by the board of directors or a committee
of the board. The board or a committee of the board will have the power to
determine the terms of the options granted, including the exercise price, the
number of shares subject to each option, the vesting provisions, the
exercisability thereof and the form of consideration payable upon such
exercise.

   The stock plan provides that in the event of a merger of Efficient with or
into another corporation, or the sale of substantially all of our assets, each
outstanding option or stock purchase right will be assumed or substituted for
by the successor corporation. In addition, if the options are not substituted
for in the merger, each outstanding option will vest and become exercisable as
to all unvested shares and each stock purchase right shall lapse as to all the
shares for a period of 15 days after receipt of notice from Efficient.

1999 Employee Stock Purchase Plan

   Our 1999 employee stock purchase plan was adopted by our board of directors
in April 1999 and by our stockholders in May 1999. A total of 200,000 shares of
common stock has been reserved for issuance under the purchase plan, plus
annual increases equal to the lesser of:

  . 100,000 shares;

  . 1% of the outstanding shares on such date; or

  . a lesser amount determined by the board on the first day of each fiscal
    year.

   The purchase plan, which is intended to qualify under Section 423 of the
Internal Revenue Code of 1986, as amended, contains successive six-month
offering periods. The offering periods generally start on the first trading day
on or after May 1 and November 1 of each year, except for the first such
offering period which commences on the first trading day on or after the
effective date of this offering and ends on the last trading day on or before
October 31.

   Our employees are eligible to participate if they are employed by us or any
of our participating subsidiaries for at least 20 hours per week and more than
five months in any calendar year. However, the following employees may not
purchase stock under the purchase plan:

  . any employee who immediately after grant owns stock possessing 5% or more
    of the total combined voting power or value of all classes of our capital
    stock; or

  . any employee whose rights to purchase stock under any of our employee
    stock purchase plans accrue at a rate that exceeds $25,000 worth of stock
    for each calendar year.

   Participants may purchase common stock through payroll deductions of up to
10% of the participant's compensation. The maximum number of shares a
participant may purchase during a single offering period is 500 shares.

   Amounts deducted and accumulated by the participant will be used to purchase
shares of common stock at the end of each offering period. The price of stock
purchased under the purchase plan is 85% of the lower of the fair market value
of the common stock at the beginning of the offering period and at the end of
each offering period.

   The purchase plan provides that, in the event of a merger of Efficient with
or into another corporation or a sale of substantially all of our assets,
outstanding options may be assumed or substituted for by the successor
corporation. If the successor corporation refuses to assume or substitute for
the outstanding options, the offering period then in progress will be shortened
and a new exercise date will be set, which will occur before the proposed sale
or merger.

   The purchase plan will terminate in 2009. The board of directors has the
authority to amend or terminate the purchase plan, except that no such action
may adversely affect any outstanding rights to purchase stock.

                                       58
<PAGE>

1999 Non-Statutory Stock Option Plan

   Our 1999 non-statutory stock option plan provides for the grant of
nonstatutory stock options to employees and consultants (excluding officers or
directors) of Efficient. The plan was approved by our board of directors in
November 1999. Unless terminated sooner, the plan will terminate automatically
in 2009. A total of 950,000 shares of common stock are currently reserved for
issuance under the plan.

   The plan may be administered by the board of directors or a committee of the
board. The board or a committee of the board has the power to determine the
terms of the options, including the exercise price, the number of shares
subject to each option, the exercisability thereof, and the form of
consideration payable upon exercise. In addition, the board or a committee of
the board has the authority to amend, suspend or terminate the plan, provided
that no such action may affect any share of common stock previously issued and
sold or any option previously granted under the plan.

   Options granted under the plan are not generally transferable by the
optionee, and each option is exercisable during the lifetime of the optionee
only by the optionee. Options granted under the plan must generally be
exercised within three months of the end of optionee's status as an employee or
consultant of Efficient, or within twelve months after the optionee's
termination by death or disability, but in no event later than the expiration
of the option's ten year term. The exercise price of stock options granted
under the plan is determined by the board or a committee of the board. The term
of stock options granted under the plan may not exceed ten years.

   The plan provides that in the event of a merger of Efficient with or into
another corporation, or a sale of substantially all of our assets, each option
shall be assumed or an equivalent option substituted by the successor
corporation. If the outstanding options are not assumed or substituted, the
board or a committee of the board will provide for the optionee to have the
right to exercise the option as to all of the optioned stock, including shares
that would otherwise not be exercisable, for a period of fifteen (15) days from
the date of the notice, and the option will terminate upon the expiration of
such period.

401(k) Plan

   On January 1, 1995, we adopted the Efficient Networks, Inc. 401(k) Plan (the
"401(k) Plan") a cash-or- deferred arrangement which covers our eligible
employees who have attained the age of 21. The 401(k) Plan is intended to
qualify under Sections 401(a), 401(m) and 401(k) of the Internal Revenue Code
of 1986, as amended (the "Code") and the 401(k) Plan trust is intended to
qualify under Section 501(a) of the Code. All contributions to the 401(k) Plan
by eligible employees or by us, and the investment earnings thereon are not
taxable to such employees until withdrawn, and any contributions we may make
are expected to be deductible by us. Our eligible employees may elect to reduce
their current eligible compensation by one percent (1%) up to fifteen (15%),
subject to the maximum statutorily prescribed annual limit of $10,500 (in
2000), and to have such salary reductions contributed on their behalf to the
401(k) Plan. The 401(k) Plan permits, but does not require, that we may make
matching contributions on behalf of all eligible employees who make salary
reduction contributions to the 401(k) Plan. We have elected to make matching
contributions for the Plan Year ending December 31, 2000, equal to 50% of a
participant's salary deferral contributions for each payroll period, on up to
6% of a participant's annual compensation. The 401(k) Plan also permits, but
does not require, that we may make additional profit-sharing contributions on
behalf of all eligible employees. To date, we have not made such additional
profit-sharing contributions to the 401(k) Plan.

Limitations on Directors' Liability and Indemnification

   Our certificate of incorporation limits the liability of our directors to
the maximum extent permitted by Delaware law. Delaware law provides that
directors of a corporation will not be personally liable for monetary damages
for breach of their fiduciary duties as directors, except liability for any of
the following:

  . any breach of their duty of loyalty to the corporation or its
    stockholders;

  . acts or omissions not in good faith or that involve intentional
    misconduct or a knowing violation of law;

                                       59
<PAGE>

  . unlawful payments of dividends or unlawful stock repurchases or
    redemptions; or

  . any transaction from which the director derived an improper personal
    benefit.

   This limitation of liability does not apply to liabilities arising under the
federal securities laws and does not affect the availability of equitable
remedies such as injunctive relief or rescission.

   Our certificate of incorporation and bylaws provide that we will indemnify
our directors and executive officers, and that we may indemnify our other
officers and employees and other agents, to the fullest extent permitted by
law. We believe that indemnification under our bylaws covers at least
negligence and gross negligence on the part of indemnified parties. Our bylaws
also permit us to secure insurance on behalf of any officer, director, employee
or other agent for any liability arising out of his or her actions in such
capacity, regardless of whether the bylaws would permit indemnification.

   We have entered into agreements to indemnify our directors and executive
officers, in addition to indemnification provided for in our bylaws. These
agreements, among other things, provide for indemnification of our directors
and executive officers for expenses, judgments, fines and settlement amounts
incurred by any such person in any action or proceeding arising out of such
person's services as a director or executive officer of Efficient or at our
request. We believe that these provisions and agreements are necessary to
attract and retain qualified persons as directors and executive officers. We
also maintain directors and officers liability insurance. At present, we are
not aware of any pending litigation or proceeding involving any director,
officer, employee or agent of Efficient where indemnification will be required
or permitted. Furthermore, we are not aware of any threatened litigation or
proceeding that might result in a claim for indemnity by these individuals.

                                       60
<PAGE>

                              CERTAIN TRANSACTIONS

   The following is a description of transactions during our last three fiscal
years to which we have been a party, in which the amount involved in the
transaction exceeds $60,000 and in which any director, executive officer or
holder of more than 5% of our capital stock had or will have a direct or
indirect material interest other than compensation arrangements that are
otherwise required to be described under "Management."

   During the past three fiscal years, we have issued redeemable convertible
preferred stock, subordinated promissory notes and warrants as follows:

  .  In December 1996, we sold 3,091,430 shares of Series E preferred stock
     in a private placement at a purchase price of $2.42 per share;

  .  In February 1998, we sold 2,057,159 shares of Series F preferred stock
     in a private placement at a purchase price of $2.92 per share;

  .  In June 1998, we sold 1,866,800 shares of Series G preferred stock in a
     private placement at a purchase price of $2.92 per share;

  .  In January 1999, we issued an aggregate $7.0 million of 10% subordinated
     promissory notes due January 2002, together with warrants to purchase
     2,397,260 shares of Series H preferred stock in a private placement at
     an exercise price of $2.92 per share;

  .  In March 1999, we sold 1,850,000 shares of Series G preferred stock in a
     private placement at a purchase price of $2.92 per share;

  .  In April 1999, we issued an aggregate $2.0 million of 10% subordinated
     promissory notes due January 2002, together with warrants to purchase
     684,931 shares of Series H preferred stock in a private placement at an
     exercise price of $2.92 per share; and

  .  On June 28, 1999, we issued a $5.0 million convertible promissory note
     to Covad. The note bore interest at the rate of 8% per year, and was
     payable on the fifth anniversary of issuance. Upon completion of our
     initial public offering in July 1999, the principal amount plus interest
     of the note converted into 497,663 shares of common stock.

   Our officers, directors and 5% stockholders participated in the foregoing
transactions as follows:

<TABLE>
<CAPTION>
                                                                  Principal
                          Number of Number of Number of Number of   Amount   Number of
                          Shares of Shares of Shares of Shares of   of 10%   Series H
   Name Of Purchaser      Series D  Series E  Series F  Series G    Notes    Warrants
   -----------------      --------- --------- --------- --------- ---------- ---------
<S>                       <C>       <C>       <C>       <C>       <C>        <C>
Texas Instruments
 Incorporated...........  2,473,644        -- 1,712,329        --         --        --
ADC Telecommunications..         -- 2,066,420    45,881        --         --        --
Enterprise Partners.....         --   265,836    81,773        --         --        --
Crosspoint Venture
 Partners...............         --   236,880    72,848        -- $5,000,000 1,712,329
El Dorado Ventures......         --   236,367    72,689        -- $2,000,000   684,931
Menlo Ventures..........         --   144,322    44,381        --         --        --
Siemens.................         --        --        -- 3,716,800         --        --
Palomar Ventures........         --        --        --        -- $2,000,000   684,931
OceanPark Ventures......         --    88,612    27,258        --         --        --
</TABLE>

   Mr. Martin, a member of our board of directors, was formerly affiliated with
ADC Telecommunications. Mr. Hoff, a member of our board of directors, is
affiliated with Crosspoint Venture Partners. Mr. Peterson, a member of our
board of directors, is affiliated with El Dorado Ventures. Mr. Maher, a member
of our board of directors, is affiliated with Siemens. Mr. Gauer, a member of
our board of directors, was formerly affiliated with Enterprise Partners and is
presently affiliated with Palomar Ventures and Ocean Park Ventures.

                                       61
<PAGE>

Note Repayment and Warrant Exercise Agreement

   Each holder of a 10% subordinated promissory note entered into a note
repayment and warrant exercise agreement with Efficient. Pursuant to the terms
of the agreement, immediately prior to the closing of our initial public
offering, the aggregate $9.0 million principal amount of the notes was applied
toward the aggregate exercise price of the warrants to purchase 3,082,191
shares of Series H preferred stock at an exercise price of $2.92 per share.

ADC Telecommunications, Inc., December 1996

   In December 1996, Efficient entered into a seven-year strategic alliance
agreement with ADC. The agreement provides for joint development and promotion
of products incorporating ADC's and Efficient's technology.

Texas Instruments Incorporated, November 1997

   In November 1997, Efficient and Texas Instruments Incorporated entered into
an agreement to develop a DSL network interface card and associated software.
In February 1998, Efficient and Texas Instruments amended the agreement to
provide that Efficient would focus a percentage of our resources on products,
product developments and marketing programs that support Texas Instruments ADSL
integrated circuits. In March 1999, Efficient and Texas Instruments amended the
agreement to provide Texas Instruments with the right to make and license a
certain Efficient ASIC.

Siemens AG, June 1998

   In June 1998, Efficient entered into an original equipment manufacturer
purchase agreement with Siemens. The agreement provides for the purchase by
Siemens of our SpeedStream 3010 and 3040 models, including supporting software
and hardware and software design, customization and support services.

Director Option and Loan

   In May 1999, Efficient effected the issuance of 150,000 shares of common
stock by granting Robert Hawk an immediately exercisable option to purchase
150,000 shares of common stock at an exercise price of $10.50 per share in
exchange for a $1,575,000 6% demand note. Mr. Hawk exercised this option in May
1999. The note, together with accrued interest, was repaid in July 1999.

Covad Communications Convertible Note Transaction

   On June 28, 1999, we issued a $5.0 million convertible promissory note to
Covad Communications as described above. Mr. Hawk, a member of our board of
directors, also serves on the board of directors of Covad Communications.

                                       62
<PAGE>

                       PRINCIPAL AND SELLING STOCKHOLDERS

   The table on the following page sets forth information regarding the
beneficial ownership of our common stock as of December 31, 1999, and as
adjusted to reflect the sale of the shares hereby, by (a) each person or entity
who is known by us to own beneficially more than 5% of our outstanding stock;
(b) each of our directors; (c) each of our executive officers listed in the
Summary Compensation Table; (d) all directors and executive officers as a
group; and (e) all other selling stockholders.

<TABLE>
<CAPTION>
                               Shares
                            Beneficially                   Shares Beneficially
                            Owned Prior                        Owned After
                            to Offering                          Offering
                         ---------------------             -----------------------
                                               Shares Sold
    Name and Address       Number      Percent In Offering   Number     Percent
    ----------------     ----------    ------- ----------- ------------ ----------
<S>                      <C>           <C>     <C>         <C>          <C>
ADC Telecommunications,
 Inc. ..................  2,169,113      4.3%      41,573     2,127,540     4.0%
  2240 Campbell Creek
   Road
  Richardson, TX 75082

Cabletron Systems,
 Inc. .................. 13,500,000(1)  26.4%   1,977,820    11,522,180    21.7%
  35 Industrial Way
  Rochester, NH 03867

Covad Communications
 Group, Inc. ...........    497,663      1.0%       9,649       488,014      *
  2330 Central
   Expressway
  Santa Clara, CA 95050

Crosspoint Venture
 Partners...............  5,116,619(2)  10.0%      99,207     5,017,412     9.5%
  18552 MacArthur Blvd.,
   Suite 400
  Irvine, CA 92612

El Dorado Ventures......  4,081,800(3)   8.0%      79,141     4,002,659     7.5%
  2400 Sand Hill Road,
   Suite 100
  Menlo Park, CA 94025

Enterprise Partners.....  3,821,374(4)   7.5%      74,093     3,747,281     7.1%
  5000 Birch Street,
   Suite 6200
  Newport Beach, CA
   92600

Menlo Ventures..........  2,043,210      4.0%      39,617     2,003,593    3.8%
  3000 Sand Hill Road,
   Bldg. 4, Suite 100
  Menlo Park, CA 94025

Ocean Park Ventures,
 LP.....................  1,273,803      2.5%      24,698     1,249,105    2.4%
  100 Wilshire
   Boulevard, Suite 400
  Santa Monica, CA 90401

Palomar Ventures........    684,931      1.3%      13,280       671,651    1.3%
  100 Wilshire
   Boulevard, Suite 400
  Santa Monica, CA 90401

Siemens AG..............  3,716,800      7.3%      72,064     3,644,736     6.9%
  Hofmannstrasse 51
  81359 Munchen, Germany

Texas Instruments
 Incorporated...........  4,185,973      8.2%      81,158     4,104,815     7.7%
  P.O. Box 660199, M.S.
   8650
  Dallas, TX 75266-0199

Mark A. Floyd(5)........  1,613,542      3.2%     205,000     1,408,542     2.7%
Bruce W. Brown(6).......     75,000       *        10,000        65,000      *
Robert A. Hoff(7).......  5,141,619     10.1%      99,207     5,042,412     9.5%
Thomas H. Peterson(8)...  4,106,800      8.0%      79,141     4,027,659     7.6%
</TABLE>

                                       63
<PAGE>

<TABLE>
<CAPTION>
                                Shares
                             Beneficially                Shares Beneficially
                             Owned Prior                     Owned After
                             to Offering                       Offering
                          ------------------             -----------------------
                                             Shares Sold
    Name and Address        Number   Percent In Offering   Number     Percent
    ----------------      ---------- ------- ----------- ------------ ----------
<S>                       <C>        <C>     <C>         <C>          <C>
James P. Gauer(9)........  1,983,734   3.9%     37,978      1,945,756     3.7%
Anthony T. Maher(10).....  3,720,550   7.3%     72,064      3,648,486     6.9%
William L. Martin III....        --    --          --             --      --
Robert Hawk(11)..........    150,000    *          --         150,000      *
David B. Stefan(12)......     97,975    *       22,500         75,475      *
Patricia W. Hosek(13)....    180,752    *       37,500        143,252      *
Gregory L. Langdon(14)...    172,916    *       35,000        137,916      *
Paul E. Couturier(15)....    132,293    *       25,000        107,293      *
James Nadeau.............    114,517    *       22,500         92,017      *
Jill Manning.............    139,836    *       22,500        117,336      *
Peter Bourne.............     73,154    *       10,200         62,954      *
Kevin Dibble.............    229,167    *       27,500        201,667      *
Klaus Fosmark............    248,692    *       32,500        216,192      *
William Perry............    249,226    *       32,500        216,726      *
Vicki Smith..............     23,125    *        5,000         18,125      *
All directors and
 officers as a group (19
 persons)(16)............ 17,702,988  34.7%    672,371     17,030,617    32.1%
</TABLE>

   Applicable percentage ownership in the above table is based on 51,063,586
shares of common stock outstanding as of December 31, 1999, after giving pro
forma effect to the conversion of preferred stock held by Cabletron into an
aggregate of 6,300,000 shares of common stock.

   Unless otherwise indicated above, each stockholder named in the table has
sole voting and investment power with respect to all shares shown as
beneficially owned by them, subject to community property laws where
applicable. Unless otherwise indicated, the address for each stockholder listed
in the following table is c/o Efficient Networks, Inc., 4201 Spring Valley
Road, Suite 1200, Dallas, Texas 75244.

* Less than 1% of the outstanding shares of common stock.

 (1) Represents 7,200,000 shares of common stock and 6,300 shares of Series A
     non-voting convertible preferred stock held by Cabletron. The preferred
     stock is automatically convertible into an aggregate of 6,300,000 shares
     of common stock, and is expected to be converted in early 2000.

 (2) Represents 3,301,480 shares held by Crosspoint Venture Partners III,
     102,810 shares held by Crosspoint 1993 Entrepreneurs Fund and 1,712,329
     shares held by Crosspoint Ventures LS 1997 L.P.

 (3) Represents 3,236,226 shares held by El Dorado Ventures III, 59,936 shares
     held by El Dorado C&L Fund, L.P., 100,707 shares held by El Dorado
     Technology IV, L.P., 52,305 shares held by El Dorado Technology 98, L.P.,
     and 632,626 shares held by El Dorado Ventures IV, L.P.

 (4) Represents 3,502,945 shares held by Enterprise Partners II, L.P., and
     318,429 shares held by Enterprise Partners Associates, L.P.

 (5) Includes 513,542 shares issuable upon exercise of stock options
     exercisable on or before March 31, 2000.

 (6) Includes 75,000 shares issuable upon exercise of stock options exercisable
     on or before March 31, 2000.

 (7) Mr. Hoff is a general partner of Crosspoint Venture Partners. The shares
     listed represent (a) 5,116,619 shares held by Crosspoint Venture Partners
     and (b) 25,000 shares held by Mr. Hoff issuable upon exercise of stock
     options exercisable on or before March 31, 2000. Mr. Hoff disclaims
     beneficial ownership of the shares held by Crosspoint Venture Partners,
     except to the extent of his pecuniary interest therein.

                                       64
<PAGE>

 (8) Mr. Peterson is a general partner of El Dorado Ventures. The shares listed
     represent (a) 4,081,800 shares held by El Dorado Ventures and (b) 25,000
     shares held by Mr. Peterson issuable upon exercise of stock options
     exercisable on or before March 31, 2000. Mr. Peterson disclaims beneficial
     ownership of the shares held by El Dorado Ventures, except to the extent
     of his pecuniary interest therein.

 (9) Mr. Gauer is a general partner of Palomar Ventures and Ocean Park
     Ventures, L.P. The shares listed represent (a) 684,931 shares held by
     Palomar Ventures, (b) 1,273,803 shares held by Ocean Park Ventures and (c)
     25,000 shares held by Mr. Gauer issuable upon exercise of stock options
     exercisable on or before March 31, 2000. Mr. Gauer disclaims beneficial
     ownership of the shares held by Palomar Ventures and Ocean Park Ventures,
     except to the extent of his pecuniary interest therein.

(10) The shares listed represented (a) 3,716,800 shares beneficially owned by
     Siemens AG, and (b) 3,750 shares held by Mr. Maher issuable upon exercise
     of stock options exercisable on or before March 31, 2000. Mr. Maher is a
     member of the board of Siemens AG Information and Communication Networks.
     Mr. Maher disclaims beneficial ownership of the shares held by Siemens.

(11) All of such shares are currently subject to a right of repurchase by
     Efficient.

(12) Includes 97,918 shares issuable upon exercise of stock options exercisable
     on or before March 31, 2000.

(13) Includes 148,460 shares issuable upon exercise of stock options
     exercisable on or before March 31, 2000.

(14) Includes 172,916 shares issuable upon exercise of stock options
     exercisable on or before March 31, 2000.

(15) Includes 132,293 shares issuable upon exercise of stock options
     exercisable on or before March 31, 2000.

(16) Includes an aggregate of 1,475,359 shares issuable upon exercise of stock
     options exercisable on or before March 31, 2000.

                                       65
<PAGE>

                          DESCRIPTION OF CAPITAL STOCK

General

   We are authorized to issue 200,000,000 shares of common stock, $0.001 par
value, and 10,000,000 shares of undesignated preferred stock, $0.001 par value.
The following description of our capital stock is subject to and qualified in
its entirety by our certificate of incorporation and bylaws, and by the
provisions of applicable Delaware law.

Common Stock

   As of December 31, 1999, there were 51,156,248 shares of common stock
outstanding after giving pro forma effect to the conversion of all outstanding
shares of Series A non-voting convertible redeemable preferred stock issued to
Cabletron. These shares were held of record by approximately 156 stockholders.

   The holders of common stock are entitled to one vote per share on all
matters to be voted upon by the stockholders. Subject to preferences that may
be applicable to any outstanding preferred stock, the holders of common stock
are entitled to receive ratably such dividends, if any, as may be declared from
time to time by the board of directors out of funds legally available for that
purpose. See "Dividend Policy." In the event of a liquidation, dissolution or
winding up of Efficient, the holders of common stock are entitled to share
ratably in all assets remaining after payment of liabilities, subject to prior
distribution rights of preferred stock, if any, then outstanding. The holders
of common stock have no preemptive or conversion rights or other subscription
rights. There are no redemption or sinking fund provisions applicable to the
common stock. Wilson Sonsini Goodrich & Rosati, Professional Corporation,
counsel to Efficient, shall opine that the shares of common stock to be issued
upon the closing of this offering, when issued and sold in the manner described
in this prospectus and in accordance with the resolutions adopted by the board
of directors, will be fully paid and nonassessable.

Preferred Stock

   The board of directors has the authority, without action by the
stockholders, to designate and issue preferred stock in one or more series and
to designate the rights, preferences and privileges of each series, which may
be greater than the rights of the common stock. It is not possible to state the
actual effect of the issuance of any shares of preferred stock upon the rights
of holders of the common stock until the board of directors determines the
specific rights of the holders of such preferred stock. However, the effects
might include, among other things:

  . restricting dividends on the common stock;

  . diluting the voting power of the common stock;

  . impairing the liquidation rights of the common stock; or

  . delaying or preventing a change in control of Efficient without further
    action by the stockholders.

Series A Non-Voting Convertible Preferred Stock

   In connection with the acquisition of Flowpoint Corporation from Cabletron,
the Board of Directors designated an aggregate of 6,300 shares of preferred
stock as "Series A Non-Voting Convertible Preferred Stock." The following is a
summary of the rights, preferences, privileges and restrictions of Series A
Preferred:

  . Voting. The Series A Preferred is non-voting. However, without the
    consent of holders of at least /66% of the Series A Preferred, Efficient
    may not: (a) alter the rights of the Series A Preferred; (b) create any
    securities that rank on a parity with or senior to the Series A Preferred
    as to dividends or distribution of assets upon liquidation; or (c)
    increase or decrease the number of shares of preferred stock authorized.

                                       66
<PAGE>

  . Dividends. Each share of Series A Preferred is entitled to receive
    dividends, when and if declared by the Board of Directors, at least equal
    in amount to the dividends declared on the common stock, multiplied by
    the conversion ratio of the Series A Preferred. Dividends are not
    mandatory or cumulative.

  . Liquidation. In the event of a liquidation of Efficient, the holders of
    the Series A Preferred are entitled to receive the par value of such
    shares in preference to the holders of common stock, and thereafter share
    on a pro rata basis with the common stock, treating the Series A
    Preferred as if converted into common stock.

  . Automatic Conversion. The Series A Preferred automatically converts into
    common stock, at the rate of 1,000 shares of common stock for each share
    of Series A Preferred (subject to adjustment for stock splits and the
    like), immediately following the affirmative vote of such conversion by
    holders of a majority of our common stock.

  . Redemption. In the event that the Series A Preferred has not converted
    into common stock on or before July 21, 2000, one fifth of the Series A
    Preferred shall be redeemed on each of December 31, 2000, 2001, 2002,
    2003, and 2004. The redemption price of the Series A Preferred is
    approximately $78,000 per share.

   It is the mutual intention and understanding of Efficient and Cabletron
that Efficient will hold a special meeting of stockholders. Holders of a
majority of Efficient's common stock have entered into Voting Agreements
pursuant to which they have agreed to vote in favor of conversion of the
Series A Preferred into common stock. The special meeting is expected to be
held in early 2000.

Warrants

   At September 30, 1999, there were warrants outstanding to purchase 34,246
shares of our common stock.


Standstill and Registration Rights

   On December 17, 1999, pursuant to an Agreement and Plan of Reorganization,
Efficient completed the acquisition of FlowPoint Corporation, a wholly-owned
subsidiary of Cabletron, in exchange for a combination of common stock and
preferred stock equal to an aggregate of 13,500,000 shares of common stock on
an as-converted basis. In connection with this transaction, Efficient and
Cabletron also entered into a Standstill and Disposition Agreement containing
certain standstill provisions, voting provisions, restrictions on transfer,
and registration rights.

   The standstill provisions contained in the Standstill and Disposition
Agreement provide that, without the prior consent of Efficient's board,
Cabletron may not:

  . acquire additional shares of Efficient;

  . solicit proxies or participate in an election contest;

  . act in concert with others to acquire, hold or dispose of Efficient
    stock;

  . seek to elect or replace members of Efficient's board;

  . seek to control management, the board, or policies of Efficient;

  . pursue a business combination with Efficient;

  . coordinate with any third person to form a business combination with
    Efficient;

  . coordinate with any third person in connection with a tender offer for
    voting securities of Efficient; and

  . assist, participate, solicit or encourage any third party to do any of
    the above.

                                      67
<PAGE>

   The voting provisions contained in the Standstill and Disposition Agreement
provide that on matters requiring the vote of Efficient stockholders, Cabletron
must vote shares in excess of 10% of the voting stock of Efficient in
proportion with the vote of other stockholders of Efficient. However, Cabletron
must vote all voting shares which it owns proportionately with respect to:

  . any transaction between Efficient and one or more person in which
    Cabletron controls a 5% equity interest; or

  . a change of control of Efficient with any of the top five data networking
    companies, from time to time, as measured by revenues.

   The standstill and voting provisions will terminate if and when Cabletron
owns less than 5% of the voting securities of Efficient or upon a change of
control of Efficient.

   The restrictions on transfer provisions contained in the Standstill and
Disposition Agreement provide that, without the prior consent of Efficient's
board, Cabletron may not sell, transfer, or otherwise dispose of Efficient
stock, except:

  . to a controlled affiliate of Cabletron;

  . in connection with a firm commitment, underwritten public offering;

  . pursuant to Rule 144 or the shelf registration statement, except in
    certain circumstances;

  . in a private sale, except if, after giving effect to the sale, the
    purchaser would own more than 5% of the voting stock of Efficient, unless
    the purchaser is a passive investor in which case the amount may be up to
    10% of the voting stock of Efficient; and

  . in response to a tender offer which is not opposed by Efficient's board.

   The restriction on transfer provisions will terminate if and when Cabletron
owns less than 5% of the voting securities of Efficient, or upon a change of
control of Efficient, or November 2009.

   The registration rights provisions contained in the Standstill and
Disposition Agreement provide that, in addition to the shares to which
Cabletron is entitled to include in this offering:

  . by July 21, 2000, Efficient shall use commercially reasonable efforts to
    file a shelf registration statement so that Cabletron may sell shares on
    a continuous basis, however, Cabletron may not sell greater than 2
    million shares pursuant to this registration statement and Rule 144;

  . after July 21, 2000, Cabletron shall be entitled to two demand
    registrations as long as the demand is for 2 million shares or more;

  . if Efficient determines to commence any public offering after this
    offering before December 31, 2000, Cabletron shall be entitled to include
    the greater of 40% of the shares to be sold in the offering or 3 million
    shares;

  . Cabletron shall also be entitled to the same registration rights held by
    other stockholders of Efficient stock, as described in the following
    paragraph; and

  . expenses of registration, other than underwriting discounts and
    commissions, will be borne by us.

   In addition to the specific registration rights of Cabletron described
above, which are senior, the holders of approximately 27.5 million shares of
common stock and Cabletron are entitled to certain registration rights.
Beginning on December 31, 2000, the holders of at least 50% of the then
outstanding registrable securities may require:

  . on up to two occasions, that we register their shares for public resale;

                                       68
<PAGE>

  . on one occasion within any twelve month period that we register their
    shares for public resale on Form S-3 or similar short-form registration
    if the value of the securities to be registered is at least $1.0 million,
    include their shares of common stock in a registration in which we elect
    to register shares of common stock of Efficient, but we may reduce the
    number of shares proposed to be registered in view of market conditions
    to an amount not less than 30% of the shares in the offering.

   All expenses incurred in connection with any registration, other than
underwriting discounts and commissions attributable to registrable securities,
will be borne by us. These registration rights will terminate in July 2005, or,
with respect to each holder of registrable securities, at such time as the
holder is entitled to sell all of its shares in any three-month period under
Rule 144(k) of the Securities Act.

Delaware Anti-Takeover Law and Certain Charter and Bylaw Provisions

   Certain provisions of Delaware law and our certificate of incorporation and
bylaws could make the following transactions more difficult:

  . the acquisition of Efficient by means of a tender offer;

  .  the acquisition of Efficient by means of a proxy contest or otherwise;
     or

  .  the removal of our incumbent officers and directors.

   These provisions, summarized below, are expected to discourage certain types
of coercive takeover practices and inadequate takeover bids. These provisions
are also designed to encourage persons seeking to acquire control of Efficient
to first negotiate with our board of directors. We believe that the benefits of
our increased ability to negotiate with the proponent of an unfriendly or
unsolicited proposal to acquire or restructure Efficient outweigh the
disadvantages of discouraging such proposals as negotiation of such proposals
could result in an improvement of their terms.

   Election and Removal of Directors. Our board of directors is divided into
three classes. The directors in each class will serve for a three-year term,
one class being elected each year by our stockholders. See "Management--
Executive Officers and Directors." This system of electing and removing
directors may tend to discourage a third party from making a tender offer or
otherwise attempting to obtain control of Efficient because it generally makes
it more difficult for stockholders to replace a majority of the directors.

   Stockholder Meetings. Under our bylaws, only our board of directors,
Chairman of the Board and President may call special meetings of stockholders.

   Requirements for Advance Notification of Stockholder Nominations and
Proposals. Our bylaws establish advance notice procedures with respect to
stockholder proposals and the nomination of candidates for election as
directors, other than nominations made by or at the direction of the board of
directors or a committee of the board.

   Delaware Anti-Takeover Law. We are subject to Section 203 of the Delaware
General Corporation Law, an anti-takeover law. In general, Section 203
prohibits a publicly held Delaware corporation from engaging in a "business
combination" with an "interested stockholder" for a period of three years
following the date the person became an interested stockholder, unless the
"business combination" or the transaction in which the person became an
interested stockholder is approved in a prescribed manner. Generally, a
"business combination" includes a merger, asset or stock sale, or other
transaction resulting in a financial benefit to the interested stockholder.
Generally, an "interested stockholder" is a person who, together with
affiliates and associates, owns or within three years prior to the
determination of interested stockholder status, did own, 15% or more of a
corporation's voting stock. The existence of this provision may have an anti-
takeover effect with respect to transactions not approved in advance by our
board of directors, including discouraging attempts that might result in a
premium over the market price for the shares of common stock held by
stockholders.

                                       69
<PAGE>

   Elimination of Stockholder Action By Written Consent. Our certificate of
incorporation eliminates the right of stockholders to act by written consent
without a meeting.

   Elimination of Cumulative Voting. Our certificate of incorporation and
bylaws do not provide for cumulative voting in the election of directors.

   Undesignated Preferred Stock. The authorization of undesignated preferred
stock makes it possible for the board of directors to issue preferred stock
with voting or other rights or preferences that could impede the success of any
attempt to change control of Efficient. These and other provisions may have the
effect of deterring hostile takeovers or delaying changes in control or
management of Efficient.

   Amendment of Charter Provisions. The amendment of any of the above
provisions would require approval by holders of at least 66 2/3% of the
outstanding common stock.

   Transfer Agent and Registrar

   The transfer agent and registrar for the common stock is Harris Trust and
Savings Bank.

The Nasdaq Stock Market Listing

   Our shares have been approved for listing on The Nasdaq Stock Market under
the symbol "EFNT."

                                       70
<PAGE>

                        SHARES ELIGIBLE FOR FUTURE SALE

   Upon completion of this offering and based on shares outstanding at December
31, 1999, we will have outstanding approximately 53.2 million shares of common
stock after giving pro forma effect to the conversion of all outstanding shares
of Series A non-voting convertible redeemable preferred stock issued to
Cabletron. Of these shares, approximately 14.6 million shares including the
5,000,000 shares sold in this offering plus any shares issued upon exercise of
the underwriters' over-allotment option, will be freely tradable.

   Our directors, officers and certain stockholders have entered into lock-up
agreements with the underwriters of this offering providing that they will not
offer, sell, contract to sell or grant any option to purchase or otherwise
dispose of our shares for a period not to exceed 90 days after the effective
date of the registration statement filed pursuant to this offering, as
described below, without the prior written consent of Credit Suisse First
Boston Corporation. As a result of these contractual restrictions,
notwithstanding possible earlier eligibility for sale under the provisions of
Rules 144, 144(k) and 701, shares subject to lock-up agreements may not be sold
until such agreements expire or are waived by Credit Suisse First Boston
Corporation. Taking into account the lock-up agreements, and assuming Credit
Suisse First Boston Corporation does not release stockholders from these
agreements prior to the expiration of the lock-up period, the following shares
will be eligible for sale in the public market at the following times:

  . beginning April 3, 2000, approximately 3.1 million additional shares will
    be available for sale in the public market, certain of which are
    restricted securities;

  . beginning May 3, 2000, approximately 23.6 million additional shares will
    be available for sale in the public market, certain of which are
    restricted securities;

  . the remaining approximately 11.9 million shares will be eligible for sale
    from time to time thereafter, subject in some cases to compliance with
    Rule 144.

   "Restricted securities" within the meaning of Rule 144 under the Securities
Act. Restricted securities may be sold in the public market only if registered
or if they qualify for an exemption from registration under Rules 144,
including applicable volume limitations, 144(k) or 701 promulgated under the
Securities Act, which are summarized below.

   In general, under Rule 144 as currently in effect, a person who has
beneficially owned restricted shares for at least one year, including the
holding period of any prior owner except an affiliate, would be entitled to
sell within any three-month period a number of shares that does not exceed the
greater of:

  . 1% of the number of shares of common stock then outstanding, which will
    equal approximately 532,000 shares immediately after this offering; or

  . the average weekly trading volume of our common stock during the four
    calendar weeks preceding the filing of a Form 144 with respect to such
    sale.

   Sales under Rule 144 are also subject to certain manner of sale provisions
and notice requirements and to the availability of current public information
about Efficient. Under Rule 144(k), a person who is not deemed to have been an
affiliate of Efficient at any time during the three months preceding a sale,
and who has beneficially owned the shares proposed to be sold for at least two
years, including the holding period of any prior owner except an affiliate, is
entitled to sell such shares without complying with the manner of sale, public
information, volume limitation or notice provisions of Rule 144.

   Rule 701, as currently in effect, permits resales of shares in reliance upon
Rule 144 but without compliance with certain restrictions, including the
holding period requirement, of Rule 144. Any of our employees, officers,
directors, or consultant who purchased shares under a written compensatory plan
or contract may be entitled to rely on the resale provisions of Rule 701. Rule
701 permits affiliates to sell their Rule 701 shares under Rule 144 without
complying with the holding period requirements of Rule 144. Rule 701 further
provides that non-affiliates may sell such shares in reliance on Rule 144
without having to comply with the holding period, public information, volume
limitation or notice provisions of Rule 144.

                                       71
<PAGE>

   On October 13, 1999, we filed three separate registration statements on Form
S-8 registering in the aggregate 10,479,329 shares of common stock subject to
outstanding options or reserved for future issuance under our stock plans. As
of December 31, 1999, options to purchase a total of 8.2 million shares were
outstanding and 2.8 million shares were reserved for future issuance under our
stock plans.

   Upon completion of this offering, holders of 39.1 million restricted shares
of common stock will be entitled to certain registration rights. See
"Description of Capital Stock--Registration Rights." Registration of such
shares under the Securities Act would result in such shares becoming freely
tradable without restriction under the Securities Act, except for shares
purchased by affiliates, immediately upon the effectiveness of such
registration.

                                       72
<PAGE>

                                  UNDERWRITING

   Under the terms and subject to the conditions contained in an underwriting
agreement dated         , 2000, Efficient and the selling stockholders have
agreed to sell to the underwriters named below, for whom Credit Suisse First
Boston Corporation, FleetBoston Robertson Stephens, Prudential Securities
Incorporated and Dain Rauscher Incorporated are acting as representatives, the
following respective numbers of shares of common stock:

<TABLE>
<CAPTION>
                                                                       Number of
                                Underwriters                            Shares
                                ------------                           ---------
      <S>                                                              <C>
      Credit Suisse First Boston Corporation..........................
      FleetBoston Robertson Stephens..................................
      Prudential Securities Incorporated..............................
      DainRauscher Incorporated.......................................

                                                                       ---------
        Total......................................................... 5,000,000
                                                                       =========
</TABLE>

   The underwriting agreement provides that the underwriters are obligated to
purchase all the shares of common stock in the offering if any are purchased,
other than those shares covered by the over-allotment option described below.
The underwriting agreement also provides that, if an underwriter defaults, the
purchase commitments of non-defaulting underwriters may be increased or the
offering of common stock may be terminated.

   We have granted to the underwriters a 30-day option to purchase on a pro
rata basis up to 750,000 additional shares at the initial public offering price
less the underwriting discounts and commissions. The option may be exercised
only to cover any over-allotments of common stock.

   The underwriters propose to offer the shares of common stock initially at
the public offering price on the cover page of this prospectus and to selling
group members at that price less a concession of $    per share. The
underwriters and selling group members may allow a discount of $    per share
on sales to other broker/dealers. After the initial public offering, the public
offering price and concession and discount to broker/dealers may be changed by
the representatives.

   The following table summarizes the compensation and estimated expenses we
and the selling stockholders will pay:

<TABLE>
<CAPTION>
                                    Per Share                       Total
                          ----------------------------- -----------------------------
                             Without          With         Without          With
                          Over-allotment Over-allotment Over-allotment Over-allotment
                          -------------- -------------- -------------- --------------
<S>                       <C>            <C>            <C>            <C>
Underwriting discounts
 and commissions payable
 by us..................       $              $              $              $
Expenses payable by us..       $              $              $              $
Underwriting discounts
 and commissions payable
 by selling
 stockholders...........       $              $              $              $
</TABLE>

   We, our officers and directors, the selling stockholders and other
stockholders holding an aggregate of     shares have agreed that we and they
will not offer, sell, pledge or otherwise dispose of, directly or indirectly,
or file with the Securities and Exchange Commission a registration statement
under the Securities Act relating to any additional shares of our common stock
or securities convertible into or exchangeable or exercisable for any shares of
our common stock, or publicly disclose the intention to make any offer, sale,
pledge, disposition or filing, without the prior written consent of Credit
Suisse First Boston Corporation for a period not to exceed 90 days after the
date of this prospectus, except in the case of issuances by Efficient upon the
exercise of employee stock options outstanding on the date hereof.

   We and the selling stockholders have agreed to indemnify the underwriters
against liabilities under the Securities Act, or contribute to payments which
the underwriters may be required to make in that respect.

                                       73
<PAGE>

   Our common stock is listed on The Nasdaq National Market under the symbol
"EFNT."

   We and the selling stockholders have agreed to indemnify the underwriters
against liabilities under the Securities Act, or contribute to payments which
the underwriters may be required to make in that respect.

   The representatives may engage in over-allotment, stabilizing transactions,
syndicate covering transactions, penalty bids and passive market making in
accordance with Regulation M under the Securities Exchange Act of 1934.

  .  Over-allotment involves syndicate sales in excess of the offering size,
     which creates a syndicate short position.
  .  Stabilizing transactions permit bids to purchase the underlying security
     so long as the stabilizing bids do not exceed a specified maximum.
  .  Syndicate covering transactions involve purchases of the common stock in
     the open market after the distribution has been completed in order to
     cover syndicate short positions.
  .  Penalty bids permit the representatives to reclaim a selling concession
     from a stabilizing or syndicate member when the common stock originally
     sold by the syndicate member is purchased in a stabilizing or syndicate
     covering transaction to cover syndicate short positions.
  .  In passive market making, market makers in the common stock who are
     underwriters or prospective underwriters may, subject to limitations,
     make bids for or purchases of the common stock until the time, if any,
     at which a stabilizing bid is made.

These stabilizing transactions, syndicate covering transactions and penalty
bids may cause the price of the common stock to be higher than it would
otherwise be in the absence of these transactions. These transactions may be
effected on The Nasdaq National Market or otherwise, and if commenced, may be
discontinued at any time.



                                       74
<PAGE>

                          NOTICE TO CANADIAN RESIDENTS

Resale Restrictions

   The distribution of the common stock in Canada is being made only on a
private placement basis exempt from the requirement that we and the selling
stockholders prepare and file a prospectus with the securities regulatory
authorities in each province where trades of common stock are effected.
Accordingly, any resale of the common stock in Canada must be made in
accordance with applicable securities laws which will vary depending on the
relevant jurisdiction, and which may require resales to be made in accordance
with available statutory exemptions or pursuant to a discretionary exemption
granted by the applicable Canadian securities regulatory authority. Purchasers
are advised to seek legal advice prior to any resale of the common stock.

Representations of Purchasers

   Each purchaser of common stock in Canada who receives a purchase
confirmation will be deemed to represent to us, the selling stockholders and
the dealer from whom such purchase confirmation is received that (i) the
purchaser is entitled under applicable provincial securities laws to purchase
the common stock without the benefit of a prospectus qualified under these
securities laws, (ii) where required by law, that the purchaser is purchasing
as principal and not as agent, and (iii) the purchaser has reviewed the text
above under "Resale Restrictions."

Rights of Action of Ontario Purchasers

   The securities being offered are those of a foreign issuer and Ontario
purchasers will not receive the contractual right of action prescribed by
Ontario securities law. As a result, Ontario purchasers must rely on other
remedies that may be available, including common law rights of action for
damages or rescission or rights of action under the civil liability provisions
of the U.S. federal securities laws.

Enforcement of Legal Rights

   All of the issuer's directors and officers as well as the experts named
herein and the selling stockholders may be located outside of Canada and, as a
result, it may not be possible for Canadian purchasers to effect service of
process within Canada upon the issuer or these persons. All or a substantial
portion of the assets of the issuer and these persons may be located outside of
Canada and, as a result, it may not be possible to satisfy a judgment against
the issuer or these persons in Canada or to enforce a judgment obtained in
Canadian courts against the issuer or these persons outside of Canada.

Notice to British Columbia Residents

   A purchaser of common stock to whom the Securities Act (British Columbia)
applies is advised that the purchaser is required to file with the British
Columbia Securities Commission a report within ten days of the sale of any
common stock acquired by the purchaser pursuant to this offering. This report
must be in the form attached to British Columbia Securities Commission Blanket
Order BOR #95/17, a copy of which may be obtained from us. Only one report must
be filed in respect of common stock acquired on the same date and under the
same prospectus exemption.

Taxation and Eligibility for Investment

   Canadian purchasers of common stock should consult their own legal and tax
advisors with respect to the tax consequences of an investment in the common
stock in their particular circumstances and with respect to the eligibility of
the common stock for investment by the purchaser under relevant Canadian
legislation.


                                       75
<PAGE>

                                 LEGAL MATTERS

   The validity of the common stock offered hereby will be passed upon for
Efficient by Wilson Sonsini Goodrich & Rosati, Professional Corporation, Palo
Alto, California. Kenneth M. Siegel, a member of Wilson Sonsini Goodrich &
Rosati, will be leaving that firm to joint Efficient as an executive officer
effective February 1, 2000. Mr. Siegel owns 2,500 shares of our common stock
and, in connection with his decision to join Efficient, was granted an option
to purchase 500,000 shares of our common stock at an exercise price of $58.50
per share. The due authorization of the shares to be sold by Efficient and the
execution and delivery of the underwriting agreement for this offering will be
passed upon for the underwriters by Brobeck, Phleger & Harrison LLP, Austin,
Texas.

                                    EXPERTS

   The consolidated financial statements of Efficient Networks, Inc. as of June
30, 1998 and 1999, and for each of the years in the three-year period ended
June 30, 1999 included in this prospectus and registration statement have been
audited by KPMG LLP, independent auditors, as set forth in their reports, which
are included in this prospectus and registration statement, and are included in
reliance upon their reports given on their authority as experts in accounting
and auditing.

   The financial statements of FlowPoint Corporation as of March 31, 1998,
August 31, 1998 and February 28, 1999 and for the years ended March 31, 1997
and 1998, the five-month period ended August 31, 1998 and the six-month period
ended February 28, 1999, included in this prospectus and registration statement
have been audited by KPMG LLP, independent auditors, as set forth in their
report, which is included in this prospectus and registration statement, and is
included in reliance upon their report given on their authority as experts in
accounting and auditing.

                        ADDITIONAL EFFICIENT INFORMATION

   We have filed with the Securities and Exchange Commission a registration
statement on Form S-1 under the Securities Act with respect to the common stock
offered in this offering. This prospectus does not contain all of the
information set forth in the registration statement and the exhibits and
schedules thereto. For further information with respect to Efficient and the
common stock offered in this offering, we refer you to the registration
statement and to the attached exhibits and schedules. With respect to each such
document filed as an exhibit to the registration statement, we refer you to the
exhibit for a more complete description of the matter involved.

   You may inspect our registration statement and the attached exhibits and
schedules without charge at the public reference facilities maintained by the
Securities and Exchange Commission at 450 Fifth Street, N.W., Washington, D.C.
20549, and at the regional offices of the Securities and Exchange Commission
located at Seven World Trade Center, 13th Floor, New York, NY 10048, and the
Northwestern Atrium Center, 500 West Madison Street, Suite 1400, Chicago,
Illinois 60661. Please call the Securities and Exchange Commission at 1-800-
SEC-0330 for further information about public reference rooms. You may obtain
copies of all or any part of our registration statement from the Securities and
Exchange Commission upon payment of prescribed fees. You may also inspect
reports, proxy, and information statements and other information regarding
registrants that file electronically with the Securities and Exchange
Commission without charge at a Web site maintained by the Securities and
Exchange Commission at http://www.sec.gov.

   Upon completion of this offering, Efficient will become subject to the
information and periodic reporting requirements of the Securities Exchange Act
and, accordingly, will file periodic reports, proxy statements and other
information with the Securities and Exchange Commission. Such periodic reports,
proxy statements and other information will be available for inspection and
copying at the Securities and Exchange Commission's public reference rooms, and
the Web site of the Securities and Exchange Commission referred to above.


                                       76
<PAGE>

                            EFFICIENT NETWORKS, INC.

                   INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----
<S>                                                                         <C>
Efficient Networks, Inc.
 Annual Financial Statements
  Independent Auditors' Report.............................................  F-2
  Consolidated Balance Sheets..............................................  F-3
  Consolidated Statements of Operations....................................  F-4
  Consolidated Statements of Stockholders' Equity (Deficit)................  F-5
  Consolidated Statements of Cash Flows....................................  F-6
  Notes to Consolidated Financial Statements...............................  F-7
 Interim Financial Statements
  Unaudited Condensed Consolidated Balance Sheets.......................... F-19
  Unaudited Condensed Consolidated Statements of Operations................ F-20
  Unaudited Condensed Consolidated Statements of Cash Flows................ F-21
  Notes to Unaudited Condensed Consolidated Financial Statements........... F-22
FlowPoint Corporation
  Independent Auditors' Report............................................. F-25
  Balance Sheets........................................................... F-26
  Statements of Operations................................................. F-27
  Statements of Cash Flows................................................. F-28
  Statements of Stockholders' Equity (Deficit)............................. F-29
  Notes to Financial Statements............................................ F-30
</TABLE>

                                      F-1
<PAGE>

                          Independent Auditors' Report

The Board of Directors
Efficient Networks, Inc.:

   We have audited the accompanying consolidated balance sheets of Efficient
Networks, Inc. and subsidiaries as of June 30, 1998 and 1999, and the related
consolidated statements of operations, stockholders' equity (deficit), and cash
flows for each of the years in the three-year period ended June 30, 1999. These
consolidated financial statements are the responsibility of the Company's
management. Our responsibility is to express an opinion on these consolidated
financial statements based on our audits.

   We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of
material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant
estimates made by management, as well as evaluating the overall financial
statement presentation. We believe that our audits provide a reasonable basis
for our opinion.

   In our opinion, the consolidated financial statements referred to above
present fairly, in all material respects, the financial position of Efficient
Networks, Inc. and subsidiaries as of June 30, 1998 and 1999, and the results
of their operations and their cash flows for each of the years in the three-
year period ended June 30, 1999, in conformity with generally accepted
accounting principles.

                                          KPMG LLP

Dallas, Texas
July 6, 1999, except as to
   note 13 which is as of
   July 20, 1999

                                      F-2
<PAGE>

                            EFFICIENT NETWORKS, INC.

                          Consolidated Balance Sheets

                             June 30, 1998 and 1999

                       (in thousands, except share data)

<TABLE>
<CAPTION>
                                                            June 30,
                                                   -----------------------------
                                                                      Pro forma
                                                                        1999
                                                    1998     1999    (unaudited)
                                                   -------  -------  -----------
<S>                                                <C>      <C>      <C>
                     Assets                                          (Note 2(l))
Current assets:
  Cash and cash equivalents......................  $ 7,607  $ 3,604  $    3,604
  Accounts receivable, net of allowance for
   doubtful accounts of $15 in 1998 and $120 in
   1999..........................................      461   12,334      12,334
  Inventories....................................      898    5,472       5,472
  Other assets...................................      202      241         241
                                                   -------  -------  ----------
    Total current assets.........................    9,168   21,651      21,651
Furniture and equipment, net.....................    1,404    2,285       2,285
Other assets, net................................       95       29          29
                                                   -------  -------  ----------
                                                   $10,667  $23,965  $   23,965
                                                   =======  =======  ==========
       Liabilities, Redeemable Convertible
     Preferred Stock and Stockholders' Equity
                    (Deficit)
Current liabilities:
  Accounts payable...............................  $   547  $ 5,689  $    5,689
  Accrued liabilities............................      751    2,641       2,641
  Deferred revenue...............................      --       736         736
                                                   -------  -------  ----------
    Total current liabilities....................    1,298    9,066       9,066
Long-term debt, net of discount..................      --    13,396         --
Other liabilities................................      --        22          22
                                                   -------  -------  ----------
    Total liabilities............................    1,298   22,484       9,088
                                                   -------  -------  ----------
Redeemable convertible preferred stock (note 7)..   34,743   40,495         --
Commitments and contingencies
Stockholders' equity (deficit):
  Common stock, par value $.001 per share,
   100,000,000 shares authorized; 3,616,964 and
   4,362,221 shares issued and outstanding in
   1998 and 1999, respectively; pro forma--
   32,662,288 shares issued and outstanding......        4        4          33
  Additional paid-in capital.....................    7,221   29,777      84,265
  Deferred stock option compensation.............   (4,815) (14,606)    (14,606)
  Accumulated deficit............................  (27,784) (54,189)    (54,815)
                                                   -------  -------  ----------
    Total stockholders' equity (deficit).........  (25,374) (39,014)     14,877
                                                   -------  -------  ----------
                                                   $10,667  $23,965  $   23,965
                                                   =======  =======  ==========
</TABLE>

See accompanying notes to consolidated financial statements.

                                      F-3
<PAGE>

                            EFFICIENT NETWORKS, INC.

                     Consolidated Statements of Operations

                    Years ended June 30, 1997, 1998 and 1999

                     (in thousands, except per share data)

<TABLE>
<CAPTION>
                                                     1997     1998      1999
                                                    -------  -------  --------
<S>                                                 <C>      <C>      <C>
Net revenues....................................... $ 4,122  $ 3,370  $ 14,828
Cost of revenues...................................   2,386    2,160    14,344
                                                    -------  -------  --------
    Gross profit...................................   1,736    1,210       484
                                                    -------  -------  --------
Operating expenses:
  Sales and marketing..............................   2,409    3,436     6,133
  Research and development.........................   4,183    4,389     7,747
  General and administrative.......................   1,245    1,641     1,993
  Stock option compensation........................     659    1,165     3,116
                                                    -------  -------  --------
    Total operating expenses.......................   8,496   10,631    18,989
                                                    -------  -------  --------
    Loss from operations...........................  (6,760)  (9,421)  (18,505)
Interest expense...................................     --       (10)   (8,092)
Interest income....................................     144      146       202
Other, net.........................................     (19)      (6)      (10)
                                                    -------  -------  --------
    Net loss....................................... $(6,635) $(9,291) $(26,405)
                                                    =======  =======  ========
    Basic and diluted net loss per share of common
     stock......................................... $ (2.19) $ (2.86) $  (6.87)
                                                    =======  =======  ========
    Weighted-average shares of common stock
     outstanding...................................   3,027    3,254     3,893
                                                    =======  =======  ========
    Unaudited pro forma basic and diluted net loss
     per share.....................................                   $  (0.97)
                                                                      ========
    Weighted average shares used to compute
     unaudited pro forma basic and diluted net loss
     per share.....................................                     28,342
                                                                      ========
</TABLE>


See accompanying notes to consolidated financial statements.

                                      F-4
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Consolidated Statements of Stockholders Equity (Deficit)

                    Years ended June 30, 1997, 1998 and 1999

                       (in thousands, except share data)

<TABLE>
<CAPTION>
                                                                                    Total
                            Common Stock    Additional   Deferred               stockholders'
                          -----------------  paid-in   stock option Accumulated    equity
                            Shares   Amount  capital   Compensation   deficit     (deficit)
                          ---------- ------ ---------- ------------ ----------- -------------
<S>                       <C>        <C>    <C>        <C>          <C>         <C>
Balance at June 30,
 1996...................   2,992,271  $  3   $ 1,439     $ (1,227)   $(11,858)    $(11,643)
 Issuance of common
  stock under stock
  option plan...........      62,500   --          9          --          --             9
 Deferred stock option
  compensation..........         --    --      2,269       (2,269)        --           --
 Amortization of
  deferred stock option
  compensation..........         --    --        --           659         --           659
 Net loss...............         --    --        --           --       (6,635)      (6,635)
                          ----------  ----   -------     --------    --------     --------
Balance at June 30,
 1997...................   3,054,771     3     3,717       (2,837)    (18,493)     (17,610)
 Issuance of common
  stock under stock
  option plan...........     448,125     1        61          --          --            62
 Issuance of common
  stock.................     114,068   --        300          --          --           300
 Deferred stock option
  compensation..........         --    --      3,143       (3,143)        --           --
 Amortization of
  deferred stock option
  compensation..........         --    --        --         1,165         --         1,165
 Net loss...............         --    --        --           --       (9,291)      (9,291)
                          ----------  ----   -------     --------    --------     --------
Balance at June 30,
 1998...................   3,616,964     4     7,221       (4,815)    (27,784)     (25,374)
 Issuance of common
  stock under stock
  option plan...........     745,257   --      1,683          --          --         1,683
 Stock options
  forfeited.............         --    --       (223)         223         --           --
 Issuance of warrants...         --    --      6,173          --          --         6,173
 Convertible promissory
  note..................         --    --      2,143          --          --         2,143
 Deferred stock option
  compensation..........         --    --     13,130      (13,130)        --           --
 Amortization of
  deferred stock option
  compensation..........         --    --        --         3,116         --         3,116
 Accretion of issuance
  costs on redeemable
  convertible preferred
  stock.................         --    --       (350)         --          --          (350)
 Net loss...............         --    --        --           --      (26,405)     (26,405)
                          ----------  ----   -------     --------    --------     --------
Balance at June 30,
 1999...................   4,362,221     4    29,777      (14,606)    (54,189)     (39,014)
 Unaudited pro forma
  issuance of common
  stock upon conversion
  of redeemable
  convertible preferred
  stock.................  24,720,213    25    40,470          --          --        40,495
 Unaudited pro forma
  issuance of common
  stock upon conversion
  of convertible
  promissory note plus
  accrued interest......     497,663     1     5,021          --          (22)       5,000
 Unaudited pro forma net
  loss related to
  accretion of remaining
  discount on
  subordinated
  promissory notes......         --    --        --           --         (604)        (604)
 Unaudited pro forma
  issuance of common
  stock upon exercise of
  warrants..............   3,082,191     3     8,997          --          --         9,000
                          ----------  ----   -------     --------    --------     --------
Unaudited pro forma
 balance at June 30,
 1999...................  32,662,288  $ 33   $84,265     $(14,606)   $(54,815)    $ 14,877
                          ==========  ====   =======     ========    ========     ========
</TABLE>

See accompanying notes to consolidated financial statements.

                                      F-5
<PAGE>

                            EFFICIENT NETWORKS, INC.

                     Consolidated Statements of Cash Flows

                    Years ended June 30, 1997, 1998 and 1999

                                 (in thousands)

<TABLE>
<CAPTION>
                                                     1997     1998      1999
                                                    -------  -------  --------
<S>                                                 <C>      <C>      <C>
Cash flows from operating activities:
 Net loss.......................................... $(6,635) $(9,291) $(26,405)
 Adjustments to reconcile net loss to net cash used
  in operating activities:
  Depreciation and amortization....................     861      727       807
  Amortization of deferred stock option
   compensation....................................     659    1,165     3,116
  Accretion of discount on subordinated promissory
   notes...........................................     --       --      7,712
Changes in operating assets and liabilities:
  Accounts receivable..............................     (12)     318   (11,873)
  Inventories......................................     443     (304)   (4,574)
  Other assets and liabilities.....................      59     (201)       49
  Accounts payable and accrued liabilities.........     (18)     967     7,043
  Deferred revenue.................................     --       --        736
                                                    -------  -------  --------
Net cash used in operating activities..............  (4,643)  (6,619)  (23,389)
                                                    -------  -------  --------
Cash flows used in investing activities--purchase
 of furniture and equipment........................    (525)    (572)   (1,688)
                                                    -------  -------  --------
Cash flows from financing activities:
 Principal payments on capital lease obligations...    (192)     (78)      (11)
 Proceeds from issuance of promissory notes and
  warrants.........................................   1,500    1,000    14,000
 Proceeds from issuance of common stock............       9      362     1,683
 Proceeds from issuance of preferred stock.........   5,961   10,101     5,402
                                                    -------  -------  --------
   Net cash provided by financing activities.......   7,278   11,385    21,074
                                                    -------  -------  --------
Increase (decrease) in cash and cash equivalents...   2,110    4,194    (4,003)
Cash and cash equivalents at beginning of year.....   1,303    3,413     7,607
                                                    -------  -------  --------
Cash and cash equivalents at end of year........... $ 3,413  $ 7,607  $  3,604
                                                    =======  =======  ========
Supplemental disclosure--cash paid during the year
 for:
 Interest.......................................... $     6  $     4  $    --
                                                    =======  =======  ========
Non-cash financing transaction--
 Exchange of promissory notes and related interest
  for redeemable convertible preferred stock....... $ 1,519  $ 1,007  $    --
                                                    =======  =======  ========
</TABLE>

See accompanying notes to consolidated financial statements.

                                      F-6
<PAGE>

                            EFFICIENT NETWORKS, INC.

                   Notes to Consolidated Financial Statements

                          June 30, 1997, 1998 and 1999

(1)Incorporation and Nature of Business

  Efficient Networks, Inc. (the "Company") was incorporated under the laws of
  the State of Delaware on June 10, 1993. The Company is a worldwide
  developer and supplier of high speed digital subscriber line customer
  premises equipment for the high speed, high volume digital communication,
  or broadband, access market.

(2)Summary of Significant Accounting Policies

  (a)Principles of Consolidation

    The consolidated financial statements include the accounts of the
    Company and its wholly-owned subsidiaries located in The Netherlands
    and Singapore. All significant intercompany accounts and transactions
    have been eliminated in consolidation.

  (b)Cash Equivalents

    Cash equivalents consist primarily of an investment account comprised
    of investments in commercial paper, repurchase agreements and money
    market funds. For purposes of the statements of cash flows, the Company
    considers all highly liquid investments with original maturities of
    three months or less to be cash equivalents.

  (c)Inventories

    Inventories are stated at the lower of average cost or market (net
    realizable value).

  (d)Furniture and Equipment

    Furniture and equipment are stated at cost. Equipment under capital
    leases is stated at the present value of minimum lease payments.

    Depreciation on plant and equipment is calculated on the straight-line
    method over the estimated useful lives of the assets. Plant and
    equipment held under capital leases and leasehold improvements are
    amortized on a straight-line basis over the shorter of the lease term
    or estimated useful life of the asset. The estimated useful lives are
    as follows:

<TABLE>
<CAPTION>
                                                    Years
                                                    -----
            <S>                                     <C>
            Computers..............................    5
            Software...............................    3
            Equipment..............................    5
            Furniture and fixtures.................    7
</TABLE>

  (e)Income Taxes

    Income taxes are accounted for under the asset and liability method.
    Deferred tax assets and liabilities are recognized for the future tax
    consequences attributable to differences between the financial
    statement carrying amounts of existing assets and liabilities and their
    respective tax bases and operating loss and tax credit carryforwards.
    Deferred tax assets and liabilities are measured using enacted tax
    rates expected to apply to taxable income in the years in which those
    temporary

                                      F-7
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Notes to Consolidated Financial Statements--(continued)

                          June 30, 1997, 1998 and 1999

    differences are expected to be recovered or settled. The effect on
    deferred tax assets and liabilities of a change in tax rates is
    recognized in income in the period that includes the enactment date.

  (f)Revenue Recognition

    Revenue from product sales is recognized upon shipment to the customer.
    Reserves for estimated sales returns and allowances are recorded in the
    same period as the related revenues. Revenue related to sales
    transactions that provide a customer with the right to return product
    is deferred until the product is deployed by the customer and/or the
    return privileges expire.

  (g)Stock-Based Compensation

    The Company applies the intrinsic value-based method of accounting
    prescribed by Accounting Principles Board ("APB") Opinion No. 25,
    Accounting for Stock Issued to Employees, and related interpretations,
    in accounting for its fixed plan stock options. As such, compensation
    expense is recorded on the date of grant only if the current market
    price of the underlying stock exceeds the exercise price.

  (h)Impairment of Long-Lived Assets and Long-Lived Assets to Be Disposed

    Long-lived assets and certain identifiable intangibles are reviewed for
    impairment whenever events or changes in circumstances indicate that
    the carrying amount of an asset may not be recoverable. Recoverability
    of assets to be held and used is measured by a comparison of the
    carrying amount of an asset to future net cash flows expected to be
    generated by the asset. Assets to be disposed of are reported at the
    lower of the carrying amount or fair value less costs to sell.

  (i)Net Loss Per Share of Common Stock

    Net loss per share of common stock is presented in accordance with the
    provisions of Statement of Financial Accounting Standards ("SFAS") No.
    128, Earnings Per Share. Under SFAS No. 128, basic earnings/loss per
    share excludes dilution for potentially dilutive securities and is
    computed by dividing income or loss available to common stockholders by
    the weighted average number of common shares outstanding during the
    period. Diluted earnings/loss per share reflects the potential dilution
    that could occur if securities or other contracts to issue common stock
    were exercised or converted into common stock. Potentially dilutive
    securities are excluded from the computation of diluted earnings/loss
    per share when their inclusion would be antidilutive. The computation
    of basic and diluted weighted average shares is as follows (in
    thousands):

<TABLE>
<CAPTION>
                                                       Year ended June 30,
                                                     --------------------------
                                                      1997     1998      1999
                                                     -------  -------  --------
     <S>                                             <C>      <C>      <C>
     Numerator:
       Net loss....................................  $(6,635) $(9,291) $(26,405)
       Accretion of issuance costs on redeemable
        convertible preferred stock................      --       --       (350)
                                                     -------  -------  --------
       Numerator for basic and diluted net loss per
        share......................................  $(6,635) $(9,291) $(26,755)
                                                     =======  =======  ========
     Denominator for basic and diluted net loss per
      share--weighted average common shares
      outstanding..................................    3,027    3,254     3,893
                                                     =======  =======  ========
</TABLE>

                                      F-8
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Notes to Consolidated Financial Statements--(continued)

                          June 30, 1997, 1998 and 1999


    Pro forma basic and diluted net loss per share has been calculated
    assuming: (a) the conversion of redeemable convertible preferred stock
    outstanding at June 30, 1999, as if the redeemable convertible
    preferred stock had converted immediately upon its issuance, resulting
    in 23,332,713 additional weighted average shares of common stock
    outstanding; (b) the warrants issued in 1999 in connection with the
    issuance of subordinated promissory notes were exercised immediately
    upon their issuance using the principal amount of the notes to satisfy
    the exercise price, resulting in 1,113,014 additional weighted average
    shares of common stock outstanding and a charge of $603,806 against
    earnings for the accretion of the remaining discount recorded on the
    notes; and (c) the convertible debt issued June 28, 1999, was converted
    immediately upon issuance resulting in 2,727 additional weighted
    average shares of common stock outstanding.

  (j)Fair Value of Financial Instruments

    The carrying values of cash equivalents, accounts receivable and
    accounts payable approximate fair value due to their short maturities.
    The fair values of the Company's convertible promissory notes and
    subordinated promissory notes and related warrants were determined
    using a valuation model with the following assumptions: a volatility
    factor of 40% obtained from the stock price volatility experienced by
    certain of the Company's principal competitors; a risk-free interest
    rate of 5.71%; the contractual term of the respective notes; the
    estimated fair value of the Company's common stock ($12.00 at June 30,
    1999); and the exercise price of the detachable warrants. The estimated
    fair values of the convertible promissory notes and subordinated
    promissory notes and related warrants as of June 30, 1999 are
    approximately $6,802,691 and $40,294,044 respectively.

  (k)Comprehensive Income

    On July 1, 1998, the Company adopted SFAS No. 130, Reporting
    Comprehensive Income, which establishes standards for reporting and
    presentation of comprehensive income and its components in the
    financial statements. Comprehensive income includes all changes in
    equity during a period except those resulting from investments by and
    distributions to owners. To date, no elements of comprehensive income
    exist other than net loss from operations.

  (l)Pro Forma Balance Sheet

    The pro forma balance sheet reflects the following transactions as
    though they had occurred as of June 30, 1999 (see notes 6 and 7):

    .  the conversion of $9,000,000 of subordinated promissory notes into
       an aggregate of 3,082,191 shares of redeemable convertible preferred
       stock through the exercise of the warrants issued therewith,

    .  the conversion of the $5,000,000 convertible promissory note plus
       accrued interest into an aggregate of 497,663 shares of redeemable
       convertible preferred stock, and

    .  the conversion of each outstanding share of redeemable convertible
       preferred stock into one share of common stock.

  (m)Use of Estimates

    Management of the Company has made a number of estimates and
    assumptions relating to the reporting of assets and liabilities and the
    disclosure of contingent assets and liabilities at the date of

                                      F-9
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Notes to Consolidated Financial Statements--(continued)

                          June 30, 1997, 1998 and 1999

    the financial statements and the reported amounts of revenue and
    expenses during the reporting period to prepare these financial
    statements in conformity with generally accepted accounting principles.
    Actual results could differ from those estimates.

(3)Inventories

  Inventories consisted of the following (in thousands):

<TABLE>
<CAPTION>
                                                                      June 30,
                                                                     -----------
                                                                     1998  1999
                                                                     ---- ------
   <S>                                                               <C>  <C>
   Raw materials.................................................... $354 $2,265
   Finished goods...................................................  544  3,207
                                                                     ---- ------
   Total............................................................ $898 $5,472
                                                                     ==== ======
</TABLE>

(4)Furniture and Equipment

  Furniture and equipment consisted of the following (in thousands):

<TABLE>
<CAPTION>
                                                                   June 30,
                                                                 --------------
                                                                  1998    1999
                                                                 ------  ------
   <S>                                                           <C>     <C>
   Computers.................................................... $1,941  $2,811
   Purchased software...........................................    611     892
   Equipment....................................................    241     585
   Furniture and fixtures.......................................     66     136
   Leasehold improvements.......................................    121     235
                                                                 ------  ------
   Total furniture and equipment................................  2,980   4,659
   Less accumulated depreciation and amortization............... (1,576) (2,374)
                                                                 ------  ------
   Furniture and equipment, net................................. $1,404  $2,285
                                                                 ======  ======
</TABLE>

  The Company leases certain equipment under capital lease arrangements. At
  June 30, 1998, the cost of assets under such leases aggregated $152,183,
  and related accumulated amortization was $134,065. At June 30, 1999, there
  were no assets under capital lease arrangements. Amortization of assets
  leased under capital lease arrangements is included in amortization
  expense.

(5)Accrued Liabilities

  Accrued liabilities consisted of the following (in thousands):

<TABLE>
<CAPTION>
                                                                     June 30,
                                                                    -----------
                                                                    1998  1999
                                                                    ---- ------
   <S>                                                              <C>  <C>
   Accrued compensation and benefits............................... $247 $1,102
   Accrued professional fees.......................................  320     55
   Other...........................................................  184  1,484
                                                                    ---- ------
   Total........................................................... $751 $2,641
                                                                    ==== ======
</TABLE>

                                      F-10
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Notes to Consolidated Financial Statements--(continued)

                          June 30, 1997, 1998 and 1999


(6)Long-term Debt

  In January 1999, the Company issued subordinated promissory notes with
  detachable warrants in exchange for $7,000,000 in cash. In April 1999, the
  Company issued a subordinated promissory note with a detachable warrant in
  exchange for $2,000,000 in cash. The notes bear interest of 10% per year
  and interest is payable quarterly. The notes are due at the earlier of
  January 2002 or (a) a consummation of a qualifying liquidation event which
  includes a firm commitment underwritten offering pursuant to a registration
  statement under the Securities Act of 1933, the public offering price of
  which is not less than $5.00 per share and $10,000,000 in the aggregate;
  (b) any consolidation or merger of the Company with or into any other
  corporation or corporations; (c) sale, conveyance or disposition of all or
  substantially all of the assets of the Company; or (d) the effectuation by
  the Company of a transaction or series of related transactions in which
  more than 50% of the voting power of the Company is disposed.

  The subordinated promissory notes were issued with detachable warrants to
  purchase an aggregate of 3,082,191 shares of the Company's Series H
  redeemable convertible preferred stock at an exercise price of $2.92 per
  share. The warrants expire at the earlier of January 2002 or the
  consummation by the Company of the sale of its common stock in a firm
  commitment underwritten offering at a price not less than $5.00 per share
  and providing not less than $10,000,000 of net proceeds. The proceeds were
  allocated between the notes and the warrants based on their pro-rata fair
  values, as determined using a valuation model (see note 2(j)). As a result,
  the warrants were valued at $6,172,699. This amount was recorded as paid-in
  capital. The resulting discount on the notes is being accreted as interest
  expense over the expected term of the related promissory notes. The holders
  of the subordinated promissory notes have entered into a note repayment and
  warrant exercise agreement with the Company which stipulates that
  immediately prior to the closing of an initial public offering, the
  aggregate $9,000,000 principal amount of the notes will be applied toward
  the aggregate exercise price of the detachable warrants (see note 13).

  On June 28, 1999, the Company issued a convertible promissory note in
  exchange for $5,000,000 in cash. The note bears interest of 8.0% per year.
  The holder of the note has the right to demand prepayment of 50% of the
  principal amount of the note at any time after the first anniversary and
  full prepayment at any time after the second anniversary of issuance. The
  note is convertible at the holder's option into shares of Series I
  preferred stock at a conversion price of $10.09 per share of Series I
  preferred stock. Upon the completion of an initial public offering, the
  note will automatically convert into Series I preferred stock at a
  conversion price equal to the lesser of (1) 70% of the initial public
  offering price per share or (2) $10.09 per share. Upon the issuance of the
  convertible promissory note, the Company recognized $2,143,000 of interest
  expense and a corresponding increase to additional paid-in capital. This
  amount represents the intrinsic value of the beneficial conversion feature
  of the convertible promissory note (see note 13).

(7)Redeemable Convertible Preferred Stock

  Preferred stock has voting rights equal to the number of shares of common
  stock into which the preferred stock is convertible. The preferred stock is
  convertible at the option of the holder into such number of shares of
  common stock as is determined by dividing the original issue price of the
  preferred stock plus all declared but unpaid dividends by the applicable
  conversion price at the date of conversion. The conversion price per share
  is the original issue price adjusted for any dilution that may occur from
  future offerings.

  Each share of outstanding preferred stock is required to convert to common
  stock upon the earlier of the time of the Company's initial public
  offering, if certain offering parameters are met, or the date on which

                                      F-11
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Notes to Consolidated Financial Statements--(continued)

                          June 30, 1997, 1998 and 1999

  the Company obtains the consent of the holders of a majority of the then
  outstanding shares of preferred stock.

  The outstanding preferred stock is redeemable into cash at the request of a
  majority of the holders of the then outstanding shares of preferred stock
  at an amount equal to the original issue price plus all declared but unpaid
  dividends. Amounts due to the preferred shareholders on redemption are
  payable in three equal annual installments on the fifth, sixth and seventh
  anniversaries of the original purchase dates (see note 13).

  Dividends may be declared at the sole discretion of the Board of Directors
  and are noncumulative. To date, no such dividends have been declared. The
  holders of the preferred stock are entitled to a liquidation preference
  equivalent to the original issue price of the respective series of
  preferred stock plus declared but unpaid dividends.

  The following indicates the series of redeemable convertible preferred
  stock in existence at June 30, 1999. Series for which preferred stock has
  been issued and remains outstanding are stated at the redemption amount;
  issuance costs are netted against the proceeds and accreted as a charge
  against additional paid-in capital over the expected life of the related
  series of preferred stock (all in thousands, except share and per share
  data):

<TABLE>
<CAPTION>
                                                      Dividend    June 30,
                                                      Rate Per ----------------
                                                       Share    1998     1999
                                                      -------- -------  -------
   <S>                                                <C>      <C>      <C>
   Series A - 7,096,000 shares authorized; 7,000,000
    shares issued and outstanding...................   $0.03   $ 3,500  $ 3,500
   Series B - 522,848 shares authorized, issued and
    outstanding.....................................   $0.07       625      625
   Series C - 5,895,832 shares authorized; 5,858,332
    shares issued and outstanding...................   $0.07     7,030    7,030
   Series D - 2,473,644 shares authorized, issued
    and outstanding.................................   $0.12     5,000    5,000
   Series E - 3,091,430 shares authorized, issued
    and outstanding.................................   $0.15     7,480    7,480
   Series F - 2,057,159 shares authorized, issued
    and outstanding in 1998 and 1999................   $0.18     6,007    6,007
   Series G - 6,000,000 shares authorized; 1,866,800
    and 3,716,800 shares issued and outstanding in
    1998 and 1999...................................   $0.18     5,451   10,853
   Series H - 4,000,000 shares authorized, none
    issued or outstanding...........................   $0.18       --       --
   Series I - 750,000 shares authorized, none issued
    or outstanding..................................   $0.60       --       --
   Issuance costs, net of accretion.................              (350)     --
                                                               -------  -------
                                                               $34,743  $40,495
                                                               =======  =======
</TABLE>

  The Company issued promissory notes in exchange for cash of $1,000,000 and
  $500,000 in September and December, 1996, respectively. The promissory
  notes bore interest at 6% and were due on demand. On December 31, 1996, the
  Company issued 3,091,430 shares of Series E redeemable convertible
  preferred stock in exchange for the principal and related accrued interest
  on the promissory notes amounting to $1,518,657 and $5,961,498 in cash.

  The Company issued promissory notes in exchange for $1,000,000 in January,
  1998. The promissory notes bore interest at 6% and were due on demand. In
  February, 1998, the Company issued 2,057,159 shares of

                                      F-12
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Notes to Consolidated Financial Statements--(continued)

                          June 30, 1997, 1998 and 1999

  Series F redeemable convertible preferred stock in exchange for the
  principal and related accrued interest on the promissory notes amounting to
  $1,006,904 and $5,000,000 in cash.

  In June, 1998, the Company issued 1,866,800 shares of Series G redeemable
  convertible preferred stock for $5,451,056 in cash. The issuance was
  recorded net of issuance costs of $350,000. In March, 1999, the Company
  issued an additional 1,850,000 shares of Series G redeemable convertible
  preferred stock for $5,402,000 in cash (see note 13).

(8)Common Stock and Stock Incentive Plans

  In 1993, the Company adopted a stock option plan (the "Plan") pursuant to
  which the Company's Board of Directors may grant stock options to officers,
  directors and key employees. The Plan authorizes grants of options to
  purchase up to 10,000,000 shares of unissued common stock. The Board of
  Directors determines the terms of each option, including exercise price
  (within limits set forth in the plan), number of shares and the rate at
  which each option is exercisable. The options generally vest ratably over a
  period of four years from the date of grant.

  In 1998, the Company adopted the Directors' Stock Option Plan (the
  "Directors' Plan") pursuant to which stock options may be granted to non-
  employee members of the Company's Board of Directors. The Directors' Plan
  authorizes grants of options to purchase up to 275,000 shares of common
  stock.

  Option grants under the Directors' Plan are nondiscretionary and automatic.
  Non-employee directors serving on the Company's board of directors at the
  date of the adoption of the Directors' Plan were granted options to
  purchase 50,000 shares on the effective date of the plan. Subsequent non-
  employee directors are granted an option to purchase 15,000 shares on the
  date they become a director. After their initial grant, non-employee
  directors are granted an option to purchase 15,000 shares on January 1 of
  each year provided they have served on the board for at least six months.
  At June 30, 1999, there were options to purchase 75,000 shares available
  for grant under the Directors' Plan.

  At June 30, 1999, there were options to purchase 2,369,853 shares available
  for grant under both plans. The per share weighted-average fair value of
  stock options granted during each of the years ended June 30, 1997, 1998
  and 1999 was $2.09, $2.60, and $5.17, respectively, on the date of grant as
  estimated using the minimum value option-pricing model with the following
  weighted-average assumptions in all years: expected dividend yield of 0.0%,
  an expected life of four years, and a risk-free interest rate of 6%.

  The Company applies APB Opinion No. 25 in accounting for stock options
  granted to employees and non-employee directors under its stock option
  plans. The Company recorded $2,269,000, $3,143,000 and $13,130,000 of
  deferred stock option compensation during each of the years ended June 30,
  1997, 1998 and 1999, respectively, as a result of granting stock options
  with exercise prices below the estimated fair value per share of the
  Company's common stock at the date of grant. Deferred stock option
  compensation has been recorded as a component of stockholders' equity
  (deficit) and is being amortized as a charge to operations over the vesting
  period of the applicable options. Amortization of deferred stock option
  compensation of $659,000, $1,165,000 and $3,116,000 was recognized in the
  years ended June 30, 1997, 1998 and 1999, respectively.

                                      F-13
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Notes to Consolidated Financial Statements--(continued)

                          June 30, 1997, 1998 and 1999


  Had the Company determined compensation cost based on the estimated fair
  value of stock options at the grant date in accordance with SFAS No. 123,
  the Company's net loss would have been increased or decreased, as
  applicable, to the pro forma amounts indicated below:

<TABLE>
<CAPTION>
                                                     Year ended June 30,
                                                   --------------------------
                                                    1997     1998      1999
                                                   -------  -------  --------
   <S>                                             <C>      <C>      <C>
   Net loss:
     As reported.................................. $(6,635) $(9,291) $(26,405)
     Pro forma.................................... $(6,680) $(9,687) $(26,187)
   Basic and diluted net loss per share of common
    stock:
     As reported.................................. $ (2.19) $ (2.86) $  (6.87)
     Pro forma.................................... $ (2.21) $ (2.98) $  (6.82)
</TABLE>

  Pro forma net loss reflects only stock options granted after June 30, 1995.
  Therefore, the full impact of calculating compensation cost for stock
  options under SFAS No. 123 is not reflected in the pro forma net loss
  amounts presented above because compensation cost is reflected over the
  options' vesting periods of four years and compensation expense pertaining
  to stock options granted in prior periods is not considered.

  Stock option activity for both plans during the periods indicated is as
  follows:

<TABLE>
<CAPTION>
                                                                        Weighted
                                                                        Average
                                                             Number of  Exercise
                                                              Shares     Price
                                                             ---------  --------
   <S>                                                       <C>        <C>
   Balance at June 30, 1996................................. 2,396,500   $0.11
       Granted.............................................. 1,716,883    0.24
       Exercised............................................   (62,500)   0.15
       Forfeited............................................  (454,883)   0.15
                                                             ---------
   Balance at June 30, 1997................................. 3,596,000    0.19
       Granted.............................................. 1,631,000    0.58
       Exercised............................................  (448,125)   0.12
       Forfeited............................................  (344,458)   0.22
                                                             ---------
   Balance at June 30, 1998................................. 4,434,417    0.46
       Granted.............................................. 2,638,500    2.88
       Exercised............................................  (745,257)   2.24
       Forfeited............................................  (195,666)   1.01
                                                             ---------
   Balance at June 30, 1999................................. 6,131,994    1.39
                                                             =========
</TABLE>

  Options granted during the years ended June 30, 1997, 1998 and 1999 had an
  exercise price less than the estimated fair value of the Company's common
  stock on the date of grant; the weighted-average grant-date fair value of
  options granted during those periods was $1.37, $2.10 and $7.89,
  respectively.

                                      F-14
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Notes to Consolidated Financial Statements--(continued)

                          June 30, 1997, 1998 and 1999


   The following presents certain information about outstanding stock options
at June 30, 1999:

<TABLE>
<CAPTION>
                                   Options Outstanding       Options Exercisable
                             ------------------------------- ---------------------
                                                  Weighted               Weighted
                                                   average                Average
                               Number   Exercise contractual Number of   Exercise
   Range of exercise price   of options  price      life      Options      Price
   -----------------------   ---------- -------- ----------- ----------- ---------
   <S>                       <C>        <C>      <C>         <C>         <C>
   $0.05-0.25..............  2,216,535   $0.19    6.7 years    1,648,075  $  0.18
   $0.50-0.60..............  1,501,459   $0.58    8.7 years      469,529  $  0.58
   $1.50-2.50..............  2,324,000   $2.22    9.5 years          --       --
   $7.50-10.50.............     90,000   $8.00    9.8 years          --       --
</TABLE>

  At June 30, 1997, 1998 and 1999, the number of options exercisable was
  1,224,042, 1,625,531 and 2,117,604, respectively, and the weighted-average
  exercise price of those options was $0.15, $0.21 and $0.33, respectively.

  In May 1999, the Company effected the issuance of 150,000 shares of common
  stock to a board member-elect, in exchange for a $1,575,000, 6% demand
  note. The demand note was repaid with interest in July 1999.

(9)Research and Development Arrangements

  In October 1997, the Company entered into a development and license
  agreement with a customer who owns preferred stock of the Company. The
  agreement obligated the Company to develop a product that meets mutually
  agreed upon specifications in exchange for $850,000. The Company has
  fulfilled its development obligations and the proceeds under the
  arrangement were offset against research and development expense during the
  year ended June 30, 1998.

  In November 1997, the Company entered into a development and marketing
  agreement with a customer. The agreement obligated the Company to develop a
  product in accordance with certain specifications and to provide 114,068
  shares of the Company's common stock for an aggregate purchase price of
  $300,000. The common stock issuance was recorded at estimated fair value of
  $300,000. The Company has fulfilled its development obligations.

(10)Lease Commitments

  The Company has operating lease agreements relating to certain facilities
  and equipment which expire at various dates. Rent expense on operating
  leases for the years ended June 30, 1997, 1998, and 1999 was $367,308,
  $380,794 and $547,774, respectively. The Company entered into several
  agreements for the sale and leaseback of certain equipment. The leases were
  classified as capital leases and expired during the year ended June 30,
  1999. Future minimum lease payments under noncancelable operating leases as
  of June 30, 1999 are:

<TABLE>
<CAPTION>
                                                                       Operating
                                                                        Leases
                                                                       ---------
     <S>                                                               <C>
     Years ended June 30:
       2000........................................................... $417,097
       2001...........................................................  329,765
       2002...........................................................  124,327
       2003...........................................................   35,955
       2004...........................................................    5,993
                                                                       --------
         Total minimum lease payments................................. $913,137
                                                                       ========
</TABLE>

                                      F-15
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Notes to Consolidated Financial Statements--(continued)

                          June 30, 1997, 1998 and 1999


  In connection with certain capital lease transactions, the Company issued
  warrants to purchase (a) 96,000 shares of Series A preferred stock at $0.50
  per share expiring on the earlier of December 16, 2003 or the fifth annual
  anniversary of the consummation of the Company's initial public offering of
  its common stock, if certain offering parameters are met, and (b) 37,500
  shares of its Series C preferred stock at $1.20 per share expiring on the
  later of March 13, 2005 or five years from the effective date of the
  Company's initial public offering.

(11)Income Taxes

  The Company has not recognized any tax benefits for its net operating loss
  carryforwards.

  Net deferred tax assets as of June 30, 1998 and 1999 are as follows (in
  thousands):

<TABLE>
<CAPTION>
                                                               1998      1999
                                                              -------  --------
     <S>                                                      <C>      <C>
     Deferred tax assets:
       Operating loss carryforwards.......................... $ 8,943  $ 17,275
       Receivables and inventory reserves....................      59       136
       Accrued liabilities...................................      87       233
                                                              -------  --------
         Deferred tax assets.................................   9,089    17,644
         Valuation allowance.................................  (8,892)  (17,444)
                                                              -------  --------
                                                                  197       200
     Deferred tax liability -- furniture and equipment.......    (197)     (200)
                                                              -------  --------
         Net deferred tax assets............................. $   --   $    --
                                                              =======  ========
</TABLE>

  The net change in the valuation allowance for the years ended June 30, 1998
  and 1999 was $3,073,000 and $8,133,000 respectively.

  As of June 30, 1999, the Company has net operating loss carryforwards of
  approximately $48,000,000 which begin to expire in 2008. The Company
  believes that as a result of the Company's initial public offering in July
  1999, and the resulting conversion of outstanding redeemable preferred
  stock into common stock, the Company has undergone an ownership change
  within the meaning of section 382 of the Internal Revenue Code (IRC). As a
  result, the Company's ability to utilize its operating loss carryforwards
  incurred prior to the ownership change are limited on an annual basis to an
  amount equal to the value of the Company, as defined by the IRC, as of the
  date of change of ownership, multiplied by the long-term tax-exempt rate of
  4.98%.

(12)Segment Information and Concentration of Credit Risk

  The Company operates in one reportable segment as it has one family of DSL
  products and markets its products to network equipment vendors and DSL
  service providers. In fiscal years 1997 and 1998, the Company also
  developed and marketed asynchronous transfer mode ("ATM") network products
  which are no longer actively marketed by the Company. For management
  purposes, the Company does not disaggregate financial information by
  product or geographically, other than export sales by region and sales by
  product. Substantially all of the Company's assets are located within the
  United States. The Company does not account for, and does not report to
  management, its assets or capital expenditures by revenue source. All of
  the Company's products are produced in the United States. The Company
  grants credit to customers located in several geographical regions in North
  America, Europe and the Pacific Rim.

                                      F-16
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Notes to Consolidated Financial Statements--(continued)

                          June 30, 1997, 1998 and 1999


  The following represents sales to customers in each of those geographical
  regions as a percentage of total revenues, and revenues and gross margins
  by product line for the years ended June 30, 1997, 1998 and 1999:

<TABLE>
<CAPTION>
     Geographic Region                                 1997    1998    1999
     -----------------                                ------  ------  -------
     <S>                                              <C>     <C>     <C>
     United States...................................     65%     48%      59%
     Europe..........................................     25%     40%      12%
     Pacific Rim.....................................     10%     12%      29%

<CAPTION>
     Product line (in thousands)                       1997    1998    1999
     ---------------------------                      ------  ------  -------
     <S>                                              <C>     <C>     <C>
     DSL revenues.................................... $  --   $   84  $12,915
     DSL gross margin................................ $  --   $  (19) $  (462)
     ATM LAN revenues................................ $4,122  $3,286  $ 1,913
     ATM LAN gross margin............................ $1,736  $1,229  $   946
</TABLE>

  For the year ended June 30, 1997, revenues from an individual customer
  amounted to 38% of total revenue. For the year ended June 30, 1998,
  revenues from individual customers amounted to 20% and 13% of total
  revenues. For the year ended June 30, 1999, revenues from individual
  customers amounted to 30% and 18% of total revenues, and accounts
  receivable related to these customers at June 30, 1999 was approximately
  $2,875,000 and $2,600,000, respectively. The Company performs ongoing
  evaluations of its customers' financial conditions and generally does not
  require collateral.

(13)Subsequent Event

  On July 15, 1999, the Company completed the initial public offering of its
  common stock. The Company issued 4,600,000 shares of common stock in
  exchange for gross proceeds of $69,000,000, net of underwriters' discount
  of $4,830,000. Upon the completion of the initial public offering, the
  Company's subordinated promissory notes converted into 3,082,191 shares of
  Series H redeemable convertible preferred stock, the convertible promissory
  note plus accrued interest converted into 497,663 shares of Series I
  redeemable convertible preferred stock, and all outstanding redeemable
  convertible preferred stock converted into 28,300,067 shares of common
  stock.

  On July 20, 1999, the Company adopted a new stock option plan (the "Stock
  Plan") and an employee stock purchase plan. The Stock Plan provides for the
  granting of stock options and stock purchase rights to employees and
  consultants. A total of 3,500,000 shares of common stock has been reserved
  for issuance plus annual increases equal to the lesser of:

  .  1,000,000 shares;

  .  3% of the outstanding shares on such a date; or

  .  a lesser amount determined by the board on the first day of each fiscal
     year.

  The Stock Plan may be administered by the board of directors or a committee
  of the board. The board or a committee of the board will have the power to
  determine the terms of the options granted, including the exercise price,
  the number of shares subject to each option, the vesting provisions, the
  exercisability thereof and the form of consideration payable upon such
  exercise.

  The Stock Plan provides that in the event of a merger of the Company with
  or into another corporation, or the sale of substantially all of its
  assets, each outstanding option or stock purchase right will be assumed

                                      F-17
<PAGE>

                            EFFICIENT NETWORKS, INC.

            Notes to Consolidated Financial Statements--(continued)

                          June 30, 1997, 1998 and 1999

  or substituted for by the successor corporation. In addition, if the
  options are not substituted for in the merger, each outstanding option will
  vest and become exercisable as to all unvested shares and each stock
  purchase right shall lapse as to all the shares for a period of 15 days
  after receipt of notice from the Company.

  On July 20, 1999, the Company also adopted an Employee Stock Purchase Plan
  ("the Purchase Plan"). A total of 200,000 shares of common stock has been
  reserved for issuance under the purchase plan, plus annual increases equal
  to the lesser of:

  .  100,000 shares;

  .  1% of the outstanding shares on such a date; or

  .  a lesser amount determined by the board on the first day of each fiscal
     year.

  The Purchase Plan, which is intended to qualify under Section 423 of the
  Internal Revenue Code of 1986, as amended, contains successive six-month
  offering periods. The offering periods generally start on the first trading
  day on or after May 1 and November 1 of each year, except for the first
  such offering period which commenced on the first trading day after the
  effective date of the Company's initial public offering and ends on the
  last trading day on or before October 31.

  Employees are eligible to participate if they are employed by the Company
  or any of its participating subsidiaries for at least 20 hours per week and
  more than five months in any calendar year. However, the following
  employees may not purchase stock under the Purchase Plan:

  .  any employee who immediately after grant owns stock possessing 5% or
     more of the total combined voting power or value of all classes of
     capital stock; or

  .  any employee whose rights to purchase stock under any of the employee
     stock purchase plans accrue at a rate that exceeds $25,000 worth of
     stock for each calendar year.

  Participants may purchase common stock through deductions of up to 10% of
  the participant's compensation. The maximum number of shares a participant
  may purchase during a single offering period is 500 shares.

  Amounts deducted and accumulated by the participant will be used to
  purchase shares of common stock at the end of each offering period. The
  price of stock purchased under the Purchase Plan is 85% of the lower of the
  fair market value of the common stock at the beginning of the offering
  period and at the end of each offering period.

  The Purchase Plan provides that, in the event of a merger of the Company
  with or into another corporation or a sale of substantially all of its
  assets, outstanding options may be assumed or substituted for by the
  successor corporation. If the successor corporation refuses to assume or
  substitute for the outstanding options, the offering period then in
  progress will be shortened and a new exercise date will be set, which will
  occur before the proposed sale or merger.

  The Purchase Plan will terminate in 2009. The board of directors has the
  authority to amend or terminate the Purchase Plan, except that no such
  action may adversely affect any outstanding rights to purchase stock.

                                      F-18
<PAGE>

                            EFFICIENT NETWORKS, INC.

                     Condensed Consolidated Balance Sheets

                September 30, 1999 (Unaudited) and June 30, 1999

                       (In thousands, except share data)

<TABLE>
<CAPTION>
                                                         September 30, June 30,
                                                             1999        1999
                                                         ------------- --------
                                                          (unaudited)
                         Assets
<S>                                                      <C>           <C>
Current assets:
  Cash and cash equivalents.............................   $ 47,456    $ 3,604
  Short-term investments................................      8,663        --
  Accounts receivable, net of allowance for doubtful
   accounts of $165 and $120 at September 30, 1999 and
   June 30, 1999, respectively..........................     13,852     10,316
  Other receivables.....................................      7,110      2,018
  Inventories...........................................      7,326      5,472
  Other assets..........................................      1,051        241
                                                           --------    -------
    Total current assets................................     85,458     21,651
Furniture and equipment, net............................      3,187      2,285
Other assets, net.......................................         35         29
                                                           --------    -------
                                                           $ 88,680    $23,965
                                                           ========    =======
<CAPTION>
          Liabilities, Redeemable Convertible
   Preferred Stock and Stockholders' Equity (Deficit)
<S>                                                      <C>           <C>
Current liabilities:
  Accounts payable......................................   $ 11,184    $ 6,122
  Accrued liabilities...................................      2,782      2,208
  Deferred revenue......................................      2,441        736
                                                           --------    -------
    Total current liabilities...........................     16,407      9,066
Long-term debt, net of discount.........................        --      13,396
Other liabilities.......................................         21         22
                                                           --------    -------
    Total liabilities...................................     16,428     22,484
                                                           --------    -------
Redeemable convertible preferred stock..................        --      40,495
Commitments and contingencies
Stockholders' equity (deficit):
  Common stock, par value $.001 per share, 100,000,000
   shares authorized; 37,482,465 and 4,362,221 shares
   issued and outstanding at September 30, 1999 and June
   30, 1999, respectively...............................         37          4
  Additional paid-in capital............................    150,320     29,777
  Deferred stock option compensation....................    (16,162)   (14,606)
  Accumulated deficit...................................    (61,943)   (54,189)
                                                           --------    -------
    Total stockholders' equity (deficit)................     72,252    (39,014)
                                                           --------    -------
                                                           $ 88,680    $23,965
                                                           ========    =======
</TABLE>

See accompanying notes to unaudited condensed consolidated financial
statements.

                                      F-19
<PAGE>

                            EFFICIENT NETWORKS, INC.

                Condensed Consolidated Statements of Operations

                 Three Months Ended September 30, 1999 and 1998

                                  (Unaudited)

                     (In thousands, except per share data)

<TABLE>
<CAPTION>
                                                          Three Months Ended
                                                             September 30,
                                                          --------------------
                                                            1999       1998
                                                          ---------  ---------
<S>                                                       <C>        <C>
Net revenues............................................. $  12,171  $   1,174
Cost of revenues.........................................    11,706        863
                                                          ---------  ---------
    Gross profit.........................................       465        311
                                                          ---------  ---------
Operating expenses:
  Sales and marketing....................................     2,652      1,168
  Research and development...............................     3,053      1,826
  General and administrative.............................     1,048        339
  Stock option compensation..............................     1,389        433
                                                          ---------  ---------
    Total operating expenses.............................     8,142      3,766
                                                          ---------  ---------
    Loss from operations.................................    (7,677)    (3,455)
Interest income..........................................       597         87
Interest expense and other, net..........................      (674)        (7)
                                                          ---------  ---------
    Net loss............................................. $  (7,754) $  (3,375)
                                                          =========  =========
    Basic and diluted net loss per share of common
     stock............................................... $   (0.25) $   (0.93)
                                                          =========  =========
    Weighted-average shares of common stock outstanding..    30,496      3,713
                                                          =========  =========
</TABLE>


   See accompanying notes to unaudited condensed consolidated financial
statements.

                                      F-20
<PAGE>

                            EFFICIENT NETWORKS, INC.

                Condensed Consolidated Statements of Cash Flows

                 Three Months Ended September 30, 1999 and 1998

                                  (Unaudited)

                                 (In thousands)

<TABLE>
<CAPTION>
                                                          Three Months Ended
                                                             September 30,
                                                          --------------------
                                                            1999       1998
                                                          ---------  ---------
<S>                                                       <C>        <C>
Cash flows from operating activities:
 Net loss................................................ $  (7,754) $  (3,375)
 Adjustments to reconcile net loss to net cash used in
  operating activities:
  Depreciation and amortization..........................       240        179
  Amortization of deferred stock option compensation.....     1,389        433
  Accretion of discount on subordinated promissory
   notes.................................................       604        --
 Changes in operating assets and liabilities:
  Accounts receivable....................................    (3,536)      (191)
  Other receivables......................................    (5,092)       --
  Inventories............................................    (1,854)       (62)
  Other assets and liabilities...........................      (817)       220
  Accounts payable and accrued liabilities...............     5,658        125
  Deferred revenue.......................................     1,705        --
                                                          ---------  ---------
 Net cash used in operating activities...................    (9,457)    (2,671)
                                                          ---------  ---------
Cash flows from investing activities:
 Purchase of fixed assets................................    (1,142)      (596)
 Purchase of investments.................................    (8,663)       --
                                                          ---------  ---------
  Net cash used for investing activities.................    (9,805)      (596)
                                                          ---------  ---------
Cash flows from financing activities:
 Principal payments on capital lease obligations.........       --         (11)
 Proceeds from issuance of common stock, net.............    63,114         14
                                                          ---------  ---------
    Net cash provided by financing activities............    63,114          3
                                                          ---------  ---------
Increase in cash and cash equivalents....................    43,852     (3,264)
Cash and cash equivalents at beginning of period.........     3,604      7,607
                                                          ---------  ---------
Cash and cash equivalents at end of period............... $  47,456  $   4,343
                                                          =========  =========
</TABLE>

   See accompanying notes to unaudited condensed consolidated financial
statements.

                                      F-21
<PAGE>

                            EFFICIENT NETWORKS, INC.

         Notes to Unaudited Condensed Consolidated Financial Statements

                     Three Months Ended September 30, 1999

(1)Basis of Presentation

  The accompanying unaudited financial data as of and for the quarters ended
  September 30, 1999 and 1998 have been prepared by the Company, pursuant to
  the rules and regulations of the Securities and Exchange Commission.
  Certain information and footnote disclosures normally included in financial
  statements prepared in accordance with generally accepted accounting
  principles have been condensed or omitted pursuant to such rules and
  regulations. These consolidated financial statements should be read in
  conjunction with the financial statements and the notes thereto included in
  the Company's Annual Report on Form 10-K for the fiscal year ended June 30,
  1999.

  In the opinion of management, all adjustments (which include only normal
  recurring adjustments) necessary to present fairly the financial position,
  results of operations, and cash flows as of and for the three months ended
  September 30, 1999 have been made. The results of operations for the
  quarter ended September 30, 1999 are not necessarily indicative of the
  operating results for the full year.

(2)Completion of Initial Public Offering

  On July 15, 1999, the Company completed its initial public offering. The
  Company issued 4.6 million shares of its common stock (the "Common Stock")
  in exchange for gross proceeds of approximately $69 million, before
  underwriters' discount of $4.8 million and other related expenses of $1.1
  million. Upon the completion of the initial public offering, the Company's
  subordinated promissory notes converted into 3.1 million shares of Series H
  redeemable convertible preferred stock, the convertible promissory note
  plus accrued interest converted into .5 million shares of Series I
  redeemable convertible preferred stock, and all outstanding redeemable
  convertible preferred stock converted into 28.3 million shares of Common
  Stock.

(3)Earnings Per Share

  Basic and diluted earnings (loss) per share has been computed in accordance
  with Statement of Financial Accounting Standards (SFAS) No. 128, "Earnings
  Per Share." Basic earnings per share is computed by dividing income or loss
  by the weighted average number of shares of Common Stock outstanding during
  the period. Diluted earnings per share is determined in the same manners as
  basic earnings per share except that the number of shares is increased
  assuming exercise of dilutive stock options and warrants using the treasury
  stock method and conversion of the Company's redeemable convertible
  preferred stock ("Preferred Stock"). The diluted earnings per share amount
  is the same as basic earnings per share because the Company had a net loss
  in each of the periods presented and the impact of the assumed exercise of
  the stock options and warrants and the assumed Preferred Stock conversion
  is antidilutive. Common Stock equivalents of 7.0 million and 27.7 million
  shares for the three months ended September 30, 1999 and 1998,
  respectively, were excluded from the calculation of diluted earnings per
  share because of the anti-dilutive effect.

  All oustanding Preferred Stock converted into Common Stock upon the
  completion of the Company's initial public offering.

                                      F-22
<PAGE>

                            EFFICIENT NETWORKS, INC.

  Notes to Unaudited Condensed Consolidated Financial Statements--(continued)

                     Three Months Ended September 30, 1999


  The following table presents the calculation of basic and diluted net loss
  per share (in thousands, except per share amounts):

<TABLE>
<CAPTION>
                                                          Three Months Ended
                                                             September 30,
                                                          --------------------
                                                            1999       1998
                                                          ---------  ---------
   <S>                                                    <C>        <C>
   Net loss.............................................  $  (7,754) $  (3,375)
   Accretion of issuance costs on redeemable convertible
    preferred stock.....................................        --         (88)
                                                          ---------  ---------
   Net loss available to common stockholders............  $  (7,754) $  (3,463)
                                                          =========  =========
   Weighted average shares outstanding..................     30,496      3,713
                                                          =========  =========
   Basic and diluted net loss per share.................  $   (0.25) $   (0.93)
                                                          =========  =========
</TABLE>

(4)Inventories

  Inventories consisted of the following (in thousands):

<TABLE>
<CAPTION>
                                                          September 30, June 30,
                                                              1999        1999
                                                          ------------- --------
   <S>                                                    <C>           <C>
   Raw materials.........................................    $1,844      $2,265
   Finished goods........................................     5,482       3,207
                                                             ------      ------
   Total.................................................    $7,326      $5,472
                                                             ======      ======
</TABLE>

(5)Accrued Liabilities

  Accrued liabilities consisted of the following (in thousands):

<TABLE>
<CAPTION>
                                                          September 30, June 30,
                                                              1999        1999
                                                          ------------- --------
   <S>                                                    <C>           <C>
   Accrued compensation and benefits.....................    $1,041      $1,102
   Other.................................................     1,741       1,106
                                                             ------      ------
   Total.................................................    $2,782      $2,208
                                                             ======      ======
</TABLE>

(6)Deferred revenue

  Deferred revenue of $2.4 million at September 30, 1999 primarily related to
  shipments of product to customers where title and risk of ownership passed
  to the customer, but revenue recognition was deferred for accounting
  purposes due to certain stock balancing and right of return privileges
  granted to the customer. The corresponding receivable of $2.4 million was
  included in the accounts receivable balance at September 30, 1999.

(7)Long-term debt

  In January 1999, the Company issued subordinated promissory notes with
  detachable warrants in exchange for $7.0 million in cash. On April 8, 1999,
  the Company issued a subordinated promissory note with a detachable warrant
  in exchange for $2.0 million in cash. The notes bore interest at 10% per
  annum with interest payable quarterly. The subordinated promissory notes
  were issued with detachable warrants to

                                      F-23
<PAGE>

                            EFFICIENT NETWORKS, INC.

  Notes to Unaudited Condensed Consolidated Financial Statements--(continued)

                     Three Months Ended September 30, 1999

  purchase an aggregate of 3.1 million shares of the Company's Series H
  redeemable convertible preferred stock at an exercise price of $2.92 per
  share. The holders of the subordinated promissory notes had entered into a
  note repayment and warrant exercise agreement with the Company which
  stipulated that immediately prior to the closing of an initial public
  offering, the aggregate $9.0 million principal amount of the notes would be
  applied toward the aggregate exercise price of the detachable warrants.
  Accordingly, immediately prior to the closing of the Company's initial
  public offering on July 15, 1999, the warrants were exercised to purchase
  the Company's Series H redeemable convertible preferred stock, which shares
  of preferred stock automatically converted into shares of Common Stock upon
  completion of the initial public offering.

  On June 28, 1999, the Company issued a convertible promissory note in
  exchange for $5.0 million in cash. The note bore interest at 8.0% per
  annum. In accordance with the conversion feature of the note, immediately
  prior to the closing of the Company's initial public offering, the note
  automatically converted into .5 million shares of Series I preferred stock
  at a conversion price $10.09 per share, and such shares of preferred stock
  automatically converted into shares of Common Stock upon completion of the
  initial public offering.

(8)Statements of Cash Flows

  The Company paid cash interest of $.4 million and $0 during the three
  months ended September 30, 1999 and 1998, respectively. No income taxes
  were paid during the three months ended September 30, 1999 and 1998. Non-
  cash financing transactions included the exchange of promissory notes of
  $13.4 million and related accrued interest for $14.0 million of redeemable
  convertible preferred stock, and the exchange of redeemable convertible
  preferred stock of $54.5 million for 28.3 million shares of common stock
  during the three months ended September 30, 1999. No non-cash financing
  transactions occurred during the three months ended September 30, 1998.

(9)Subsequent Event

  On November 21, 1999 the Company entered into an agreement with Cabletron
  Systems, Inc. ("Cabletron") to acquire its wholly-owned subsidiary
  FlowPoint Corporation from Cabletron. The Company agreed to issue 7.2
  million shares of common stock and 6,300 shares of Series A non-voting
  convertible preferred stock ("the Series A Preferred") as consideration in
  the transaction. The Series A preferred is convertible into an aggregate of
  6.3 million shares of common stock. The acquisition was completed on
  December 17, 1999, and is being accounted for under the purchase method of
  accounting.

                                      F-24
<PAGE>

                          Independent Auditors' Report

The Board of Directors
Cabletron Systems, Inc.:

   We have audited the accompanying balance sheets of FlowPoint Corporation
(the "Company") as of February 28, 1999, August 31, 1998, and March 31, 1998
and the related statements of operations, cash flows, and stockholder's equity
for the six months ended February 28, 1999, five months ended August 31, 1998,
and the years ended March 31, 1998 and 1997 (as defined in note 2a). These
financial statements are the responsibility of the Company's management. Our
responsibility is to express an opinion on these financial statements based on
our audits.

   We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of
material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant
estimates made by management, as well as evaluating the overall financial
statement presentation. We believe that our audits provide a reasonable basis
for our opinion.

   In our opinion, the financial statements referred to above present fairly,
in all material respects, the financial position of the Company as of February
28, 1999, August 31, 1998, and March 31, 1998 and the results of its operations
and its cash flows for the six months ended February 28, 1999, five months
ended August 31, 1998, and the years ended March 31, 1998 and 1997, in
conformity with generally accepted accounting principles.

   As discussed in Note 2(a) to the financial statements, the Company was
acquired by Cabletron Systems, Inc. as of September 1, 1998 in a business
combination accounted for as a purchase. As a result of the application of
purchase accounting, the financial statements of the Company for the six months
ended February 28, 1999 are presented on a different cost basis than those for
periods prior to September 1, 1998, and accordingly, are not directly
comparable.

                                    KPMG LLP

Boston, Massachusetts
November 15, 1999

                                      F-25
<PAGE>

                             FLOWPOINT CORPORATION

                                 Balance Sheets

<TABLE>
<CAPTION>
                                                                             Successor (Note 2(a))      Predecessor (Note 2(a))
                                                                           ---------------------------  ------------------------
                                                                           September 30,  February 28,  August 31,    March 31,
                                                                               1999           1999         1998         1998
                                  Assets                                   -------------  ------------  ------------ -----------
                                                                            (Unaudited)
<S>                                                                        <C>            <C>           <C>          <C>
Current assets:
 Cash and cash equivalents................................................ $    302,381     1,202,150       457,153    2,566,498
 Accounts receivables, net of allowances of $240,788, $136,265, $86,114,
  and $58,298 respectively................................................    3,484,467     1,589,130       592,330      528,599
 Related party receivable (note 12).......................................          --            --        575,491      162,428
 Inventories..............................................................    3,172,188     1,577,191     1,325,110      773,859
 Prepaid expenses.........................................................      243,247       154,805        93,102       80,182
 Deferred income taxes....................................................      138,734       332,597           --           --
                                                                           ------------   -----------   -----------  -----------
  Total current assets....................................................    7,341,017     4,855,873     3,043,186    4,111,566
                                                                           ------------   -----------   -----------  -----------
Property, plant and equipment.............................................      416,224       197,966       402,908      364,903
Accumulated depreciation..................................................     (137,882)      (62,831)     (250,004)    (195,853)
                                                                           ------------   -----------   -----------  -----------
                                                                                278,342       135,135       152,904      169,050
                                                                           ------------   -----------   -----------  -----------
Intangible assets, net....................................................   12,282,489    13,203,507           --           --
Deferred income taxes.....................................................        8,329         6,810           --           --
Deposits..................................................................          --         15,147        13,311       15,090
                                                                           ------------   -----------   -----------  -----------
  Total assets............................................................ $ 19,910,177    18,216,472     3,209,401    4,295,706
                                                                           ============   ===========   ===========  ===========
              Liabilities and Stockholder's Equity (Deficit)
Current liabilities:
 Accounts payable......................................................... $  3,763,984     1,786,727     1,118,634      646,167
 Accrued expenses.........................................................      804,427       418,565       488,066      376,295
 Related party payable (note 12)..........................................    2,111,073     3,603,329           --           --
 Current portion of related party notes payable...........................          --            --      2,307,776    2,307,776
 Current portion of obligations under capital leases......................       22,718        39,616        51,186       53,164
                                                                           ------------   -----------   -----------  -----------
  Total current liabilities...............................................    6,702,202     5,848,237     3,965,662    3,383,402
 Non-current portion of obligations under capital leases..................        3,409        11,988        26,264       31,782
 Non-current portion of related party notes payable.......................          --            --        103,224      110,374
                                                                           ------------   -----------   -----------  -----------
  Total liabilities.......................................................    6,705,611     5,860,225     4,095,150    3,525,558
Stockholder's Equity (Deficit)
 Preferred stock (notes 3 and 13):
 Series A, no par value. Authorized, issued and outstanding 400,000
  shares at August 31, 1998 and March 31, 1998............................          --            --        200,000      200,000
 Series B, no par value. Authorized, issued and outstanding 360,000
  shares at August 31, 1998 and March 31, 1998............................          --            --        367,500      367,500
 Series C, no par value. Authorized 1,200,000 shares; issued and
  outstanding 1,167,667 shares at August 31, 1998 and March 31, 1998......          --            --      2,800,000    2,800,000
 Series D, no par value. Authorized 1,000,000 shares; issued and
  outstanding 700,000 shares at August 31, 1998 and March 31, 1998........          --            --      1,995,000    1,995,000
                                                                           ------------   -----------   -----------  -----------
                                                                                    --            --      5,362,500    5,362,500
 Common stock, $.01 par value. Authorized, issued and outstanding, 10,000
  shares at September 30, 1999 and February 28, 1999. Common Stock, no par
  value. Authorized 6,000,000 shares; issued and outstanding 1,730,430 and
  1,721,000 shares at August 31, 1998 and March 31, 1998, respectively....          100           100        70,619       68,162
 Additional paid-in-capital...............................................   25,383,308    25,383,308           --           --
 Accumulated deficit......................................................  (12,178,842)  (13,027,161)   (6,318,868)  (4,660,514)
                                                                           ------------   -----------   -----------  -----------
  Total stockholder's equity (deficit)....................................   13,204,566    12,356,247      (885,749)     770,148
                                                                           ------------   -----------   -----------  -----------
  Total liabilities and stockholder's equity (deficit).................... $ 19,910,177    18,216,472     3,209,401    4,295,706
- --------------------------------------------------
                                                                           ============   ===========   ===========  ===========
</TABLE>

See accompanying notes to financial statements

                                      F-26
<PAGE>

                             FLOWPOINT CORPORATION

                            Statements of Operations

<TABLE>
<CAPTION>
                                                                Successor (Note 2(a))         Predecessor (Note 2(a))
                                                              --------------------------  ----------------------------------
                                                                  Seven         Six          Five
                                                                 months        months       months         Years ended
                                                                  ended        ended        ended           March 31,
                                                              September 30, February 28,  August 31,  ----------------------
                                                                  1999          1999         1998        1998        1997
                                                              ------------- ------------  ----------  ----------  ----------
<S>                                                           <C>           <C>           <C>         <C>         <C>
                                                               (Unaudited)
Trade sales..................................................  $14,844,576    3,968,625      940,918   2,138,310     362,331
Related party sales (notes 3 and 10).........................    5,139,911      809,586      808,555   1,538,859   3,128,202
                                                               -----------  -----------   ----------  ----------  ----------
  Net sales..................................................   19,984,487    4,778,211    1,749,473   3,677,169   3,490,533
Cost of sales................................................   13,147,058    3,251,208    1,660,765   2,994,542   2,901,194
                                                               -----------  -----------   ----------  ----------  ----------
    Gross profit.............................................    6,837,429    1,527,003       88,708     682,627     589,339
Operating expenses:
  Selling, general and administrative........................    3,027,613    1,559,825    1,323,017   1,704,221   1,103,487
  Research and engineering...................................    1,218,122      660,727      419,591   1,049,983     984,985
  Amortization of intangibles................................      850,948      727,304          --          --          --
  In process research and development charge (note 3)........          --    11,953,093          --          --          --
                                                               -----------  -----------   ----------  ----------  ----------
    Income (loss) from operations............................    1,740,746  (13,373,946)  (1,653,900) (2,071,577) (1,499,133)
                                                               -----------  -----------   ----------  ----------  ----------
Interest (income) expense, net...............................        8,521       (8,178)       4,454       1,542       2,047
                                                               -----------  -----------   ----------  ----------  ----------
    Income (loss) before income taxes........................    1,732,225  (13,365,768)  (1,658,354) (2,073,119) (1,501,180)
Income tax expense (benefit).................................      883,906     (338,607)         --          --          800
                                                               -----------  -----------   ----------  ----------  ----------
    Net income (loss)........................................  $   848,319  (13,027,161)  (1,658,354) (2,073,119) (1,501,980)
- --------------------------------------------------
                                                               ===========  ===========   ==========  ==========  ==========
</TABLE>


See accompanying notes to financial statements

                                      F-27
<PAGE>

                             FLOWPOINT CORPORATION

                            Statements of Cash Flows

<TABLE>
<CAPTION>
                                                                Successor (Note 2(a))         Predecessor (Note 2(a))
                                                              --------------------------  ----------------------------------
                                                                  Seven         Six          Five
                                                                 months        months       months         Years ended
                                                                  ended        ended        ended           March 31,
                                                              September 30, February 28,  August 31,  ----------------------
                                                                  1999          1999         1998        1998        1997
                                                              ------------- ------------  ----------  ----------  ----------
<S>                                                           <C>           <C>           <C>         <C>         <C>
                                                               (Unaudited)
Cash flows from operating activities:
  Net income (loss)..........................................  $   848,319  (13,027,161)  (1,658,354) (2,073,119) (1,501,980)
Adjustments to reconcile net income (loss) to net cash
 provided by (used in) operating activities:
  Depreciation...............................................       75,051       62,831       54,151     112,978      76,231
  Amortization of intangibles................................      850,948      727,304           --          --          --
  Purchased research and development from acquisition........           --   11,953,093           --          --          --
  Deferred income taxes......................................      192,344     (339,407)          --          --          --
  Accounts receivable........................................   (1,895,337)    (321,309)     (63,731)   (497,074)     57,475
  Related party receivable...................................           --           --     (413,063)    759,731    (914,631)
  Inventories................................................   (1,594,997)     (52,081)    (551,251)   (141,747)   (420,474)
  Prepaid expenses...........................................      (88,442)     (61,703)     (12,920)    (36,106)    (38,095)
  Deposits...................................................       15,147       (1,836)       1,779      (4,119)     (6,724)
  Accounts payable...........................................    1,977,357      667,993      472,467     307,343     210,422
  Accrued expenses...........................................      385,862      (69,501)     126,557      31,646     287,753
                                                               -----------  -----------   ----------  ----------  ----------
    Net cash provided by (used in) operating activities......      766,252     (461,777)  (2,044,365) (1,540,467) (2,250,023)
                                                               -----------  -----------   ----------  ----------  ----------
Cash flows from investing activity:
  Capital expenditures.......................................     (218,258)     (45,062)     (38,005)    (80,336)   (169,365)
                                                               -----------  -----------   ----------  ----------  ----------
    Net cash used in investing activity......................     (218,258)     (45,062)     (38,005)    (80,336)   (169,365)
                                                               -----------  -----------   ----------  ----------  ----------
Cash flows from financing activities:
  Proceeds from issuance of related party note payable.......           --           --           --   2,225,000          --
  Payments on related party note payable.....................           --     (186,000)      (7,150)    (16,250)    (22,625)
  Payments on capital leases.................................      (25,285)     (25,846)     (22,282)    (36,809)    (13,133)
  Proceeds from issuance of common stock.....................           --          100        2,457       6,538       2,063
  Proceeds from issuance of preferred stock..................           --           --           --     997,500   2,555,000
  Related party payable......................................   (1,422,478)   1,463,582           --          --          --
                                                               -----------  -----------   ----------  ----------  ----------
    Net cash provided by (used in) financing.................   (1,447,763)   1,251,836      (26,975)  3,175,979   2,521,305
                                                               -----------  -----------   ----------  ----------  ----------
Net increase (decrease) increase in cash.....................     (899,769)     744,997   (2,109,345)  1,555,176     101,917
Cash and cash equivalents, beginning of period...............    1,202,150      457,153    2,566,498   1,011,322     909,405
                                                               -----------  -----------   ----------  ----------  ----------
Cash and cash equivalents, end of period.....................  $   302,381    1,202,150      457,153   2,566,498   1,011,322
                                                               ===========  ===========   ==========  ==========  ==========
Cash paid for interest.......................................  $        --           --           --      10,910      21,531
- --------------------------------------------------
                                                               ===========  ===========   ==========  ==========  ==========
</TABLE>

See accompanying notes to financial statements.

                                      F-28
<PAGE>

                             FLOWPOINT CORPORATION

                       Statements of Stockholder's Equity

<TABLE>
<CAPTION>
                                                                                                                Total
                          Preferred  Preferred  Preferred   Preferred               Additional              stockholder's
                            Stock      Stock      Stock       Stock       Common     paid-in   Accumulated     equity
                          Series A   Series B    Series C    Series D     Stock      capital     deficit      (deficit)
                          ---------  ---------  ----------  ----------  ----------  ---------- -----------  -------------
<S>                       <C>        <C>        <C>         <C>         <C>         <C>        <C>          <C>
Balances at March 31,
 1996...................  $ 200,000   310,000    1,300,000          --      59,561          --  (1,085,415)      784,146
 Net loss...............         --        --           --          --          --          --  (1,501,980)   (1,501,980)
 Issuance of Preferred
  Stock Series B........         --    57,500           --          --          --          --          --        57,500
 Issuance of Preferred
  Stock Series C........         --        --    1,500,000          --          --          --          --     1,500,000
 Issuance of Preferred
  Stock Series D........         --        --           --     997,500          --          --          --       997,500
 Issuance of Common
  Stock.................         --        --           --          --       2,063          --          --         2,063
                          ---------  --------   ----------  ----------  ----------  ---------- -----------   -----------
Balances at March 31,
 1997...................  $ 200,000   367,500    2,800,000     997,500      61,624          --  (2,587,395)    1,839,229
 Net loss...............         --        --           --          --          --          --  (2,073,119)   (2,073,119)
 Issuance of Preferred
  Stock Series D........         --        --           --     997,500          --          --          --       997,500
 Issuance of Common
  Stock.................         --        --           --          --       6,538          --          --         6,538
                          ---------  --------   ----------  ----------  ----------  ---------- -----------   -----------
Balances at March 31,
 1998...................  $ 200,000   367,500    2,800,000   1,995,000      68,162          --  (4,660,514)      770,148
 Net loss...............         --        --           --          --          --          --  (1,658,354)   (1,658,354)
 Issuance of Common
  Stock.................         --        --           --          --       2,457          --          --         2,457
                          ---------  --------   ----------  ----------  ----------  ---------- -----------   -----------
Balances at August 31,
 1998...................  $ 200,000   367,500    2,800,000   1,995,000      70,619          --  (6,318,868)     (885,749)
 Conversion of preferred
  stock to common
  stock.................   (200,000) (367,500)  (2,800,000) (1,995,000)  5,362,500          --          --            --
                          ---------  --------   ----------  ----------  ----------  ---------- -----------   -----------
                                 --        --           --          --   5,433,119          --  (6,318,868)     (885,749)
 Cabletron acquisition
  (notes 2(a) and 3)....         --        --           --          --  (5,433,119)         --   6,318,868       885,749
 Cabletron acquisition
  (notes 2(a) and 3)....         --        --           --          --          --  25,383,308          --    25,383,308
 Issuance of Common
  Stock.................         --        --           --          --         100          --          --           100
                          ---------  --------   ----------  ----------  ----------  ---------- -----------   -----------
Balances at September 1,
 1998...................  $      --        --           --          --         100  25,383,308          --    25,383,408
 Net loss...............         --        --           --          --          --          -- (13,027,161)  (13,027,161)
                          ---------  --------   ----------  ----------  ----------  ---------- -----------   -----------
Balances at February 28,
 1999...................  $      --        --           --          --         100  25,383,308 (13,027,161)   12,356,247
 Net income
  (unaudited)...........         --        --           --          --          --          --     848,319       848,319
                          ---------  --------   ----------  ----------  ----------  ---------- -----------   -----------
Balances at
 September 30, 1999
 (unaudited)............  $      --        --           --          --         100  25,383,308 (12,178,842)   13,204,566
                          =========  ========   ==========  ==========  ==========  ========== ===========   ===========
</TABLE>

See accompanying notes to financial statements.

                                      F-29
<PAGE>

                             FLOWPOINT CORPORATION

                         Notes to Financial Statements

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)

(1) Business Operations

  FlowPoint Corporation, (the "Company"), develops, manufactures, markets,
  designs, installs and supports a complete line of broadband remote access,
  high-speed corporate and internet access modems and routers primarily
  utilizing digital subscriber line ("DSL") technologies.

(2) Summary of Significant Accounting Policies

  (a) Basis of Presentation

    The financial statements of the Company are derived from its historic
    books and records through August 31, 1998. As a result of the
    acquisition of the Company by Cabletron Systems, Inc. ("Cabletron")
    effective as of September 1, 1998, the financial statements of the
    Company after the acquisition date are derived from the historic books
    and records of Cabletron and reflect the "pushdown" of Cabletron's
    basis in the assets acquired and liabilities assumed.

    As a result of the acquisition by Cabletron and the application of
    purchase accounting, financial information in the accompanying
    financial statements and notes thereto as of and for the six months
    ended February 28, 1999 (the "Successor Period") are presented on a
    different cost basis than the financial information as of August 31,
    1998 and March 31, 1998 and for the five months ended August 31, 1998
    and the years ended March 31, 1998 and 1997 (the "Predecessor Period"),
    and therefore, such information is not comparable.

    The statement of operations includes all revenues and costs directly
    attributable to the Company including charges for shared facilities,
    functions and services used by the Company and provided by Cabletron.
    Certain costs and expenses have been allocated based upon management's
    estimates of the cost of services provided to the Company by Cabletron.
    Such costs include sales support, customer service and technical
    support, and general and administrative expenses (see note 12). Such
    allocations and charges are based on a percentage of total costs for
    the services provided based on factors such as headcount or revenues.
    Management believes that these allocations are based on assumptions
    that are reasonable under the circumstances. However, these allocations
    and estimates are not necessarily indicative of the cost and expenses
    which would have resulted if the Company had been operated as a
    separate entity.

    The Company has historically incurred recurring losses from operations.
    Cabletron has committed to provide the funds required for the conduct
    of the Company's operations up to the date on which it ceases to be the
    controlling shareholder.

  (b) Change in fiscal year

    Prior to its acquisition by Cabletron, the Company's fiscal year end
    was March 31. Upon the acquisition the Company adopted Cabletron's
    February 28 fiscal year end.

  (c) Inventories

    Inventories are stated at the lower of cost or market. Costs are
    determined principally by use of the average-cost method, which
    approximates the first-in, first-out (FIFO) method.

                                      F-30
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)


  (d) Property, Plant and Equipment

    Property, plant and equipment are stated at cost. Depreciation is
    provided on a straight-line method over the estimated useful lives of
    the assets. The Company reviews its long-lived assets for impairment
    whenever events or changes in circumstances indicate that the carrying
    amount of an asset may not be recoverable. If it is determined that the
    carrying amount of an asset cannot be fully recovered, an impairment
    loss is recognized.

  (e) Intangible Assets

    Intangible assets consist of goodwill and developed technology
    resulting from the "pushdown" of the fair market value of the
    intangible assets attributable to the Company as recorded on
    Cabletron's books as part of Cabletron's acquisition of the Company.
    Amortization of these intangible assets is provided on a straight-line
    basis over the respective useful lives which range from five to ten
    years. Purchased in-process research and development without
    alternative future use is expensed when acquired. The carrying amount
    of intangible assets is reviewed for impairment whenever events or
    changes in circumstances indicate that the carrying amount of an asset
    may not be recoverable. The measurement of possible impairment is based
    primarily on an evaluation of undiscounted projected cash flows through
    the remaining amortization period.

  (f) Income Taxes

    The Company accounts for income taxes under the asset and liability
    method. Under this method, deferred tax assets and liabilities are
    recognized for the future tax consequences attributable to differences
    between the financial statement carrying amounts of existing assets and
    liabilities and their respective tax bases and operating loss and tax
    credit carryforwards. Deferred tax assets and liabilities are measured
    using enacted tax rates expected to apply to taxable income in the
    years in which those temporary differences are expected to be recovered
    or settled. The effect of a change in tax rates on deferred tax assets
    and liabilities is recognized in income in the period that includes the
    enactment date.

    As a result of its acquisition by Cabletron, the Company is included in
    the consolidated federal income tax return of Cabletron. Income taxes
    in the Company's financial statements subsequent to the acquisition
    have been determined on a separate-return basis.

  (g) Advertising Costs

    Advertising costs of $17,594, $105,547, $308,061, $297,360 and $67,134
    were expensed as incurred during the seven months ended September 30,
    1999, the six months ended February 28, 1999, the five months ended
    August 31, 1998 and the years ended March 31, 1998 and 1997,
    respectively. No assets were recorded related to advertising costs at
    the respective balance sheet dates.

  (h) Statements of Cash Flows

    Cash and cash equivalents consist of cash in banks and short-term
    investments with original maturities of three months or less.

                                      F-31
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)


  (i) Revenue Recognition

    The vast majority of the Company's revenues are related to hardware
    based routers with revenue recognized based upon shipment of the
    products. The Company accrues for estimated warranty costs related to
    product shipments based on historical experience. The Company generates
    an insignificant portion of its revenues from software products and
    records such revenue in accordance with (SOP) 97-2, "Software Revenue
    Recognition".

  (j) Use of Estimates

    The preparation of financial statements in conformity with generally
    accepted accounting principles requires management to make estimates
    and assumptions that affect the reported amounts of assets and
    liabilities and disclosure of contingent assets and liabilities at the
    date of the financial statements and the reported amounts of revenues
    and expenses during the reporting period. Actual results could differ
    from those estimates.

  (k) Research and Engineering

    Research and engineering costs are charged to expense as incurred.

  (l) Employee Stock Plan

    The Company accounts for its stock option plan in accordance with
    Accounting Principles Board Opinion No. 25 (APB 25), "Accounting for
    Stock Issued to Employees." In 1995, the Financial Accounting Standards
    Board issued SFAS No. 123, "Accounting for Stock-Based Compensation"
    (SFAS 123). SFAS 123 provides an alternative to APB 25 and is effective
    for fiscal years beginning after December 15, 1999. As permitted under
    SFAS 123, the Company continues to account for its stock option plan in
    accordance with the provisions of APB 25 and provides the disclosure
    pro forma net income as if the fair value method under SFAS 123 had
    been applied.

  (m) New Accounting Pronouncements

    In the period ended February 28, 1999, the Company adopted Financial
    Accounting Standards Board Statement No. 130, "Reporting Comprehensive
    Income" (SFAS 130) which establishes standards for reporting and
    display of comprehensive income and its components in a full set of
    financial statements. For the Company, comprehensive income includes
    net income or loss only. The adoption of SFAS 130 did not have any
    impact on the Company's financial statements for any of the periods
    presented.

    In the period ended February 28, 1999, the Company adopted Financial
    Accounting Standards Board Statement No. 131, "Disclosures about
    Segments of an Enterprise and Related Information" (SFAS 131) which
    establishes standards for the way that public business enterprises
    report selected information about operating segments in annual
    financial statements and requires that those enterprises report
    selected information about operating segments in interim financial
    reports to shareholders. It also establishes standards for related
    disclosures about products and services, geographic areas and major
    customers. The adoption of SFAS 131 did not have any impact on the
    Company's financial statement disclosures for the period ended February
    28, 1999.

                                      F-32
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)


    In October 1997, the AICPA Accounting Standards Executive Committee
    issued Statement of Position (SOP) 97-2, "Software Revenue Recognition"
    which provides guidance on applying generally accepted accounting
    principles in recognizing revenue for licensing, selling, leasing or
    otherwise marketing computer software and supersedes SOP 91-1. The
    adoption of SOP 97-2 did not have a material impact on the Company's
    results of operations for the period ended February 28, 1999.

  (n) Unaudited Results

    The financial statements as of and for the seven months ended September
    30, 1999 have been prepared using the same accounting principles as
    were used in preparing the audited financial statements and in the
    opinion of management reflect all adjustments, which include only
    normal recurring adjustments, necessary to present fairly the Company's
    financial position, results of operations and cash flows. The results
    for the seven months ended September 30, 1999 are not necessarily
    indicative of future results.

(3) Cabletron Acquisition

  Effective as of September 1, 1999 Cabletron acquired all of the outstanding
  common stock of FlowPoint Corporation, a privately held manufacturer of DSL
  router networking products. Immediately prior to the acquisition each share
  of FlowPoint preferred stock Series A, B, C, and D was converted into one
  share of FlowPoint common stock. Cabletron owned 1,866,667 shares of
  FlowPoint preferred stock (at a cost of approximately $1,700,000), and as a
  result of the preferred stock conversion owned 42.8% of the outstanding
  common stock. Pursuant to the acquisition agreement the amount paid for the
  remaining 57.2% of FlowPoint common stock amounted to approximately
  $20,600,000 to be paid in four installments, within nine months of the
  acquisition date. Each installment could be paid in either cash or
  Cabletron common stock, as determined by Cabletron management at the time
  of the distribution. In addition, Cabletron assumed approximately 478,000
  FlowPoint options, valued at approximately $2,700,000.

  Cabletron recorded the cost of the acquisition at $25,383,306 including
  direct costs of approximately $400,000. The acquisition was accounted for
  under the purchase method of accounting, and, accordingly, the acquired
  assets and liabilities were recorded at their estimated fair market value.
  The total purchase price of $25,383,306 was allocated as follows: a
  $11,953,093 special charge for in process research and development
  ("IPR&D") projects, $14,136,655 for goodwill and other intangibles and net
  liabilities of $706,442.

  The following unaudited pro forma financial information presents a summary
  of the results of operations as if the acquisition had occurred on March 1,
  1998, the first day of the fiscal year ending February 28, 1999.

<TABLE>
<CAPTION>
                                          (Unaudited)
                                      Twelve months ended
                                       February 28, 1999
                                      -------------------
            <S>                       <C>
            Net sales................    $  7,098,515
            Operating loss...........    $(15,326,163)
</TABLE>

  In management's opinion, the unaudited pro forma results of operations are
  not indicative of actual results that would have occurred had the
  acquisition been consummated on March 1, 1998.

                                      F-33
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)


  The valuation of the IPR&D incorporated the guidance on IPR&D valuation
  methodologies promulgated by the Securities and Exchange Commission
  ("SEC"). These methodologies incorporate the notion that cash flows
  attributable to development efforts, including the effort to be completed
  on the development effort underway, and development of future versions of
  the product that have not yet been undertaken, should be excluded in the
  valuation of IPR&D. This allocation represents risk-adjusted cash flows
  related to the incomplete products. At the date of acquisition, the
  development of these projects had not yet reached technological feasibility
  and the research and development in progress had no alternative future
  uses. Accordingly, these costs were expensed as of the acquisition date.

  Cabletron used independent third-party appraisers to assess and allocate
  values to the in-process research and development. The value assigned to
  these assets were determined by identifying significant research projects
  for which technological feasibility had not been established, including
  development, engineering and testing activities associated with the
  introduction of the Company's next-generation router technologies.

  The nature of the efforts to develop the acquired in-process technology
  into commercially viable products principally relate to the completion of
  all planning, designing, prototyping, high-volume verification, and testing
  activities that are necessary to establish that the proposed technologies
  meet their design specifications including functional, technical, and
  economic performance requirements.

  To date, the Company's results have not differed significantly from the
  forecast assumptions. The Company's research and development expenditures
  since the acquisition have not differed materially from expectations. The
  Company has completed the projects that were underway at the time of the
  acquisition and began to realize the economic benefits related to these
  projects during the six months ended February 28, 1999.

  The value assigned to purchased in-process technology was determined by
  estimating the costs to develop the purchased in-process technology into
  commercially viable products, estimating the resulting net cash flows from
  the projects and discounting the net cash flows to their present value. The
  revenue projection used to value the in-process research and development is
  based on estimates of relevant market sizes and growth factors, expected
  trends in technology and the nature and expected timing of new product
  introductions by the Company and its competitors.

  For purposes of the IPR&D valuation, the total revenues attributable to the
  Company were projected to exceed $150 million within 5 years, assuming the
  successful completion and market acceptance of the major research and
  development efforts. As of the valuation date, the Company had a few
  existing products, which lack the technological breadth and depth necessary
  in the evolving networking equipment market. Accordingly, for purposes of
  the IPR&D valuation, it was estimated that significant revenue growth in
  the first several years would be primarily related to the in-process
  technologies. The estimated revenues for the in-process projects were
  projected to peak in 2004 and then decline as other new products and
  technologies were expected to enter the market.

  Cost of sales was estimated based on the Company's internally generated
  projections and discussions with management regarding anticipated gross
  margin improvements. Due to the market opportunities in the network
  equipment arena and the Company's unique technology architecture,
  substantial gross margins were projected through the forecast period. Cost
  of sales as a percentage of sales was forecasted to decline until 2003 and
  then remain constant at 55%. Selling, general and administrative expenses
  (including depreciation) as a percentage of sales were projected to remain
  constant at 23%. Research and development expenditures as a percentage of
  sales were projected to decline significantly from 30% in 1999 to 10% in
  2001 and remain constant at 10% thereafter.

                                      F-34
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)


  The rates utilized to discount the net cash flows to their present value
  were based on venture capital rates of return. Due to the nature of the
  forecast and the risks associated with the projected growth, profitability
  and developmental projects, a discount rate of 27.5 percent was determined
  to be appropriate for the IPR&D. This discount rate was commensurate with
  the Company's stage of development; the uncertainties in the economic
  estimates described above; the inherent uncertainty surrounding the
  successful development of the purchased in-process technology; the useful
  life of such technology; the profitability levels of such technology; and,
  the uncertainty of technological advances that were unknown at the time of
  the acquisition.

  The forecasts used by Cabletron in valuing in-process research and
  development were based upon assumptions Cabletron believes to be reasonable
  but which are inherently uncertain and unpredictable. Cabletron's
  assumptions may be incomplete or inaccurate, and unanticipated events and
  circumstances are likely to occur. For these reasons, actual results may
  vary from the projected results.

  Cabletron believes that the foregoing assumptions used in the forecasts
  were reasonable at the time of the acquisition. No assurance can be given,
  however, that the underlying assumptions used to estimate expected project
  sales, development costs or profitability, or the events associated with
  such projects, will transpire as estimated. For these reasons, actual
  results may vary from the projected results.

  The Company's in-process research and development value is comprised of
  several significant individual on-going projects. Remaining development
  efforts for these projects include various phases of design, development
  and testing. Anticipated completion dates for the projects in progress are
  estimated to occur over the first nine months following the acquisition.
  The Company estimated it will begin generating the economic benefits from
  the technologies in the second half of fiscal year 2000. Funding for such
  projects was estimated to be obtained from internally generated sources.
  Expenditures to complete these projects were estimated to total
  approximately $1.0 million over the next six months. These estimates are
  subject to change, given the uncertainties of the development process, and
  no assurance can be given that deviations from these estimates will not
  occur.

  Cabletron management expects to continue their support of these efforts and
  believes the Company has a reasonable chance of successfully completing the
  research and development programs. However, there is risk associated with
  the completion of the projects and there is no assurance that any will meet
  with either technological or commercial success.

(4) Inventories

   Inventories consist of the following:

<TABLE>
<CAPTION>
                                         Successor              Predecessor
                                 -------------------------- --------------------
                                 September 30, February 28, August 31, March 31,
                                     1999          1999        1998      1998
                                 ------------- ------------ ---------- ---------
<S>                              <C>           <C>          <C>        <C>
Raw materials...................  $1,864,122    1,237,660     893,461   666,255
Work-in-process.................      79,344      147,467     214,100   105,854
Finished goods..................   1,228,722      192,064     217,549     1,750
                                  ----------    ---------   ---------   -------
Total...........................  $3,172,188    1,577,191   1,325,110   773,859
                                  ==========    =========   =========   =======
</TABLE>

                                      F-35
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)


(5) Property, Plant and Equipment

  Property, plant and equipment consist of the following:

<TABLE>
<CAPTION>
                                  Successor              Predecessor
                          -------------------------- -------------------
                                                                 March    Estimated
                          September 30, February 28, August 31,   31,      useful
                              1999          1999        1998      1998      lives
                          ------------- ------------ ---------- --------  ---------
<S>                       <C>           <C>          <C>        <C>       <C>
Capitalized software....    $ 38,886       27,139       29,186    25,818    3 years
Machinery and
 equipment..............     357,592      163,967      360,642   326,005  3-5 years
Furniture and fixtures..      19,746        6,860       13,080    13,080  3-5 years
                            --------      -------     --------  --------
                             416,224      197,966      402,908   364,903
Less accumulated
 depreciation and
 amortization...........    (137,882)     (62,831)    (250,004) (195,853)
                            --------      -------     --------  --------
                            $278,342      135,135      152,904   169,050
                            ========      =======     ========  ========
</TABLE>

(6) Intangible Assets

  Intangible assets consist of the following:

<TABLE>
<CAPTION>
                                               September    February   Estimated
                                                  30,         28,       useful
                                                 1999         1999       lives
                                              -----------  ----------  ---------
   <S>                                        <C>          <C>         <C>
   Goodwill.................................. $13,409,105  13,479,175  10 years
   Acquired patents and technologies.........     451,636     451,636   5 years
                                              -----------  ----------
                                               13,860,741  13,930,811
   Less accumulated amortization.............  (1,578,252)   (727,304)
                                              -----------  ----------
                                              $12,282,489  13,203,507
                                              ===========  ==========
</TABLE>

  Goodwill has been reduced by $70,070 and $205,844 at September 30, 1999 and
  February 28, 1999 respectively. This reduction is a result of acquired tax
  benefits from stock options exercised.

(7) Leases

  The Company is obligated under various capital leases for certain machinery
  and equipment. Future minimum lease payments by fiscal year and in the
  aggregate under capital leases as of February 28, 1999 are as follows:

<TABLE>
<CAPTION>
   Fiscal year ending February 28,
   <S>                                                                  <C>
     2000.............................................................. $41,241
     2001..............................................................  14,237
     2002..............................................................   1,241
                                                                        -------
     Total minimum lease payments......................................  56,719
   Less amounts representing interest (at 12.79%)......................   5,115
                                                                        -------
     Present value of net minimum capital lease payments...............  51,604
   Less current portion of obligations under capital leases............  39,616
                                                                        -------
     Obligations under capital leases excluding current portion........ $11,988
                                                                        =======
</TABLE>

                                      F-36
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)


   Included in property plant and equipment are the following assets held under
capital leases:

<TABLE>
<CAPTION>
                                        Successor              Predecessor
                                -------------------------- --------------------
                                September 30, February 28, August 31, March 31,
                                    1999          1999        1998      1998
                                ------------- ------------ ---------- ---------
<S>                             <C>           <C>          <C>        <C>
 Machinery and equipment......     $72,780       72,780     176,162    157,505
 Less accumulated
  amortization................      50,277       27,173     103,382     78,804
                                   -------       ------     -------    -------
                                   $22,503       45,607      72,780     78,701
                                   =======       ======     =======    =======
</TABLE>

  Amortization of assets held under capital leases is included with
  depreciation expense.

  Prior to the acquisition by Cabletron, the Company leased a manufacturing
  and office facility under an operating lease. In June 1999, the Company
  relocated to a facility leased by Cabletron. Cabletron allocates a portion
  of its lease cost to the Company. Rent expense, including intercompany
  allocations for the seven months ended September 30, 1999, the six months
  ended February 28, 1999, the five months ended August 31, 1998 and the
  years ended March 31, 1998, and 1997, was $225,819, $100,001, $71,742,
  $135,018 and $73,912, respectively.

(8) Income Taxes

  Total income tax expense (benefit) was allocated as follows:

<TABLE>
<CAPTION>
                                 Successor                      Predecessor
                         -------------------------- -----------------------------------
                         Seven months   Six months  Five months Fiscal year Fiscal year
                             ended        ended        ended       ended       ended
                         September 30, February 28, August 31,   March 31,   March 31,
                             1999          1999        1998        1998        1997
                         ------------- ------------ ----------- ----------- -----------
<S>                      <C>           <C>          <C>         <C>         <C>
Income from continuing
 operations.............   $883,906      (338,607)      --          --          800
Reduction in goodwill,
 for recognition of tax
 benefits from stock
 options exercised......    (70,070)     (205,844)      --          --          --
                           --------      --------       ---         ---         ---
                           $813,836      (544,451)      --          --          800
                           ========      ========       ===         ===         ===
</TABLE>
   Income tax attributable to income from continuing operations consist of:

<TABLE>
<CAPTION>
                                 Successor                      Predecessor
                         -------------------------- -----------------------------------
                         Seven months   Six months  Five months Fiscal year Fiscal year
                             ended        ended        ended       ended       ended
                         September 30, February 28, August 31,   March 31,   March 31,
                             1999          1999        1998        1998        1997
                         ------------- ------------ ----------- ----------- -----------
<S>                      <C>           <C>          <C>         <C>         <C>
Currently payable:
Federal.................   $538,238           --        --          --          --
State...................    153,324           800       --          --          800
Deferred tax expense
 (benefit)..............    192,344      (339,407)      --          --          --
                           --------      --------       ---         ---         ---
Tax expense (benefit)...   $883,906      (338,607)      --          --          800
                           ========      ========       ===         ===         ===
</TABLE>

                                      F-37
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)

   The following is a reconciliation of the effective tax rates to the
statutory federal tax rate:

<TABLE>
<CAPTION>
                                  Successor                      Predecessor
                          -------------------------- -----------------------------------
                          Seven months   Six months  Five months Fiscal year Fiscal year
                              ended        ended        ended       ended       ended
                          September 30, February 28, August 31,   March 31,   March 31,
                              1999          1999        1998        1998        1997
                          ------------- ------------ ----------- ----------- -----------
<S>                       <C>           <C>          <C>         <C>         <C>
Statutory federal income
 tax (benefit) rate.....      35.0%        (35.0)%      (35.0)%     (35.0)%     (35.0)%
State income tax, net of
 federal tax benefit....       5.8            --           --          --          --
Exempt income of foreign
 sales corporation, net
 of tax.................      (0.2)           --           --          --          --
Research and
 experimentation
 credit.................      (6.4)         (0.7)          --          --          --
Unbenefitted net
 operating loss.........        --            --         35.0        35.0        35.0
Nondeductible
 amortization of
 intangible assets......      16.8           1.9           --          --          --
Nondeductible in--
 process research and
 development charge.....        --          31.3           --          --          --
                              ----         -----        -----       -----       -----
                              51.0%         (2.5)%        0.0%        0.0%        0.0%
                              ====         =====        =====       =====       =====
</TABLE>

  The tax effects of temporary differences that give rise to significant
  portions of deferred tax assets and deferred tax liabilities are presented
  below:

<TABLE>
<CAPTION>
                                     Successor                Predecessor
                             -------------------------- ------------------------
                             Seven months   Six months  Five months  Fiscal year
                                 ended        ended        ended        ended
                             September 30, February 28, August 31,    March 31,
                                 1999          1999        1998         1998
                             ------------- ------------ -----------  -----------
<S>                          <C>           <C>          <C>          <C>
Deferred tax assets:
  Accounts receivable.......  $    8,343         8,266       8,266        8,343
  Inventories...............      70,000        70,000          --           --
  Property, plant and
   equipment................      40,478        38,959      30,991       19,531
  Other reserves and
   accruals.................     113,946        (4,815)         35           --
  Net operating loss
   carryforwards............   2,112,231     2,424,932   2,112,231    1,541,505
                              ----------    ----------  ----------   ----------
  Total gross deferred tax
   assets...................   2,344,998     2,537,342   2,151,523    1,569,379
  Less valuation allowance..  (2,148,806)   (2,148,806) (2,148,806)  (1,569,067)
                              ----------    ----------  ----------   ----------
  Net deferred tax assets...     196,192       388,536       2,717          312
                              ----------    ----------  ----------   ----------
Deferred tax liabilities:
  Other reserves and
   accruals.................     (49,129)      (49,129)     (2,717)        (312)
                              ----------    ----------  ----------   ----------
  Total gross deferred
   liabilities..............     (49,129)      (49,129)     (2,717)        (312)
                              ----------    ----------  ----------   ----------
  Net deferred tax assets...  $  147,063       339,407          --           --
                              ==========    ==========  ==========   ==========
</TABLE>

  At September 30, 1999, February 28, 1999, August 31, 1998 and March 31,
  1998, the Company had net operating loss (NOL) carryforwards for tax
  purposes of $5,695,112, $6,187,662, $5,695,112, and $4,129,836 respectively
  expiring in fiscal February 2008 through fiscal February 2011. The
  utilization of these net operating losses may be limited pursuant to
  Internal Revenue Code section 382 as a result of ownership changes.

                                      F-38
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)


  The valuation allowance was increased by $0, $0, $579,739 and $721,065
  during the periods ended September 30, 1999, February 28, 1999, August 31,
  1998 and March 31, 1998, respectively. Subsequently reported tax benefits
  relating to the valuation allowance for deferred tax assets as of September
  30, 1999, February 28, 1999 and August 31, 1998 will be recorded as a
  decrease to goodwill and other non-current intangible assets. In assessing
  the realizability of net deferred tax assets, management considers whether
  it is more likely than not that some portion or all of the deferred tax
  assets will not be realized. Based upon the level of historical taxable
  income and projections for future taxable income over the periods which the
  deferred tax assets are deductible, management believes it is more likely
  than not the Company will realize the benefits of these deductible
  differences, net of the existing valuation allowance at September 30, 1999.

(9)Related Party Notes Payable
  On August 8, 1995, the Company entered into a $250,000 note payable with
  Soliton Systems, K.K. ("Soliton") with an interest rate of five percent. On
  August 5, 1997, the note was amended to require variable quarterly
  repayments of the note over three years with the principle amount
  outstanding at the end of three years due in full. The Company repaid the
  note in full on October 8, 1998. Soliton was a preferred stock shareholder
  of the Company.

  In anticipation of Cabletron's acquisition of the Company, the two parties
  entered into a Memorandum of Understanding ("MOU") on February 4, 1998. As
  part of the MOU, the Company entered into a note payable to Cabletron for
  $2,225,000 with an interest rate of six percent. The note payable was
  convertible into shares of Series E Preferred Stock of the Company at $7.50
  per share if the acquisition was not consummated.

(10)Financial Instruments and Concentration of Credit Risk

  The carrying amounts of cash and cash equivalents, accounts receivables,
  and current liabilities approximate fair value because of the short
  maturity of these financial instruments.

  The carrying amount of the notes payable to Cabletron, as discussed in note
  9, approximated fair value based on the short maturity of the instrument.
  The carrying amount of the note payable to Soliton also approximated fair
  value based on estimated discounted cash flows prior to the repayment by
  the Company.

  For the seven months ended September 30, 1999 and the six months ended
  February 28, 1999, the Company had one customer, Covad and a related party,
  Cabletron, which accounted for 52% and 26% of sales and 70% and 17% of
  sales, respectively. For the five months ended August 31, 1998, the Company
  had two customers, Covad and British Telecom that accounted for 28% and 19%
  of sales, respectively. Additionally for this same period sales to related
  parties, Cabletron and Soliton, accounted for 25% and 21% of sales,
  respectively. For the year ended March 31, 1998, the Company had one
  customer, Diamond Lane, which accounted for 36% of sales. Additionally for
  this same period sales to related parties, Cabletron and Soliton, accounted
  for 31% and 11% of sales, respectively. For the year ended March 31, 1997,
  sales to related parties, Cabletron and Soliton, accounted for 69% and 20%
  of sales, respectively.

(11)Segment and Geographical Information

  The Company operates in one operating segment. The Company provides a line
  of broadband remote access, high-speed corporate and internet access modems
  and routers primarily utilizing DSL technologies. Substantially all
  revenues result from the sales of hardware products. The vast majority of
  the Company's sales are generated in the United States.


                                      F-39
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)

(12)Related Party

  Subsequent to the acquisition date, the Company maintained a certain level
  of autonomy. During the six months ended February 28, 1999, Cabletron
  provided the Company with certain services including cash management,
  payroll processing, insurance, limited legal and information technology
  support as well as the ability for Company employees to participate in
  Cabletron's medical plan beginning in January of 1999. During this period,
  Cabletron began to allocate expenses primarily related to the medical plan
  coverage to the Company on a monthly basis as the costs associated with the
  other services were nominal. The total amount of expenses allocated to the
  Company by Cabletron during the six months ended February 28, 1999 was
  $15,026 and is included in the respective categories in the statement of
  operations including cost of sales, selling general and administrative, and
  research and engineering expenses.
  Also beginning in the six month period ending February 28, 1999, Company
  employees were able to participate in Cabletron's incentive plans. These
  plans include Cabletron's Equity Incentive Plan and the Employee Stock
  Purchase Plan. These plans are accounted for by Cabletron as non-
  compensatory under APB 25 and thus there is no expense allocation.

  Beginning in the seven month period ending September 30, 1999, Cabletron
  began to provide the Company with services in addition to those described
  above. These services included external and inside sales support, customer
  service and technical support, software licenses, limited software
  development and assistance with year 2000 remediation processes. The
  Company also moved into a Cabletron facility in June of 1999 and began to
  receive a related cost allocation from Cabletron representing rent and
  other occupancy costs. The total amount of expenses allocated to the
  Company by Cabletron during the seven months ended September 30, 1999 was
  $574,151 and is included in the respective categories in the statement of
  operations including cost of sales, selling general and administrative, and
  research and engineering expenses.

  Cabletron was a significant customer of the Company prior to the completion
  of the acquisition and the Company has generated significant intercompany
  sales to Cabletron subsequent to the acquisition as outlined in footnote 10
  of these financial statements.

(13)Stockholders' Equity

  The Company's preferred stock was convertible into common stock on a one-
  for-one conversion rate. Each holder of preferred stock was entitled to
  vote on all matters and was entitled to the number of votes equal to the
  whole number of shares of common stock into which such preferred shares
  could be converted. Dividends on the preferred stock were not cumulative
  and no right to any dividends would accrue to the holders unless declared
  by the Board of Directors.

  The preferred stock had liquidation preferences as follows:

<TABLE>
<CAPTION>
            Series A..................... $0.50 per share
            <S>                           <C>
            Series B..................... $1.00 per share
            Series C..................... $2.40 per share
            Series D..................... $2.85 per share
</TABLE>

  Prior to the acquisition by Cabletron, the Company maintained a 1994 Stock
  Option Plan (the "Plan") which provided for up to 400,000 shares of common
  stock of the Company for purchase by employees, directors or consultants of
  the Company. The Plan was amended on October 1, 1997 to provide up to

                                      F-40
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)

  600,000 shares. The Plan provides for issuance of options at their fair
  market value on the date of the grant. The Plan allowed varying vesting
  provisions but in each case the options were issued with four year vesting
  periods. The Plan also includes a provision whereby at least 20% per year
  of the total number of shares pursuant to a grant would vest. The maximum
  term for an option was ten years from the date of grant. As part of the
  acquisition by Cabletron, the options for Company common stock were
  converted to options for Cabletron common stock.

  A summary of option transactions follows:

<TABLE>
<CAPTION>
                                                       Number   Weighted Average
                                                         of         Exercise
                                                       options       Price
                                                       -------  ----------------
   <S>                                                 <C>      <C>
   Options outstanding at March 31, 1996..............      --
     Granted.......................................... 314,750       $0.14
     Exercised........................................ (14,479)      $0.15
     Forfeited........................................ (60,521)      $0.15
                                                       -------
   Options outstanding at March 31, 1997.............. 239,750       $0.14
     Granted.......................................... 222,400       $0.25
     Exercised........................................ (47,706)      $0.12
     Forfeited........................................  (1,615)      $0.20
                                                       -------
   Options outstanding at March 31, 1998.............. 412,829       $0.19
     Granted..........................................  67,100       $0.75
     Exercised........................................    (885)      $0.20
     Forfeited........................................  (1,000)      $0.75
                                                       -------
   Options outstanding at August 31, 1998............. 478,044       $0.27
                                                       =======
   Options exercisable at:
     March 31, 1997...................................  73,141       $0.11
     March 31, 1998................................... 122,777       $0.16
     August 31, 1998.................................. 170,678       $0.27
</TABLE>

  Subsequent to the acquisition by Cabletron, Company employees were eligible
  to participate in Cabletron's Equity Incentive Plan ("EIP") which provides
  shares of common stock for the granting of a variety of incentive awards to
  eligible employees. As of February 28, 1999, Cabletron had issued Company
  employees 75,100 stock options under the EIP, which were granted at fair
  market value at the date of grant, vest over a three to five year period
  and expire within six to ten years from the date of grant.

                                      F-41
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)


   A summary of option transactions follows:

<TABLE>
<CAPTION>
                                                              Weighted Average
                                                     Number       Exercise
                                                   of options      Price
                                                   ---------- ----------------
   <S>                                             <C>        <C>
   Company options outstanding at August 31, 1998
    assumed by and converted to Cabletron options
    at a ratio of 1.033 to 1......................  493,970        $0.26
   Granted........................................   75,100        $7.63
   Exercised......................................  (86,020)       $0.16
   Forfeited......................................   (1,983)       $0.60
                                                    -------
   Options outstanding at February 28, 1999.......  481,067        $1.42
     Granted......................................       --           --
     Exercised....................................  (80,835)       $0.28
     Forfeited....................................   (7,566)       $0.60
                                                    -------
   Options outstanding at September 30, 1999......  392,666        $1.69
                                                    =======
   Options exercisable at :
     February 28, 1999............................  209,983        $0.75
     September 30, 1999...........................  190,608        $0.82
</TABLE>

  The following table summarizes information concerning currently outstanding
  and exercisable options as of February 28, 1999:

<TABLE>
<CAPTION>
                                     Options Outstanding         Options Exercisable
                              --------------------------------- ---------------------
                                           Weighted-
                                            Average
                                           Remaining  Weighted-             Weighted-
                                          Contractual  Average               Average
                                Number       Life     Exercise    Number    Exercise
   Range of Exercise Prices   Outstanding   (years)     Price   Exercisable   Price
   ------------------------   ----------- ----------- --------- ----------- ---------
   <S>                        <C>         <C>         <C>       <C>         <C>
   $0.00 to $0.25..........     218,592       7.7       $0.17     139,760     $0.15
   $0.26 to $0.50..........     121,443       8.6       $0.27      36,341     $0.26
   $0.51 to $0.75..........      65,932       9.2       $0.64      18,862     $0.63
   $0.76 to $14.00.........      75,100       9.6       $7.63      15,020     $7.63
                                -------                           -------
   $0.00 to $14.00.........     481,067       8.1       $1.42     209,983     $0.75
                                =======       ===       =====     =======
</TABLE>

  The Company accounts for its stock option plans in accordance with the
  provisions of APB 25. As such compensation expense is recorded on the date
  of grant only if the fair value of the underlying stock exceeds the
  exercise price. Had compensation cost associated with options held by
  Company employees been determined consistent with SFAS 123, the Company
  would have reported net losses of $13,078,156, $1,660,426, $2,077,613, and
  $1,503,479, respectively for the six months ended February 28, 1999, the
  five months ended August 31, 1998 and the years ended March 31, 1998 and
  1997.

                                      F-42
<PAGE>

                             FLOWPOINT CORPORATION

                   Notes to Financial Statements--(Continued)

    (Information as of and for the seven months ended September 30, 1999 is
                                   unaudited)


  The Company estimates the fair value of each option as of the date of grant
  using a Black-Scholes pricing model with the following weighted average
  assumptions:

<TABLE>
<CAPTION>
                                Six Months  Five Months Fiscal year Fiscal year
                                  ended        ended       ended       ended
                               February 28, August 31,   March 31,   March 31,
                                   1999        1998        1998        1997
                               ------------ ----------- ----------- -----------
   <S>                         <C>          <C>         <C>         <C>
   Expected volatility........    *76.32%        --          --          --
   Dividend yield.............        --         --          --          --
   Risk-free interest rate....       5.1%      4.87%       5.70%       6.57%
   Expected life, in years....       3.7        3.8         3.8         3.7
</TABLE>
  --------
  *based on Company employee holdings in Cabletron common stock

  The weighted average estimated fair values of stock options granted during
  the six months ended February 28, 1999, the five months ended August 31,
  1998 and the fiscal years ended March 31, 1998 and 1997 were $7.63, $.73,
  $.25 and $.17 per share, respectively.

  Also subsequent to the acquisition by Cabletron, Company employees were
  eligible to participate in Cabletron' two Employee Stock Purchase Plans
  ("ESPPs"), which provide shares of common stock to be purchased by
  employees who have completed a minimum period of employment. Under the 1989
  ESPP, employees must be continuously employed for a period of six months
  and under the 1995 ESPP employees must be continuously employed for a
  period of two years. Under these plans, options are granted to eligible
  employees twice yearly and are exercisable through the accumulation of
  employee payroll deductions from two to ten percent of employee
  compensation as defined in the plan, to a maximum of $12,500 annually, for
  each plan, (adjusted to reflect increases in the consumer price index)
  which may be used to purchase stock at 85 percent of the fair market value
  of the common stock at the beginning or end of the option period, whichever
  amount is lower. In the seven months ended September 30, 1999, 6,932 shares
  were purchased at a weighted average price of $6.96.

(14)Subsequent Event (Unaudited)

  On November 22, 1999, Cabletron announced that it had reached an agreement
  for the sale of the Company to Efficient Networks ("Efficient") a leading,
  independent supplier of DSL access products for the customer premises.
  Under the terms of the sale, Efficient would pay a combination of 7.2
  million common shares and 6,300 convertible preferred shares (convertible
  into an aggregate of 6.3 million common shares of Efficient) to Cabletron
  in exchange for all the outstanding common stock of the Company. The sale
  closed on December 17, 1999.

                                      F-43
<PAGE>





                [LOGO OF EFFICIENT NETWORKS, INC. APPEARS HERE]
<PAGE>

                                    PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

Item 13. Other Expenses of Issuance and Distribution

   The following table sets forth the costs and expenses, other than
underwriting discounts and commissions, payable by Efficient in connection with
the sale of common stock being registered. All amounts are estimates except the
SEC registration fee and the NASD filing fee.

<TABLE>
   <S>                                                               <C>
   SEC registration fee............................................. $   98,860
   NASD filing fee..................................................     30,500
   Nasdaq National Market listing fee...............................     17,500
   Printing and engraving costs.....................................    100,000
   Legal fees and expenses..........................................    350,000
   Accounting fees and expenses.....................................    150,000
   Blue Sky fees and expenses.......................................      5,000
   Miscellaneous expenses...........................................    248,140
                                                                     ----------
     Total.......................................................... $1,000,000
                                                                     ==========
</TABLE>

Item 14. Indemnification of Directors and Officers

   Section 145 of the Delaware General Corporation Law permits a corporation to
include in its charter documents, and in agreements between the corporation and
its directors and officers, provisions expanding the scope of indemnification
beyond that specifically provided by the current law.

   Article IX of the Registrant's Restated Certificate of Incorporation
provides that directors and officers may be indemnified to the fullest extent
permissible under Delaware law.

   Article VI of the Registrant's Bylaws provides for the indemnification of
officers and directors to the fullest extent permissible under Delaware Law.

   The Registrant has entered into indemnification agreements with its
directors and executive officers, in addition to indemnification provided for
in the Registrant's Bylaws, and intends to enter into indemnification
agreements with any new directors and executive officers in the future.

   The Underwriting Agreement, Exhibit 1.1 hereto, provides for indemnification
by the Underwriters of the registrant and its executive officers and directors,
and by the registrant of the underwriters for certain liabilities, including
liabilities arising under the Securities Act, in connection with matters
specifically provided in writing by the Underwriters for inclusion in the
Registration Statement.

Item 15. Recent Sales of Unregistered Securities

   During the past three years, the Registrant has issued unregistered
securities to a limited number of persons as described below. In each case, we
relied on the exemption from registration provided by Section 4(2) under the
Securities Act.

   In December 1996, we sold 3,091,430 shares of Series E Preferred Stock to
certain accredited investors at a purchase price of $2.41 per share.

                                      II-1
<PAGE>

   In November 1997, we sold 114,068 shares of Common Stock to DSC Telecom,
L.P. at a purchase price of $2.63 per share.

   In February 1998, we sold 2,057,159 shares of Series F Preferred Stock to
certain accredited investors at a purchase price of $2.92 per share.

   In June 1998, we sold 1,866,800 shares of Series G Preferred Stock to
Siemens A.G. at a purchase price of $2.92 per share.

   In June 1998, we issued a warrant to purchase 34,264 shares of Series G
Preferred Stock to Hambrecht & Quist LLC at an exercise price of $2.92 per
share.

   In January 1999, we issued Subordinated Promissory Notes for an aggregate
principal amount of $7.0 million and warrants to purchase an aggregate of
2,397,261 shares of Series H Preferred Stock to El Dorado Ventures IV, LP and
Crosspoint Ventures LS 1997 LP, at an exercise price of $2.92 per share.

   In March 1999, we sold 1,850,000 shares of Series G Preferred Stock to
Siemens A.G. at a purchase price of $2.92 per share.

   In April 1999, we issued a Subordinated Promissory Note for an aggregate
principal amount of $2.0 million and a warrant to purchase 684,932 shares of
Series H Preferred Stock to Palomar Ventures L.P., at an exercise price of
$2.92 per share.

   In June 1999, we issued a convertible promissory note to an affiliate of
Covad Communications Group, Inc. for an aggregate principal amount of $5.0
million. The note was convertible into 497,663 shares of Series I Preferred
Stock at an exercise price of $10.09 per share.

Item 16. Exhibits and Financial Statement Schedules

   (a) Exhibits

<TABLE>
<CAPTION>
 Exhibit
  Number
 -------
 <C>      <S>
  1.1*    Form of Underwriting Agreement.
  3.1(1)  Restated Certificate of Incorporation of the Registrant.
  3.2(2)  Restated Bylaws of the Registrant.
  3.3     Certificate of Determination defining rights, preferences and
          privileges of Registrant's Series A non-voting convertible preferred
          stock.
  4.1(1)  Specimen Common Stock Certificate.
  5.1*    Opinion of Wilson Sonsini Goodrich & Rosati, Professional
          Corporation.
 10.1(1)  Form of Indemnification Agreement between the Registrant and each of
          its directors and officers.
 10.2(1)  1999 Stock Plan and form of agreements thereunder.
 10.3(1)  1999 Employee Stock Purchase Plan and form of agreements thereunder.
 10.4     1999 Nonstatutory Stock Option Plan and form of agreements
          thereunder.
 10.5(1)  Investor's Rights Agreement dated July 30, 1993 executed in
          connection with the issuance and sale of our Series A Preferred
          Stock.
 10.6(1)  Amendment No. 1 to the Investors' Rights Agreement, dated February 9,
          1994.
 10.7(1)  Amendment No. 2 to the Investors' Rights Agreement, dated September
          30, 1994.
 10.8(1)  Amendment No. 3 to the Investors' Rights Agreement, dated September
          1, 1995.
 10.9(1)  Amendment No. 4 to the Investors' Rights Agreement, dated December
          31, 1996.
 10.10(1) Amendment No. 5 to the Investors' Rights Agreement, dated February
          17, 1998
 10.11(1) Amendment No. 6 to the Investors' Rights Agreement, dated June 10,
          1998.
 10.12(1) Amendment No. 7 to the Investors' Rights Agreement, dated January 11,
          1999.
 10.13(1) Amendment No. 9 to the Investors' Rights Agreement, dated June 28,
          1999.
 10.14    Amendment No. 10 to the Investors' Rights Agreement, dated November
          21, 1999.
 10.15(1) Geico Building Office Lease dated August 19, 1993 by and between
          Government Employees Insurance Company and Efficient.
 10.16(1) Modification of Geico Office Lease dated May 8, 1995 by and between
          Government Employees Insurance Company and Efficient.
</TABLE>

                                      II-2
<PAGE>

<TABLE>
<CAPTION>
 Exhibit
  Number
 -------
 <C>      <S>
 10.17(1) Graystone Office Park Lease dated September 8, 1998 by and between
          Lanny Houillion and Efficient.
 10.18    Office Lease Agreement dated November 5, 1999 by and between Jackson-
          Shaw/Alpha Metro Limited Partnership and Efficient.
 10.19(3) Agreement and Plan of Merger and Reorganization dated as of November
          21, 1999 by and among Efficient Networks, Inc., Cabletron Systems,
          Inc., Flowpoint Corporation and Fire Acquisition Corporation (the
          "Merger Agreement").
 10.20(3) Amendment No. 1 to the Merger Agreement dated December 14, 1999.
 10.21(3) Amendment No. 2 to the Merger Agreement dated December 17, 1999.
 10.22    Voting Agreement dated November 20, 1999 entered into in connection
          with the Merger Agreement.
 10.23    Reseller Agreement effective as of December 17, 1999 between the
          Registrant and Cabletron Systems, Inc.
 10.24    Standstill and Disposition Agreement dated December 17, 1999 between
          the Registrant and Cabletron Systems, Inc.
 10.25    Cross License Agreement dated December 17, 1999 between the
          Registrant and Cabletron Systems, Inc.
 23.1     Consent of Independent Auditors regarding Efficient Networks, Inc.
 23.2     Consent of Independent Auditors regarding FlowPoint Corporation.
 23.3*    Consent of Counsel (see Exhibit 5.1).
 24.1     Power of Attorney--See Page II-5.
</TABLE>
- --------
*  To be filed by amendment.

(1) Incorporated by reference to Registrant's Registration Statement on Form S-
    1 declared effective July 14, 1999 (Commission File No. 333-77795).
(2) Incorporated by reference to Registrant's Annual Report on Form 10-K for
    fiscal 1999, filed September 13, 1999.
(3) Incorporated by reference to Registrant's Current Report on Form 8-K filed
    December 30, 1999.

   (b) Financial Statement Schedules

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----
     <S>                                                                    <C>
     Independent Auditors' Report on Schedule.............................. S-1
     Schedule II--Valuation and Qualifying Accounts........................ S-2
</TABLE>

   Schedules not listed above have been omitted because the information
required to be set forth therein is not applicable or is shown in the
Consolidated Financial Statements or Notes thereto.

Item 17. Undertakings

   The undersigned Registrant hereby undertakes to provide to the Underwriters
at the closing specified in the Underwriting Agreement certificates in such
denominations and registered in such names as required by the Underwriters to
permit prompt delivery to each purchaser.

   Insofar as indemnification by the Registrant for liabilities arising under
the Securities Act may be permitted to directors, officers and controlling
persons of the Registrant pursuant to the provisions referenced in Item 14 of
this Registration Statement or otherwise, the Registrant has been advised that
in the opinion of the Securities and Exchange Commission such indemnification
is against public policy as expressed in the Securities Act, and is, therefore,
unenforceable. In the event that a claim for indemnification against such
liabilities (other than the payment by the Registrant of expenses incurred or
paid by a director, officer, or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by a
director, officer or controlling person in connection with the securities being
registered hereunder, the Registrant will, unless in the opinion of its counsel
the matter has been settled by controlling precedent, submit to a court of
appropriate jurisdiction the question whether such indemnification by it is
against public policy as expressed in the Securities Act and will be governed
by the final adjudication of such issue.

                                      II-3
<PAGE>

   The undersigned Registrant hereby undertakes that:

     (1) For purposes of determining any liability under the Securities Act,
  the information omitted from the form of Prospectus filed as part of this
  Registration Statement in reliance upon Rule 430A and contained in a form
  of Prospectus filed by the Registrant pursuant to Rule 424(b)(1) or (4) or
  497(h) under the Securities Act shall be deemed to be part of this
  Registration Statement as of the time it was declared effective.

     (2) For the purpose of determining any liability under the Securities
  Act, each post-effective amendment that contains a form of Prospectus shall
  be deemed to be a new registration statement relating to the securities
  offered therein, and the offering of such securities at that time shall be
  deemed to be the initial bona fide offering thereof.

                                      II-4
<PAGE>

                                   SIGNATURES

   Pursuant to the requirements of the Securities Act of 1933, as amended, the
registrant has duly caused this Registration Statement to be signed on its
behalf by the undersigned, thereunto duly authorized, in the City of Dallas,
State of Texas, on the 7th day of January, 2000.

                                          EFFICIENT NETWORKS, INC.

                                                  /s/ Mark A. Floyd
                                          By:__________________________________
                                                      Mark A. Floyd
                                              President and Chief Executive
                                                         Officer

                               POWER OF ATTORNEY

   KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints Mark A. Floyd and Jill S. Manning and each of
them severally, as true and lawful attorneys-in-fact and agents with full power
of substitution and resubstitution, for him and in his name, place and stead,
in any and all capacities to sign the Registration Statement filed herewith and
any or all amendments to said Registration Statement (including post-effective
amendments and registration statements filed pursuant to Rule 462 and
otherwise), and to file the same, with all exhibits thereto, and other
documents in connection therewith, with the Securities and Exchange Commission
granting unto said attorneys-in-fact and agents the full power and authority to
do and perform each and every act and thing requisite and necessary to be done
in and about the foregoing, as to all intents and purposes as he or she might
or could do in person, hereby ratifying and confirming all that said attorneys-
in-fact and agents or any of them, or his substitute, may lawfully do or cause
to be done by virtue hereof.

   Pursuant to the requirements of the Securities Act of 1933, as amended, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated below.

<TABLE>
<CAPTION>
              Signature                          Title                   Date
              ---------                          -----                   ----

<S>                                    <C>                        <C>
         /s/ Mark A. Floyd             President, Chief Executive   January 7, 2000
______________________________________  Officer and Chairman of
            Mark A. Floyd               the Board (Principal
                                        Executive Officer)

        /s/ Jill S. Manning            Vice President and Chief     January 7, 2000
______________________________________  Financial Officer
           Jill S. Manning              (Principal Financial
                                        Officer)

        /s/ Bruce W. Brown             Director                     January 7, 2000
______________________________________
            Bruce W. Brown

        /s/ James P. Gauer             Director                     January 7, 2000
______________________________________
            James P. Gauer
</TABLE>

                                      II-5
<PAGE>

<TABLE>
<CAPTION>
              Signature                          Title                   Date
              ---------                          -----                   ----

<S>                                    <C>                        <C>
                                       Director
______________________________________
             Robert Hawk

                                       Director
______________________________________
            Robert A. Hoff

                                       Director
______________________________________
            Anthony Maher

     /s/ William L. Martin III         Director                     January 7, 2000
______________________________________
        William L. Martin III

      /s/ Thomas H. Peterson           Director                     January 7, 2000
______________________________________
          Thomas H. Peterson
</TABLE>

                                      II-6
<PAGE>

                    Independent Auditors' Report on Schedule

The Board of Directors
Efficient Networks, Inc.:

   Under date of July 6, 1999, except as to note 13 which is as of July 20,
1999, we reported on the consolidated balance sheets of Efficient Networks,
Inc. and subsidiary as of June 30, 1998 and 1999 and the related consolidated
statements of operations, stockholders' equity (deficit), and cash flows for
each of the years in the three-year period ended June 30, 1999, which are
included in the Company's annual report on form 10-K. In connection with our
audits of the aforementioned consolidated financial statements, we also audited
the related consolidated financial statement schedule included in the annual
report on form 10-K. This financial statement schedule is the responsibility of
the Company's management. Our responsibility is to express an opinion on this
financial statement schedule based on our audits.

   In our opinion, such consolidated financial statement schedule, when
considered in relation to the basic consolidated financial statements taken as
a whole, presents fairly, in all material respects, the information set forth
therein.

                                          KPMG LLP

Dallas, Texas
July 6, 1999

                                      S-1
<PAGE>

                            EFFICIENT NETWORKS, INC.

                 SCHEDULE II--VALUATION AND QUALIFYING ACCOUNTS
                                 (in thousands)

<TABLE>
<CAPTION>
                                    Additions  Additions
                         Balance at charged to charged to            Balance at
                         Beginning  costs and    other                 end of
Description              of period   expenses   accounts  Deductions   period
- -----------              ---------- ---------- ---------- ---------- ----------
<S>                      <C>        <C>        <C>        <C>        <C>
FOR THE YEAR ENDED JUNE
 30, 1999
Allowances Deducted
 from Assets
 Accounts receivable...     $ 15       105        --         --         $120
 Inventories...........      150       130        --         --          280
                            ----       ---        ---        ---        ----
  Total Allowances
   Deducted from
   Assets..............     $165       235        --         --         $400
                            ====       ===        ===        ===        ====
FOR THE YEAR ENDED JUNE
 30, 1998
Allowances Deducted
 from Assets
 Accounts receivable...     $ 25        11        --          21        $ 15
 Inventories...........       57       124        --          31         150
                            ----       ---        ---        ---        ----
  Total Allowances
   Deducted from
   Assets..............     $ 82       135        --          52        $165
                            ====       ===        ===        ===        ====
FOR THE YEAR ENDED JUNE
 30, 1997
Allowances Deducted
 from Assets
 Accounts receivable...     $ 23         2        --         --         $ 25
 Inventories...........      --         57        --         --           57
                            ----       ---        ---        ---        ----
  Total Allowances
   Deducted from
   Assets..............     $ 23        59        --         --         $ 82
                            ====       ===        ===        ===        ====
</TABLE>

                                      S-2
<PAGE>

                                 EXHIBIT INDEX

<TABLE>
<CAPTION>
 Exhibit
  Number
 -------
 <C>      <S>
  1.1*    Form of Underwriting Agreement.
  3.1(1)  Restated Certificate of Incorporation of the Registrant.
  3.2(2)  Restated Bylaws of the Registrant.
  3.3     Certificate of Determination defining rights, preferences and
          privileges of Registrant's Series A non-voting convertible preferred
          stock.
  4.1(1)  Specimen Common Stock Certificate.
  5.1*    Opinion of Wilson Sonsini Goodrich & Rosati, Professional
          Corporation.
 10.1(1)  Form of Indemnification Agreement between the Registrant and each of
          its directors and officers.
 10.2(1)  1999 Stock Plan and form of agreements thereunder.
 10.3(1)  1999 Employee Stock Purchase Plan and form of agreements thereunder.
 10.4     1999 Nonstatutory Stock Option Plan and form of agreements
          thereunder.
 10.5(1)  Investor's Rights Agreement dated July 30, 1993 executed in
          connection with the issuance and sale of our Series A Preferred
          Stock.
 10.6(1)  Amendment No. 1 to the Investors' Rights Agreement, dated February 9,
          1994.
 10.7(1)  Amendment No. 2 to the Investors' Rights Agreement, dated September
          30, 1994.
 10.8(1)  Amendment No. 3 to the Investors' Rights Agreement, dated September
          1, 1995.
 10.9(1)  Amendment No. 4 to the Investors' Rights Agreement, dated December
          31, 1996.
 10.10(1) Amendment No. 5 to the Investors' Rights Agreement, dated February
          17, 1998
 10.11(1) Amendment No. 6 to the Investors' Rights Agreement, dated June 10,
          1998.
 10.12(1) Amendment No. 7 to the Investors' Rights Agreement, dated January 11,
          1999.
 10.13(1) Amendment No. 9 to the Investors' Rights Agreement, dated June 28,
          1999.
 10.14    Amendment No. 10 to the Investors' Rights Agreement, dated November
          21, 1999.
 10.15(1) Geico Building Office Lease dated August 19, 1993 by and between
          Government Employees Insurance Company and Efficient.
 10.16(1) Modification of Geico Office Lease dated May 8, 1995 by and between
          Government Employees Insurance Company and Efficient.
 10.17(1) Graystone Office Park Lease dated September 8, 1998 by and between
          Lanny Houillion and Efficient.
 10.18    Office Lease Agreement dated November 5, 1999 by and between Jackson-
          Shaw/Alpha Metro Limited Partnership and Efficient.
 10.19(3) Agreement and Plan of Merger and Reorganization dated as of November
          21, 1999 by and among Efficient Networks, Inc., Cabletron Systems,
          Inc., Flowpoint Corporation and Fire Acquisition Corporation (the
          "Merger Agreement").
 10.20(3) Amendment No. 1 to the Merger Agreement dated December 14, 1999.
 10.21(3) Amendment No. 2 to the Merger Agreement dated December 17, 1999.
 10.22    Voting Agreement dated November 20, 1999 entered into in connection
          with the Merger Agreement.
 10.23    Reseller Agreement effective as of December 17, 1999 between the
          Registrant and Cabletron Systems, Inc.
 10.24    Standstill and Disposition Agreement dated December 17, 1999 between
          the Registrant and Cabletron Systems, Inc.
 10.25    Cross License Agreement dated December 17, 1999 between the
          Registrant and Cabletron Systems, Inc.
 23.1     Consent of Independent Auditors regarding Efficient Networks, Inc.
 23.2     Consent of Independent Auditors regarding FlowPoint Corporation.
 23.3*    Consent of Counsel (see Exhibit 5.1).
 24.1     Power of Attorney--See Page II-5.
</TABLE>
- --------
*  To be filed by amendment.

(1) Incorporated by reference to Registrant's Registration Statement on Form S-
    1 declared effective July 14, 1999 (Commission File No. 333-77795).
(2) Incorporated by reference to Registrant's Annual Report on Form 10-K for
    fiscal 1999, filed September 13, 1999.
(3) Incorporated by reference to Registrant's Current Report on Form 8-K filed
    December 30, 1999.

<PAGE>

                                                                     EXHIBIT 3.3

                          CERTIFICATE OF DESIGNATION
                    OF RIGHTS, PREFERENCES AND PRIVILEGES
             OF SERIES A NON-VOTING CONVERTIBLE PREFERRED STOCK OF
                           EFFICIENT NETWORKS, INC.,
                            A DELAWARE CORPORATION

Pursuant to Section 151 of the General Corporation Law of the State of Delaware,
Mark Floyd and Jill Manning hereby certify that:

          (a)  They are the duly elected Chief Executive Officer and Secretary,
respectively, of Efficient Networks, Inc., a Delaware corporation (the
"Corporation").
 -----------

          (b)  Pursuant to the authority conferred upon the Board of Directors
of the Corporation by Article Four of the Corporation's Amended and Restated
Certificate of Incorporation (the "Certificate"), the Board of Directors of the
                                   -----------
Corporation on November 19, 1999 adopted the following recitals and resolutions
creating a new series of preferred stock designated as Series A Non-Voting
Convertible Preferred Stock:

          "WHEREAS, the Certificate provides for a class of shares known as
Preferred Stock, issuable from time to time in one or more series;

          WHEREAS, the Board of Directors of the Corporation is authorized by
the Certificate to determine the powers, rights, preferences, limitations and
restrictions granted to or imposed upon any wholly unissued series of Preferred
Stock, to fix the number of shares constituting any such series, and to
determine the designation thereof, or any of them;

          WHEREAS, the Board of Directors of the Corporation desires, pursuant
to its authority as aforesaid, to determine and fix the powers, rights
preferences, limitations and restrictions relating to a series of Preferred
Stock and the number of shares constituting, and the designation of, such
series;

          NOW, THEREFORE, BE IT RESOLVED, that pursuant to the authority vested
in the Board of Directors of the Corporation in accordance with the provisions
of the Certificate, a new series of Preferred Stock to be designated "Series A
Non-Voting Convertible Preferred Stock," is hereby created, and the Board of
Directors hereby fixes and determines the designation of, the number of shares
constituting, and the rights, preferences, privileges and restrictions relating
to, such series of Preferred Stock as follows (all terms used herein which are
not otherwise defined shall have the meanings set forth in the Certificate);

          Section 1.  Designation, Amount and Par Value. The series of preferred
                      ---------------------------------
stock shall be designated as its Series A Non-Voting Convertible Preferred Stock
(the "Series A Preferred") and the number of shares so designated shall be six
      ------------------
thousand three hundred (6,300) (which shall not be subject to increase without
the consent of the holders of the Series A Preferred (each, a "Holder" and
                                                               ------
collectively, the "Holders")). Each share of Series A Preferred shall have a par
                   -------
value of $.001.

          Section 2.  Voting Rights. Except as otherwise provided herein and as
                      -------------
otherwise required by law, the Series A Preferred shall have no voting rights.
However, so long as any shares of Series A Preferred are outstanding, the
Corporation shall not, without the affirmative vote of the
<PAGE>

Holders of 66% of the shares of the Series A Preferred then outstanding, (a)
alter or change adversely the powers, preferences or rights given to the Series
A Preferred or alter or amend this Certificate of Designation, (b) authorize or
create or issue any class of stock ranking as to dividends or distribution of
assets upon a Liquidation (as defined in Section 4) or redemption senior to or
on parity with the Series A Preferred, (c) amend its certificate of
incorporation or other charter documents so as to affect adversely any rights of
the Holders, (d) increase or decrease the authorized number of shares of Series
A Preferred, or (e) enter into any agreement with respect to the foregoing.

          Section 3.  Dividends. In each fiscal year of the Corporation, the
                      ---------
Holders of shares of Series A Preferred shall be entitled to receive, before any
cash dividends shall be declared and paid upon or set aside for the Common Stock
in such fiscal year, if, when and as declared by the Board of Directors of the
Corporation, dividends payable in cash in an amount per share for such fiscal
year at least equal to the product of (i) the per share amount, if any, of the
cash dividend declared, paid or set aside for the Common Stock during such
fiscal year, multiplied by (ii) the number of shares of Common Stock into which
each such share of Series A Preferred is then convertible.

          Section 4.  Liquidation. Upon any liquidation, dissolution or winding-
                      -----------
up of the Corporation, whether voluntary or involuntary (a "Liquidation"), the
                                                            -----------
Holders shall be entitled to receive out of the assets of the Corporation,
whether such assets are capital or surplus, for each share of Series A Preferred
an amount equal to $0.001 per share before any distribution or payment shall be
made to the holders of any Junior Securities, and thereafter an amount equal to
the amount per share of Series A Preferred that would be distributable to such
Holder if such Holder had converted his or her Series A Preferred into Common
Stock immediately prior to such Liquidation. The Corporation shall mail written
notice of any such Liquidation, not less than 45 days prior to the payment date
stated therein, to each record Holder.

          The merger or consolidation of the Corporation into or with another
corporation (other than one in which the holders of the capital stock of the
Corporation immediately prior to the merger or consolidation continue to hold,
directly or indirectly, more than 50% of the voting power of the capital stock
of the surviving corporation), or the sale, lease, exchange, or other conveyance
of all or substantially all the assets of the Corporation, shall be deemed to be
a liquidation, dissolution, or winding-up of the Corporation for purposes of
this Section 4, in which case the Holders of Series A Preferred shall, unless
the Series A Preferred is or was to be converted into Common Stock in such
transaction or would receive in such transaction consideration equal (on an as
converted basis) to that received by the Common Stock in such transaction, be
entitled to receive the amount payable to such Holders set forth above, unless
the Holders of 66% of the then outstanding shares of Series A Preferred, voting
separately as a single class, elect not to treat any of the foregoing events as
a liquidation, dissolution or winding up by giving written notice thereof to the
Corporation.

          Section 5.  Automatic Conversion.
                      --------------------

          (a)  Automatic Conversions. All shares of Series A Preferred shall be
               ---------------------
automatically converted into shares of Common Stock, at the Conversion Ratio (as
defined in

                                      -2-
<PAGE>

Section (5)(c)), immediately upon the Stockholder Vote. The date upon which
such conversion takes place shall be referred to as the "Conversion Date".
                                                         ---------------

          (b) Immediately after the Conversion Date, the Corporation will
deliver to the Holder a certificate or certificates, subject to the terms of the
Standstill and Disposition Agreement, representing the number of shares of
Common Stock acquired upon the conversion of shares of Series A Preferred.
Notwithstanding the foregoing or anything to the contrary contained herein, the
Corporation shall not be obligated to issue certificates evidencing the shares
of Common Stock issuable upon conversion of any shares of Series A Preferred
until after certificates evidencing such shares of Series A Preferred are
delivered for conversion to the Corporation, or the Holder of such Series A
Preferred notifies the Corporation that such certificates have been lost, stolen
or destroyed and provides a bond (or other adequate security) reasonably
satisfactory to the Corporation to indemnify the Corporation from any loss
incurred by it in connection therewith. The Corporation shall, upon request of
the Holder, if available, use its best efforts to deliver any certificate or
certificates required to be delivered by the Corporation under this Section
electronically through the Depositary Trust Corporation or another established
clearing corporation performing similar functions.

          (c)(i) The conversion ratio for each share of Series A Preferred in
effect on the Conversion Date (the "Conversion Ratio") shall be equal to one
                                    ----------------
thousand shares of Common Stock for one share of Series A Preferred.

                 (ii)  If the Corporation, at any time while any shares of
Series A Preferred are outstanding, shall (a) pay a stock dividend or otherwise
make a distribution or distributions on shares of its Junior Securities payable
in shares of Common Stock, (b) subdivide or split outstanding shares of Common
Stock into a larger number of shares, or (c) combine or reclassify outstanding
shares of Common Stock into a smaller number of shares, or (d) issue by
reclassification and exchange of the Common Stock any shares of capital stock of
the Corporation, then the Conversion Ratio shall be multiplied by a fraction of
which the numerator shall be the number of shares of Common Stock outstanding
before such event. Any adjustment made pursuant to this Section 5(c)(ii) shall
become effective immediately after the record date for the determination of
stockholders entitled to receive such dividend or distribution and shall become
effective immediately after the effective date in the case of a subdivision,
combination or reclassification.

                 (iii) Whenever the Conversion Ratio is adjusted pursuant to
Section 5(c)(ii) the Corporation shall promptly mail to each Holder, a notice
setting forth the Conversion Ratio after such adjustment and setting forth a
reasonably detailed statement of the facts requiring such adjustment.

                 (iv)  In case of any reclassification of the Common Stock, or
any compulsory share exchange pursuant to which the Common Stock is converted
into other securities, cash or property, the Holders of the Series A Preferred
then outstanding shall have the right thereafter to convert such shares only
into the shares of stock and other securities, cash and property receivable upon
or deemed to be held by holders of Common Stock following such reclassification
or share exchange, and the Holders of the Series A Preferred shall be entitled
upon such event to

                                      -3-
<PAGE>

receive such amount of securities, cash or property as a holder of the number of
shares of Common Stock of the Corporation into which such shares of Series A
Preferred could have been converted immediately prior to such reclassification
or share exchange would have been entitled. This provision shall similarly apply
to successive reclassifications or share exchanges.

          (d)  Upon a conversion hereunder the Corporation shall not be required
to issue stock certificates representing fractions of shares of Common Stock,
but may if otherwise permitted, make a cash payment in respect of any final
fraction of a share based on the Per Share Market Value at such time. If the
Corporation elects not, or is unable, to make such a cash payment, the Holder of
a share of Series A Preferred shall be entitled to receive, in lieu of the final
fraction of a share, one whole share of Common Stock.

          (e)  The issuance of certificates for Common Stock on conversion of
Series A Preferred shall be made without charge to the Holders thereof for any
documentary stamp or similar taxes that may be payable in respect of the issue
or delivery of such certificate, provided that the Corporation shall not be
required to pay any tax that may be payable in respect of any transfer involved
in the issuance and delivery of any such certificate upon conversion in a name
other than that of the Holder of such shares of Series A Preferred so converted.

          (f)  The Corporation will take all such actions as may be requisite to
assure that all shares of Common Stock which may be issued upon conversion of
Series A Preferred will, upon issuance, be legally and validly issued, fully
paid and non-assessable and free from all liens and charges with respect to the
issue thereof.

          (g)  Any and all notices or other communications or deliveries to be
provided by the Holders of the Series A Preferred hereunder, shall be in writing
and delivered personally, by facsimile or sent by a nationally recognized
overnight courier service, addressed to the attention of the Chief Executive
Officer of the Corporation addressed to 4201 Spring Valley Road, Dallas, TX
75244, Attention: Mark Floyd, Chief Executive Officer or to facsimile number
972-991-3887, or to such other address or facsimile number as shall be specified
in writing by the Corporation for such purpose. Any and all notices or other
communications or deliveries to be provided by the Corporation hereunder shall
be in writing and delivered personally, by facsimile or sent by a nationally
recognized overnight courier service, addressed to each Holder at the facsimile
telephone number or address of such Holder appearing on the books of the
Corporation, or if no such facsimile telephone number or address appears, at the
principal place of business of the Holder. Any notice or other communication or
deliveries hereunder shall be deemed given and effective on the earliest of (i)
the date of transmission, if such notice or communication is delivered via
facsimile at the facsimile telephone number specified in this Section prior to
6:30 p.m. (New York City time), (ii) the date after the date of transmission, if
such notice or communication is delivered via facsimile at the facsimile
telephone number specified in this Section later than 6:30 p.m. (New York City
time) on any date and earlier than 11:59 p.m. (New York City time) on such date,
(iii) upon receipt, if sent by a nationally recognized overnight courier
service, or (iv) upon actual receipt by the party to whom such notice is
required to be given.

                                      -4-
<PAGE>

          Section 6.  Redemption.
                      ----------

          (a)  If the Series A Preferred has not been automatically converted
pursuant to Section 5(a) prior to July 21, 2000, then, until such time as such
Series A Preferred is converted pursuant to Section 5(a) or otherwise, the
Corporation shall redeem one-fifth (20%) of the Series A Preferred, for cash, at
the Redemption Price on the following dates:

               December 31, 2000
               December 31, 2001
               December 31, 2002
               December 31, 2003
               December 31, 2004

          (b)  Notice of redemption will be mailed at least 30 days but not more
than 80 days before the redemption date to each Holder of Series A Preferred to
be redeemed at his registered address; provided, however, that the Corporation's
                                       --------  -------
failure to give such notice of redemption shall in no way affect its obligation
to redeem the Series A Preferred as provided in this Section 6. The notice of
redemption shall contain the number of shares of Series A Preferred held by the
Holder which shall be redeemed, the date on which the redemption shall be
effective, the Redemption Price, and the address at which the Holder may
surrender to the Corporation its certificates representing shares of Series A
Preferred to be redeemed. Series A Preferred in denominations larger than $1,000
may be redeemed in part but only in whole multiples of $1,000.

          (ii) Once notice of redemption is mailed, the Series A Preferred
called for redemption become due and payable on the redemption date and at the
Redemption Price stated in the notice. Upon surrender of such shares of Series A
Preferred to the Corporation, the Corporation shall pay the redemption Price
stated in the notice and each surrendered certificate shall be canceled and a
new certificate representing the remaining unredeemed shares of Series A
Preferred, if any, shall be issued to each Holder, at the expense of the
Corporation.

          Section 7.  Definitions. For the purposes hereof, the following terms
                      -----------
shall have the following meanings:

     "Common Stock" means the Corporation's common stock, par value $.001 per
      ------------
share, and stock of any other class into which such shares may hereafter have
been reclassified or changed.

     "Junior Securities" means the Common Stock and all other equity securities
      -----------------
of the Corporation which are explicitly junior in liquidation preference to the
Series A Preferred.

     "Per Share Market Value" means on any particular date (a) the closing price
      ----------------------
per share of Common Stock on such date on the NASDAQ or on any subsequent market
on which the Common Stock is then listed or quoted, or if there is no such price
on such date, then the closing bid price on the NASDAQ or on such subsequent
market on the date nearest preceding such date, or (b) if the Common Stock is
not then listed or quoted on the NASDAQ or on such subsequent market, the
closing bid price for a shares of Common Stock in the over-the-counter market,
as reported by the National Quotation Bureau Incorporated or similar
organization or agency succeeding to its

                                      -5-
<PAGE>

functions of reporting prices) at the close of business on such date, or (c) if
the Common Stock is not then reported by the National Quotation Bureau
Incorporated (or similar organization or agency succeeding to its functions of
reporting prices), then the average of the "Pink Sheet" quotes for the relevant
conversion period, as determined in good faith by the Holder, or (d) if the
Common Stock are not then publicly traded the fair market value of a Common
Share as determined in good faith by the Board of Directors of the Corporation.

     "Person" means a corporation, an association, a partnership, organization,
      ------
a business, an individual, a government or political subdivision thereof or a
governmental agency.

     "Redemption Price" means, with respect to each share of Series A Preferred,
      ----------------
an amount of cash (rounded to the nearest whole cent), without interest, equal
to the product of (A) 1,000 times (B) the average closing price of one share of
the Corporation's Common Stock for the five (5) most recent days that the
Corporation's Common Stock has traded ending on the trading day immediately
prior to the Closing Date (as that term is defined in the Agreement and Plan of
Reorganization dated November 21, 1999, as amended), as reported on the Nasdaq
National Market System, and any declared but unpaid dividends on the
Corporation's Common Stock, subject to proportionate adjustment in the event of
any subdivision or split of outstanding shares of Series A Preferred into a
larger number of shares or any combination or reclassification of outstanding
shares of Series A Preferred into a smaller number of shares.

     "Stockholder Vote" means the affirmative vote of a stockholders holding a
      ----------------
majority of the Corporation's Common Stock at a meeting of the Corporation's
stockholders in favor of approving the conversion of the Series A Preferred into
Common Stock in accordance with the terms hereof.

                                     *****

                                      -6-
<PAGE>

     IN WITNESS WHEREOF, Efficient Networks, Inc. has caused this Certificate of
Designation of Rights, Preferences and Privileges of Series A Non-Voting
Convertible Preferred Stock to be signed by the undersigned this 17th day of
December, 1999.


                                            /s/ Mark Floyd
                                   ------------------------------------
                                   Mark Floyd, Chief Executive Officer

                                      -7-

<PAGE>

                                                                    Exhibit 10.4

                           EFFICIENT NETWORKS, INC.

                      1999 NONSTATUTORY STOCK OPTION PLAN
     1.   Purposes of the Plan. The purposes of this Nonstatutory Stock Option
          --------------------
          Plan are:

          .    to attract and retain the best available personnel for positions
               of substantial responsibility,

          .    to provide additional incentive to Employees, Directors and
               Consultants, and

          .    to promote the success of the Company's business.

          Options granted under the Plan will be Nonstatutory Stock Options.

     2.   Definitions.  As used herein, the following definitions shall apply:
          -----------

          (a)  "Administrator" means the Board or any of its Committees as shall
                -------------
be administering the Plan, in accordance with Section 4 of the Plan.

          (b)  "Applicable Laws" means the requirements relating to the
                ---------------
administration of stock option plans under U.S. state corporate laws, U.S.
federal and state securities laws, the Code, any stock exchange or quotation
system on which the Common Stock is listed or quoted and the applicable laws of
any foreign country or jurisdiction where Options are, or will be, granted under
the Plan.

          (c)  "Board" means the Board of Directors of the Company.
                -----
          (d)  "Code" means the Internal Revenue Code of 1986, as amended.
                ----

          (e)  "Committee" means a committee of Directors appointed by the Board
                ---------
in accordance with Section 4 of the Plan.

          (f)  "Common Stock" means the Common Stock of the Company.
                ------------

          (g)  "Company" means Efficient Networks, Inc.
                -------

          (h)  "Consultant" means any person, including an advisor, engaged by
                ----------
the Company or a Parent or Subsidiary to render services to such entity.

          (i)  "Director" means a member of the Board.
                --------

          (j)  "Disability" means total and permanent disability as defined in
                ----------
Section 22(e)(3) of the Code.
<PAGE>

          (k)  "Employee" means any person, including Officers, employed by the
                --------
Company or any Parent or Subsidiary of the Company. A Service Provider shall not
cease to be an Employee in the case of (i) any leave of absence approved by the
Company or (ii) transfers between locations of the Company or between the
Company, its Parent, any Subsidiary, or any successor. Neither service as a
Director nor payment of a director's fee by the Company shall be sufficient to
constitute "employment" by the Company.

          (l)  "Exchange Act" means the Securities Exchange Act of 1934, as
                ------------
amended.

          (m)  "Fair Market Value" means, as of any date, the value of Common
                -----------------
Stock determined as follows:

               (i)    If the Common Stock is listed on any established stock
exchange or a national market system, including without limitation the Nasdaq
National Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market, its
Fair Market Value shall be the closing sales price for such stock (or the
closing bid, if no sales were reported) as quoted on such exchange or system for
the last market trading day prior to the time of determination, as reported in
The Wall Street Journal or such other source as the Administrator deems
reliable;

               (ii)   If the Common Stock is regularly quoted by a recognized
securities dealer but selling prices are not reported, the Fair Market Value of
a Share of Common Stock shall be the mean between the high bid and low asked
prices for the Common Stock on the last market trading day prior to the day of
determination, as reported in The Wall Street Journal or such other source as
the Administrator deems reliable;

               (iii)  In the absence of an established market for the Common
Stock, the Fair Market Value shall be determined in good faith by the
Administrator.

          (n)  "Notice of Grant" means a written or electronic notice evidencing
                ---------------
certain terms and conditions of an individual Option grant. The Notice of Grant
is part of the Option Agreement.

          (o)  "Officer" means a person who is an officer of the Company within
                -------
the meaning of Section 16 of the Exchange Act and the rules and regulations
promulgated thereunder.

          (p)  "Option" means a nonstatutory stock option granted pursuant to
                ------
the Plan, that is not intended to qualify as an incentive stock option within
the meaning of Section 422 of the Code and the regulations promulgated
thereunder.

          (q)  "Option Agreement" means an agreement between the Company and an
                ----------------
Optionee evidencing the terms and conditions of an individual Option grant. The
Option Agreement is subject to the terms and conditions of the Plan.

          (r)  "Option Exchange Program" means a program whereby outstanding
                -----------------------
options are surrendered in exchange for options with a lower exercise price.

                                      -2-
<PAGE>

          (s)  "Optioned Stock" means the Common Stock subject to an Option.
                --------------

          (t)  "Optionee" means the holder of an outstanding Option granted
                --------
under the Plan.

          (u)  "Parent" means a "parent corporation," whether now or hereafter
                ------
existing, as defined in Section 424(e) of the Code.

          (v)  "Plan" means this 1999 Nonstatutory Stock Option Plan.
                ----

          (w)  "Service Provider" means an Employee including an Officer,
                ----------------
Consultant or Director.

          (x)  "Share" means a share of the Common Stock, as adjusted in
                -----
accordance with Section 12 of the Plan.

          (y)  "Subsidiary" means a "subsidiary corporation," whether now or
                ----------
hereafter existing, as defined in Section 424(f) of the Code.

     3.   Stock Subject to the Plan. Subject to the provisions of Section 12 of
          -------------------------
the Plan, the maximum aggregate number of Shares which may be optioned and sold
under the Plan is Nine Hundred Fifty Thousand (950,000) Shares. The Shares may
be authorized, but unissued, or reacquired Common Stock.

          If an Option expires or becomes unexercisable without having been
exercised in full, or is surrendered pursuant to an Option Exchange Program, the
unpurchased Shares which were subject thereto shall become available for future
grant or sale under the Plan (unless the Plan has terminated).

     4.   Administration of the Plan.
          --------------------------

          (a)  Administration. The Plan shall be administered by (i) the Board
               --------------
or (ii) a Committee, which committee shall be constituted to satisfy Applicable
Laws.

          (b)  Powers of the Administrator.  Subject to the provisions of the
               ---------------------------
Plan, and in the case of a Committee, subject to the specific duties delegated
by the Board to such Committee, the Administrator shall have the authority, in
its discretion:

               (i)    to determine the Fair Market Value of the Common Stock;

               (ii)   to select the Service Providers to whom Options may be
granted hereunder;

               (iii)  to determine whether and to what extent Options are
granted hereunder;

                                      -3-
<PAGE>

               (iv)    to determine the number of shares of Common Stock to be
covered by each Option granted hereunder;

               (v)     to approve forms of agreement for use under the Plan;

               (vi)    to determine the terms and conditions, not inconsistent
with the terms of (ii) to select the Service Providers to whom Options may be
granted hereunder; the Plan, of any award granted hereunder. Such terms and
conditions include, but are not limited to, the exercise price, the time or
times when Options may be exercised (which may be based on performance
criteria), any vesting acceleration or waiver of forfeiture restrictions, and
any restriction or limitation regarding any Option or the shares of Common Stock
relating thereto, based in each case on such factors as the Administrator, in
its sole discretion, shall determine;

               (vii)   to reduce the exercise price of any Option to the then
current Fair Market Value if the Fair Market Value of the Common Stock covered
by such Option shall have declined since the date the Option was granted;

               (viii)  to institute an Option Exchange Program;

               (ix)    to construe and interpret the terms of the Plan and
awards granted pursuant to the Plan;

               (x)     to prescribe, amend and rescind rules and regulations
relating to the Plan, including rules and regulations relating to sub-plans
established for the purpose of qualifying for preferred tax treatment under
foreign tax laws;

               (xi)    to modify or amend each Option (subject to Section 14(b)
of the Plan), including the discretionary authority to extend the post-
termination exercisability period of Options longer than is otherwise provided
for in the Plan;

               (xii)   to authorize any person to execute on behalf of the
Company any instrument required to effect the grant of an Option previously
granted by the Administrator;

               (xiii)  to determine the terms and restrictions applicable to
Options;

               (xiv)   to allow Optionees to satisfy withholding tax obligations
by electing to have the Company withhold from the Shares to be issued upon
exercise of an Option that number of Shares having a Fair Market Value equal to
the amount required to be withheld. The Fair Market Value of the Shares to be
withheld shall be determined on the date that the amount of tax to be withheld
is to be determined. All elections by an Optionee to have Shares withheld for
this purpose shall be made in such form and under such conditions as the
Administrator may deem necessary or advisable; and

               (xv)    to make all other determinations deemed necessary or
advisable for administering the Plan.

                                      -4-
<PAGE>

          (c)  Effect of Administrator's Decision. The Administrator's
               ----------------------------------
 decisions, determinations and interpretations shall be final and binding on all
 Optionees and any other holders of Options.

     5.   Eligibility.  Options may be granted to Service Providers; provided,
          -----------
however, that notwithstanding anything to the contrary contained in the Plan,
Options may not be granted to Officers and Directors.

     6.   Limitation. Neither the Plan nor any Option shall confer upon an
          ----------
Optionee any right with respect to continuing the Optionee's relationship as a
Service Provider with the Company, nor shall they interfere in any way with the
Optionee's right or the Company's right to terminate such relationship at any
time, with or without cause.

     7.   Term of Plan. The Plan shall become effective upon its adoption by the
          ------------
Board. It shall continue in effect for ten (10) years, unless sooner terminated
under Section 14 of the Plan.

     8.   Term of Option.  The term of each Option shall be stated in the Option
          --------------
Agreement.

     9.   Option Exercise Price and Consideration.
          ---------------------------------------

          (a)  Exercise Price. The per share exercise price for the Shares to be
               --------------
issued pursuant to exercise of an Option shall be determined by the
Administrator.

          (b)  Waiting Period and Exercise Dates. At the time an Option is
               ---------------------------------
granted, the Administrator shall fix the period within which the Option may be
exercised and shall determine any conditions which must be satisfied before the
Option may be exercised.

          (c)  Form of Consideration. The Administrator shall determine the
               ---------------------
acceptable form of consideration for exercising an Option, including the method
of payment. Such consideration may consist entirely of:

               (i)    cash;

               (ii)   check;

               (iii)  promissory note;

               (iv)   other Shares which (A) in the case of Shares acquired upon
exercise of an option, have been owned by the Optionee for more than six months
on the date of surrender, and (B) have a Fair Market Value on the date of
surrender equal to the aggregate exercise price of the Shares as to which said
Option shall be exercised;

               (v)    consideration received by the Company under a cashless
exercise program implemented by the Company in connection with the Plan;

                                      -5-
<PAGE>

               (vi)   a reduction in the amount of any Company liability to the
Optionee, including any liability attributable to the Optionee's participation
in any Company-sponsored deferred compensation program or arrangement;

               (vii)  such other consideration and method of payment for the
issuance of Shares to the extent permitted by Applicable Laws; or

               (viii) any combination of the foregoing methods of payment.

     10.  Exercise of Option.
          ------------------

          (a)  Procedure for Exercise; Rights as a Shareholder. Any Option
               -----------------------------------------------
granted hereunder shall be exercisable according to the terms of the Plan and at
such times and under such conditions as determined by the Administrator and set
forth in the Option Agreement. An Option may not be exercised for a fraction of
a Share.

               An Option shall be deemed exercised when the Company receives:
(i) written or electronic notice of exercise (in accordance with the Option
Agreement) from the person entitled to exercise the Option, and (ii) full
payment for the Shares with respect to which the Option is exercised. Full
payment may consist of any consideration and method of payment authorized by the
Administrator and permitted by the Option Agreement and the Plan. Shares issued
upon exercise of an Option shall be issued in the name of the Optionee or, if
requested by the Optionee, in the name of the Optionee and his or her spouse.
Until the Shares are issued (as evidenced by the appropriate entry on the books
of the Company or of a duly authorized transfer agent of the Company), no right
to vote or receive dividends or any other rights as a shareholder shall exist
with respect to the Optioned Stock, notwithstanding the exercise of the Option.
The Company shall issue (or cause to be issued) such Shares promptly after the
Option is exercised. No adjustment will be made for a dividend or other right
for which the record date is prior to the date the Shares are issued, except as
provided in Section 12 of the Plan.

               Exercising an Option in any manner shall decrease the number of
Shares thereafter available, both for purposes of the Plan and for sale under
the Option, by the number of Shares as to which the Option is exercised.

          (b)  Termination of Relationship as a Service Provider. If an Optionee
               -------------------------------------------------
ceases to be a Service Provider, other than upon the Optionee's death or
Disability, the Optionee may exercise his or her Option, but only within such
period of time as is specified in the Option Agreement, and only to the extent
that the Option is vested on the date of termination (but in no event later than
the expiration of the term of such Option as set forth in the Option Agreement).
In the absence of a specified time in the Option Agreement, the Option shall
remain exercisable for three (3) months following the Optionee's termination.
If, on the date of termination, the Optionee is not vested as to his or her
entire Option, the Shares covered by the unvested portion of the Option shall
revert to the Plan. If, after termination, the Optionee does not exercise his or
her Option within the time specified by the Administrator, the Option shall
terminate, and the Shares covered by such Option shall revert to the Plan.

                                      -6-
<PAGE>

          (c)  Disability of Optionee. If an Optionee ceases to be a Service
Provider as a result of the Optionee's Disability, the Optionee may exercise his
or her Option within such period of time as is specified in the Option
Agreement, to the extent the Option is vested on the date of termination (but in
no event later than the expiration of the term of such Option as set forth in
the Option Agreement). In the absence of a specified time in the Option
Agreement, the Option shall remain exercisable for twelve (12) months following
the Optionee's termination. If, on the date of termination, the Optionee is not
vested as to his or her entire Option, the Shares covered by the unvested
portion of the Option shall revert to the Plan. If, after termination, the
Optionee does not exercise his or her Option within the time specified herein,
the Option shall terminate, and the Shares covered by such Option shall revert
to the Plan.

          (d)  Death of Optionee. If an Optionee dies while a Service Provider,
               -----------------
the Option may be exercised within such period of time as is specified in the
Option Agreement (but in no event later than the expiration of the term of such
Option as set forth in the Notice of Grant), by the Optionee's estate or by a
person who acquires the right to exercise the Option by bequest or inheritance,
but only to the extent that the Option is vested on the date of death. In the
absence of a specified time in the Option Agreement, the Option shall remain
exercisable for twelve (12) months following the Optionee's termination. If, at
the time of death, the Optionee is not vested as to his or her entire Option,
the Shares covered by the unvested portion of the Option shall immediately
revert to the Plan. The Option may be exercised by the executor or administrator
of the Optionee's estate or, if none, by the person(s) entitled to exercise the
Option under the Optionee's will or the laws of descent or distribution. If the
Option is not so exercised within the time specified herein, the Option shall
terminate, and the Shares covered by such Option shall revert to the Plan.

          (e)  Buyout Provisions. The Administrator may at any time offer to buy
               -----------------
out for a payment in cash or Shares, an Option previously granted based on such
terms and conditions as the Administrator shall establish and communicate to the
Optionee at the time that such offer is made.

     11.  Non-Transferability of Options.  Unless determined otherwise by the
          ------------------------------
Administrator, an Option may not be sold, pledged, assigned, hypothecated,
transferred, or disposed of in any manner other than by will or by the laws of
descent or distribution and may be exercised, during the lifetime of the
Optionee, only by the Optionee. If the Administrator makes an Option
transferable, such Option shall contain such additional terms and conditions as
the Administrator deems appropriate.

     12.  Adjustments Upon Changes in Capitalization, Dissolution, Merger or
          ------------------------------------------------------------------
Asset Sale.
- ----------

          (a)  Changes in Capitalization.  Subject to any required action by the
               -------------------------
shareholders of the Company, the number of shares of Common Stock covered by
each outstanding Option, and the number of shares of Common Stock which have
been authorized for issuance under the Plan but as to which no Options have yet
been granted or which have been returned to the Plan upon cancellation or
expiration of an Option, as well as the price per share of Common Stock covered
by each such outstanding Option, shall be proportionately adjusted for any
increase or decrease in the number of issued shares of Common Stock resulting
from a stock split, reverse stock split, stock

                                      -7-
<PAGE>

dividend, combination or reclassification of the Common Stock, or any other
increase or decrease in the number of issued shares of Common Stock effected
without receipt of consideration by the Company; provided, however, that
conversion of any convertible securities of the Company shall not be deemed to
have been "effected without receipt of consideration." Such adjustment shall be
made by the Board, whose determination in that respect shall be final, binding
and conclusive. Except as expressly provided herein, no issuance by the Company
of shares of stock of any class, or securities convertible into shares of stock
of any class, shall affect, and no adjustment by reason thereof shall be made
with respect to, the number or price of shares of Common Stock subject to an
Option.

          (b)  Dissolution or Liquidation. In the event of the proposed
               --------------------------
dissolution or liquidation of the Company, the Administrator shall notify each
Optionee as soon as practicable prior to the effective date of such proposed
transaction. The Administrator in its discretion may provide for an Optionee to
have the right to exercise his or her Option until ten (10) days prior to such
transaction as to all of the Optioned Stock covered thereby, including Shares as
to which the Option would not otherwise be exercisable. In addition, the
Administrator may provide that any Company repurchase option applicable to any
Shares purchased upon exercise of an Option shall lapse as to all such Shares,
provided the proposed dissolution or liquidation takes place at the time and in
the manner contemplated. To the extent it has not been previously exercised, an
Option will terminate immediately prior to the consummation of such proposed
action.

          (c)  Merger or Asset Sale. In the event of a merger of the Company
               --------------------
with or into another corporation, or the sale of substantially all of the assets
of the Company, each outstanding Option shall be assumed or an equivalent option
or right substituted by the successor corporation or a Parent or Subsidiary of
the successor corporation. In the event that the successor corporation refuses
to assume or substitute for the Option, the Optionee shall fully vest in and
have the right to exercise the Option as to all of the Optioned Stock, including
Shares as to which it would not otherwise be vested or exercisable. If an Option
becomes fully vested and exercisable in lieu of assumption or substitution in
the event of a merger or sale of assets, the Administrator shall notify the
Optionee in writing or electronically that the Option shall be fully vested and
exercisable for a period of fifteen (15) days from the date of such notice, and
the Option shall terminate upon the expiration of such period. For the purposes
of this paragraph, the Option shall be considered assumed if, following the
merger or sale of assets, the option or right confers the right to purchase or
receive, for each Share of Optioned Stock, immediately prior to the merger or
sale of assets, the consideration (whether stock, cash, or other securities or
property) received in the merger or sale of assets by holders of Common Stock
for each Share held on the effective date of the transaction (and if holders
were offered a choice of consideration, the type of consideration chosen by the
holders of a majority of the outstanding Shares); provided, however, that if
such consideration received in the merger or sale of assets is not solely common
stock of the successor corporation or its Parent, the Administrator may, with
the consent of the successor corporation, provide for the consideration to be
received upon the exercise of the Option, for each Share of Optioned Stock to be
solely common stock of the successor corporation or its Parent equal in fair
market value to the per share consideration received by holders of Common Stock
in the merger or sale of assets.

                                      -8-
<PAGE>

     13.  Date of Grant. The date of grant of an Option shall be, for all
          -------------
purposes, the date on which the Administrator makes the determination granting
such Option, or such other later date as is determined by the Administrator.
Notice of the determination shall be provided to each Optionee within a
reasonable time after the date of such grant.

     14.  Amendment and Termination of the Plan.
          -------------------------------------

          (a)  Amendment and Termination. The Board may at any time amend,
               -------------------------
alter, suspend or terminate the Plan.

          (b)  Effect of Amendment or Termination. No amendment, alteration,
               ----------------------------------
suspension or termination of the Plan shall impair the rights of any Optionee,
unless mutually agreed otherwise between the Optionee and the Administrator,
which agreement must be in writing and signed by the Optionee and the Company.
Termination of the Plan shall not affect the Administrator's ability to exercise
the powers granted to it hereunder with respect to options granted under the
Plan prior to the date of such termination.

     15.  Conditions Upon Issuance of Shares.
          ----------------------------------

          (a)  Legal Compliance. Shares shall not be issued pursuant to the
               ----------------
exercise of an Option unless the exercise of such Option and the issuance and
delivery of such Shares shall comply with Applicable Laws and shall be further
subject to the approval of counsel for the Company with respect to such
compliance.

          (b)  Investment Representations. As a condition to the exercise of an
               --------------------------
Option the Company may require the person exercising such Option to represent
and warrant at the time of any such exercise that the Shares are being purchased
only for investment and without any present intention to sell or distribute such
Shares if, in the opinion of counsel for the Company, such a representation is
required.

     16.  Inability to Obtain Authority.  The inability of the Company to obtain
          -----------------------------
authority from any regulatory body having jurisdiction, which authority is
deemed by the Company's counsel to be necessary to the lawful issuance and sale
of any Shares hereunder, shall relieve the Company of any liability in respect
of the failure to issue or sell such Shares as to which such requisite authority
shall not have been obtained.

     17.  Reservation of Shares. The Company, during the term of this Plan, will
          ---------------------
at all times reserve and keep available such number of Shares as shall be
sufficient to satisfy the requirements of the Plan.

                                      -9-
<PAGE>

                           EFFICIENT NETWORKS, INC.


                      1999 NONSTATUTORY STOCK OPTION PLAN


                            STOCK OPTION AGREEMENT

     Unless otherwise defined herein, the terms defined in the Plan shall have
the same defined meanings in this Option Agreement.

I.   NOTICE OF STOCK OPTION GRANT
     ----------------------------

     ((OptioneeName))

     ((OptioneeAddress1))

     ((OptioneeAddress2))

     You have been granted an option to purchase Common Stock of the Company,
subject to the terms and conditions of the Plan and this Option Agreement, as
follows:

     Grant Number                     ((GrantNumber))____________________

     Date of Grant                    ((DateofGrant))____________________

     Vesting Commencement Date        ((VestingCommencement))____________

     Exercise Price per Share         $((ExercisePrice))_________________

     Total Number of Shares Granted   ((SharesGranted))__________________

     Total Exercise Price             $((ExercisePrice))_________________

     Type of Option:                  Nonstatutory Stock Option

     Term/Expiration Date:            ((ExpirationDate))_________________

     Note:
     ----

     Stock options are complicated instruments. Please contact your tax advisor
for any personal tax issues that may arise with any stock transactions.

     Vesting Schedule:
     ----------------

     Subject to the Optionee continuing to be a Service Provider on such dates,
this Option shall vest and become exercisable in accordance with the following
schedule:
<PAGE>

     25% of the Shares subject to the Option shall vest twelve months after the
Vesting Commencement Date, and 1/48th of the Shares subject to the Option shall
vest upon the last day of each month thereafter, subject to the Optionee
continuing to be a Service Provider on such dates.

     Termination Period:
     ------------------

     This Option may be exercised for three months after Optionee ceases to be a
Service Provider. Upon the death or Disability of the Optionee, this Option may
be exercised for such longer period as provided in the Plan. In no event shall
this Option be exercised later than the Term/Expiration Date as provided above.

II.  AGREEMENT
     ---------

     1.   Grant of Option. The Plan Administrator of the Company hereby grants
          ---------------
to the Optionee named in the Notice of Grant attached as Part I of this
Agreement (the "Optionee") an option (the "Option") to purchase the number of
Shares, as set forth in the Notice of Grant, at the exercise price per share set
forth in the Notice of Grant (the "Exercise Price"), subject to the terms and
conditions of the Plan, which is incorporated herein by reference. Subject to
Section 14(b) of the Plan, in the event of a conflict between the terms and
conditions of the Plan and the terms and conditions of this Option Agreement,
the terms and conditions of the Plan shall prevail.

     2.   Exercise of Option.
          ------------------

          (a)  Right to Exercise.  This Option is exercisable during its term in
               -----------------
accordance with the Vesting Schedule set out in the Notice of Grant and the
applicable provisions of the Plan and this Option Agreement.

          (b)  Method of Exercise. This Option is exercisable by delivery of an
               ------------------
exercise notice, in the form attached as Exhibit A (the "Exercise Notice"),
which shall state the election to exercise the Option, the number of Shares in
respect of which the Option is being exercised (the "Exercised Shares"), and
such other representations and agreements as may be required by the Company
pursuant to the provisions of the Plan. The Exercise Notice shall be completed
by the Optionee and delivered to the Company's Chief Financial Officer. The
Exercise Notice shall be accompanied by payment of the aggregate Exercise Price
as to all Exercised Shares. This Option shall be deemed to be exercised upon
receipt by the Company of such fully executed Exercise Notice accompanied by
such aggregate Exercise Price.

          No Shares shall be issued pursuant to the exercise of this Option
unless such issuance and exercise complies with Applicable Laws. Assuming such
compliance, for income tax purposes the Exercised Shares shall be considered
transferred to the Optionee on the date the Option is exercised with respect to
such Exercised Shares.

                                      -2-
<PAGE>

     3.   Method of Payment.  Payment of the aggregate Exercise Price shall be
          -----------------
by any of the following, or a combination thereof, at the election of the
Optionee:

          (a)  cash;

          (b)  check;

          (c)  consideration received by the Company under a cashless exercise
program implemented by the Company in connection with the Plan; or

          (d)  surrender of other Shares which (i) in the case of Shares
acquired upon (6) months on the date of surrender, and (ii) have a Fair Market
Value on the date of surrender equal to the aggregate Exercise Price of the
Exercised Shares.

     4.   Non-Transferability of Option.  This Option may not be transferred
          -----------------------------
in any manner otherwise than by will or by the laws of descent or distribution
and may be exercised during the lifetime of Optionee only by the Optionee. The
terms of the Plan and this Option Agreement shall be binding upon the executors,
administrators, heirs, successors and assigns of the Optionee.

     5.   Term of Option.  This Option may be exercised only within the term set
          --------------
out in the Notice of Grant, and may be exercised during such term only in
accordance with the Plan and the terms of this Option Agreement.

     6.   Tax Consequences.  Some of the federal tax consequences relating to
          ----------------
this Option, as of the date of this Option, are set forth below. THIS SUMMARY IS
NECESSARILY INCOMPLETE, AND THE TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE.
THE OPTIONEE SHOULD CONSULT A TAX ADVISER BEFORE EXERCISING THIS OPTION OR
DISPOSING OF THE SHARES.

          (a)  Exercising the Option. The Optionee may incur regular federal
               ---------------------
income tax liability upon exercise of an NSO. The Optionee will be treated as
having received compensation income (taxable at ordinary income tax rates) equal
to the excess, if any, of the Fair Market Value of the Exercised Shares on the
date of exercise over their aggregate Exercise Price. If the Optionee is an
Employee or a former Employee, the Company will be required to withhold from his
or her compensation or collect from Optionee and pay to the applicable taxing
authorities an amount in cash equal to a percentage of this compensation income
at the time of exercise, and may refuse to honor the exercise and refuse to
deliver Shares if such withholding amounts are not delivered at the time of
exercise.

          (b)  Disposition of Shares. If the Optionee holds NSO Shares for at
               ---------------------
least one year, any gain realized on disposition of the Shares will be treated
as long-term capital gain for federal income tax purposes.

                                      -3-
<PAGE>

     7.   Entire Agreement; Governing Law.  The Plan is incorporated herein by
          -------------------------------
reference. The Plan and this Option Agreement constitute the entire agreement of
the parties with respect to the subject matter hereof and supersede in their
entirety all prior undertakings and agreements of the Company and Optionee with
respect to the subject matter hereof, and may not be modified adversely to the
Optionee's interest except by means of a writing signed by the Company and
Optionee. This agreement is governed by the internal substantive laws, but not
the choice of law rules, of California.

     8.   NO GUARANTEE OF CONTINUED SERVICE.  OPTIONEE ACKNOWLEDGES AND AGREES
          ---------------------------------
THAT THE VESTING OF SHARES PURSUANT TO THE VESTING SCHEDULE HEREOF IS EARNED
ONLY BY CONTINUING AS A SERVICE PROVIDER AT THE WILL OF THE COMPANY (AND NOT
THROUGH THE ACT OF BEING HIRED, BEING GRANTED AN OPTION OR PURCHASING SHARES
HEREUNDER). OPTIONEE FURTHER ACKNOWLEDGES AND AGREES THAT THIS AGREEMENT, THE
TRANSACTIONS CONTEMPLATED HEREUNDER AND THE VESTING SCHEDULE SET FORTH HEREIN DO
NOT CONSTITUTE AN EXPRESS OR IMPLIED PROMISE OF CONTINUED ENGAGEMENT AS A
SERVICE PROVIDER FOR THE VESTING PERIOD, FOR ANY PERIOD, OR AT ALL, AND SHALL
NOT INTERFERE WITH OPTIONEE'S RIGHT OR THE COMPANY'S RIGHT TO TERMINATE
OPTIONEE'S RELATIONSHIP AS A SERVICE PROVIDER AT ANY TIME, WITH OR WITHOUT
CAUSE.

     By your signature and the signature of the Company's representative below,
you and the Company agree that this Option is granted under and governed by the
terms and conditions of the Plan and this Option Agreement. Optionee has
reviewed the Plan and this Option Agreement in their entirety, has had an
opportunity to obtain the advice of counsel prior to executing this Option
Agreement and fully understands all provisions of the Plan and Option Agreement.
Optionee hereby agrees to accept as binding, conclusive and final all decisions
or interpretations of the Administrator upon any questions relating to the Plan
and Option Agreement. Optionee further agrees to notify the Company upon any
change in the residence address indicated below.

OPTIONEE                                EFFICIENT NETWORKS, INC.


_______________________________         ___________________________________
Signature                               By

_______________________________         ___________________________________
((OptioneeName))                        Title

((OptioneeAddress1))
((OptioneeAddress2))

                                      -4-
<PAGE>

                                   EXHIBIT A
                                   ---------


                           EFFICIENT NETWORKS, INC.


                      1999 NONSTATUTORY STOCK OPTION PLAN


                                EXERCISE NOTICE


Efficient Networks, Inc.
4201 Spring Valley Road, Suite 1200
Dallas, Texas  75244

Attention:  Chief Financial Officer

     1.   Exercise of Option. Effective as of today, ________________, _____,
          ------------------
the undersigned ("Purchaser") hereby elects to purchase ______________ shares
(the "Shares") of the Common Stock of Efficient Networks, Inc. (the "Company")
under and pursuant to the 1999 Nonstatutory Stock Option Plan (the "Plan") and
the Stock Option Agreement dated, ___________, _____ (the "Option Agreement").
The purchase price for the Shares shall be $__________, as required by the
Option Agreement.

     2.   Delivery of Payment. Purchaser herewith delivers to the Company the
          -------------------
full purchase price for the Shares.

     3.   Representations of Purchaser. Purchaser acknowledges that Purchaser
          ----------------------------
has received, read and understood the Plan and the Option Agreement and agrees
to abide by and be bound by their terms and conditions.

     4.   Rights as Shareholder. Until the issuance (as evidenced by the
          ---------------------
appropriate entry on the books of the Company or of a duly authorized transfer
agent of the Company) of the Shares, no right to vote or receive dividends or
any other rights as a shareholder shall exist with respect to the Optioned
Stock, notwithstanding the exercise of the Option. The Shares so acquired shall
be issued to the Optionee as soon as practicable after exercise of the Option.
No adjustment will be made for a dividend or other right for which the record
date is prior to the date of issuance, except as provided in Section 12 of the
Plan.

     5.   Tax Consultation. Purchaser understands that Purchaser may suffer
          ----------------
adverse tax consequences as a result of Purchaser's purchase or disposition of
the Shares. Purchaser represents that Purchaser has consulted with any tax
consultants Purchaser deems advisable in connection with the purchase or
disposition of the Shares and that Purchaser is not relying on the Company for
any tax advice.
<PAGE>

     6.   Entire Agreement; Governing Law.  The Plan and Option Agreement are
          -------------------------------
incorporated herein by reference. This Agreement, the Plan and the Option
Agreement constitute the entire agreement of the parties with respect to the
subject matter hereof and supersede in their entirety all prior undertakings and
agreements of the Company and Purchaser with respect to the subject matter
hereof, and may not be modified adversely to the Purchaser's interest except by
means of a writing signed by the Company and Purchaser. This agreement is
governed by the internal substantive laws, but not the choice of law rules, of
California.

Submitted by:                      Accepted by:

PURCHASER                          EFFICIENT NETWORKS, INC.


____________________________       ______________________________________
Signature                          By


____________________________       ______________________________________
Print Name                         Title

                                   _____________________________________
                                   Date Received

Address: ____________________      Address:  4201 Spring Valley Road, Suite 1200
- -------                            -------
         ____________________                Dallas, Texas  75244

         ____________________


                                      -2-

<PAGE>

                                                                   Exhibit 10.14

                                                                  Execution Copy
                                                                  --------------
                            EFFICIENT NETWORKS, INC.

              AMENDMENT NO. 10 TO THE INVESTORS' RIGHTS AGREEMENT

     This Amendment No. 10 ("Amendment") to the Investors' Rights Agreement
dated July 30, 1993, as previously amended by Amendments No. 1 through 7 and 9
thereof [there is no Amendment No. 8, the eighth Amendment was mistakenly
numbered No. 9] (together, as amended the "Agreement"), is made as of this 20th
day of November, 1999, by and among Efficient Networks, Inc., a Delaware
corporation (the "Company") and each of the entities listed on Exhibit A hereto
                                                               ---------
(the "Existing Investors").  Capitalized terms used herein which are not defined
herein shall have the definition ascribed to them in the Agreement.

                                    RECITALS
                                    --------

        A.   WHEREAS, the Company intends to enter into an Agreement and Plan of
Reorganization by and among the Company, Fire Acquisition Corporation, a
California corporation and a wholly-owned subsidiary of the Company, Comet
Company, Inc., a Delaware corporation, and Fire Company, Inc., a California
corporation and a wholly-owned subsidiary of Comet Company, Inc., whereby the
Company shall acquire Fire Company, Inc. by merging Fire Company, Inc. into Fire
Acquisition Corporation (the "Merger").

        B.   WHEREAS, pursuant to the terms of the Merger, the Company shall
grant certain registration rights as contained in that certain Standstill &
Disposition Agreement set forth as Attachment I hereto (the "Senior &
                                   ------------
Controlling Registration Rights"), which Senior & Controlling Registration
Rights conflict with or are senior to the the registration rights granted to the
Existing Investors in Section 1 of the Agreement (the "Pre-Existing Registration
Rights").

        C.   WHEREAS, in order to induce Comet Company, Inc. and Fire Company,
Inc. to enter into the Agreement and Plan of Reorganization and consummate the
Merger, the Existing Investors hereby shall agree to New & Controlling
Registration Rights and subordinate the Pre-Existing Registration Rights to the
New & Controlling Registration Rights.

        D.   WHEREAS, in addition, the Company completed its initial public
offering of shares of its Common Stock in July 1999, and consequently, the
affairs of the Company should be governed by its charter documents, and
therefore the Company and the Existing Investors desire to amend the Agreement
in certain other respects, as set forth below.

IN CONSIDERATION OF THE FOREGOING, THE PARTIES HERETO AGREE AS FOLLOWS:

     Pursuant to Section 3.7 of the Agreement, any term of the Agreement may be
amended, and the observance of any term may be waived, by the written consent of
the Company and a majority of the holders of Registrable Securities then
outstanding, (provided that the effect of such amendment or waiver will be that
all holders of Registrable Securities are treated equally)
<PAGE>

and any amendment or waiver effected in accordance therewith shall be binding
upon the Company and each holder of any Registrable Securities then outstanding;
provided, however, that any amendment to or waiver of any term of the Agreement
- --------  -------
that adversely affects the rights of Covad (as defined in Amendment No. 9) shall
require the written consent of Covad.

     1.  AGREEMENT WITH NEW & CONTROLLING REGISTRATION RIGHTS AND SUBORDINATION
         ----------------------------------------------------------------------
OF PRE-EXISTING  REGISTRATION RIGHTS.
- ------------------------------------

     The Existing Investors and Covad, on behalf of themselves and the other
holders of Registrable Securities under the Agreement, hereby (i) consent to the
Senior & Controlling Registration Rights, which consent is given pursuant to
Section 1.14 of the Agreement, and (ii) agree to the Senior & Controlling
Registration Rights, (iii) and, to the extent that the Senior & Controlling
Registration Rights may, by any means of construction or interpretation,
conflict with the Pre-Existing Registration Rights, agree to subordinate in all
respects the Pre-Existing Registration Rights to avoid any conflict whatsoever
with the rights to be granted in Attachment I.  The consents and agreements set
forth in this paragraph are made on behalf of each of the Existing Investors
themselves and on behalf of all holders of Registrable Securities (to ensure
compliance with the amendment and waiver requirements provisions of Section 3.7
and, with respect to Covad, as required by Section 3 of Amendment No. 9).

     2.  AMENDMENTS TO AGREEMENT.
         -----------------------

     In order that the Company's charter documents govern the affairs of the
Company, the Company and the Existing Investors desire to terminate the
following provisions in their entirety and waive any claim relating to any prior
non-compliance therewith:

     Section 2.6 - Management Stock; Section 2.7 - Election of Directors; Board
Meeting Expenses; Indemnities; Board Observer Rights; Section 2.9 - Salaries of
Officers; Section 2.10 - Payment of Dividends.

     3.  EFFECT OF AMENDMENT.
         -------------------

     Except as amended and set forth above, the Agreement shall continue in full
force and effect.  This Amendment No. 10 is binding on all Existing Investors.

     4.  COUNTERPARTS.
         ------------

     This Amendment may be executed in any number of counterparts, each which
will be deemed an original, and all of which together shall constitute one
instrument.

     5.  SEVERABILITY.
         ------------

     If one or more provisions of this Amendment are held to be unenforceable
under applicable law, such provision shall be excluded from this Amendment and
the balance of the Amendment shall be interpreted as if such provision were so
excluded and shall be enforceable in accordance with its terms.
<PAGE>

    6.  ENTIRE AGREEMENT.
        ----------------

    This Amendment, together with the Agreement and Attachment 1 hereto,
constitutes the full and entire understanding and agreement between the parties
with regard to the subjects hereof and thereof.

    7.  GOVERNING LAW.
        -------------

    This Amendment shall be governed by and construed under the laws of the
State of Delaware.

    8.  LEGAL REPRESENTATION.  EACH OF THE EXISTING INVESTORS ACKNOWLEDGES AND
        --------------------
UNDERSTANDS THAT (A) THE COMPANY HAS BEEN REPRESENTED BY WILSON SONSINI GOODRICH
& ROSATI, PROFESSIONAL CORPORATION, (THE "REPRESENTATION") (B) IT OR HE OR SHE
HAS READ AND UNDERSTANDS THE AGREEMENT AND THIS AMENDMENT, (C) IT OR HE OR SHE
HAS BE REPRESENTED IN THE PREPARATION, NEGOTIATION AND EXECUTION OF THIS
AGREEMENT BY OTHER LEGAL COUNSEL OR HAS VOLUNTARILY DECLINED TO SEEK SUCH
REPRESENTATION, AND (D) HE, SHE OR IT EXPRESSLY WAIVES ANY CONFLICT BY VIRTUE OF
THE REPRESENTATION IN THE EVENT THAT HE, SHE, OR IT HAS BEEN, OR PRESENTLY IS, A
CLIENT OF WILSON SONSINI GOODRICH & ROSATI, PROFESSIONAL CORPORATION.



                 [Remainder of Page Intentionally Left Blank]
<PAGE>

     This Amendment is hereby executed as of the date first above written.


                                EFFICIENT NETWORKS, INC.

                                a Delaware corporation


                                By:   /s/ Mark A. Floyd
                                   -----------------------------
                                      Mark A. Floyd, President



      [Signature Page to Amendment No. 10 to Investors' Rights Agreement]
<PAGE>

                                EXISTING INVESTORS

                                COVAD *
                                a Delaware corporation


                                By:   /s/  Robert R. Davenport
                                   ---------------------------------------

                                Name:     Robert R. Davenport
                                     -------------------------------------

                                Title:   E.V.P., Corporate Development
                                      ------------------------------------



                                *as defined in Amendment No. 9


[Signature Page to Amendment No. 10 to Investors' Rights Agreement]
<PAGE>

                                CROSSPOINT VENTURE PARTNERS 1993

                                By:   /s/  Robert A. Hoff
                                   ---------------------------------------

                                Name:   Robert A. Hoff
                                     -------------------------------------

                                Title:   General Partner
                                      ------------------------------------



                                CROSSPOINT 1993 ENTREPRENEURS FUND


                                By:   /s/  Robert A. Hoff
                                   ---------------------------------------

                                Name:   Robert A. Hoff
                                     -------------------------------------

                                Title:     General Partner
                                      ------------------------------------


                                CROSSPOINT VENTURES LS 1997, L.P.


                                By:   /s/ Robert A. Hoff
                                   ---------------------------------------

                                Name:   Robert A. Hoff
                                     -------------------------------------

                                Title:     General Partner
                                      ------------------------------------


      [Signature Page to Amendment No. 10 to Investors' Rights Agreement]
<PAGE>

                                ENTERPRISE PARTNERS II L.P.

                                By:   Enterprise Management Partners II, L.P.,
                                      Its General Partner


                                By:   /s/ Andrew Senyei
                                   ---------------------------------------

                                Name:     Andrew Senyei
                                     -------------------------------------

                                Title:    General Partner
                                      ------------------------------------



                                ENTERPRISE PARTNERS II ASSOCIATES, L.P.

                                By:    Enterprise Management Partners II, L.P.,
                                       Its General Partner


                                By:     /s/ Andrew Senyei
                                   ---------------------------------------

                                Name:       Andrew Senyei
                                     -------------------------------------

                                Title:      General Partner
                                      ------------------------------------


      [Signature Page to Amendment No. 10 to Investors' Rights Agreement]
<PAGE>

                                OCEAN PARK VENTURES, L.P.


                                By:     /s/ Jim Gauer
                                   ---------------------------------------

                                Name:   Jim Gauer
                                     -------------------------------------

                                Title:  General Partner
                                      ------------------------------------




                                PALOMAR VENTURES I, L.P.


                                By:     /s/ Jim Gauer
                                   ---------------------------------------

                                Name:     Jim Gauer
                                     -------------------------------------

                                Title:    General Partner
                                      ------------------------------------


      [Signature Page to Amendment No. 10 to Investors' Rights Agreement]
<PAGE>

                                EL DORADO VENTURES III, L.P.

                                By:   El Dorado Venture Partners III,
                                      Its General Partner


                                By:   /s/  Thomas H. Peterson
                                   ---------------------------------------

                                Name:   Thomas H. Peterson
                                     -------------------------------------

                                Title:  General Partner
                                      ------------------------------------



                                EL DORADO C & L FUND, L.P.

                                By:   El Dorado Venture Partners III,
                                      Its General Partner


                                By:     /s/ Thomas H. Peterson
                                   ---------------------------------------

                                Name:    Thomas H. Peterson
                                     -------------------------------------

                                Title:   General Partner
                                      ------------------------------------



                                EL DORADO TECHNOLOGY IV, L.P.

                                By:   El Dorado Venture Partners III,
                                      Its General Partner


                                By:     /s/ Thomas H. Peterson
                                   ---------------------------------------

                                Name:    Thomas H. Peterson
                                     -------------------------------------

                                Title:     General Partner
                                      ------------------------------------


      [Signature Page to Amendment No. 10 to Investors' Rights Agreement]
<PAGE>

                                EL DORADO VENTURES IV, L.P.

                                By:   El Dorado Venture Partners IV, LLC,
                                      Its General Partner


                                By:     /s/ Thomas H. Peterson
                                   ---------------------------------------

                                Name:    Thomas H. Peterson
                                     -------------------------------------

                                Title:   Managing Member
                                      ------------------------------------



                                EL DORADO TECHNOLOGY 98, L.P.

                                By:   El Dorado Venture Partners IV, LLC,
                                      Its General Partner


                                By:     /s/ Thomas H. Peterson
                                   ---------------------------------------

                                Name:    Thomas H. Peterson
                                     -------------------------------------

                                Title:   Managing Member
                                      ------------------------------------


      [Signature Page to Amendment No. 10 to Investors' Rights Agreement]
<PAGE>

                                MENLO ENTREPRENEURS FUND VI

                                By:  MV Management VI, L.P.
                                     Its General Partner

                                By:     /s/ General Partner
                                   ---------------------------------------

                                Name:
                                     -------------------------------------

                                Title:   General Partner
                                      ------------------------------------



                                MENLO VENTURES VI

                                By:  MV Management VI, L.P.
                                     Its General Partner

                                By:     /s/  General Partner
                                   ---------------------------------------

                                Name:
                                     -------------------------------------

                                Title:   General Partner
                                      ------------------------------------


      [Signature Page to Amendment No. 10 to Investors' Rights Agreement]
<PAGE>

                                ADC TELECOMMUNICATIONS, INC.


                                By:
                                   ---------------------------------------

                                Name:
                                     -------------------------------------

                                Title:
                                      ------------------------------------


      [Signature Page to Amendment No. 10 to Investors' Rights Agreement]
<PAGE>

                                SIEMENS AG


                                By:   /s/ Anthony Maher
                                   ---------------------------------------

                                Name:   Anthony Maher
                                     -------------------------------------

                                Title:  Member of the Executive Board
                                      ------------------------------------
<PAGE>

                                TEXAS INSTRUMENTS, INC.


                                By:   /s/ Thomas J. Gentry
                                   ---------------------------------------

                                Name:   Thomas J. Gentry
                                     -------------------------------------

                                Title:  Vice President, Mgr. Treasury Services
                                      ----------------------------------------


      [Signature Page to Amendment No. 10 to Investors' Rights Agreement]
<PAGE>

                                  EXHIBIT "A"
                                  -----------

                         SCHEDULE OF EXISTING INVESTORS


Name and Address
- ----------------

Covad Communications, Inc.
2330 Central Expressway
Santa Clara, CA  95050

Crosspoint Venture Partners 1993
18551 MacArthur Blvd., Suite 400
Irvine, CA  92715

Crosspoint 1993 Entrepreneurs Fund
18551 MacArthur Blvd., Suite 400
Irvine, CA  92715

Crosspoint Ventures LS 1997, L.P.
18551 MacArthur Blvd., Suite 400
Irvine, CA  92715

Enterprise Partners II, L.P.
7979 Ivanhoe Avenue, Suite 550
La Jolla, CA  92037

Enterprise Partners II Associates, L.P.
7979 Ivanhoe Avenue, Suite 550
La Jolla, CA  92037

Ocean Park Ventures, L.P.
100 Wilshire Boulevard, Suite 400
Santa Monica, CA 90401

El Dorado Ventures III, L.P.
2400 Sand Hill Road, Suite 100
Menlo Park, CA 94025

El Dorado Ventures IV, L.P.
2400 Sand Hill Road, Suite 100
Menlo Park, CA 94025

El Dorado C & L Fund, L.P.
2400 Sand Hill Road, Suite 100
Menlo Park, CA 94025

<PAGE>

                                  EXHIBIT "A"
                                  -----------
                                    (CONT).


Name and Address
- ----------------

El Dorado Technology IV, L.P.
2400 Sand Hill Road, Suite 100
Menlo Park, CA 94025

Menlo Ventures VI, L.P.
3000 Sand Hill Road
Bldg. 4, Suite 100
Menlo Park, CA  94025

Menlo Entrepreneurs Fund VI, L.P.
3000 Sand Hill Road
Bldg. 4, Suite 100
Menlo Park, CA  94025

Siemens Aktiengesellschaft
Hofmannstrasse 51
81359 Munich Germany

Aperture Associates, L.P.
505 Montgomery Street
San Francisco, CA  94111

Texas Instruments Incorporated
7839 Churchill Way
Attn: Corporate Development
Mail Stop 3995
Dallas, Texas  75251

ADC Telecommunications, Inc.
4900 West 78th Street
Minneapolis, Minnesota 55435

Palomar Ventures I, L.P.
100 Wilshire Boulevard, Suite 400
Santa Monica, CA 90401
<PAGE>

                                  ATTACHMENT I
                                  ------------

                       Standstill & Disposition Agreement
                       ----------------------------------

<PAGE>

                                                                   EXHIBIT 10.18

                            OFFICE LEASE AGREEMENT
                            ----------------------



                Jackson-Shaw/Alpha Metro Limited Partnership,
                                   Landlord

                                      and


                           Efficient Networks, Inc.
                                    Tenant
<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<S>                                                                         <C>
1.   LANDLORD..............................................................  1
2.   TENANT................................................................  1
3.   LEASED PREMISES.......................................................  1
4.   TERM:.................................................................  2
5.   BASE RENT; ABATEMENT; SECURITY DEPOSIT................................  2
6.   ADDITIONAL RENT.......................................................  4
7.   TENANT REPAIRS AND MAINTENANCE........................................  8
8.   LANDLORD'S REPAIRS AND MAINTENANCE RESPONSIBILITIES...................  9
9.   UTILITY SERVICE....................................................... 13
10.  SIGNS................................................................. 13
11.  USAGE................................................................. 15
12.  TENANT'S INSURANCE OBLIGATIONS........................................ 15
13.  (INTENTIONALLY DELETED)............................................... 16
14.  COMPLIANCE WITH LAWS, RULES AND REGULATIONS........................... 16
15.  ASSIGNMENT AND SUBLETTING............................................. 17
16.  ALTERATIONS AND IMPROVEMENTS.......................................... 18
17.  CONDEMNATION.......................................................... 19
18.  FIRE AND CASUALTY..................................................... 20
19.  LANDLORD'S INSURANCE OBLIGATION....................................... 21
20.  WAIVER OF SUBROGATION................................................. 22
21.  HOLD HARMLESS......................................................... 22
</TABLE>
<PAGE>

<TABLE>
<S>                                                                         <C>
22.  QUIET ENJOYMENT....................................................... 23
23.  LANDLORD'S RIGHT OF ENTRY............................................. 23
24.  ASSIGNMENT OF LANDLORD'S INTEREST IN LEASE............................ 23
25.  LANDLORD'S LIEN:...................................................... 23
26.  DEFAULT BY TENANT..................................................... 24
27.  REMEDIES FOR TENANT'S DEFAULT......................................... 24
28.  TERMINATION OF OPTIONS................................................ 26
29.  WAIVER OF DEFAULT OR REMEDY........................................... 26
30.  CHOICE OF LAW; VENUE; ATTORNEY'S FEES................................. 27
31.  HOLDING OVER.......................................................... 27
32.  RIGHTS OF MORTGAGEE................................................... 27
33.  ESTOPPEL CERTIFICATES................................................. 28
34.  SUCCESSORS............................................................ 28
35.  REAL ESTATE COMMISSION................................................ 28
36.  DEFAULT BY LANDLORD................................................... 29
37.  MECHANIC'S LIENS...................................................... 29
38.  HAZARDOUS MATERIALS................................................... 29
39.  ENTIRE AGREEMENT AND LIMITATION OF WARRANTIES......................... 31
40.  FINANCIAL STATEMENTS.................................................. 32
41.  FORCE MAJEURE......................................................... 32
42.  ROOF AND OTHER AREAS.................................................. 32
43.  MISCELLANEOUS......................................................... 33
</TABLE>
<PAGE>

<TABLE>
<S>                                                                         <C>
44.  NOTICE................................................................ 35
45.  LANDLORD'S REPRESENTATIONS............................................ 36
46.  TENANT FINANCING...................................................... 36
47.  TENANT'S CONDUCT...................................................... 36
48.  PARKING............................................................... 37
49.  (INTENTIONALLY DELETED)............................................... 37
50.  ALLOWANCES............................................................ 37
51.  IMPROVEMENTS.......................................................... 37
52.  RENT ABATEMENT........................................................ 38
53.  RENEWAL OPTION........................................................ 39
54.  ADDITIONAL SPACE...................................................... 39
55.  SPACE PLAN/DESIGN SERVICES ALLOWANCE.................................. 39
56.  TENANT'S RIGHT OF FIRST REFUSAL....................................... 40
</TABLE>
<PAGE>

                            OFFICE LEASE AGREEMENT


THIS LEASE AGREEMENT is entered into this ______ day of ______________, 1999
(the "Execution Date") by and between:
      --------------

1.   LANDLORD:      Jackson-Shaw/Alpha Metro Limited Partnership ("Landlord"),
                                           and,                    --------
2.   TENANT:        Efficient Networks, Inc., ("Tenant").
                                                ------
3.   LEASED PREMISES:

     (a) In consideration of the rents, terms and covenants of this Office Lease
Agreement (this "Lease"), Landlord hereby leases to Tenant the "Project" locally
                 -----
known as the Alpha Metro building which includes and is defined as (i) those
certain premises (the "Leased Premises" or "Premises") consisting of all of the
                       ---------------      --------
"rentable area" (as defined below) within the 125,538 square foot of "rentable
area" building (the "Building") located at 4849 Alpha Road, Dallas, Texas, (ii)
                     --------
the land upon which the Building is located as described in the attached Exhibit
                                                                         -------
"A" (of which Exhibit "A-1" is the "Site Plan"), and, (iii) all landscaping,
- ---           -------------         ---------
parking and driveway areas, sidewalks, and other improvements thereon.

     (b) The rentable area in the Premises and Building has been calculated in
accordance with BOMA standards for single occupancy buildings. Such rentable
area is hereby stipulated for all purposes hereof to be as stated in Paragraph
                                                                     ---------
3(a) above, whether the same should be more or less as a result of a minor
- ----
variation resulting from actual construction and completion of the Premises for
occupancy so long as such work is done in substantial accordance with the Work
Drawings (hereafter defined).

     (c) The term "Common Areas" as used herein shall mean and refer to the
                   ------------
areas of the Project the repair and maintenance of which are the responsibility
of Landlord under the terms hereof, such as the Building plumbing, elevators,
fire protection alarm and sprinkler systems, access and parking areas, service
roads, loading facilities, sidewalks, landscaping, and the like. The Common
Areas shown on the Site Plan are a material consideration for Tenant entering
into this Lease, and Landlord shall not voluntarily allow any change or
alteration thereto (except as allowed by the Working Drawings), including but
not limited to the parking areas, methods of ingress and egress, direction of
traffic, or any change which would materially affect the operation of Tenant's
business, without Tenant's prior written consent. Landlord shall not voluntarily
permit any public telephones, newspaper machines, vending machines or signage to
be affixed by or on behalf of Landlord on the exterior walls of the Building or
placed in front, or surrounding, the Leased Premises.

OFFICE LEASE AGREEMENT - Page - 1
- ----------------------
<PAGE>

4.   TERM: The term of this Lease shall be One Hundred Twenty-Three (123) months
(the "Primary Term") commencing on the Commencement Date (hereafter defined),
      ------------
and terminating on the last day of the 123/rd/ full calendar month following the
Commencement Date (the "Termination Date") For purposes of this Lease, a "Lease
                        ----------------                                  -----
Year" shall be defined as that twelve (12) month period during the Primary Term
- ----
or any Extension Term (hereinafter defined) commencing on the Commencement Date
or the annual anniversary thereof, as may be applicable; provided, however, that
if the Commencement Date is a day other than the first day of a calendar month,
then the first Lease Year shall include that period of time from the
Commencement Date up to the first day of the next calendar month, and any
subsequent Lease Year shall be the twelve (12) month period beginning on the
first day of such month. For purposes of this Lease, a "Lease Month" shall be
                                                        -----------
defined as those successive calendar month periods beginning with the
Commencement Date and continuing through the Primary Term or any Extension Term
of this Lease; provided, however, if the Commencement Date is a day other than
the first day of a calendar month, then the first Lease Month shall include that
period of time from the Commencement Date up to the first day of the next
calendar month, and each subsequent Lease Month shall be a calendar month period
beginning on the first day of such month. The Primary Term and any Extension
Terms are sometimes collectively referred to herein as the "Term". For purposes
                                                            ----
of this Lease, the "Commencement Date" shall be the earlier to occur of (i)
                    -----------------
Substantial Completion (defined along with derivations thereof in Exhibit "B"
                                                                  ----------
attached hereto) or (ii) March 1, 2000; provided, however if Substantial
Completion has not occurred by March 1, 2000, and such failure has not been
caused by Tenant or Tenant's Representatives (below defined), Base Rent shall be
abated until Substantial Completion has occurred (and the Rent Abatement Period,
as hereinafter defined, shall likewise be extended), provided further that if
Substantial Completion has not occurred by September 30, 2000, and such failure
has not been caused by force majeure or Tenant or Tenant's Representatives, then
Tenant may terminate this Lease by written notice to Landlord no later than
October 15, 2000, such termination to be effective as of the date of said
notice, and the Security Deposit (below defined) and any Rent deposit shall be
returned to Tenant, and neither party shall have any further liability one to
the other.

5.   BASE RENT; ABATEMENT; SECURITY DEPOSIT:

     (a) Tenant's obligation to pay Rent (including Additional Rent (hereafter
defined) shall commence on the Commencement Date. Commencing on the
Commencement Date, Tenant agrees to pay to Landlord the following rental amounts
(sometimes referred to in this Lease as the "Base Rent" or "Base Rental"):
                                             ---------      -----------

  LEASE   RENTABLE         ANNUAL RENT      MONTHLY      COST/SQ FT OF
  -----   --------         -----------      -------      -------------
 MONTHS     AREA                             RENT       RENTABLE AREA IN
 ------     ----                             ----       ----------------
                                                        LEASED PREMISES
                                                        ---------------

  1-9     104,435 sf.    $ 2,088,700.00   $ 174,058.33  $ 20.00
  10-62   125,538 sf.    $ 2,510,760.00   $ 209,230.00  $ 20.00
  63-123  125,538 sf.    $ 2,855,989.50   $ 237,999.12  $ 22.75

OFFICE LEASE AGREEMENT - Page - 2
- ----------------------
<PAGE>

However, no Base Rent shall be due for the Early Occupancy Period (hereafter
defined) or for the first two full Lease Months thereafter (collectively, the
"Rent Abatement Period"). Payment of Rent is subject to proration for partial
 ---------------------
months and to adjustment for early or delayed occupancy under the terms hereof.
If the Commencement Date is a day that is other than the first day of a calendar
month, then (i) the Rental Abatement Period shall not include the first Lease
Month and shall, instead, include the second, third and fourth full Lease
Months, and (ii) the Base Rent for such partial first month (prorated as above
provided) shall be due and payable within three (3) days of the Commencement
Date and, subject to the credit for which provision is made in the first
sentence of Paragraph 5(b) below, the next installment shall be due and payable
            --------------
on or before expiration of the Rent Abatement Period. If the Commencement Date
is the first day of a calendar month, then, subject to the credit for which
provision is made in the first sentence of Paragraph 5(b) below, the first
                                           --------------
installment of Base Rent shall be due and payable by Tenant on or before
expiration of the Rent Abatement Period. All subsequent installments of Base
Rent shall be due and payable on or before the first (1st) day of each calendar
month during the Lease Term, except as otherwise provided herein. Base Rent
shall be payable to Landlord monthly, in advance, without demand, deduction or
offset, unless otherwise provided herein, in lawful money of the United States
of America at the address stated below. All sums of money, other than Base Rent,
which become due under this Lease are deemed to be "Additional Rent" (and are
                                                    ---------------
herein so called). The nonpayment of any Additional Rent shall afford Landlord
all the rights and remedies as are herein provided in the case of nonpayment of
any Base Rent.

     (b)  On the Execution Date, Base Rent for the first full calendar month for
which Base Rent is due under Paragraph 5(a) above shall be deposited with
                             --------------
Landlord, and Landlord shall apply such deposit to the Base Rent for such first
full calendar month for which Base Rent is due. Further, on the Execution Date,
there shall be due and payable by Tenant a security deposit (the "Security
Deposit") in the amount of $174,058.33. Such Security Deposit shall be held by
Landlord (without any obligation to pay interest thereon or segregate such money
from Landlord's general funds except as may be required by applicable law) as
security for the performance of Tenant's obligations under this Lease. Tenant
agrees to increase such Security Deposit from time to time so that it is at all
times equal to one monthly Base Rental installment plus the average monthly
Additional Rentals arising pursuant to Paragraph 6 below. Tenant shall deposit
                                       -----------
cash with Landlord in an amount sufficient so to increase the Security Deposit
to such amount within ten (10) days after written demand by Landlord. It is
expressly understood that the Security Deposit is not an advance payment of
rental or a measure of Landlord's damages in the event of Tenant's default under
this Lease.  Upon the occurrence of any event of default by Tenant under this
Lease, Landlord may, from time to time, without prejudice to any other remedy
provided herein or provided by law and upon notice to Tenant, use, apply, or
retain all or part of the Security Deposit for the payment of (i) Base Rent,
(ii) Additional Rent, and (iii) other sums due hereunder, including without
limitation any amount which Landlord may spend or become obligated to spend by
reason of Tenant's default or to compensate Landlord for any damage, injury,
expense or liability caused to Landlord by such default or breach. If any
portion of the Security Deposit is so used or applied, Tenant shall, within ten
(10) days after written demand therefor, deposit cash with Landlord in an amount
sufficient to restore the Security Deposit to the amount required by this
Paragraph. Tenant's failure to do so shall be an event of default under this
Lease. Unless Tenant receives a timely notice with respect to an event of
default

OFFICE LEASE AGREEMENT - Page - 3
- ----------------------
<PAGE>

(below defined) and fails timely to cure same as herein provided, the balance of
the Security Deposit shall be returned by Landlord to Tenant within fifteen (15)
days after the termination of this Lease.

     (c)  Other remedies for nonpayment of Rent notwithstanding, if the monthly
Base Rental payment is not received by Landlord on or before the tenth (10th)
day of the month for which such rent is due, or if any other Rent payment due
Landlord by Tenant hereunder is not received by Landlord within ten (10) days of
the due date, a service charge of Four hundred ($400.00) dollars shall be
additionally due and payable by Tenant as an administrative charge for the extra
efforts necessitated by such tardiness in payment. Such service charge shall be
cumulative of any other remedies Landlord may have for nonpayment of Rent and
other sums payable under this Lease.

     (d)  If three (3) consecutive monthly Base Rental payments or any five (5)
(in total, cumulative from the beginning of the Lease Term) monthly Base Rental
payments during the Lease Term (or any renewal or extension thereof) are not
received by Landlord within ten (10) days of the due date, upon written notice
to Tenant the Base Rent hereunder shall thereafter be due and payable by Tenant
in advance in quarterly installments equal to three (3) months' Base Rent each.
The first of such quarterly Base Rent payments shall be due and payable on the
first day of the next succeeding month and on the first day of every third (3rd)
month thereafter. This remedy shall be cumulative of any other remedies of
Landlord under this Lease for nonpayment of Rent.

6.   ADDITIONAL RENT:

     (a)  Operating Costs:

          (1)  Landlord shall pay all Operating Costs (below defined) for the
Project except that Tenant shall pay its proportionate share (below defined) of
the amount equal to the difference between (x) the actual Operating Costs for
the Project for the year in question, and (y) the actual Operating Costs for the
calendar year 2000 (the "Base Year"). The Base Year calculation shall be
                         ---------
inclusive of a fully assessed building for tax purposes, such difference being
referred to herein as the "Operating Costs Increase Expense." If the
                           --------------------------------
Commencement Date is a date later an January 1, 2000, then "the actual Operating
Costs for the calendar year 2000" shall be calculated as follows: The days
elapsing from the Commencement Date through December 31,2000, shall be the
"Actual Days". The actual Operating Costs for the Actual Days shall be the "Base
 -----------                                                                ----
Operating Costs". Divide the Base Operating Costs by the number of Actual Days,
- ---------------
and multiply the result by 365. By April 15 of each year from and after the Base
Year, Landlord shall deliver to Tenant a good faith estimate of the Operating
Costs Increase Expense and any Additional Rent to be paid by Tenant for each
calendar year following the Base Year during the Term, and Tenant shall pay to
Landlord, along with the Base Rent each month, an amount equal to one-twelfth of
its estimated proportionate share for such calendar year or part thereof. From
time to time Landlord may estimate and re-estimate the Operating Costs to be due
from Tenant and deliver a copy of the estimate or re-estimate to Tenant.
Thereafter, the monthly installments of Operating Costs Increase Expense payable
by Tenant shall be appropriately adjusted in accordance with the estimation so
that, by the end of the calendar year in question, Tenant shall have paid all of
its proportionate share of the estimated Operating Costs Increase Expense. Any
amounts paid based on such an estimate shall be subject to adjustment as

OFFICE LEASE AGREEMENT - Page - 4
- ----------------------
<PAGE>

herein provided based on the actual Operating Costs for each calendar year. The
Operating Costs Increase Expense shall be "Additional Rent" hereunder. The
failure of Landlord to exercise its rights hereunder to estimate the Operating
Costs Increase Expense and require payment of same as Additional Rent shall not
constitute a waiver of such rights which rights may be exercised from time
to time at Landlord's discretion.

          (2)  The term "Operating Costs" shall mean all expenses and
                         ---------------
disbursements (subject to the limitations set forth below) that Landlord incurs
in connection with the ownership, operation, maintenance and repair of the
Project (exclusive of such expenses and disbursements that are paid by Tenant or
are Landlord's express responsibility hereunder), determined in accordance with
sound accounting principles used in practice by accounting professionals
consistently applied, including, but not limited to, the following costs: (A)
wages and salaries (including management fees) of all employees engaged in the
operation and maintenance of the Project, including taxes, insurance and
benefits relating thereto which wages and salaries are prorated according to the
percentage of time each employee spends in the operation and maintenance of the
Project; (B) all supplies and materials used in the operation, maintenance,
repair, and replacement of the Project; (C) costs for improvements made to the
Project which, although capital in nature, are expected to reduce the normal
operating costs of the Project, as well as capital improvements made in order to
comply with any law hereafter promulgated by any governmental authority, as
amortized over the useful economic life of such improvements as determined by
Landlord in its reasonable discretion; (D) insurance expenses; (E) repairs,
replacements, and general maintenance of the Project; (F) service or maintenance
contracts with independent contractors for the operation, maintenance, repair,
or replacement of the Building (including without limitation, alarm service,
card entry system, window cleaning, landscaping service, and elevator
maintenance); (G) all provided utilities, other than electricity, telephone and
other telecommunications the cost of which are the responsibility of Tenant; (H)
janitorial services (subject to Paragraph 8(c)(3) below); and (I) Taxes (defined
                                -----------------
below).

     Operating Costs shall not include costs for (i) capital improvements made
to the Building, other than capital improvements described above and except for
items which are generally considered maintenance and repair items, such as
painting of common areas, replacement of carpet in elevator lobbies, and the
like; (ii) repair, replacements and general maintenance paid by proceeds of
insurance or by Tenant or by other third parties; (iii) interest, amortization
or other payments on loans to Landlord; (iv) depreciation, (v) leasing
commissions; (vi) legal expenses for services in negotiation of this Lease;
(viii) federal income taxes imposed on or measured by the income of Landlord
from the operation of the Building, (viii) janitorial services paid directly by
Tenant if Tenant so elects to provide its own services, (ix) electric,
telephone, and other telecommunications costs attributable to the Project, (x)
Landlord's obligations under Exhibit "B" hereto, (xi) overhead and profit
                             -----------
increment paid to subsidiaries or affiliates of Landlord or its partners for
services on or to the Project, to the extent that the costs of such services
exceed competitive costs for such services rendered by persons or entities of
similar skill, competence and experience, other than a subsidiary or affiliate
of Landlord or its partners; (xii) costs of Landlord's general overhead and
general administrative expenses which would not be chargeable to operating
expenses of the Project in accordance with sound accounting principles
consistently applied; (xiii) rent, if any, incurred in

OFFICE LEASE AGREEMENT - Page - 5
- ----------------------
<PAGE>

leasing air conditioning systems, elevators or other equipment ordinarily
considered to be of a capital nature, except equipment which is used in
providing janitorial services and which is not affixed to the Project; (xiv) all
items and services for which Tenant reimburses Landlord (other than through
Tenant paying Operating Costs Increase Expense) or for which Tenant pays third
persons; (xv) any expenses relating to the structural integrity of the
foundation, exterior walls, or roof of the Project, except as specifically
provided for in this Lease; and (xvi) any fines, penalties, legal judgments or
settlements of causes of action by or against Landlord unless caused by Tenant
or Tenant's Representatives. Tenant acknowledges and agrees that other than
Landlord's installation of the door card entry system as part of the Work and
maintenance thereof as an Operating Cost, Tenant shall be wholly and solely
responsible for all other matters of security for the Project, and Landlord
shall have no responsibility or liability of any kind therefor.

          (3)  Landlord shall pay on or before the due dates thereof, including
any extensions occasioned by Landlord's lawful rights of contest with respect
thereto, all Taxes (other than the personal property taxes of Tenant). The term
"Taxes" shall mean taxes, assessments, and governmental charges whether federal,
 -----
state, county, or municipal, and whether they be by taxing districts or
authorities presently taxing or by others, subsequently created or otherwise,
and any other taxes and assessments attributable to the Project (or its
operation), excluding, however, penalties and interest thereon and federal and
state taxes on income (if the present method of taxation changes so that in lieu
of the whole or any part of any Taxes, there is levied on Landlord a capital tax
directly on the rents received therefrom or a franchise tax, assessment, or
charge based, in whole or in part, upon such rents for the Building, then all
such taxes, assessments, or charges, or the part thereof so based, shall be
deemed to be included within the term "Taxes" for purposes hereof), excluding
                                       -----
further any franchise, estate, inheritance, succession, transfer, income or
excess profit tax or tax imposed on Landlord due to the change of ownership of
the Project as defined in the law during the Term of this Lease under which
reassessment or tax increase results from a transfer of all or a portion of
Landlord's estate as opposed to an increase in Project valuation. Taxes shall
include the reasonable costs of consultants retained by Landlord in an effort to
lower taxes and all reasonable costs incurred by Landlord in disputing any taxes
or in seeking to lower the tax valuation of the Project. Upon Tenant's written
request, Landlord shall deliver to Tenant evidence of Landlord's payment of
bills for Taxes.

     Tenant may, upon the receipt of prior written approval of Landlord, such
approval not to be unreasonably withheld, contest any Taxes against the Premises
and attempt to obtain a reduction in the assessed valuation of the Premises for
the purpose of reducing any such tax assessment. In the event Landlord approves,
and upon the request of Tenant, but without expense or liability to Landlord,
Landlord shall cooperate with Tenant and execute any document which may be
reasonably necessary and proper for any proceeding. In such event Tenant shall
be solely responsible for all legal and related expenses relating to such
documents; provided however, Tenant shall be authorized to collect from any tax
refund received as a result of Tenant's proceedings (i) any Taxes that Tenant
has paid which are reduced as a result of such proceedings and (ii) a refund of
all costs and expenses incurred in connection with obtaining such refund. If a
tax reduction is obtained, there shall be a subsequent reduction in Tenant's
total Taxes for such year, and any excess payments by Tenant shall

OFFICE LEASE AGREEMENT - Page 6
- ----------------------
<PAGE>

be refunded by Landlord, without interest, when all refunds to which Landlord is
entitled from the taxing authority with respect to such year have been received
by Landlord. In the event Landlord desires to contest any Taxes, Tenant agrees
to cooperate with Landlord and execute any document which may be reasonably
necessary and proper for any proceeding. During the pendency of any contest by
Landlord or Tenant, Tenant shall become and remain obligated to pay or to
provide an appropriate bond or security for the payment of all Taxes at least
ten (10) days prior to the date due, and otherwise follow the payment and
notification obligations set forth in this Paragraph, provided, however, if the
taxing authority forwards the tax notification letter to Landlord, Landlord
shall forward same to Tenant and Tenant shall be obligated to pay Tenant's
Proportionate Share of the increase in the Taxes as provided herein upon the
later to occur of (i) thirty (30) days after receipt thereof, or (ii) five (5)
days prior to the date such Taxes are due to be paid to the taxing authority.

     In any event, Tenant shall be responsible for insuring and paying all taxes
upon Tenant's furniture, machinery, goods, supplies, fixtures, Alterations
(below defined) or other improvements, and other property on the Premises.

     (b)  Operating Costs Statement/Right to Audit: By April 15, 2001, and by
April 15 of each calendar year thereafter, or as soon thereafter as practicable,
Landlord shall furnish to Tenant a statement of the actual Operating Costs (the
"Operating Costs Statement") for the previous year. If the Operating Costs
 -------------------------
Statement reveals that Tenant paid more for Operating Costs than the actual
amount attributable to Tenant pursuant hereto for the year for which such
statement was prepared, then Landlord shall promptly credit or reimburse Tenant
for such excess; likewise, if Tenant paid less than Tenant's actual
proportionate share of the Operating Costs Increase Expense, then Tenant shall
promptly pay to Landlord such deficiency. Tenant shall have the right to cause a
certified public accountant selected by Tenant to audit the books and records of
Landlord, with respect to any cost or item which is passed through to Tenant
("Tenant's Audit"), upon thirty (30) days advance written notice by Tenant to
Landlord which notice shall be given, if at all, within sixty (60) days of the
date that Tenant receives the Operating Costs Statement. Landlord shall
cooperate with Tenant in providing Tenant's accountant reasonable access to its
books and records during normal business hours, at Landlord's business address
or other place in Dallas, Texas, designated by Landlord, for this purpose. If
the results of Tenant's Audit show an overcharge to Tenant of more than the
actual amount owed by Tenant, Landlord may cause a certified public accountant
to review such audit ("Landlord's Audit"), and the two accountants shall
reconcile any differences. If the final result shall show an overpayment by
Tenant of the amount owed, Landlord shall credit or refund to Tenant or offset
against any Rents becoming due under the Lease any overcharge of such items
within thirty (30) days of completion of such audits. In the event such audit
discloses an undercharge of such items as billed to Tenant, Tenant shall pay
Landlord the amount of such undercharge within thirty (30) days of completion of
such audits. Tenant shall pay the costs of Tenant's Audit, and Landlord shall
pay the costs of Landlord's Audit.

     For the calendar year in which this Lease terminates, Tenant's liability
for Tenant's Proportionate Share of Operating Costs Increase Expense for such
partial calendar year shall be subject to pro rata adjustment based upon the
number of days of the Term elapsing during such

OFFICE LEASE AGREEMENT - Page - 7
- ----------------------
<PAGE>

partial year. If the applicable charges are not available prior to the end of
the Term hereof, then the aforesaid adjustment shall be made between Landlord
and Tenant after Landlord shall have received the charges for such period, it
being specifically agreed that Landlord's and Tenant's obligations under this
Paragraph shall survive the expiration of the term of this Lease.

     (c)  Proportionate Share: As used in this Lease, the term "proportionate
                                                                -------------
share" or "Tenant's Proportionate Share" is defined as follows: As of the
- -----      ----------------------------
Commencement Date through and including the last day of the ninth full calendar
month of the Term, Tenant's Proportionate Share shall be 83% [104,435 divided by
125,538], and from and after the last day of the ninth full calendar month of
the Term, Tenant's Proportionate Share shall be 100%.

     (d)  Cap on Certain Operating Costs: For the purpose of determining
Additional Rent, Operating Costs (exclusive of the Non-Capped Operating Costs,
as hereinafter defined) for any calendar year shall not be increased over the
amount of Operating Costs (exclusive of Non-Capped Operating Costs) during the
prior calendar year by more than five percent (5%). For example, if Operating
Costs (exclusive of Non-Capped Operating Costs) during the second calendar year
after the calendar year in which the term of this Lease commences were $100,000,
the cap on Operating Costs (exclusive of Non-Capped Operating Costs) for the
third full calendar year would be $105,000.00 ($100,000 times 1.05). It is
understood and agreed that there shall be no cap on "Non-Capped Operating
                                                     --------------------
Costs", which are hereby defined to mean all utilities, all Taxes and all
- -----
Insurance Premiums.

     7.   TENANT REPAIRS AND MAINTENANCE:

     (a)  Tenant, at its own expense, shall maintain all parts of the Leased
Premises and their appurtenances (except those for which Landlord is expressly
responsible to maintain under this Lease) in good, clean and sanitary condition
and shall promptly make all necessary repairs and replacements to the Leased
Premises including but not limited to electrical light lamps or tubes (other
than lamps in Building standard ceiling mounted fixtures installed by Landlord),
interior windows, interior glass and plate glass, interior doors, special office
entries, interior walls and finish work, floors and floor coverings, the
Generator, the equipment in the UPS Area, Tenant-installed heating and air
conditioning systems, Tenant-installed fire sprinkler systems, and Tenant-
installed plumbing work and fixtures. Replacement and repair parts, materials
and equipment shall be of quality equivalent to those initially installed within
the Leased Premises, and repair and maintenance work shall be done in a good and
workmanlike manner and in accordance with existing laws, rules, regulations and
ordinances.

     (b)  Tenant shall not damage or disturb the structural integrity or support
of any wall, roof, or foundation of the Building, without the prior written
consent of Landlord pursuant to Paragraph 16. The costs and expenses of repair
                                ------------
of any damage to these areas caused by Tenant or Tenant's Representatives
(defined in Paragraph 7(e)) shall be paid within ten (10) days business days
            --------------
after written notice thereof to Tenant (including a description of the damage
and itemized cost of repair of same).

OFFICE LEASE AGREEMENT - Page - 8
- ----------------------
<PAGE>

     (c) Tenant shall at its own expense keep the Leased Premises pest-free and
pay all charges for pest control and extermination within the Leased Premises.

     (d)  On the Termination Date, Tenant shall deliver the Leased Premises to
Landlord "broom clean" in the same good order and condition as existed at the
Commencement Date of this Lease, ordinary wear, natural deterioration beyond the
control of Tenant, and damage by fire, tornado or other casualty excepted.
Tenant shall give written notice to Landlord at least thirty (30) days prior to
vacating the Leased Premises and shall arrange to meet with Landlord for a joint
inspection of the Leased Premises prior to vacating. In the event of Tenant's
failure to give such notice or arrange such joint inspection, Landlord's
inspection at or after Tenant's vacating the Leased Premises shall be
conclusively deemed correct for purposes of determining Tenant's responsibility
for repairs and restoration.

     (e)  Tenant shall be responsible for all costs, expenses and liabilities
caused by the willful or negligent acts or omissions of Tenant or Tenant's
employees, officers, directors, partners, agents, invitees, guests, patrons,
licensees, contractors, representatives, trespassers, or others for whom Tenant
is legally responsible (all such persons and entities being herein collectively
referred to as "Tenant's Representatives") or caused by Tenant's default
                ------------------------
hereunder.

     (f)  If Landlord shall give Tenant written notice of defects or need for
repairs for which Tenant is responsible under this Lease, and if Tenant shall
fail to make same within thirty (30) days of Landlord's notification (subject to
the provisions of Paragraph 41 below) or such shorter time as is reasonable if
                  ------------
expedited repair is needed to avoid injury or damage, Landlord shall have the
option to cure said defect or repair, and Tenant shall pay to Landlord all costs
and expenses incurred within thirty (30) days after written notice to Tenant
thereof (including a description of the damage and itemized costs of repair or
same).

8.   LANDLORD'S REPAIRS AND MAINTENANCE RESPONSIBILITIES:

     (a)  Landlord has agreed, at its expense, to construct the structural and
exterior portions of the Building, excluding for purposes of this Paragraph the
Leased Premises which are dealt with in Paragraph 51 and Exhibit "B" below,
                                        ------------     -----------
("Landlord's Construction")in accordance with the Landlord's Plans and
  -----------------------
Specifications more particularly described herein in Exhibit "E" attached hereto
                                                     -----------
(the "Landlord's Plans and Specifications"). Landlord certifies that it has
      -----------------------------------
provided Tenant with a complete and accurate set of Landlord's Plans and
Specifications and that they have not been materially amended or modified except
as reflected in Exhibit "E". The plumbing, electrical, and other utilities
                ----------
contemplated by Landlord's Plans and Specifications are or will be on the
Commencement Date in good working condition and order. As of the Commencement
Date, to Landlord's actual knowledge, the Building shall be in compliance with
all existing laws, codes, regulations and ordinances of any governmental
authorities. Landlord's Construction shall be completed in accordance with all
Applicable Laws in a good and workmanlike manner, utilizing first quality, new
materials. Tenant has reviewed the Landlord's Plans and Specifications and

OFFICE LEASE AGREEMENT - Page - 9
- ----------------------
<PAGE>

acknowledges that, to the best of its knowledge, the Building has been
constructed substantially in compliance therewith. Landlord agrees to correct or
cause to be corrected any original latent defects in Landlord's Construction of
which written notice is provided to Landlord within the applicable period of
limitations.

     (b)  Landlord shall be responsible, at its expense, for, but only for, the
structural integrity of the roof, foundation and exterior walls of the Building
and the repair, maintenance, and replacement needed with respect to the
structural integrity thereof. The costs of any repair to the roof, foundation or
exterior walls occasioned by the act of omission of Tenant or Tenant's
Representatives shall be the responsibility of Tenant except to the extent that
proceeds of any warranties or insurance shall be received by Landlord.
Landlord's liability with respect to any defects, repairs or maintenance for
which Landlord is responsible at its expense under this Lease shall be limited
to the cost of such repairs or maintenance or the curing of such defect. Tenant
shall promptly give Landlord written notice of defects or need for repairs,
after which Landlord shall have thirty (30) days to commence to repair or cure
such defect. To the extent required by Landlord's Plans and Specifications and
the Working Drawings, Landlord, at its expense, has caused or will cause
Landlord's Construction and the Work (as defined in Paragraph 51 below)
                                                    ------------
initially to comply with all laws, orders, ordinances, rules and regulations
applicable thereto including, without limitation, the Americans With
Disabilities Act. Any changes to the Premises required thereby shall be the sole
responsibility and expense of Tenant though, at Tenant's request and expense and
in accordance with Paragraph 8(e) below, Landlord will assist in such efforts.
                   --------------
Any subsequent changes in the Project outside the Premises required thereby
shall be performed by Landlord as Operating Costs.

     (c)  Landlord shall diligently perform the work which gives rise to
Operating Costs in accordance with all Applicable Laws and in a good and
workmanlike manner and shall furnish Tenant the following services, all being
subject to payment therefor by Tenant pursuant to the provisions of Paragraph
                                                                    ---------
6(b) above. Any services performed by Landlord, to or affecting, the Leased
- ----
Premises shall be done in such a manner as to limit as much as is practicable
interference with Tenant's use and occupancy of the Premises, and only limited
materials and tools used in connection with such services shall be stored in the
Premises. The services that Landlord shall furnish include:

          (1)  Air conditioning and heating as provided in Landlord's Plans and
Specifications and the Working Drawings. Tenant acknowledges that such service
and temperature may be subject to regulation by local, county, state or federal
regulation. Whenever machines or equipment that generate abnormal heat are used
in the Premises which affect the temperature otherwise maintained by the air
conditioning system, Landlord shall have the right to install supplemental air
conditioning in the Premises, and the reasonable cost thereof including the
cost of installation, operation, use and maintenance, shall be paid by Tenant to
Landlord as Additional Rental upon demand.

          (2)  Water at those points of supply reflected in the Working Drawings
for drinking, lavatory and toilet purposes. Landlord shall pay to the
appropriate utility company, in time

OFFICE LEASE AGREEMENT - Page - 10
- ----------------------
<PAGE>

to avoid interruption of service for non payment and to avoid late charges, all
charges for water use consumed on the Project during Tenant's occupancy and such
costs shall be included in Operating Costs.

          (3)  Janitorial service in and about the Building and the Premises, as
may in the judgment of Landlord be reasonably required; however, Tenant shall
pay all additional costs attributable to the cleaning of improvements within the
Premises. If Tenant elects to provide its own janitorial service (subject to
Landlord's reasonable approval of the insurance carried by the contractor), the
Base Rent shall be reduced by $0.90 per square foot of rentable area per year.

          (4)  Elevators as shown in Landlord's Plans and Specifications for
ingress to the egress from the second floor of the Building - 24 hours per day,
7 days per week.

          (5)  Electricity at those points of supply reflected in the
Working Drawings, Tenant shall pay to the appropriate public utility company all
charges for electric current consumed on the Project during the Term of this
Lease, as extended, and such costs shall not be included in Operating Costs.

          (6)  Replacement of lighting fixture lamps in Building ceiling mounted
fixtures.

          (7)  The secured card entry system at all entrances and exits, except
for those additional entrances or exits, including overhead doors added by
Tenant, as provided in the Working Drawings. Landlord shall allow Tenant access
to the Premises seven (7) days a week, twenty-four (24) hours a day.

          (8)  Landlord shall provide a Building directory and the in-ceiling
florescent lighting throughout the Building shown in the Working Drawings or
Landlord's Plans and Specifications.

          (9)  Maintenance of the Project outside the Leased Premises in good
operating condition and repair, clean and free from rubbish and debris,
maintenance of the landscaping, and adequate illumination and draining of the
Project.

     (d)  Tenant shall promptly give Landlord written notice of defects or need
for repairs for which Landlord is responsible hereunder after which Landlord
shall have thirty (30) days to commence to repair or cure such defect. If not
caused by the interference of Tenant or Tenant's Representatives, if Landlord
fails to make repairs that materially interfere with Tenant's use and enjoyment
of the Leased Premises after notice of same, Tenant may make such repairs and
offset the actual, necessary cost thereof against Base Rent. No interruption or
malfunction of any such services shall constitute an eviction or disturbance of
Tenant's use and possession of the Premises or the Building or a breach by
Landlord or any of Landlord's obligations hereunder or render Landlord liable
for damages or entitle Tenant to be relieved from any of Tenant's obligations
hereunder (including the obligation to pay rental unless, and to the extent,
Landlord receives rental interruption

OFFICE LEASE AGREEMENT - Page - 11
- ----------------------
<PAGE>

insurance proceeds therefor) or grant Tenant any right of set off or recoupment
except as expressly set forth herein. In the event of any such interruption,
however, Landlord shall use reasonable diligence during the business hours set
forth herein promptly to restore such service or cause same to be restored in
any circumstances in which such restoration is within the reasonable control of
Landlord and the interruption was not caused solely by Tenant or Tenant's
Representatives.

     (e)  Should Tenant desire any additional services (other than Project
security which shall be Tenant's exclusive responsibility) beyond those
described in this Paragraph 8 or rendition of any services outside the normal
                  -----------
time established by Landlord for providing any services, Landlord may (at
Landlord's option), upon reasonable advance notice from Tenant to Landlord,
furnish such services, and unless otherwise provided herein, Tenant shall pay
directly for such services or shall agree to pay Landlord such reasonable
charges as may be agreed upon between Landlord and Tenant, but in no event at a
charge less than Landlord's reasonable actual cost plus reasonable overhead for
the additional services provided.

     (f)  Landlord shall furnish and install window coverings on all exterior
windows to maintain a uniform exterior appearance. Tenant shall not remove or
replace such window coverings or install any other window covering which would
affect the exterior appearance of the Building or the Premises. Tenant may
install lined or unlined over-draperies on the interior side of the Landlord
furnished window coverings for interior appearance or to reduce light
transmission, provided such over-draperies do not affect the exterior appearance
of the Building or the Premises.

     (g)  Tenant acknowledges that, except as expressly set forth in this Lease
or any exhibit hereto, no representations or promises regarding construction,
repairs, alterations, remodeling, or improvements to the Leased Premises have
been made by Landlord, its agents, employees, or other representatives.

     (h)  Landlord has provided Tenant with a true copy of Landlord's Owner
Policy of Title Insurance (Policy No. 44 0298 100 9812) issued by Chicago Title
Insurance Company, dated November 4, 1998 (the "Title Policy") and a current
                                                ------------
survey of the Project. Landlord represents that, except as shown in the Title
Policy, to Landlord's current actual knowledge, there are no other restrictions
in the deed records affecting the Project. Based upon its review of the Title
Policy and the documents referred to therein, Tenant has satisfied itself as to
any restrictions of record. Tenant will satisfy itself as to all zoning and
other governmental restrictions and regulations with respect to all uses of the
Premises prior to commencement of any construction of the Premises. Failure of
Tenant to provide written notice of any limitations on such use that are
unacceptable to Tenant prior to commencement of construction shall be deemed
acceptance by Tenant. Tenant's taking possession of the Leased Premises shall
conclusively establish that, subject to any express representation or obligation
of Landlord in this Lease, the improvements to be made by Landlord under the
terms of this Lease have been completed in accordance with the Working Drawings
and Landlord's Plans and Specifications and that the Leased Premises are in good
and satisfactory condition as of the date of Tenant's possession subject only to
Paragraph 8 of Exhibit "B" to this Lease. In conjunction with, or at any time
               -----------
after, the Commencement Date, Tenant shall, upon

OFFICE LEASE AGREEMENT - Page - 12
- ----------------------
<PAGE>

Landlord's request, execute and deliver to Landlord an estoppel certificate (as
referred to in Paragraph 33 of this Lease) to acknowledge the Commencement Date.
               ------------

9.   UTILITY SERVICE:

     (a)  Subject to availability from the utility provider, Landlord shall
provide utility services of the type and quality reflected in the Working
Drawings and/or Landlord's Plans and Specifications which the parties
acknowledge are at least in accordance with standards typical of first-class
commercial office/flex buildings in the submarket area of the Project in Dallas,
Texas. Such services include water, sewer, telephone and electric current.
Subject to availability from the utility provider, such services shall be
provided to Tenant on a 24-hour a day, 7 day a week basis.

     (b)  Tenant shall pay the cost of all telephone or other telecommunications
service used on the Leased Premises and the cost of electric service
attributable to the Project as provided for hereinabove.

     (c)  Tenant shall pay all costs caused by Tenant introducing excessive
pollutants into the sanitary or storm sewer system, including permits, fees,
assessments, and charges levied by any governmental subdivision, for any
pollutants or solids other than ordinary human waste.

     (d)  Landlord acknowledges that there shall be no start-up charge, minimum
usage requirements or other surcharges or impositions imposed upon Tenant.

     (e)  Defined holidays shall be: New Year's Day, Labor Day, Memorial Day,
Fourth of July, Thanksgiving Day and Christmas Day.

10.  SIGNS:

     (a)  Tenant may place signage as desired by Tenant within the interior
areas of the Premises. Such signs shall be placed by a contractor reasonably
approved by Landlord and paid for by Tenant. Tenant shall remove all such signs
at the termination of this Lease. Such installations and removals shall be made
in such manner as to avoid injury or defacement of the Premises, and Tenant, at
its sole expense, shall repair any material injury or defacement in removing
such signs; provided however, Tenant shall not be responsible for any
discoloration caused by ordinary wear and tear.

     (b)  Exterior Signage. Tenant shall not inscribe, paint, affix or display
any signs, door plaques, advertisements or notices on or around the exterior of
the Building or areas of the Project outside the Building except as provided
below:

          (1)  Subject to Paragraph 28 below, Tenant and only Tenant, but no
                          ------------
subtenant or assignee of any rights hereunder, shall have the right, at its sole
cost and expense, to install its corporate identification or logo upon the top
spandrel panel of the Building between Pod C & W, (the

OFFICE LEASE AGREEMENT - Page - 13
- ----------------------
<PAGE>

"Building Sign"), provided that (i) Tenant obtains all necessary approvals from
 -------------
the City of Farmers Branch and all other governmental authorities having
jurisdiction over Tenant, the Project and the Building Sign, (ii) the Building
Sign conforms to all applicable laws, rules and regulations of any governmental
authorities having jurisdiction over the Building Sign or the Project, and (iii)
Landlord and Tenant shall mutually agree upon the design, color, character,
style, material, installation method and size of the Building Sign, which
approval shall not be unreasonably withheld or delayed.

          (2)  Tenant shall also have the right, at Tenant's expense, to install
a Building Monument Sign (the "Building Monument Sign") at the center entrance
                               -----------------------
of the Building adjacent to Alpha Road, provided that (i) Tenant obtains all
necessary approvals from the City of Farmers Branch and all other governmental
authorities having jurisdiction over Tenant, the Project and the Building
Monument Sign, (ii) the Building Monument Sign conforms to all applicable laws,
rules and regulations of any governmental authorities having jurisdiction over
the Building Monument Sign or the Project, and (iii) Landlord and Tenant shall
mutually agree upon the location, design and size of such sign, which approval
shall not be unreasonably withheld or delayed.

          (3)  Landlord agrees that Tenant's signs shall be displayed in a
prominent (or top) position and no other tenant(s)' signs shall be larger than
Tenant's without Tenant's consent. Landlord agrees that if Landlord makes
available to any other tenant any signage located in the Common Areas or on the
Project, including the Building, then such signage shall also include Tenant's
identification sign in the top position and at least as large as the largest
sign made available to such other tenant(s). Tenant shall have the right,
without Landlord's approval, to change its sign from time to time so long as
such new signs are no larger than the sign it replaces and complies with
Subparagraphs (1) and (2) immediately preceding. At Tenant's sole cost and
expense, Landlord will fully cooperate with Tenant in Tenant's filing any
required signage application, permit and/or variance for said signage.

     (c)  Prior to commencement of any sign construction, Tenant shall deliver
to Landlord certificates of insurance evidencing that Tenant's contractors,
agents, workmen, engineers or other persons installing the Building Sign and/or
Building Monument Sign have in effect valid workmen's compensation, public
liability and builder's risk insurance in amounts, with such companies and in
such forms as Landlord may consider reasonably necessary or appropriate for its
protection. Except for the gross negligence or wilful misconduct of Landlord or
Landlord's Representatives, during the Term of this Lease, Tenant shall
indemnify and hold Landlord harmless from and against any and all claims,
demands, fines, liabilities, costs, expenses, damages, actions and causes of
action accruing from or related to the Building Sign and/or Building Monument
Sign. The indemnity set out in the preceding sentence will be limited only by
the gross negligence or wilful misconduct of Landlord or anyone acting for
Landlord. Tenant agrees that Landlord shall have the right, at its expense,
temporarily to remove and replace the Building Sign and/or Building Monument
Sign in connection with and during the course of any repairs, changes,
alterations. modifications, renovations or additions to the Building in which
case Landlord shall replace the signage upon completion of the work.

OFFICE LEASE AGREEMENT - Page - 14
- ----------------------
<PAGE>

     (d)  Tenant shall maintain the Building Sign and the Building Monument
Sign, at Tenants sole cost and expense. If Tenant is in default under this
Lease, Tenant's rights to signage shall terminate and Landlord shall have the
option to remove such signage at Tenant's sole cost and expense. Tenant shall,
at its sole cost and expense, remove all such signs at the termination of this
Lease. Such installations and removals shall be made in such manner as to avoid
injury or defacement of the Project and other improvements. Tenant shall repair
any damage or defacement, including, without limitation, any discoloration,
caused by the removal of such signs.

     (e)  Landlord shall at all times maintain all pylons, monuments, and
spendrals in good order and repair and the cost of maintenance of such pylons,
monuments and spendrals, and the cost of any electricity to illuminate them
shall be included as an Operating Cost.

     (f)  Landlord may erect a sign or signs on the Leased Premises at a
location reasonably acceptable to Tenant indicating that the Project are for
lease during the six (6) month period prior to the expiration of this Lease.

     (g)  The right to signage is not assignable by Tenant except in conjunction
with the assignment of this Lease as elsewhere herein provided.

11.  USAGE:

     (a)  Tenant warrants and represents to Landlord that the Leased Premises
shall be used and occupied only for general office uses, which may include
product distribution from the Premises as well as research and development of
computer related telecommunication products. Tenant shall occupy the Leased
Premises and conduct its business, and Tenant's Representatives shall conduct
themselves, in compliance with all laws, rules and regulations and in a lawful,
quiet, and reputable way and as not to create any nuisance. Tenant shall not
commit, or allow to be committed, any waste on the Leased Premises or the
Project. Tenant may not use the Leased Premises for the use, storage, or
distribution of hazardous or environmentally offensive substances, or for
underground storage, or for any unlawful purposes.

     (b)  Tenant shall have the right after written notice to Landlord to
contest by appropriate legal proceedings the validity or application of any law,
ordinance or other legal requirement affecting Tenant, the Premises, or the
operation of Tenant's business on the Premises and to delay compliance therewith
pending the prosecution of such proceedings, provided that no civil or criminal
penalty is or could be incurred by Landlord and no lien or charge is or could be
imposed upon the Premises or any other part of the Project.

     12.  TENANT'S INSURANCE OBLIGATIONS:

     (a)  Tenant shall not permit the Leased Premises to be used in any way
which would violate laws, rules, or regulations governing hazardous substances
or which would in any way increase the cost of or render void any insurance on
the improvements, and Tenant shall

OFFICE LEASE AGREEMENT - Page - 15
- ----------------------
<PAGE>

immediately, on demand, cease any use which violates the foregoing or to which
Landlord's insurer or any governmental or regulatory authority objects. If at
any time during the term of this Lease Tenant's use of the Premises shall cause
an increase in premiums, and in particular, but without limitation, if the State
Board of Insurance or other insurance authority disallows any of Landlord's
sprinkler credits or imposes an additional penalty or surcharge in Landlord's
insurance premiums because of any act solely attributable to or arising from the
direct acts of Tenant, Tenant agrees to pay as Additional Rent the commercially
reasonable increase in Landlord's insurance premiums.

     (b)  Tenant, at its sole cost and expense, shall procure and maintain
throughout the term of this Lease a policy or policies of insurance insuring
Landlord, Landlord's management company and lender, and Tenant against all
claims for property damages, personal injury or death of others occurring on or
in connection with: (i) the Leased Premises and all personal property therein;
(ii) the condition of the Leased Premises; (iii) Tenant's operations in and
maintenance and use of the Leased Premises; (iv) Tenant's and Tenant's
Representatives' use of the Common Areas of the Project, and (v) Tenant's
liability assumed under this Lease. The limits of such policy or policies shall
be not less than $ 2,000,000.00 combined single limit coverage per occurrence
for injury to persons (including death) and/or property damage or destruction,
including loss of use.

     (c)  All such policies shall be procured by Tenant from insurance companies
reasonably satisfactory to Landlord naming the following as co-insureds: (i)
Landlord; (ii) Landlord's management company, Jackson-Shaw Company or its
successor; and, (iii) Landlord's mortgage holder, as changed from time to time.
Certified copies of such policies, together with receipt for payment of
premiums, shall be delivered to Landlord prior to the Commencement Date. Not
less than fifteen (15) days prior to the expiration date of any such policies,
certified copies of renewal policies and evidence of the payment of renewal
premiums shall be delivered to Landlord. All such original and renewal policies
shall provide for at least thirty (30) days written notice to Landlord before
such policy may be canceled or changed to reduce insurance coverage provided
thereby. Copies of such policies and duly executed certificates evidencing
insurance coverage, together with copies of receipts for payment of premiums,
shall be delivered to Landlord prior to the Commencement Date. Not less than
fifteen (15) days prior to the expiration date of any such policies, copies of
renewal policies and duly executed certificates evidencing insurance coverage
and evidence of the payment of renewal premiums shall be delivered to Landlord.
If required of Landlord by its insurance carrier, Tenant shall, within fifteen
(15) days after request therefor provide reasonable information concerning use
of and insurance coverages for the Lease Premises.

13.  (INTENTIONALLY DELETED)

14.  COMPLIANCE WITH LAWS, RULES AND REGULATIONS: Except as provided in
Paragraph 8(b) above and subject to the limitations thereof, and unless
- --------------
otherwise herein expressly stated to be the responsibility of Landlord, Tenant
shall comply with all applicable laws, ordinances, orders, rules and regulations
of state, federal, municipal, or other agencies or bodies relating to the use,
condition and occupancy of and business conducted on the Project and the Leased
Premises, respectively, including without limitation, the Americans with
Disabilities Act, the Resource

OFFICE LEASE AGREEMENT - Page - 16
- ----------------------
<PAGE>

Conservation and Recovery Act, the Comprehensive Environmental Response Act, and
the rules, regulations and directives of the United States Environmental
Protection Agency and/or the Texas Natural Resource Conservation Commission.

15.  ASSIGNMENT AND SUBLETTING: Tenant agrees not to assign, transfer, or
mortgage this Lease or any right or interest therein or sublet the Leased
Premises or any part thereof, without the prior written consent of Landlord
which shall not be unreasonably withheld or delayed, except that Tenant shall
have the right to mortgage its interest in this Lease to a bona fide lender in
an arms-length loan transaction and to sublease, assign or otherwise transfer
its interest in the Lease, upon assumption of all obligations with respect
thereto, to any parent, subsidiary, or affiliate of Tenant, or to a corporation
with which Tenant may merge or consolidate, without Landlord's approval.
Landlord shall, however, be notified in writing of any such assignment,
sublease, transfer or mortgage. No assignment, subletting, transfer, or
mortgaging shall relieve Tenant of its obligations hereunder, and Tenant shall
continue to be liable as a principal (and not as a guarantor or-surety) to the
same extent as though no assignment, subletting, transfer, or mortgaging shall
had been made. Consent by Landlord (to the extent such consent is required) to
any one assignment, subletting, transfer, or mortgaging shall not be construed
to be consent to any additional assignment, subletting, transfer, or mortgaging.
Each such successive act shall require similar consent of Landlord. Landlord
shall be reimbursed by Tenant for any reasonable costs or expenses actually
incurred as a result of Tenant's request for consent to any such assignment,
subletting, transfer, or mortgaging, including reasonable legal costs. In the
event Tenant subleases the Leased Premises, or any portion thereof, or assigns
this Lease with the consent of the Landlord at an annual Base Rental exceeding
that stated herein (the "Excess Rent"), such excess shall be retained by and be
                         -----------
the exclusive property of Tenant; however, upon the occurrence of an event of
default (defined below), if all or any part of the Leased Premises is then
assigned or sublet, Landlord may, in addition to any other remedies provided by
this Lease or provided by law, collect directly from the assignee or subtenant
all rents due to Tenant, and any Excess Rents shall belong to Landlord, though
such Excess Rents actually received by Landlord shall be credited to any sums at
any time owed by Tenant hereunder. Any collection directly by Landlord from the
assignee or subtenant shall not be construed, however, to constitute a novation
or a release of Tenant from the further performance of its obligations under
this Lease. Notwithstanding the foregoing, it is expressly agreed that if this
Lease is assigned to any person or entity pursuant to the provisions of the
Bankruptcy Code, 11 U.S.C. Sec. 101 et seq, as amended (the "Bankruptcy Code"),
                                                             ---------------
any and all monies or other considerations payable or otherwise to be delivered
in connection with such assignment, including without limitation Excess Rents,
shall be paid or delivered to Landlord, shall be and remain the exclusive
property of Landlord and shall not constitute property of Tenant or of the
estate of Tenant within the meaning of the Bankruptcy Code. Any and all monies
or other considerations constituting Landlord's property under the preceding
sentence not paid or delivered to Landlord shall be held in trust for the
benefit of Landlord and be promptly paid or delivered to Landlord. Any person or
entity to which this Lease is assigned pursuant to the provisions of the
Bankruptcy Code shall be deemed without further act or deed to have assumed all
of the obligations arising under this Lease on and after the date of such
assignment. Any such assignee shall upon demand execute and deliver to Landlord
an instrument confirming such assumption.

OFFICE LEASE AGREEMENT - Page - 17
- ----------------------
<PAGE>

16.  ALTERATIONS AND IMPROVEMENTS:

     (a)  Tenant shall not make or perform, or permit the making or performance
of, any initial or subsequent tenant finish work or any alterations,
installations, decorations, improvements, additions or other physical changes
in or about the Leased Premises that are structural in nature or that exceed
$6,000.00 in costs (referred to collectively as "Alterations") without
                                                 -----------
Landlord's prior consent. Landlord may withhold consent in its sole discretion
if the Alterations in any way penetrate the roof (except as provided in
Paragraph 42(a) below) or outer walls of the Building or impact the structure or
- ---------------
structural integrity of the Building or any of its systems. Otherwise, such
consent shall not be unreasonably withheld or delayed. Notwithstanding the
foregoing provisions or Landlord's consent to any Alterations, all Alterations
shall be made and performed in conformity with and subject to the following
provisions: All Alterations shall be made and performed at Tenant's sole cost
and expense in a good and workmanlike manner. Alterations shall be made only by
contractors or mechanics approved by Landlord, such approval not to be
unreasonably withheld or delayed. Tenant shall submit to Landlord detailed plans
and specifications (including architectural layout, mechanical and structural
drawings) for each proposed Alteration and shall not commence any such
Alteration without first obtaining Landlord's written approval of such plans and
specifications. Prior to the commencement of each proposed Alteration, Tenant
shall furnish to Landlord a certificate evidencing worker's compensation
insurance coverage for all persons to be employed in connection with such
Alterations, including those to be employed by all contractors and
subcontractors, and of comprehensive public liability insurance (including
property damage coverage) in which Landlord, Landlord's Representatives, and any
mortgagee of the Building shall be named as parties insured, which policies
shall be issued by companies and shall be in form and amounts as customarily
required and satisfactory to Landlord in its reasonable discretion and shall be
maintained by Tenant until the completion of such Alteration. Tenant shall cause
its contractor and each subcontractor to provide Landlord with a Certificate of
Completion of the Alterations and a Bills Paid Affidavit and full Lien Waiver in
form and content as reasonably required by Landlord and as customarily required.
Tenant shall, if required by Landlord at the time of Landlord's consent to the
Alterations, agree to restore the affected portions of the Project at the
termination of this Lease to their condition prior to making such Alterations.
All permits, approvals and certificates required by all governmental authorities
shall be timely obtained by Tenant and copies shall be submitted to Landlord.
Notwithstanding Landlord's approval of plans and specifications for any
Alterations, all Alterations shall be made and performed in full compliance with
all applicable laws, orders, rules, standards and regulations of Federal, State,
County, and Municipal authorities, including, without limitation, all
directions, pursuant to law, of all public officers, and with all applicable
rules, orders, regulations and requirements of the local Board of Fire
Underwriters or any similar body ("Applicable Laws"). Landlord's approval shall
                                   ---------------
not in any way be considered an indication that the plans and specifications
comply with Applicable Laws. All materials and equipment to be incorporated in
the Leased Premises as a result of all Alterations shall be new and first
quality. No such materials or equipment shall be subject to any lien,
encumbrance, chattel mortgage or title retention or security agreement. Whether
such Alterations are being performed by Tenant in connection with Tenant's
initial occupancy of the Leased Premises or subsequently, Tenant agrees to make
proper application for, and obtain, a Building Permit and a Certificate of
Occupancy from

OFFICE LEASE AGREEMENT - Page - 18
- ----------------------
<PAGE>

the city in which the Leased Premises are located. Tenant shall furnish copies
of such permit and certificate to Landlord promptly after issuance of same.

     (b)  Except for Tenant's Property (below defined), all appurtenances,
fixtures, improvements, and other property attached to or installed in the
Leased Premises, whether by Landlord or Tenant or others, and whether at
Landlord's expense or Tenant's expense, or the joint expense of Landlord and
Tenant, shall be and remain the property of Landlord. Any replacements of any
property of Landlord, whether made at Tenant's expense or otherwise, shall be
and remain the property of Landlord. Any trade fixtures, business equipment,
inventory, trademarked items, signs, decorative soffit, counters, shelving,
showcases, mirrors and other removable personal property installed in or on the
Premises by Tenant at its sole expense, and the Generator (below defined), the
equipment in the UPS Area (below defined) regardless of who paid the cost
thereof, shall remain the property of Tenant (the "Tenant's Property"). Landlord
                                                   -----------------
agrees that, if Tenant is not in default hereunder, Tenant shall have the right,
at any time or from time to time, to remove any and all of Tenant's Property,
but Tenant shall repair, or at Landlord's option shall pay Landlord the cost of
repairing, any damage arising from such removal and shall leave the Premises in
a neat, clean, operating condition, free of debris, normal wear and tear
excepted.

17.  CONDEMNATION:

     (a)  If, during the Term (or extension or renewal) of this Lease, (i) all
or a substantial part of the Leased Premises or (ii) a number of the Parking
Spaces (which cannot be replaced by other parking spaces reasonably satisfactory
to Tenant) which reduces the available parking on the Project to below that
required by Applicable Laws, are taken for any public or quasi-public use under
any governmental law, ordinance or regulation, or by right of eminent domain or
by private purchase in lieu thereof, and the taking would prevent or materially
interfere with the authorized use hereunder of the Leased Premises, or make it
commercially unreasonable or unfeasible for Tenant to conduct its normal
business, in accordance with the uses authorized hereunder, in the Premises,
including any such taking by the powers of eminent domain which eliminates
access to the Building or the Project, this Lease shall terminate, Tenant's
obligation to pay the Base Rent shall cease, and Tenant's obligation to pay the
Additional Rent shall cease subject to final reconciliation of the amounts owed
under Paragraph 6 above, all effective on the date physical possession is taken
      -----------
by the condemning authority.

     (b)  If a portion of the Leased Premises or the Parking Spaces is taken and
this Lease is not terminated as provided in Paragraph 17(a) above, if
                                            ---------------
condemnation proceeds are sufficient and if restoration is feasible, Landlord
may, at its option restore the Project (other than Alterations) in order to make
it reasonably tenantable and suitable for Tenant's approved use. From the date
physical possession is taken through the date restoration is completed, Base
Rent shall be reduced by a dollar amount in proportion to the proportionate
share of the square footage of the Leased Premises taken compared to the
original square footage of the Leased Premises. Upon completion of such
restoration, the Base Rent from time to time payable under this Lease during the
unexpired portion of the term shall be similarly adjusted permanently to reflect
the square footage of the Leased

OFFICE LEASE AGREEMENT - Page - 19
- ----------------------
<PAGE>

Premises not taken.

     (c)  In the event of such taking or private purchase in lieu thereof,
Tenant may seek a separate award for any loss of improvements made and paid for
by Tenant, its personal property, and its moving expenses (so long as no such
claim diminishes Landlord's claim or award), but all other claims of any nature
shall belong to Landlord. In the event Tenant does not receive such a separate
award, Landlord shall be entitled to receive any and all sums awarded for the
taking.

     (d)  Notwithstanding anything herein to the contrary, if the holder (for
purposes of this Paragraph 17(d) and Paragraph 18(d) below, "holder" shall not
                 ---------------     ---------------
include any holder who or which is not an unrelated third party pursuant to an
arms-length loan transaction) of any indebtedness secured by a mortgage or deed
of trust covering the Building and/or Project requires that the condemnation
proceeds be applied to such indebtedness and the proceeds are so applied, unless
Landlord, in its sole discretion shall elect to provide the necessary funds for
restoration, then either Tenant or Landlord shall have the right to terminate
this Lease by delivering written notice of termination to the other within
fifteen (15) days after such requirement is imposed. All rights and obligations
under this Lease shall then cease. If Landlord does not receive condemnation
proceeds sufficient for restoration (such as when its mortgagee does not allow
the proceeds to be used for such purposes) and if restoration is economically
reasonably feasible, Tenant will have the option of supplementing available
proceeds to allow restoration, and Tenant's actual costs will be reimbursed
through a monthly prorata credit against Base Rent after all monthly Operating
Costs and sums due on or under Landlord's mortgage have been paid in full.

18.  FIRE AND CASUALTY:

     (a)  If the Building should be damaged or destroyed by fire, tornado, or
other casualty, Tenant shall give immediate verbal and written notice thereof to
Landlord.

     (b)  If the Building should be totally destroyed by fire, tornado, or other
casualty, or if it should be so damaged thereby that rebuilding or repairs
cannot reasonably be completed within one hundred eighty (180) days after the
date on which Landlord is notified by Tenant of such damage at the option of
either Landlord or Tenant, this Lease shall terminate, and the Rent shall be
abated during the unexpired portion of this Lease effective upon the date of
occurrence of such damage.

     (c)  If the Building should be damaged by any peril that will be wholly
compensated (subject to deductibles) by the insurance maintained by Landlord or
if Landlord, in its sole discretion, so chooses notwithstanding a deficiency in
such proceeds, and if rebuilding or repairs can reasonably be completed within
one hundred eighty (180) days after the date on which Landlord is notified by
Tenant of such damage, this Lease shall not terminate, and Landlord shall then
proceed with reasonable diligence to rebuild and repair the Building to
substantially the same condition in which it existed prior to such damage.
Landlord shall not be required, however, to rebuild, repair or replace Tenant's
furniture, fixtures, Alterations, inventory or other personal property. If the
Leased Premises are untenantable in whole or in part during restoration, the
Base Rent payable hereunder

OFFICE LEASE AGREEMENT - Page - 20
- ----------------------
<PAGE>

during the period in which they are untenantable shall be reduced by a dollar
amount in proportion to the proportionate share of the square footage of the
Leased Premises damaged to the original square footage of the Leased Premises.
If Landlord should fail to complete such repairs and rebuilding within one
hundred eighty (180) days after the date on which Landlord is notified by
Tenant of such damage, Tenant may terminate this Lease by delivering written
notice of termination to Landlord. Such termination shall be Tenant's exclusive
remedy and all rights and obligations of the parties under the Lease shall then
cease. Notwithstanding the foregoing provisions of this Paragraph 18(c), Tenant
                                                        ---------------
agrees that if the Leased Premises, the Building and/or Project are damaged by
fire or other casualty caused by the fault or negligence of Tenant or Tenant's
Representatives, Tenant shall have no option to terminate this Lease even if the
damage cannot be repaired within one hundred eighty (180) days, and the Rent
shall not be abated or reduced before or during the repair period, except to the
extent of the amount of business or rent interruption insurance proceeds
actually received by Landlord.

     (d)  Notwithstanding anything herein to the contrary, if the holder (as
qualified in Paragraph 17(d) above) of any indebtedness secured by a mortgage or
             ---------------
deed of trust covering the Building and/or Project requires that the insurance
proceeds be applied to such indebtedness and the proceeds are so applied, unless
Landlord, in its sole discretion shall elect to provide the necessary funds for
restoration, then either Tenant or Landlord shall have the right to terminate
this Lease by delivering written notice of termination to the other within
fifteen (15) days after such requirement is imposed. All rights and obligations
under this Lease shall then cease. If Landlord does not receive insurance
proceeds sufficient for restoration (such as when its mortgagee does not allow
the proceeds to be used for such purposes) and if restoration is economically
reasonably feasible, Tenant shall have the option of supplementing available
proceeds to allow restoration, and Tenant's actual costs will be reimbursed
through a monthly prorata credit against Base Rent after all monthly Operating
Costs and sums due on or under Landlord's mortgage have been paid in full.

19.  LANDLORD'S INSURANCE OBLIGATION:

     (a)  Landlord shall, as Operating Costs, procure and maintain in full force
and effect at all times during the Term of this Lease (i) a policy or policies
of business or rental interruption insurance, (ii) a policy or policies of
general liability insurance insuring Landlord and naming Tenant as an additional
insured and providing coverage of not less than $2,000,000 per occurrence
combined single limit for bodily injury and for personal injury liability, and
(iii) a policy or policies of standard "All Risk" insurance of full replacement
cost, covering fire and extended coverage, vandalism and mischief, sprinkler
leakage and other perils including, flood, windstorm, sinkholes, demolition,
increased cost of construction of building laws coverage, insuring for the full
replacement value thereof, the Building and the Project, including worker's
compensation insurance coverage for all persons to be employed in construction
of the Work and any other work performed by Landlord, including all contractors
and subcontractors. Landlord shall provide Tenant with a certificate evidencing
such insurance. Tenant shall pay the insurance premiums attributable to the
policies required to be obtained above (the "Insurance Premiums") as an
                                             ------------------
Operating Cost.

OFFICE LEASE AGREEMENT - Page - 21
- ----------------------
<PAGE>

     (b)  Such policies will not insure any personal property (including, but
not limited to any furniture, equipment, goods, or supplies) of Tenant or which
Tenant may have in the Leased Premises or any fixtures installed by or paid for
by Tenant upon or within the Leased Premises or any Alterations or other
improvements which Tenant may construct or install on the Leased Premises (other
than the Work after the Commencement Date), or any signs identifying Tenant's
business located on the exterior of the Building, insurance for all of which
shall be Tenant's responsibility.

20.  WAIVER OF SUBROGATION: To the extent that Landlord or Tenant receives
casualty insurance proceeds and to the extent of such proceeds actually paid,
such recipient hereby waives and releases any and all rights, claims, demands
and causes of action such recipient may have against the other on account of any
loss or damage occasioned to such recipient or its businesses, real and personal
properties, the Leased Premises, the Building, the Project, or its contents,
arising from any risk or peril covered by any insurance policy carried by either
party and for which such proceeds are actually received and Landlord and Tenant
hereby waive any right of subrogation which might otherwise exist in, or accrue
to, any person on account thereof. Inasmuch as the above mutual waivers will
preclude the assignment of any such claim by way of subrogation (or otherwise)
to an insurance company (or any other person), each party hereto agrees
immediately to give to its respective insurance companies written notice of the
terms of such mutual waivers and to have their respective insurance policies
properly endorsed, if necessary, to prevent the invalidation of such insurance
coverages by reason of such waivers. If such waivers shall invalidate such
coverages, then the mutual waivers of this Paragraph 20 shall be void. This
                                           ------------
provision shall be cumulative of Paragraph 21 below.
                                 ------------

21.  HOLD HARMLESS: Landlord shall not be liable to Tenant, Tenant's
Representatives, or any other person for any injury to person or damage to
property on or about the Leased Premises or the Project caused by the negligence
or misconduct of Tenant, Tenant's Representatives, or any other persons, other
than Landlord or Landlord's Representatives, entering upon the Leased Premises
or the Project OR ARISING FROM AN OCCURRENCE FOR WHICH LANDLORD IS BY LAW
STRICTLY LIABLE unless Landlord or Landlord's Representatives are also liable
                ------
because of their negligence or misconduct. Tenant agrees to indemnify and hold
Landlord and Landlord's employees, officers, directors, partners, agents,
invitees, guests, patrons, licensees, contractors, representatives, trespassers,
and others for whom Landlord is legally responsible (collectively, "Landlord's
                                                                    ----------
Representatives") harmless from any and all loss, attorney's fees, expenses, or
- ---------------
claims arising out of any such damage, loss or injury. Tenant shall not be
liable to Landlord or Landlord's Representatives or any other person for any
injury to person or damage to property on or about the Leased Premises or the
Project caused by the negligence or misconduct of Landlord, Landlord's
Representatives, or any other persons other than Tenant or Tenant's
Representatives, entering upon the Leased Premises or the Project OR ARISING
FROM AN OCCURRENCE FOR WHICH TENANT IS BY LAW STRICTLY LIABLE unless Tenant or
                                                              ------
Tenant's Representatives are also liable because of their negligence or
misconduct. Landlord agrees to indemnify and hold Tenant and Tenant's
Representatives harmless from any and all loss, attorney's fees, expenses, or
claims arising out of any such damage, loss or injury.

OFFICE LEASE AGREEMENT - Page - 22
- ----------------------
<PAGE>

22.  QUIET ENJOYMENT: Landlord certifies that it has full right to execute and
to perform this Lease and to grant the estate demised herein and that Tenant,
upon payment of the required Rent and performance of the covenants and
agreements contained in this Lease, shall peaceably and quietly have, hold, and
enjoy the Leased Premises and the Common Areas during the full term of this
Lease, including any extensions or renewals thereof without hindrance or
interference from Landlord or any party, claiming through or under Landlord.

23.  LANDLORD'S RIGHT OF ENTRY: Landlord shall have the right to enter the
Leased Premises during the hours of 8:00 a.m. to 5:00 p.m., or at any time in an
emergency situation for the following reasons: inspection, cleaning or making
repairs, making such alterations or additions as Landlord may deem necessary or
desirable; installation of utility lines servicing the Leased Premises;
determining Tenant's use of the Leased Premises; and determining if any event of
default under this Lease has occurred, Landlord shall give twenty-four (24)
hours written notice to Tenant prior to such entry, except in cases of emergency
or when Landlord has reason to believe that an event of default has occurred, in
which cases Landlord may enter the Leased Premises at any time and without prior
notice. During the period that is six (6) months prior to the end of the Lease
term, Landlord and Landlord's agents and representatives shall have the right to
enter the Leased Premises at any reasonable time during the business hours
stipulated above, upon prior written notice to Tenant, for the purpose of
showing the Leased Premises (provided that Landlord shall, in all such cases, be
accompanied by an authorized employee or representative of Tenant).

24.  ASSIGNMENT OF LANDLORD'S INTEREST IN LEASE: Landlord shall have the right
to transfer and assign, in whole or in part, its rights and obligations with
respect to the Project, the Leased Premises, and this Lease, including Tenant's
Security Deposit. Upon and after such transfer, Landlord shall be released from
any further obligation under this Lease and Tenant agrees to look solely to
Landlord's successor for the performance of such obligations, provided that such
transferee or assignee shall agree in writing to be bound by the terms,
covenants, conditions and agreements herein contained and which accrue after the
effective date of such assignment and such transferee or assignee shall
expressly assume and agree to perform the covenants, conditions and agreements
of Landlord set forth in this Lease which accrue after the effective date of
such assignment.

25.  LANDLORD'S LIEN: In addition to any statutory lien for Rent in Landlord's
favor, Landlord shall have, and Tenant hereby grants to Landlord, a continuing
security interest for all Rent and other sums of money becoming due under this
Lease from Tenant upon all goods, wares, general office equipment (but not any
equipment used by Tenant in research, development, or production of its computer
related telecommunication products), fixtures, furniture, inventory, accounts,
and other personal property of Tenant situated on or arising from the Leased
Premises, provided that such security interest shall be subordinate to any
security interest granted by Tenant in such property under an arms-length third
party loan transaction of which Tenant has given Landlord written notice
accompanied by a reasonably detailed description of the terms thereof. Such
property shall not be removed without the consent of Landlord which consent may
be withheld by Landlord until all of Tenant's duties and obligations have been
performed in full. In the event of a default under this

OFFICE LEASE AGREEMENT - Page - 23
- ----------------------
<PAGE>

Lease, Landlord shall have, in addition to any other remedies provided in this
Lease or by law, all rights and remedies under the Texas Uniform Commercial
Code, including without limitation the right to sell the property described in
this Paragraph at public or private sale upon five (5) days notice to Tenant.
Tenant hereby agrees to execute such financing statements and other instruments
necessary or desirable in Landlord's discretion to perfect the security interest
hereby created, and Landlord may, at any time, file this Lease as a financing
statement or may file a financing statement without Tenant's execution so long
as complying with all requirements at law.

26.  DEFAULT BY TENANT: The following shall be events of default by Tenant
under this Lease:

     (a)  Tenant's failure to pay, within five (5) days after written notice
that it is due, any installment of Rent or other payment required pursuant to
this Lease; provided that after the third such notice during any twelve-month
period, no further such written notice shall be required to establish the event
of default;

     (b)  Tenant's failure to comply with any term, provision or covenant of
this Lease, other than the defaults listed in the other subparagraphs of this
Paragraph 26, and the failure is not cured within ten (10) days after written
- ------------
notice thereof to Tenant, except that this ten (10) day period shall be extended
for a reasonable period of time if such alleged default is not reasonably
capable of being cured within said ten (10) day period so long as Tenant
commences the cure and diligently pursues same during the ten (10) day period;

     (c)  Tenant's filing of a petition or adjudication as a debtor or bankrupt
insolvent under the Bankruptcy Code or any similar law or statute of the United
States or any state (unless in the case of a petition filed against Tenant, the
same is dismissed within sixty (60) days);

     (d)  The appointment of a trustee or receiver of the property of Tenant, or
the attachment, execution or other judicial seizure of Tenant's property, that
is not discharged within thirty (30) days, or Tenant's general assignment for
the benefit of creditors, or any transfer of assets by Tenant in fraud of
creditors;

     (e)  Tenant doing or permitting to be done any act which results in a lien
being filed against the Leased Premises and the same is not removed within sixty
(60) days after Landlord's notice thereof to Tenant.

27.  REMEDIES FOR TENANT'S DEFAULT: Upon the occurrence of any event of default,
Landlord shall have the option to pursue any one or more of the following
remedies without any prior notice or demand:

     (a)  Landlord may terminate this Lease, in which event Tenant shall
immediately surrender the Leased Premises to Landlord, and if Tenant fails to do
so, Landlord may, without prejudice to any other remedy which it may have, enter
upon and take possession of the Leased

OFFICE LEASE AGREEMENT - Page - 24
- ----------------------
<PAGE>

Premises, and expel or remove Tenant and any other person who may be occupying
all or any part of the Leased Premises. Landlord shall not be liable for
prosecution or any claim for damages as a result of such actions except for
damages caused by the gross negligence or wilful misconduct of Landlord or
Landlord's Representatives. Tenant agrees to pay on demand the amount of all
losses, costs, expenses, deficiencies, and damages, including, without
limitation, reasonable reconfiguration expenses, rental concessions and other
inducements to new tenants, advertising expenses and broker's commissions, which
Landlord may incur or suffer by reason of Tenant's default or the termination of
this Lease under this subparagraph, whether through inability to rent the Leased
Premises on commercially reasonable terms or otherwise. Tenant acknowledges that
its obligation to pay Base Rent and all Additional Rent hereunder is not only
compensation for use of the Leased Premises but also compensation for sums
already expended and/or being expended by Landlord with respect to its
obligations hereunder and with respect to the Leased Premises, and Tenant
acknowledges that Tenant's default in timely payment of all sums due hereunder
shall constitute significant financial loss to Landlord. In such event, in
addition to Landlord's other remedies hereunder, Landlord shall be entitled to
accelerate all Base Rental remaining unpaid hereunder, the entirety of which
shall at the option of Landlord be immediately due and payable to the extent
allowed by law.

     (b)  Without termination of this Lease, Landlord may enter upon and take
possession of the Leased Premises and expel or remove Tenant and any other
person who may be occupying all or any part of the Leased Premises (without
being liable for prosecution or any claim for damages therefor except for
damages caused by the gross negligence or wilful misconduct of Landlord's
Representatives) and relet the Leased Premises on behalf of Tenant and receive
directly the rent from the reletting. Tenant agrees to pay Landlord on demand
any deficiency that may arise by reason of any reletting of the Leased Premises
and to reimburse Landlord on demand for any losses, cost and expenses,
including without limitation, reconfiguration expenses, rental concessions and
other inducements to new tenants, advertising costs or broker's commissions,
which Landlord may incur or suffer as a result of Tenant's default or in
reletting the Leased Premises. In the event Landlord is successful in reletting
the Leased Premises at a rental in excess of that agreed to be paid by Tenant
pursuant to this Lease, Tenant agrees that Tenant shall not be entitled, under
any circumstances, to such excess rental, and Tenant does hereby specifically
waive any claim to such excess rental.

     (c)  Without terminating this Lease, Landlord may enter upon the Leased
Premises (without being liable for prosecution or any claim for damages therefor
except for damages caused by the gross negligence or wilful misconduct of
Landlord or Landlord's Representatives) and do whatever Tenant is obligated to
do under the terms of this Lease. Tenant agrees to reimburse Landlord on demand
for any losses, reasonable costs and expenses which Landlord may reasonably
incur in effecting compliance with Tenant's obligations under this Lease. Tenant
further agrees that Landlord shall not be liable for any damages resulting to
Tenant from effecting compliance with Tenant's obligations under this
subparagraph, unless caused by the gross negligence or wilful misconduct of
Landlord or Landlord's Representatives.

OFFICE LEASE AGREEMENT - Page - 25
- ----------------------
<PAGE>

     (d)  With respect to Landlord's entry upon the Leased Premises under the
provisions of subparagraphs (a), (b), and (c) above, no restriction of, or
obligation imposed upon Landlord by, Texas Property Code Section 93.002(f) shall
apply, such Section being superseded hereby.

     (e)  Landlord may pursue any remedy provided at law or in equity.

     (f)  Except as otherwise provided by law, Landlord shall have no duty to
relet the Premises, and the failure of Landlord to do so shall not release or
affect Tenant's liability for Rent and other charges due hereunder or for
damages.

     (g)  No re-entry or reletting of the Premises or any filing or service of
an unlawful detainer action or similar action shall be construed as an election
by Landlord to terminate this Lease unless a written notice of such intention is
given by Landlord to Tenant. Notwithstanding any such reletting without
termination, Landlord may at any time thereafter elect to terminate this Lease
and Tenant's right to possession hereunder.

28.  TERMINATION OF OPTIONS: All options and special rights granted by Landlord
in this Lease to use of the roof, to signage, to extend the Term, to expand into
adjoining properties, or to acquire any other interest in the Leased Premises,
the Building, or the Project are independent of the leasehold estate hereby
granted to Tenant by Landlord. Landlord and Tenant agree and acknowledge that
the negotiated consideration for any such options or special rights is Tenant's
entry into this Lease and that no portion of any sums due and payable by Tenant
to Landlord hereunder is attributable thereto. In addition to, and not in lieu
of, the above remedies of Landlord for Tenant's default, any and all such
options or special rights shall be automatically terminated upon the occurrence
of the following events:

     (a)  Tenant shall have failed to pay when due any installment of Rent or
other sums payable under this Lease for any three (3) consecutive months during
the Lease term or any renewal or extension thereof, or for any ten (10) months
during the Lease term or any renewal or extension thereof, whether or not said
defaults are cured by Tenant; or

     (b)  Tenant shall have received two (2) or more notices of default under
Paragraph 26 within any one calendar year with respect to any other covenant of
- ------------
this Lease, whether or not such default(s) is/are cured; or

     (c)  Tenant shall have committed or suffered to exist any other event of
default described under Paragraph 26 above which is not cured within the time
                        ------------
period allowed herein for cure.

29.  WAIVER OF DEFAULT OR REMEDY: Failure of Landlord to declare a default
immediately upon its occurrence, or delay in taking any action in connection
with an event of default, shall not be a waiver of the default. Landlord shall
have the right to declare the default at any time and take such action as its
lawful or authorized under this Lease. Pursuit of any one or more of the
remedies set forth in Paragraphs 27 or 28 above shall not preclude pursuit of
                      -------------------
any one

OFFICE LEASE AGREEMENT - Page - 26
- ----------------------
<PAGE>

or more of the other remedies provided therein or elsewhere in this Lease or as
provided by law, nor shall pursuit of any remedy be a forfeiture or waiver of
any Rent or damages accruing to Landlord by reason of the violation of any of
the terms of this Lease. Failure by Landlord to enforce one or more of its
remedies upon an event of default shall not be construed as a waiver of the
default or of any other violation or breach of any of the terms contained in
this Lease.

30. CHOICE OF LAW; VENUE; ATTORNEY'S FEES: It is specifically stipulated that
this Lease shall be interpreted and construed according to the laws of the State
in which the Leased Premises are located, and any suit brought on this Lease
shall be maintained in the county in which the Leased Premises are located.
Further, the prevailing party in any such litigation between the parties shall
be entitled to recover, as a part of its judgment, reasonable attorney's fees
and costs and expenses incurred therein.

31. HOLDING OVER: Tenant will, at the termination of this Lease by lapse of time
or otherwise, surrender immediate possession to Landlord. If Landlord agrees in
writing that Tenant may hold over after the expiration or termination of this
Lease and if the parties do not otherwise agree, the hold over tenancy shall be
subject to termination by Landlord at any time upon not less than fifteen (15)
days advance written notice, or by Tenant at any time upon not less than fifteen
(15) days advance written notice. Further, all of the terms and provisions of
this Lease shall be applicable during the hold over period, except that Tenant
shall pay Landlord from time to time upon demand, as Base Rent for the period of
any hold over, an amount equal to one and one-half times (1-1/2) the Base Rent
in effect on the date of termination, computed on a daily basis for each day of
the hold over period, plus all Additional Rent and other sums due hereunder. If
Tenant shall fail immediately to surrender possession of the Leased Premises to
Landlord upon termination of this Lease, by lapse of time or otherwise, and
Landlord has not agreed to such continued possession, as above provided, then,
until Landlord can dispossess Tenant under the terms hereof or otherwise, Tenant
shall pay Landlord from time to time upon demand, as Base Rent for the period of
any such hold over, an amount equal to twice the Base Rent in effect on the date
of termination, computed on a daily basis for each day of the hold over period,
plus all additional Rent and other sums due hereunder. No holding over by
Tenant, whether with or without consent of Landlord, shall operate to extend
this Lease except as otherwise expressly agreed by the parties. The preceding
provisions of this Paragraph shall not be construed as Landlord's consent for
Tenant to hold over.

32. RIGHTS OF MORTGAGEE: Landlord represents that Landlord is the current fee
simple owner of the Project, and Tenant accepts this Lease subject and
subordinate to the liens, interests, mortgages and/or deeds of trust set forth
on Exhibit "C-1" attached hereto (the "Existing Mortgages") copies of which have
   -------------                       ------------------
been provided to Tenant prior to the date hereof. Tenant agrees
contemporaneously to provide to the holder of any Existing Mortgage, whose name
and address are set forth on Exhibit "C-1" and to any future holder of a
                             -------------
mortgagee or deed of trust whose name and address have been provided to Tenant
(each a "Mortgagee"), a copy of each notice to Landlord which alleges any act,
         ---------
omission, or condition that might constitute a default by Landlord hereunder or
otherwise give rise to any Tenant remedy hereunder or at law, and Mortgagee, in
its sole discretion, shall have all rights of Landlord hereunder to cure any
such default. Landlord reserves the right to

OFFICE LEASE AGREEMENT - Page - 27
- ----------------------
<PAGE>

subject and subordinate this Lease at all times to the lien of any other deeds
of trust, vendor's liens, or mortgages now or hereafter affecting Landlord's
interest in the Project (any one of which shall be referred to herein as the
"Deed of Trust"); provided, however, that so long as Tenant is not in default of
 -------------
its obligations beyond the applicable notice and grace periods provided herein
(i) no default by Landlord under any such Deed of Trust shall affect Tenant's
rights under this Lease; (ii) Tenant will not be named by the holder or Landlord
as a party in any foreclosure or other proceeding with respect to such Deed of
Trust unless required by law; (iii) the holder of any such Deed of Trust agrees
that the insurance proceeds resulting from any fire or other casualty or from
any taking by eminent domain will be available for restoration of the Building
and Project under terms and conditions acceptable to the holder; (iv) the holder
of the Deed of Trust shall recognize the Lease and any amendments allowed under
the Deed of Trust or otherwise approved by the Mortgagee in writing in advance
of execution and be bound thereto; and (v) the holder of any such Deed of Trust
will execute with Tenant and Landlord a Subordination, Non-Disturbance and
Attornment Agreement in the form required by such holder and reasonably
Acceptable to Tenant. Attached hereto as Exhibit "C" is the form of such
                                         -----------
agreement that the current Mortgagee has agreed to sign with Landlord and
Tenant, subject to such Mortgagee's review of this Lease. If Tenant has not
received such agreement signed by the Lender, Landlord and Guarantor to be named
therein within thirty (30) days after the full execution hereof, Tenant may
terminate this Lease by written notice to Landlord within the following five (5)
days and receive the return of the Security Deposit and Base Rent deposit, and
neither party shall have any further liability hereunder, failing in which
timely termination such right shall automatically end.

33. ESTOPPEL CERTIFICATES: If requested by Landlord, Tenant agrees to furnish on
the Commencement Date and from time to time within ten (10) days of request by
Landlord or Landlord's mortgagee, a statement certifying that, if the same be
true and if not true qualifying the statement to make it true, the Tenant is in
possession of the Leased Premises; the Leased Premises are acceptable; this
Lease is in full force and effect; this Lease is unmodified; Tenant claims no
present charge, lien, or claim of offset against Rent; the Rent is paid for the
current month but is not paid and will not be paid for more than one month in
advance (except estimated Additional Rent under Paragraph 6); there is no
                                                -----------
existing default under this Lease; and such other matters as may be reasonably
required by Landlord or Landlord's mortgagee.

34. SUCCESSORS: This Lease shall be binding upon and inure to the benefit of
Landlord and Tenant and their respective heirs, personal representatives,
successors and assigns.

35. REAL ESTATE COMMISSION: Landlord and Tenant each represents and warrants
that except for Landlord's agent, Jean Farris of Jones Lang LaSalle, and
Tenant's Agent, Bruce Worth of McCaslin Commercial, Corporate Real Estate
Services, with whom Landlord has entered into a separate written agreement, it
has dealt with no other broker, agent, or other person in connection with this
transaction, and that no other broker, agent, or other person brought about this
transaction. Landlord and Tenant each agree to indemnify and hold the other
harmless from and against any claims by any broker, agent, or other person
claiming a commission or other form of compensation by virtue of having dealt
with Tenant or Landlord respectively with regard to this transaction. The
provisions of this Paragraph shall survive the termination of this Lease.

OFFICE LEASE AGREEMENT - Page - 28
- ----------------------
<PAGE>

36. DEFAULT BY LANDLORD: If Landlord fails to observe or perform any covenants
or agreements required to be performed by Landlord hereunder, and if such
failure shall have continued uncured or unabated for a period of thirty (30)
days following written notice to Landlord, Landlord shall not be in default, and
Tenant shall have no right to any remedy at law or in equity, unless the act,
omission, or condition allegedly giving rise to such default shall have
continued uncured or unabated for a period of thirty (30) days following written
notice to Landlord (with a copy to Mortgagee as provided in Paragraph 32 above)
                                                            ------------
or, if such cure or abatement cannot be accomplished within said 30-day period,
then, so long as Landlord or Mortgagee has commenced such cure or abatement
within such 30-day period and diligently pursues same, such period shall be
extended a reasonable time to allow completion of the cure or abatement.

37. MECHANIC'S LIENS: Tenant shall have no authority, express or implied, to
create or place any lien or encumbrance of any kind or nature whatsoever upon,
or in any manner to bind, the interest of Landlord in the Leased Premises or the
Project or to charge the Rent payable hereunder for any claim in favor of any
person dealing with Tenant, including those who may furnish materials or perform
labor for any construction or repairs. Each such claim shall affect, and each
such lien shall attach to, if at all, only the leasehold interest granted to
Tenant by this Lease. Tenant covenants and agrees that it will pay or cause to
be paid all sums legally due and payable by it on account of any labor performed
or materials furnished in connection with any work performed on the Leased
Premises on which any lien is or can be validly and legally asserted against its
leasehold interest in the Leased Premises or the improvements thereon. Tenant
further agrees to save and hold Landlord harmless from any and all loss, cost,
or expense based on or arising out of claims or liens asserted by parties by
virtue of their dealings with Tenant and encumbering the leasehold estate or the
right, title and interest of the Landlord in the Leased Premises or the Project.
Under no circumstances shall Tenant be or hold itself out to be the agent or
representative of Landlord with respect to any Alterations of the Leased
Premises whether or not consented to or approved by Landlord hereunder.

38. HAZARDOUS MATERIALS:

          (a) Attached hereto as Schedule A is a compilation of materials that
                                 ----------
culminate in the recorded Voluntary Cleanup Program Final Certificate of
Completion with respect to the land of the Project certifying, among other
things, that response actions achieved response action levels acceptable for
Non-Residential land use. Tenant acknowledges its review and understanding of
such materials.

          (b) Landlord certifies to Tenant that to Landlord's current actual
knowledge, no handling, transportation, storage, treatment or usage of hazardous
or toxic substances (as defined by any applicable government authority) or
petroleum or petroleum products (hereinafter being referred to as "Hazardous
                                                                   ---------
Materials") currently exists or has existed with respect to the Project,
- ---------
including the Premises, that is not currently in compliance with all Applicable
Laws. Landlord further certifies to Tenant that Landlord has no current actual
knowledge of any current or past leak, spill, discharge, emission or disposal of
Hazardous Materials occurring on the Project that is now in violation of
Applicable Laws and that Landlord has no current actual knowledge that the soil,
groundwater, and

OFFICE LEASE AGREEMENT - Page - 29
- ----------------------
<PAGE>

soil vapor on or under the Project is not in compliance with Applicable Laws.
Landlord certifies to Tenant that to Landlord's current actual knowledge no
underground storage tank or asbestos-containing materials exist in, on or under
the Project. Landlord certifies to Tenant that to Landlord's current actual
knowledge no part of the remediation system addressing the contamination on the
property located adjacent to and west of the Project is located in, on or under
the Project. If Landlord is given the opportunity to conduct the defense,
Landlord agrees to indemnify, defend and hold Tenant and its officers, partners,
directors, shareholders, employees and agents harmless from any claims,
judgments, damages, fines, penalties, costs (including reasonable attorney,
consultant and expert fees), liabilities (including sums necessarily and
properly paid in settlement of claims) or loss which arise during or after the
Term or any extension thereof, in connection with the presence of Hazardous
Materials in, or migrating from, the soil, groundwater, or soil vapor on or
under the Project, unless, but only to the extent, such Hazardous Materials
were, are, or come to be present as the result of the acts of Tenant or Tenant's
Representatives. Without limiting the generality of the foregoing, this
indemnification (i) shall survive the expiration of this Lease for four (4)
years, (ii) does not cover costs incurred in connection with any investigation
of site conditions that are not conducted in response to written governmental
allegations or order or bona fide, substantiated, written third party claims,
(iii) does cover costs incurred in connection with any investigation of site
conditions that are conducted in response to written governmental allegations or
orders or bona fide, substantiated, written third party claims, and (iv) does
cover cleanup, remedial, removal or restoration work required by any federal,
state or local governmental agency or political subdivision because of the
presence or suspected presence of Hazardous Materials in the soil, groundwater
or soil vapor on or under the Project, unless, but only to the extent, the
Hazardous Materials are present as the result of the acts of Tenant or Tenant's
Representatives. Without limiting the generality of or the qualifications on the
foregoing, this indemnification shall also specifically cover costs in
connection with:

          (i)   Hazardous Materials present in the soil, ground water or soil
     vapor on or under the Project unless caused by Tenant or Tenant's
     Representatives; or

          (ii)  Hazardous Materials that migrate, flow, percolate, diffuse or in
     any way move onto or under the Project unless caused by Tenant or Tenant's
     Representatives; or

          (iii) Hazardous Materials present on or under the Premises as a result
     of any discharge, dumping, spilling (accidental or otherwise) onto the
     Project by any person or entity other than Tenant or Tenant's
     Representatives.

Such indemnity shall exclude all claims arising from or related to the release
of or exposure to Hazardous Materials which were caused, directly and
indirectly, by Tenant or Tenant's Representatives or the use of the Project by
Tenant or Tenant's Representatives.

     (c) If, during the Term of this Lease, any governmental authority requires
the investigation, remediation and/or monitoring of Hazardous Materials at the
Premises or the Project and such investigation, remediation and/or monitoring
materially adversely affects Tenant's business

OFFICE LEASE AGREEMENT - Page - 30
- ----------------------
<PAGE>

operations or poses a bona fide safety threat to Tenant's employees or
customers, then Tenant shall be entitled to an equitable abatement of Rent from
the date such interference or safety hazard occurs to the date such interference
and safety hazard is no longer present. Notwithstanding anything herein to the
contrary, nothing in this Lease shall be construed to obligate Tenant to
remediate any Hazardous Materials located in, on, or under the Premises or the
Project, unless the acts of Tenant or Tenant's Representatives cause the
presence of such Hazardous Materials. If required by law, Landlord shall remove,
or cause to be removed, at its sole cost and expense and in Landlord's name, any
Hazardous Materials from the Premises or the Project unless such Hazardous
Materials are present because of Tenant or Tenant's Representatives in which
case Tenant, at its sole cost and expense and in Tenant's name, shall remove
same.

     (d) Tenant hereby agrees that (i) no activity will be conducted on the
Project that will produce any Hazardous Materials in violation of Applicable
Laws; (ii) the Project will not be used in any manner not in compliance with
local, state and federal laws for the storage of any Hazardous Materials; (iii)
no portion of the Project will be used as a landfill or a dump; (iv) Tenant will
not install any underground tanks of any type; (v) Tenant will not allow any
surface or subsurface conditions to exist or come into existence that
constitute, or with the passage of time may constitute, a public or private
nuisance; and (vi) Tenant will not permit any Hazardous Materials to be brought
onto the Project that are not stored and used in compliance with all local,
state and federal laws regarding same. Landlord shall have the right but not the
obligation to enter the Project after providing reasonable notice (except in the
event of emergency when no notice shall be required) for the purpose of ensuring
compliance with all Applicable Laws.

     (e) For purposes of this Paragraph 38, the Project shall not include any
                              ------------
soil beneath the surface of the land, any groundwater, any subsurface structure,
object, fixture or device, other than utility lines which are necessary for the
use of the Premises by Tenant, any underground storage tanks or associated
piping, any buried drums or other containers, or abandoned septic or sewer
lines.

39.  ENTIRE AGREEMENT AND LIMITATION OF WARRANTIES: It is expressly agreed by
Tenant, as a material consideration for the execution of this Lease, that this
Lease and all Exhibits, Schedules and other attachments to this Lease constitute
the entire agreement of the parties and that there are and were no verbal
representations, warranties, understandings, stipulations, agreements, or
promises pertaining to this Lease not incorporated in this Lease. Except
as otherwise expressly provided herein, Tenant expressly agrees that there are
and shall be no implied warranties of merchantability, fitness, habitability, or
of any other kind. It is likewise agreed that this Lease may not be altered,
waived, amended, or extended except by an instrument in writing signed by both
Landlord and Tenant. Not in limitation upon the foregoing, Landlord agrees that
to the extent assignable, all warranties, if any shall exist, from contractors
or suppliers with respect to the improvements to the Leased Premises hereunder
are hereby partially assigned to Tenant to the extent necessary to avail Tenant
of the benefits thereof with respect to its obligations herein and the leasehold
estate and property located at the Leased Premises.

OFFICE LEASE AGREEMENT - Page - 31
- ----------------------
<PAGE>

40.  FINANCIAL STATEMENTS: From time to time Landlord may need to obtain
financing or renew financing on the Project, or perform calculations for various
reasons regarding the value of the Project. Tenant hereby agrees to provide to
Landlord the most recently published and publicly available financial statements
on its business when requested, but not more than once annually.

41.  FORCE MAJEURE:

     (a) Landlord shall not be required to perform any covenant or obligation of
this Lease or be liable in damages to Tenant for that time period during which
the performance or non-performance of the covenant or obligation is delayed,
caused by, or prevented by Tenant or Tenant's Representatives or by an act of
God or force majeure.

     (b) Except with respect to the payment of Rent or any other sum due
hereunder for which Tenant does not have an offset or abatement right under the
terms of this Lease, Tenant shall not be required to perform any covenant or
obligation of this Lease or be liable in damages to Landlord for that time
period during which the performance or non-performance of the covenant or
obligation is delayed, caused by, or prevented by Landlord or Landlord's
Representatives or by an act of God or force majeure.

     (c) An "act of God" or "force majeure" is defined for purposes of this
Lease as strikes, lockouts, sit-downs, material or labor restrictions by any
governmental authority, riots, floods, washouts, explosions, earthquakes, fire,
storms, acts of the public enemy, wars, insurrections and any other similar
cause not caused by or reasonably within the control of the obligated party and
which by the exercise of due diligence such party is unable, wholly or in part,
to prevent or overcome.

42.  ROOF AND OTHER AREAS:

     (a) Subject to Paragraph 28 above, and subject to Tenant's compliance with
                    ------------
all of the planning, construction, and other requirements of Paragraph 16 above,
                                                             ------------
Tenant shall have the right to erect and maintain communication devices and
equipment, including, without limitation, antenna and a satellite dish and other
similar equipment Tenant shall deem necessary or desirable, on the roof of the
Building and shall have the right to run wires and cables for such equipment
into the Premises. Tenant shall maintain the area where the roof penetrations
are made while Tenant's equipment is present and Tenant shall repair any damage
to the roof caused by the equipment or roof penetrations, including repairs upon
the removal of any such equipment. Any penetrations to the roof must be made
either by Landlord or, at Tenant's option, by a contractor approved by Landlord
which approval shall not be capriciously withheld or unreasonably delayed. No
additional rental or assessments shall be charged by Landlord to Tenant for use
of the roof area. Tenant's right to use the roof is to inure to the benefit of
Tenant only and is not transferable or assignable to any other entity or for any
purpose other than that stated above.

OFFICE LEASE AGREEMENT - Page - 32
- ----------------------
<PAGE>

     (b) Landlord agrees that Tenant shall have access to and be allowed the use
of a dock high loading area (the "Dock Area") acceptable to Tenant to be located
                                  ---------
at the rear of the Building at the location provided in the Working Drawings or,
if not so provided, then at a location mutually agreeable to both by Landlord
and Tenant.

     (c) Tenant shall be allowed to install, operate and maintain and use, when
necessary, an emergency standby generator (the "Generator") for the exclusive
                                                ---------
use of the Premises to be located at the location provided in the Working
Drawings or, if not so provided, then at a location approved by Landlord (which
approval shall not be unreasonably withheld or delayed).

     (d) Landlord shall allow Tenant to operate, use and maintain for Tenant's
exclusive use within the Lease Premises an uninterrupted power source (UPS) room
(the "UPS Area") to be located at the location provided in the Working Drawings
      --------
or, if not so provided, then at a location approved by Landlord, which approval
shall not be unreasonably withheld or delayed, and acceptable to Tenant. The
location and method of installation of all equipment shall be approved by
Landlord.

43.  MISCELLANEOUS:

     (a) Words of any gender used in this Lease shall be held and construed to
include any other gender; and words in the singular number shall be held to
include the plural, unless the context otherwise requires.

     (b) Each party agrees to furnish to the other, promptly upon demand, a
corporate resolution, proof of due authorization by partners, or other
appropriate documentation evidencing the due authorization and power of such
party to enter into this Lease and the empowerment and authority of the
individual signing below to bind his or her principal.

     (c) The captions inserted in this Lease are for convenience only and in no
way define, limit, or otherwise describe the scope or intent of this Lease or
any provision hereof, or in any way affect the interpretation of this Lease.

     (d) If any clause or provision of this Lease is illegal, invalid, or
unenforceable under present or future laws effective during the term of this
Lease, then and in that event, it is the intention of the parties hereto that
the remainder of this Lease shall not be affected thereby; and it is also the
intention of the parties to this Lease that in lieu of each clause or provision
of this Lease that is illegal, invalid, or unenforceable there be added as a
part of this Lease a clause as similar in terms to such illegal, invalid, or
unenforceable clause or provision as may be possible and be legal, valid, and
enforceable.

     (e) All references in this Lease to "the date hereof" or similar references
shall be deemed to refer to the Execution Date, but if the blanks defining same
are not completed, then the last date, in point of time, on which all parties
hereto have executed this Lease.

OFFICE LEASE AGREEMENT - Page - 33
- ----------------------
<PAGE>

     (f) Landlord does not in any way or for any purpose become a partner with
Tenant in the conduct of its business or otherwise, nor a member of a joint
venture with Tenant.

     (g) In the event that Tenant shall fail to perform any duty or obligation
hereunder (other than maintenance, repair or replacement of the Leased Premises
for which provision is made in Paragraph 7(f) above), whether maintenance of
                               --------------
insurance, or otherwise, then Landlord may, but shall in no event be obligated
to, without notice of any kind, take such actions as Landlord deems necessary or
appropriate to remedy such Tenant failure, and any sums expended by Landlord
together with fair and just compensation for the time and effort of Landlord in
such efforts shall be deemed additional Rent hereunder due and payable by Tenant
on demand. In particular, but without limitation, since Tenant is responsible
for all taxes levied or assessed against personal property or fixtures placed by
Tenant in the Premises and/or Building, if any such taxes are levied or assessed
against Landlord or Landlord's property and if Landlord elects to pay the same
or if the assessed value of the Landlord's property is increased by inclusion of
personal property or fixtures placed by Tenant in the Premises and/or Building,
and Landlord elects to pay the taxes based on such increase, Tenant shall pay to
Landlord upon demand that part of such taxes for which Tenant is responsible
hereunder.

     (h) If Tenant shall fail to pay, when the same is due and payable, any Rent
or any other sum due from Tenant hereunder, or if Landlord shall fail to pay,
when the same is due and payable, any sum due from Landlord hereunder, such
unpaid amount shall bear interest from the due date thereof to the date of
remittance at the rate of the lesser of 18% per annum and the maximum rate
allowed by law.

     (i) Tenant shall not record this Lease without the prior written consent of
Landlord. However, upon the request of either party hereto, the other party
shall join in the execution of a memorandum or so-called "short form" of this
Lease for the purposes of recordation. If such recordation occurs, then Tenant
agrees immediately, on demand, to execute a complete release thereof, in
recordable form, upon rightful termination of this Lease for any reason, and if
Tenant fails to do so within five (5) days of receipt of such demand, Landlord
may execute same for Tenant as Tenant's agent for such limited purpose and, in
any event, Tenant shall be liable for all damages, if any, suffered by Landlord
resulting therefrom.

     (j) Time is of the essence in the performance of all the covenants,
conditions, and agreements contained in this Lease.

     (k) Any duty, obligation, or debt and any right or remedy arising hereunder
and not otherwise consummated and/or extinguished by the express terms hereof at
or as of the time of termination of this Lease, whether at the end of the term
hereof or otherwise, shall survive such termination as continuing duties,
obligations, and debts of the obligated party to the other or continuing rights
and remedies of the benefitted party against the other.

OFFICE LEASE AGREEMENT - Page - 34
- ----------------------
<PAGE>

     (1) This Agreement may be executed in one or more counterparts, each of
which counterpart shall for all purposes be deemed to be an original; but all
such counterparts together shall constitute but one instrument.

     (m) Tenant and Tenant's Representatives will comply fully with all
requirements of the Rules and Regulations of the Building and related facilities
which are attached hereto as Exhibit "D", and made a part hereof as though fully
                             -----------
set forth herein. Tenant shall be responsible for the compliance with such Rules
and Regulations by Tenant's Representatives. Landlord will not materially
discriminate among tenants in enforcement of the Rules and Regulations.

     (n) Attached hereto are the following exhibits and one schedule to this
Lease all of which are hereby incorporated herein by reference:

         Exhibit A   -      Legal Description
         Exhibit A-1 -      Site Plan (with depiction of the Premises
                            and Additional Space)
         Exhibit B   -      Tenant Finish Work/Work Letter
         Exhibit C   -      Current Mortgagee form SNDA
         Exhibit C-1 -      Existing Mortgages
         Exhibit D   -      Rules and Regulations
         Exhibit E   -      Landlord's Plans and Specifications
         Schedule A  -      Voluntary Cleanup Program documentation

44.  NOTICE:

     (a) All Rent and other payments required to be made by Tenant to Landlord
shall be payable to Landlord at the address set forth below or any other address
that Landlord may specify from time to time by written notice delivered to
Tenant.

     (b) All payments, if any, required to be made by Landlord to Tenant shall
be payable to Tenant at the address set forth below or at any other address that
Tenant may specify from time to time by written notice delivered to Landlord.

     (c) Any notice or document required or permitted to be delivered by this
Lease shall be deemed to be delivered (i) (whether or not actually received)
three days after deposit in the United States Mail, postage prepaid, certified
mail return receipt requested, (ii) upon hand-delivery as evidenced by written
confirmation of receipt thereof, (iii) upon facsimile transmission as evidenced
by confirmation receipt thereof and further confirmed by delivery by the methods
described in (i) or (ii) above, addressed to the parties at the respective
addresses and facsimile telephone numbers set forth below or such other
addresses and facsimile telephone numbers as hereinafter specified by notice
given in accordance with this paragraph.

OFFICE LEASE AGREEMENT - Page - 35
- ----------------------
<PAGE>

          If to Landlord:            c/o Jackson-Shaw Company
                                     Attn: Property Manager
                                     4890 Alpha Road, Suite 100
                                     Dallas, Texas 75244
                                     Fax: 972/628-7444

          If to Tenant:              Efficient Networks, Inc.
          (after the Commencement    4849 Alpha Road, Suite 100
          Date)                      Dallas, Texas 75244
                                     Attention: Ms. Jill Manning
                                     Fax: 972/991-3887

          (Prior to the Commencement Efficient Networks, Inc.
          Date)                      4201 Spring Valley, Suite 1200
                                     Dallas, Texas 75244
                                     Attention: Ms. Jill Manning
                                     Fax: 972/991-3887

45.  LANDLORD'S REPRESENTATIONS: Landlord certifies that (i) Landlord is the fee
simple owner and record title holder of the Project, including, with limitation,
the Premises, (ii) Landlord has not received any written notice, and does not
have any current actual knowledge, of any eminent domain or similar proceeding
which would affect the Premises subject to the last sentence of Exhibit "A"
                                                                -----------
hereto which describes a twenty-foot expansion of Alpha Road as reflected on the
plat of the land of the Project, (iii) Landlord has the full right, power and
authority to make this Lease subject to approval by its current Mortgagee, and
(iv) to Landlord's current actual knowledge, no restrictive covenant, easement,
lease or other written agreement restricts, prohibits or otherwise affects
Tenant's rights set forth in this Lease, including, without limitation, Tenant's
parking rights, rights to signage, construction, permitted general office use or
ingress and egress to and from the Premises.

46.  TENANT FINANCING: Tenant shall have the absolute right from time to time
during the Term hereof and without Landlord's further approval, written or
otherwise, to grant and assign a mortgage or other security interest in Tenant's
interest in this Lease and all of Tenant's Property (subject to the terms
hereof) to Tenant's lenders in connection with Tenant's financing arrangements,
provided such Tenant Financing is subordinate to the interest of Landlord and
its current and future lenders in the Project and Tenant's leasehold interest
therein subject to the limitations of this Lease. Landlord agrees to execute
such confirmation, certificates and other documents (except amendments to this
Lease unless Landlord hereafter consents) as Tenant's lenders may reasonably
request in connection with any such financing, all at Tenant's sole expense.

47.  TENANT'S CONDUCT: Nothing in this Lease shall be construed as an obligation
for Tenant to operate its business in the Premises. Tenant shall have the right
to remove Tenant's Property and cease operations in the Premises at any time and
at Tenant's sole discretion. Tenant's

OFFICE LEASE AGREEMENT - Page - 36
- ----------------------
<PAGE>

right to cease to operate its business shall not affect Tenant's obligation to
pay all amounts due hereunder and to perform all covenants and obligations
hereunder.

48.  PARKING: Landlord has made provision for 534 parking spaces on the Project.
Tenant has required the Dock Area and space for the Generator which will
displace thirteen (13) parking spaces. The resulting parking spaces are herein
referenced to as the "Parking Spaces". Landlord shall provide for Tenant's
exclusive use, at no cost to Tenant or Tenant's employees or invitees, all of
the Parking Spaces to be located at the Project. One hundred (100) spaces of the
Parking Spaces shall be covered, carport spaces. Landlord shall not (i) alter or
change the Parking Spaces or access thereto, or (ii) materially alter the
entrances or exits to the Project, without the prior written consent of Tenant
unless required to do so by law. Tenant shall have the right to mark the Parking
Spaces "Reserved Parking for Efficient Networks, Inc. Only". Tenant shall have
the right, if necessary, to post signs in order to enforce these parking
provisions, as well as the right to tow cars subject to compliance with all
Applicable Laws. If requested, and subject to the limitations of the site,
Landlord shall use its best efforts to assist Tenant, at Tenant's cost, to
provide additional parking as shall be necessary, in Tenant's discretion, to
accommodate Tenant's needs.

49.  (INTENTIONALLY DELETED)

50.  ALLOWANCES: Landlord acknowledges and agrees that the Construction
Allowance, the Space Plan Allowance and any other allowances provided for herein
may be used, at Tenant's sole discretion, until depleted for any other allowance
provided for hereunder.

51.  IMPROVEMENTS:

     (a)  Landlord agrees to install the improvements to the Leased Premises and
perform the work (all together, the "Work") pursuant to the terms of attached
                                     ----
Exhibit "B" (the "Work Letter") and in accordance with the Working Drawings (as
- -----------       -----------
therein defined). Landlord acknowledges that upon Substantial Completion of the
Premises, Tenant shall be entitled to occupy the Premises for thirty (30) days
following Substantial Completion for installation of Tenant's furnishings and
other items as required by Tenant (the "Early Occupancy Period"). During the
                                        ----------------------
Early Occupancy Period, all terms, provisions, covenants and agreements of the
Lease shall be in full force and effect provided the payment of the Base Rent
shall not commence until the time set forth in this Lease.

     (b)  Landlord shall cause the Work to be performed in good and workmanlike
manner using first class materials and shall be free from material defects of
workmanship or material and shall comply with the Work Letter and with all
applicable building codes or other legal requirements and all Applicable Laws.
For a period of one (1) year following the Commencement Date, Landlord, at
Landlord's expense, shall cause the Contractor (as defined in the Work Letter)
to replace or repair any defects in workmanship or materials in the improvements
made to the Premises per the Work Letter. Landlord represents that it has no
current actual knowledge of any material defects in the Leased Premises.


OFFICE LEASE AGREEMENT - Page - 37
- ----------------------
<PAGE>

     (c)  Notwithstanding anything herein to the contrary, if Substantial
Completion of the Work has not occurred by August 31, 2000, Tenant shall have
the right, but not the obligation, to incur any expense necessary to perform
such incomplete Work. If such delay has not been caused by Tenant or Tenant's
Representatives or force majeure, (i) Tenant may deduct such expense from the
Rent or other charges next becoming due, (ii) there shall be an abatement of all
Rent (in addition to the Rent Abatement Period) and other charges payable as
Rent until such time as the Work is substantially completed. Landlord is solely
responsible for applying for and obtaining a building permit. Unless caused by
Tenant or Tenant's Representatives, if by January 1, 2000, Landlord is unable to
secure all required licenses, permits and approvals from the applicable
government authority necessary for it to perform the Work, Tenant may terminate
this Lease upon written notice to Landlord no later than January 15, 2000, the
Security Deposit will be returned to Tenant, and neither party shall have any
further liability to the other. After January 15, 2000, Tenant's termination
rights under this subparagraph shall expire. With respect to general office use
of the Leased Premises, Landlord will satisfy itself as to any restrictions of
record and all zoning and other governmental restrictions and regulations prior
to commencement of any construction. Tenant agrees that if its occupancy of the
Leased Premises is delayed due to an omission or default by Tenant, this Lease
shall nonetheless continue in full force and effect.

     (d)  Landlord agrees to cause the Contractor, as part of the Construction
Allowance, to obtain and maintain public liability insurance and worker's
compensation insurance adequate to protect all parties, as their interests may
appear, from and against any and all liability for death or injury to person, or
damage to property, caused by the construction of the Work. Tenant agrees, at
Tenant's expense, to obtain and maintain public liability insurance and worker's
compensation insurance adequate to protect all parties, as their interests may
appear, from and against any and all liability for death or injury to person, or
damage to property, caused by the construction of Tenant's Work (hereinafter
defined).

     (e)  In addition to the Work, subject to the provisions of Paragraph 16
                                                                ------------
above Landlord hereby consents to Tenant constructing all work necessary for
Tenant's business operations (the "Tenant's Work").
                                   -------------

52.  RENT ABATEMENT: As provided in Paragraph 5(a) above, notwithstanding any
                                    --------------
other provisions herein to the contrary, Landlord acknowledges and agrees that
no Base Rent shall be due or owing from Tenant for the Early Occupancy Period or
for the first two (2) full Lease Months of the Term thereafter (the Early
Occupancy Period and the first two full months of the Lease Term thereafter in
which Base Rent shall be abated are defined in Paragraph 5(a) above as the "Rent
                                               --------------               ----
Abatement Period"). Commencing on the 1/st/ day of the first full month
- ----------------
following the Rent Abatement Period, Tenant shall make payments of Base Rent as
otherwise required by this Lease. The abatement of Base Rent as provided for
herein is in addition and not in derogation of or in lieu of any other provision
hereof providing for abatement of rent. Tenant's right to abate Base Rent during
the Rent Abatement Period is conditioned upon Tenant's full and timely
performance of all of its obligations under the Lease. If at any time during the
Term an event of default by Tenant occurs, then Tenant's right to the Rent
Abatement Period as provided for herein shall become void

OFFICE LEASE AGREEMENT - Page - 38
- ----------------------
<PAGE>

and Tenant shall promptly pay to Landlord, in addition to all other amounts
owing under the Lease, the full amount of the Base Rent as would otherwise be
due.

53.  RENEWAL OPTION: Subject to Paragraph 28 above, Tenant is granted the option
                                ------------
to extend the Term of this Lease for two (2) successive terms of five (5) years
each (the "Extension Term"), provided that (i) no event of default exists at the
           --------------
time of exercise of the option, and (ii) Tenant provides Landlord with nine (9)
months advance written notice of its intention to renew prior to the expiration
of the initial Term or, as the case may be in the second renewal option, at the
end of the first Extension Term. The Extension Term(s) shall be upon the same
terms and conditions as set forth herein, except (i) Tenant shall have no
further right of renewal after the expiration of the initial Term if Tenant does
not exercise its option for the first Extension Term and shall have no further
right of renewal after the second Extension Term, and (ii) the Base Rental will
be equal to the then prevailing rate for comparable space for a comparable term.

54.  ADDITIONAL SPACE:

     (a)  The space depicted on Exhibit "A-1" hereto, containing 21,103 rentable
                                -------------
square feet (the "Additional Space"), is part of the Leased Premises on which
                  ----------------
Base Rent commences on the first day of the tenth Lease Month as reflected in
Paragraph 5(a) above.
- -------------

     (b)  Tenant may enter the Additional Space prior to Substantial Completion
(the "Pre-Occupancy Period") for the purpose of Tenant's installation of its
      --------------------
modular furniture system, data cabling and other set up, provided that (i)
Tenant shall not conduct business in the Additional Space during the
Pre-Occupancy Period, (ii) Landlord shall be given prior written notice of any
such entry by Tenant, and (iii) Tenant shall deliver to Landlord evidence that
the insurance required under this Lease has been obtained. Tenant's early entry
into the Additional Space shall be at its risk and expense, and Landlord shall
not be liable in any way for any injury, loss or damage (except to the extent
caused by Landlord's negligence) to Tenant or Tenant's Representatives or
personal property. Any such entry shall be on the terms of this Lease other than
the provisions defining the Rent Abatement Period, but no Base Rent shall accrue
during the Pre-Occupancy Period.

55.  SPACE PLAN/DESIGN SERVICES ALLOWANCE: Landlord agrees to provide, in
addition to the Construction Allowance, a space plan/design services allowance
(the "Space Plan Allowance") of two dollars and twenty cents ($2.20) per square
      --------------------
foot of rentable area of the Premises (which includes the Additional Space) for
the preparation of space design, space planning, construction documents, and the
mechanical, electrical, and plumbing drawings and other work done by Tenant's
space planning firm of Haldeman Powell + Partners (the "Space Plan Firm"). This
                                                        ---------------
allowance shall be funded and paid (or reimbursed to Tenant, as the case may be)
by the Landlord on or before the date due following presentations by Tenant of
Tenant's letter requesting payment accompanied by the Space Plan Firm's
Tenant-approved invoices or bills for completed services furnished or rendered
to Tenant pursuant to the agreement between Tenant and the Space Plan Firm and
further accompanied by such lien waivers as Landlord may reasonably require. If
Landlord has not paid such invoices or bills within twenty (20) days of written
notice that they have not been paid


OFFICE LEASE AGREEMENT - Page - 39
- ----------------------
<PAGE>

when due, Tenant shall have the right to pay same and to offset against Rents
for any amounts thus paid. Landlord shall have no responsibility or liability
for determining whether any services of the Space Plan Firm have been rendered
or have been rendered properly.

56.  TENANT'S RIGHT OF FIRST REFUSAL: The real property adjacent on the west to
the Project is owned by the entity who previously owned the land of the Project.
Such property is the subject of ongoing environmental remediation work. Landlord
holds no rights of any kind to acquire such property. However, if, in the
future, Landlord elects to acquire such property and to develop it with
office/flex improvements similar to the Building, then provided that no event of
default exists and subject to Paragraph 28 above, and if occurring during the
                              ------------
Term, in conjunction with Landlord initiating its pre-construction marketing of
the proposed building for lease, Landlord shall provide Tenant in writing with
the leasing parameters for such building. Tenant shall have fifteen (15) days
from its receipt of such lease parameters in which to notify Landlord in writing
of its intention to lease the entire building based upon the terms of Landlord's
written lease parameters failing in which Tenant's rights under this Paragraph
                                                                     ---------
56 shall terminate, which termination Tenant shall, on request, evidence by a
- --
written certification to that effect. If Tenant timely elects so to lease the
building, except for the terms set forth in the lease parameters, the lease
shall be on terms and conditions generally similar to this Lease, modified as
appropriate to suit the new project as developed, and mutually, reasonably
acceptable to the parties.

     Executed by Landlord and Tenant as of the below dates.


                                        LANDLORD:


                                        JACKSON-SHAW/ALPHA METRO
                                        LIMITED PARTNERSHIP,
                                        a Texas Limited Partnership
                                          -------------------------


                                        By: Jackson-Shaw/Texas, Inc.
                                            General Partner


                                              By: /s/ [ILLEGIBLE]
                                                  -----------------
                                              Its:  AGENT

                                        Date:   11-5-99
                                              ---------------------


OFFICE LEASE AGREEMENT - Page - 40
- ----------------------
<PAGE>

                                        TENANT:

                                        EFFICIENT NETWORKS, INC.
                                        a Texas corporation
                                        4201 Spring Valley Road, Ste. 1200
                                        Dallas, Texas 75244



                                        By:   /s/ Jill Manning
                                              -----------------
                                              Signature

                                        Its: Chief Financial Officer
                                             -----------------------

                                             JILL MANNING
                                        ----------------------------
                                        Print Name

                                        Date:  11/1/99
                                              ----------------------


OFFICE LEASE AGREEMENT - Page - 41
- ----------------------

<PAGE>

                                                                   Exhibit 10.22

                                                                  EXECUTION COPY
                                                                  --------------

                                VOTING AGREEMENT

     THIS VOTING AGREEMENT (this "Agreement") is made and entered into as of
November 20, 1999, among Efficient Networks, Inc., a Delaware corporation (the
"Purchaser"), Cabletron Systems, Inc., a Delaware corporation ("Parent") and the
undersigned stockholder and/or option holder (the "Stockholder") of Purchaser.

                                    RECITALS
                                    --------

     A.   The Purchaser, Merger Sub (as defined below), Parent and Flowpoint
Corporation, a California corporation and a wholly-owned subsidiary of Parent
(the "Company"), concurrently with entering into this Agreement, are entering
into an Agreement and Plan of Reorganization (the "Reorganization Agreement"),
which provides for the merger (the "Merger") of the Company with and into Fire
Acquisition Corporation, a California corporation and a wholly-owned subsidiary
of Parent ("Merger Sub").  Pursuant to the Merger, all outstanding capital stock
of the Company shall be converted into the right to receive shares of Common
Stock of Purchaser and shares of Series A Non-Voting Convertible Preferred Stock
having the terms set forth in the Certificate of Designation attached hereto as
Exhibit A (the "Preferred Stock" and the "Certificate"), as set forth in the
- ---------
Reorganization Agreement;

     B.   Stockholder is the beneficial owner (as defined in Rule 13d-3 under
the Securities Exchange Act of 1934, as amended (the "Exchange Act")) of such
number of shares of the outstanding capital stock of the Purchaser and shares
subject to outstanding options and warrants as is indicated on the signature
page of this Agreement;

     C.   It is a condition to Parent's willingness to enter into the
Reorganization Agreement and consummate the Merger that Stockholder enter into
and deliver this Agreement; and

     D.   In order to induce Parent to enter into the Reorganization Agreement,
Stockholder (in his or her capacity as such), as a major stockholder of
Purchaser, agrees to vote the Shares (as defined below) and other such shares of
capital stock of the Purchaser over which Stockholder has voting power so as to
facilitate the conversion of the Preferred Stock into shares of Common Stock of
the Purchaser on or before the Expiration Date.

     NOW, THEREFORE, intending to be legally bound, the parties hereto agree as
follows:

     1.   Certain Definitions. Capitalized terms not defined herein shall have
          -------------------
the meanings ascribed to them in the Reorganization Agreement. For purposes of
this Agreement:

          (a)  "Expiration Date" shall mean the earlier of the date and time on
which the Preferred Stock shall have been converted into shares of Common Stock
or termination of the Reorganization Agreement.
<PAGE>

          (b)  "Person" shall mean any (i) individual, (ii) corporation, limited
liability company, partnership or other entity, or (iii) governmental authority.

          (c)  "Shares" shall mean: (i) all securities of the Purchaser
(including all shares of Purchaser Common Stock and all options, warrants and
other rights to acquire shares of Purchaser Common Stock) owned by Stockholder
as of the date of this Agreement; and (ii) all additional securities of the
Purchaser (including all additional shares of Purchaser Common Stock and all
additional options, warrants and other rights to acquire shares of Purchaser
Common Stock) of which Stockholder acquires ownership during the period from the
date of this Agreement through the Expiration Date.

          (d)  Transfer. A Person shall be deemed to have effected a "Transfer"
               --------
of a security if such person directly or indirectly: (i) sells, pledges,
encumbers, grants an option with respect to, transfers or disposes of such
security or any interest in such security; or (ii) enters into an agreement or
commitment providing for the sale of, pledge of, encumbrance of, grant of an
option with respect to, transfer of or disposition of such security or any
interest therein.

     2.   Transfer of Shares.
          ------------------

          (a)  Transferee of Shares to be Bound by this Agreement. Stockholder
               --------------------------------------------------
agrees that, during the period from the date of this Agreement through the
Expiration Date, Stockholder shall not cause or permit any Transfer of any of
the Shares to be effected unless each Person to which any of such Shares, or any
interest in any of such Shares, is or may be transferred shall have: (a)
executed a counterpart of this Agreement and a proxy in the form attached hereto
as Exhibit B (with such modifications as Purchaser may reasonably request); and
   ---------
(b) agreed in writing to hold such Shares (or interest in such Shares) subject
to all of the terms and provisions of this Agreement.

          (b)  Transfer of Voting Rights. Stockholder agrees that, during the
               -------------------------
period from the date of this Agreement through the Expiration Date, Stockholder
shall not deposit (or permit the deposit of) any Shares in a voting trust or
grant any proxy or enter into any voting agreement or similar agreement in
contravention of the obligations of Stockholder under this Agreement with
respect to any of the Shares.

     3.   Agreement to Vote Shares. At every meeting of the stockholders of the
          ------------------------
Purchaser called, and at every adjournment thereof, and on every action or
approval by written consent of the stockholders of the Purchaser, Stockholder
(in his or her capacity as such) shall cause the Shares to be voted in favor of
consummation of any of the matters contemplated by the Reorganization Agreement
with respect to which Stockholder may be entitled to vote and conversion of the
Preferred Stock into shares of Purchaser Common Stock as contemplated by the
Reorganization Agreement and pursuant to the Certificate.

     4.   Irrevocable Proxy.  Concurrently with the execution of this Agreement,
          -----------------
Stockholder agrees to deliver to Purchaser a proxy in the form attached hereto
as Exhibit B (the "Proxy"), which shall be irrevocable to the fullest extent
   ---------
permissible by law, with respect to the Shares.

     5.   Representations and Warranties of the Stockholder. (a) Stockholder (i)
          -------------------------------------------------
is the beneficial owner of the shares of Purchaser Common Stock and the options
and warrants to purchase shares of
<PAGE>

Common Stock of the Purchaser indicated on the final page of this Agreement,
free and clear of any liens, claims, options, rights of first refusal, co-sale
rights, charges or other encumbrances; (ii) does not beneficially own any
securities of the Purchaser other than the shares of Purchaser Common Stock and
options and warrants to purchase shares of Common Stock of the Purchaser
indicated on the final page of this Agreement; and (iii) has full power and
authority to make, enter into and carry out the terms of this Agreement and the
Proxy.

     6.   Additional Documents. Stockholder (in his or her capacity as such)
          --------------------
hereby covenants and agrees to execute and deliver any additional documents, and
to take additional actions, necessary or desirable, in the reasonable opinion of
Purchaser or Parent, to carry out the intent of this Agreement.

     7.   Consent and Waiver. Stockholder (not in his capacity as a director or
          ------------------
officer of the Purchaser) hereby gives any consents or waivers that are
reasonably required for the conversion of the Preferred Stock into shares of
Purchaser Common Stock as set forth in the Reorganization Agreement under the
terms of any agreements to which Stockholder is a party or pursuant to any
rights Stockholder may have.

     8.   Legending of Shares. If so requested by Purchaser, Stockholder agrees
          -------------------
that the Shares shall bear a legend stating that they are subject to this
Agreement and to an irrevocable proxy. Subject to the terms of Section 2 hereof,
Stockholder agrees that Stockholder shall not Transfer the Shares without first
having the aforementioned legend affixed to the certificates representing the
Shares.

     9.   Termination. This Agreement shall terminate and shall have no further
          -----------
force or effect as of the Expiration Date.

     10.  Miscellaneous.
          -------------

          (a)  Severability. If any term, provision, covenant or restriction of
               ------------
this Agreement is held by a court of competent jurisdiction to be invalid, void
or unenforceable, then the remainder of the terms, provisions, covenants and
restrictions of this Agreement shall remain in full force and effect and shall
in no way be affected, impaired or invalidated.

          (b)  Binding Effect and Assignment. This Agreement and all of the
               -----------------------------
provisions hereof shall be binding upon and inure to the benefit of the parties
hereto and their respective successors and permitted assigns, but, except as
otherwise specifically provided herein, neither this Agreement nor any of the
rights, interests or obligations of the parties hereto may be assigned by either
of the parties without prior written consent of the other.

          (c)  Amendments and Modification. This Agreement may not be modified,
               ---------------------------
amended, altered or supplemented except upon the execution and delivery of a
written agreement executed by the parties hereto.

          (d)  Specific Performance; Injunctive Relief. The parties hereto
               ---------------------------------------
acknowledge that Purchaser shall be irreparably harmed and that there shall be
no adequate remedy at law for a violation of any of the covenants or agreements
of Stockholder set forth herein. Therefore, it is agreed that, in addition to
any other remedies that may be available to Purchaser upon any such violation,
Purchaser
<PAGE>

shall have the right to enforce such covenants and agreements by specific
performance, injunctive relief or by any other means available to Purchaser at
law or in equity.

          (e)  Notices. All notices and other communications pursuant to this
               -------
Agreement shall be in writing and deemed to be sufficient if contained in a
written instrument and shall be deemed given if delivered personally,
telecopied, sent by nationally-recognized overnight courier or mailed by
registered or certified mail (return receipt requested), postage prepaid, to the
parties at the following address (or at such other address for a party as shall
be specified by like notice):

          If to Purchaser:    Efficient Networks, Inc.
                              4201 Spring Valley Road, Suite 1200
                              Dallas, Texas 75244
                              Attention: Jill Manning
                              Telecopy No.: (972) 991-8579

          With a copy to:     Wilson Sonsini Goodrich & Rosati
                              Professional Corporation
                              650 Page Mill Road
                              Palo Alto, California 94304
                              Attention: Kenneth M. Siegel, Esq.
                                         Michael J. Kennedy, Esq.
                              Telecopy No.: (650) 461-5375

          If to Parent:       Cabletron Systems, Inc.
                              ___________________________________
                              ___________________________________
                              Attention:
                              Telecopy No.

          With a copy to:     Ropes & Gray
                              One International Place
                              Boston, MA 02110
                              Attention: David A. Fine, Esq.
                              Telephone No.: (617) 951-7000
                              Telecopy No.: (617) 951-7050

          If to Stockholder:  To the address for notice set forth on the
                              signature page hereof.

          (f)  Governing Law. This Agreement shall be governed by the laws of
               -------------
the State of Delaware, without reference to rules of conflicts of law.

          (g)  Entire Agreement. This Agreement and the Proxy contain the entire
               ----------------
understanding of the parties in respect of the subject matter hereof, and
supersede all prior negotiations and understandings between the parties with
respect to such subject matter.
<PAGE>

          (h)  Effect of Headings. The section headings are for convenience only
               -------------------
and shall not affect the construction or interpretation of this Agreement.

          (i)  Counterparts. This Agreement may be executed in several
               ------------
counterparts, each of which shall be an original, but all of which together
shall constitute one and the same agreement.
<PAGE>

EFFICIENT NETWORKS, INC.                    STOCKHOLDER


By:   /s/ Mark Floyd                        By:
   ----------------------------------          -----------------------------
   Signature of Authorized Signatory           Signature

Name:   Mark Floyd                          Name:
     --------------------------------            ---------------------------

Title: Chief Executive Officer              Title:
      -------------------------------             --------------------------

                                            --------------------------------


                                            Print Address

                                            --------------------------------
                                            Telephone

                                            --------------------------------
                                            Facsimile No.

                                            Shares beneficially owned:

                                                shares of Purchaser Common Stock
                                            ----

                                                shares of Purchaser Common Stock
                                            ----
                                            issuable upon exercise of
                                            outstanding options or warrants

   CABLETRON SYSTEMS, INC.


By:
   ---------------------------------
   Signature of Authorized Signatory

Name:
     -------------------------------

Title:
      ------------------------------

                      [Signature Page to Voting Agreement]
<PAGE>

     IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed on the day and year first above written.


EFFICIENT NETWORKS, INC.            STOCKHOLDER


By:                                 By:    /s/  Mark Floyd
   ------------------------------      -----------------------------------
Signature of Authorized Signatory       Signature

Name:                               Name:   Mark Floyd
     ----------------------------        ---------------------------------

Title:                              Title:
      ---------------------------         --------------------------------
                                       4201 Spring Valley Road, Suite 1200
                                     -------------------------------------

                                       Dallas, Texas 75244
                                     -------------------------------------
                                     Print Address

                                     972-991-3884
                                     -------------------------------------
                                     Telephone

                                     972-991-8579
                                     -------------------------------------
                                     Facsimile No.

                                     Shares beneficially owned:

                                     1,548,958  shares of Purchaser Common Stock
                                     ---------
                                               shares of Purchaser Common Stock
                                     ---------
                                     issuable upon exercise of outstanding
                                     options or warrants

   CABLETRON SYSTEMS, INC.


By:
   ---------------------------------
   Signature of Authorized Signatory

Name:
     -------------------------------

Title:
      ------------------------------

                      [Signature Page to Voting Agreement]
<PAGE>

     IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed on the day and year first above written.


EFFICIENT NETWORKS, INC.            STOCKHOLDER


By:                                 By:    /s/  Robert R. Davenport
   -------------------------------      -------------------------------------
 Signature of Authorized Signatory       Signature

Name:                               Name:   Robert R. Davenport
     -----------------------------       ------------------------------------

Title:                              Title:    E.V.P., Corporate Development
      ----------------------------        -----------------------------------

                                    Covad Communications Group, Inc.
                                    -----------------------------------------

                                     2330 Central Expressway
                                    -----------------------------------------

                                     Santa Clara, CA 95050
                                    -----------------------------------------
                                    Print Address

                                     (408) 844-7709
                                    -----------------------------------------
                                    Telephone

                                     (408) 844-7680
                                    -----------------------------------------
                                    Facsimile No.

                                    Shares beneficially owned:

                                     497,663 shares of Purchaser Common Stock
                                    --------

                                             shares of Purchaser Common Stock
                                    --------
                                    issuable upon exercise of outstanding
                                    options or warrants

   CABLETRON SYSTEMS, INC.

By:
   ---------------------------------
   Signature of Authorized Signatory

Name:
     -------------------------------

Title:
      ------------------------------

[Signature Page to Voting Agreement]
<PAGE>

     IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed on the day and year first above written.


EFFICIENT NETWORKS, INC.                STOCKHOLDER


By:                                     By:    /s/  Andrew Sengei
   ---------------------------------       ---------------------------------
   Signature of Authorized Signatory        Signature

Name:                                   Name:   Andrew Sengei
     -------------------------------         -------------------------------

Title:                                  Title:  General Partner, Enterprise
      ------------------------------          ------------------------------
                                                Partners
                                              ------------------------------

                                        7979 IvanHoe Ave., Suite 556
                                        ------------------------------------

                                        La Jolla, CA 92037
                                        ------------------------------------
                                        Print Address

                                        858-454-8833
                                        ------------------------------------
                                        Telephone

                                        858-551-1206
                                        ------------------------------------
                                        Facsimile No.

                                        Shares beneficially owned:

                                        3,821,374  shares of Purchaser Common
                                        ---------
                                        Stock

                                                shares of Purchaser Common Stock
                                        -------
                                        issuable upon exercise of outstanding
                                        options or warrants

   CABLETRON SYSTEMS, INC.


By:
   ----------------------------------
   Signature of Authorized Signatory

Name:
     --------------------------------

Title:
      -------------------------------

                      [Signature Page to Voting Agreement]
<PAGE>

     IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed on the day and year first above written.

EFFICIENT NETWORKS, INC.                STOCKHOLDER
                                        MENLO VENTURES VI, L.P.


By:                                     By:    /s/ General Partner
   ---------------------------------       -----------------------------------
   Signature of Authorized Signatory       Signature

Name:                                   Name:  MV Management VI LP
     -------------------------------         ---------------------------------

Title:                                  Title: General Partner, Menlo Ventures
      ------------------------------          --------------------------------
                                               VI, LP
                                              --------------------------------

                                        3000 Sand Hill Road, #4-100
                                        --------------------------------------

                                        Menlo Park, CA 94025
                                        --------------------------------------
                                        Print Address

                                        650-854-8540
                                        --------------------------------------
                                        Telephone

                                        650-854-7059
                                        --------------------------------------
                                        Facsimile No.

                                        Shares beneficially owned:

                                        2,013,011 shares of Purchaser Common
                                        ----------
                                        Stock
                                                shares of Purchaser Common Stock
                                        --------
                                        issuable upon exercise of outstanding
                                        options or warrants

   CABLETRON SYSTEMS, INC.


By:
   ---------------------------------
   Signature of Authorized Signatory

Name:
     -------------------------------

Title:
      ------------------------------

                      [Signature Page to Voting Agreement]
<PAGE>

     IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed on the day and year first above written.


EFFICIENT NETWORKS, INC.                STOCKHOLDER
                                        MENLO ENTREPRENEURS FUND VI, L.P.


By:                                     By:    /s/  General Partner
   ---------------------------------       ----------------------------------
   Signature of Authorized Signatory           Signature

Name:                                   Name:   MV Management VI, LP
     -------------------------------         --------------------------------

Title:                                  Title:   General Partner
      ------------------------------          -------------------------------

                                        Menlo Entrepreneurs Fund VI, LP
                                        -------------------------------------

                                        3000 Sand Hill Road, #4-100
                                        -------------------------------------

                                        Menlo Park, CA 94025
                                        -------------------------------------
                                        Print Address

                                        650-854-8540
                                        -------------------------------------
                                        Telephone

                                        650-854-7059
                                        -------------------------------------
                                        Facsimile No.

                                        Shares beneficially owned:

                                        30,199  shares of Purchaser Common Stock
                                        ------
                                                shares of Purchaser Common Stock
                                        ------
                                        issuable upon exercise of outstanding
                                        options or warrants

   CABLETRON SYSTEMS, INC.

By:
   ----------------------------------
   Signature of Authorized Signatory

Name:
     --------------------------------

Title:
      -------------------------------

                      [Signature Page to Voting Agreement]
<PAGE>

     IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed on the day and year first above written.


EFFICIENT NETWORKS, INC.                STOCKHOLDER


By:                                     By:    /s/  Jim Gauer
   ---------------------------------       ----------------------------------
   Signature of Authorized Signatory           Signature

Name:                                   Name:  Jim Gauer/Ocean Park Ventures
     -------------------------------         --------------------------------

Title:                                  Title: General Partner
      ------------------------------          -------------------------------

                                        -------------------------------------

                                        -------------------------------------
                                        Print Address

                                        -------------------------------------
                                        Telephone

                                        -------------------------------------
                                        Facsimile No.

                                        Shares beneficially owned:

                                        1,273,803 shares of Purchaser Common
                                        ---------
                                        Stock
                                                shares of Purchaser Common Stock
                                        -------
                                        issuable upon exercise of outstanding
                                        options or warrants

   CABLETRON SYSTEMS, INC.


By:
   ---------------------------------
   Signature of Authorized Signatory

Name:
     -------------------------------

Title:
      ------------------------------

                      [Signature Page to Voting Agreement]
<PAGE>

     IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed on the day and year first above written.

EFFICIENT NETWORKS, INC.                STOCKHOLDER


By:                                     By:    /s/  Jim Gauer
   ---------------------------------       ----------------------------------
   Signature of Authorized Signatory           Signature

Name:                                   Name:    Jim Gauer/Palomar Ventures
     -------------------------------         --------------------------------

Title:                                  Title:   General Partner
      ------------------------------          -------------------------------

                                        -------------------------------------

                                        -------------------------------------
                                        Print Address

                                        -------------------------------------
                                        Telephone

                                        -------------------------------------
                                        Facsimile No.

                                        Shares beneficially owned:

                                        684,931 shares of Purchaser Common Stock
                                        -------

                                                shares of Purchaser Common Stock
                                        -------
                                        issuable upon exercise of outstanding
                                        options or warrants

   CABLETRON SYSTEMS, INC.


By:
   ----------------------------------
   Signature of Authorized Signatory

Name:
     --------------------------------

Title:
      -------------------------------

                      [Signature Page to Voting Agreement]
<PAGE>

     IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed on the day and year first above written.


EFFICIENT NETWORKS, INC.                STOCKHOLDER


By:                                     By:  /s/  Robert A. Hoff
   ---------------------------------       ----------------------------------
   Signature of Authorized Signatory         Signature

Name:                                   Name:  Robert A. Hoff
     -------------------------------         --------------------------------

Title:                                  Title:  General Partner/Crosspoint
      ------------------------------          -------------------------------
                                                Venture Partners
                                              -------------------------------

                                        -------------------------------------

                                        -------------------------------------
                                        Print Address

                                        -------------------------------------
                                        Telephone

                                        -------------------------------------
                                        Facsimile No.

                                        Shares beneficially owned:

                                        5,116,619 shares of Purchaser Common
                                        ---------
                                        Stock

                                                shares of Purchaser Common Stock
                                        -------
                                        issuable upon exercise of outstanding
                                        options or warrants

   CABLETRON SYSTEMS, INC.


By:
   ---------------------------------
   Signature of Authorized Signatory

Name:
     -------------------------------

Title:
      ------------------------------

                      [Signature Page to Voting Agreement]
<PAGE>

     IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed on the day and year first above written.


EFFICIENT NETWORKS, INC.                STOCKHOLDER


By:                                     By:  /s/  Anthony Maher
   ---------------------------------       ------------------------------------
   Signature of Authorized Signatory         Signature

Name:                                   Name:    Anthony Maher
     -------------------------------         ----------------------------------

Title:                                  Title: Siemens AG, Member Executive
      ------------------------------          ---------------------------------
                                               Board
                                              ---------------------------------

                                        Hofmann Str. 51
                                        ---------------------------------------

                                        81359 Munchen, Germany
                                        ---------------------------------------
                                        Print Address

                                        +49 89 722 38158
                                        ---------------------------------------
                                        Telephone

                                        +49 89 722 46262
                                        ---------------------------------------
                                        Facsimile No.

                                        Shares beneficially owned:

                                        3,716,800   shares of Purchaser Common
                                        ----------
                                        Stock

                                                shares of Purchaser Common Stock
                                        --------
                                        issuable upon exercise of outstanding
                                        options or warrants

   CABLETRON SYSTEMS, INC.


By:
   -----------------------------------
   Signature of Authorized Signatory

Name:
     ---------------------------------

Title:
      --------------------------------

                      [Signature Page to Voting Agreement]
<PAGE>

     IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed on the day and year first above written.


EFFICIENT NETWORKS, INC.                STOCKHOLDER


By:                                     By:  /s/ Robert C. Hawk
   ---------------------------------       ------------------------------------
   Signature of Authorized Signatory         Signature

Name:                                   Name:  Robert C. Hawk
     -------------------------------         ----------------------------------

Title:                                  Title:  Director
      ------------------------------          ---------------------------------

                                        7585 S. Biscay Street
                                        ---------------------------------------

                                        Aurora, CO  80016
                                        ---------------------------------------
                                        Print Address

                                        303-699-2602
                                        ---------------------------------------
                                        Telephone

                                        303-699-2603
                                        ---------------------------------------
                                        Facsimile No.

                                        Shares beneficially owned:

                                        150,000 shares of Purchaser Common Stock
                                        -------

                                                shares of Purchaser Common Stock
                                        -------
                                        issuable upon exercise of outstanding
                                        options or warrants

   CABLETRON SYSTEMS, INC.


By:
   ------------------------------------
   Signature of Authorized Signatory

Name:
     ----------------------------------

Title:
      ---------------------------------

                      [Signature Page to Voting Agreement]
<PAGE>

                               IRREVOCABLE PROXY

     The undersigned stockholder of Efficient Networks, Inc., a Delaware
corporation (the "Purchaser"), hereby irrevocably (to the fullest extent
permitted by law) appoints Purchaser as the sole and exclusive attorneys and
proxies of the undersigned, with full power of substitution and resubstitution,
to vote and exercise all voting and related rights (to the full extent that the
undersigned is entitled to do so) with respect to all of the shares of capital
stock of the Purchaser that now are or hereafter may be beneficially owned by
the undersigned, and any and all other shares or securities of the Purchaser
issued or issuable in respect thereof on or after the date hereof (collectively,
the "Shares") in accordance with the terms of this Proxy. The Shares
beneficially owned by the undersigned stockholder of the Purchaser as of the
date of this Proxy are listed on the final page of this Proxy.  Upon the
undersigned's execution of this Proxy, any and all prior proxies given by the
undersigned with respect to any Shares are hereby revoked and the undersigned
agrees not to grant any subsequent proxies with respect to the Shares until
after the Expiration Date (as defined below).

     This Proxy is irrevocable (to the fullest extent permitted by law), is
coupled with an interest and is granted pursuant to that certain voting
agreement of even date herewith by and among Purchaser and the undersigned
stockholder (the "Voting Agreement"), and is granted in connection with the
Purchaser and Parent entering into that certain Agreement and Plan of
Reorganization (the "Reorganization Agreement"), among Purchaser, Fire
Acquisition Corporation, a California corporation and a wholly-owned subsidiary
of Purchaser ("Merger Sub"), Cabletron Systems, Inc., a Delaware corporation
("Parent") and Flowpoint Corporation, a California corporation and a wholly-
owned subsidiary of Parent.  The Reorganization Agreement provides for the
merger of the Company with and into Merger Sub in accordance with its terms (the
"Merger").  As used herein, the term "Expiration Date" means the date and time
on which the Series A Non-Voting Convertible Preferred Stock (the "Preferred
Stock") shall have been converted into shares of Purchaser Common Stock or the
Reorganization Agreement shall have been terminated.

     The attorneys and proxies named above, and each of them, are hereby
authorized and empowered by the undersigned, at any time prior to the Expiration
Date, to act as the undersigned's attorney and proxy to vote the Shares, and to
exercise all voting, consent and similar rights of the undersigned with respect
to the Shares (including, without limitation, the power to execute and deliver
written consents and call a special meeting of stockholders) at every annual,
special or adjourned meeting of stockholders of the Purchaser and in every
written consent in lieu of such meeting in favor of approval of the Merger and
conversion of the Preferred Stock into Purchaser Common Stock as contemplated by
the Reorganization Agreement.

     The attorneys and proxies named above may not exercise this Proxy on any
other matter except as provided above.  The undersigned stockholder may vote the
Shares on all other matters.

     Any obligation of the undersigned hereunder shall be binding upon the
successors and assigns of the undersigned.
<PAGE>

      This Proxy is irrevocable (to the fullest extent permitted by law).  This
Proxy shall terminate, and be of no further force and effect, automatically
upon the Expiration Date.


Dated:  November 19, 1999


                         Signature of Stockholder:   /s/  Mark Floyd
                                                   ------------------------

                         Print Name of Stockholder:    Mark Floyd
                                                   ------------------------

                         Shares beneficially owned:  1,548,958


                     [Signature Page to Irrevocable Proxy]
<PAGE>

     This Proxy is irrevocable (to the fullest extent permitted by law).  This
Proxy shall terminate, and be of no further force and effect, automatically upon
the Expiration Date.


Dated:  November 19, 1999


                         Signature of Stockholder:   /s/  Robert R. Davenport
                                                   ----------------------------

                         Print Name of Stockholder:   Covad Communications
                                                   ----------------------------

                         Shares beneficially owned:

                                  497,663   shares of the Purchaser Common Stock
                                -----------

                                            shares of the Purchaser Common Stock
                                -----------
                                issuable upon exercise of outstanding options or
                                warrants

                     [Signature Page to Irrevocable Proxy]
<PAGE>

     This Proxy is irrevocable (to the fullest extent permitted by law).  This
Proxy shall terminate, and be of no further force and effect, automatically upon
the Expiration Date.


Dated:  November 19, 1999


                         Signature of Stockholder:   /s/  Andrew Sengei
                                                   ------------------------

                         Print Name of Stockholder:    Enterprise Partners
                                                   ------------------------

                         Shares beneficially owned:

                                 3,821,374  shares of the Purchaser Common Stock
                                -----------

                                            shares of the Purchaser Common Stock
                                -----------
                                issuable upon exercise of outstanding options or
                                warrants

                     [Signature Page to Irrevocable Proxy]
<PAGE>

     This Proxy is irrevocable (to the fullest extent permitted by law).  This
Proxy shall terminate, and be of no further force and effect, automatically upon
the Expiration Date.


Dated:  November 19, 1999


                         MENLO ENTREPRENEURS FUND VI, L.P.
                         By:  MV Management VI, L.P.
                         It's General Partner

                         By:    /s/  General Partner
                              ----------------------

                         Shares beneficially owned:

                                 30,199   shares of the Purchaser Common Stock
                                ---------

                                          shares of the Purchaser Common Stock
                                ---------
                                issuable upon exercise of outstanding options or
                                warrants

                     [Signature Page to Irrevocable Proxy]
<PAGE>

     This Proxy is irrevocable (to the fullest extent permitted by law).  This
Proxy shall terminate, and be of no further force and effect, automatically upon
the Expiration Date.


Dated:  November 19, 1999


                         MENLO ENTREPRENEURS FUND VI, L.P.
                         By:  MV Management VI, L.P.
                         It's General Partner

                         By:    /s/  General Partner
                              -----------------------

                         Shares beneficially owned:

                           2,013,011   shares of the Purchaser Common Stock
                          ------------

                                       shares of the Purchaser Common Stock
                          ------------
                          issuable upon exercise of outstanding options or
                          warrants

                     [Signature Page to Irrevocable Proxy]
<PAGE>

     This Proxy is irrevocable (to the fullest extent permitted by law).  This
Proxy shall terminate, and be of no further force and effect, automatically upon
the Expiration Date.


Dated:  November 19, 1999


                         Signature of Stockholder:   /s/  Jim Gauer
                                                   -------------------------

                         Print Name of Stockholder:    Ocean Park Ventures
                                                   -------------------------

                         Shares beneficially owned:

                             1,273,803    shares of the Purchaser Common Stock
                            -------------

                                          shares of the Purchaser Common Stock
                            -------------
                            issuable upon exercise of outstanding options or
                            warrants

                     [Signature Page to Irrevocable Proxy]
<PAGE>

     This Proxy is irrevocable (to the fullest extent permitted by law).  This
Proxy shall terminate, and be of no further force and effect, automatically upon
the Expiration Date.


Dated:  November 19, 1999


                         Signature of Stockholder:   /s/  Jim Gauer
                                                   -----------------------

                         Print Name of Stockholder:    Palomar Ventures
                                                   -----------------------

                         Shares beneficially owned:

                                 684,931    shares of the Purchaser Common Stock
                                -----------

                                            shares of the Purchaser Common Stock
                                -----------
                                issuable upon exercise of outstanding options or
                                warrants

                     [Signature Page to Irrevocable Proxy]
<PAGE>

     This Proxy is irrevocable (to the fullest extent permitted by law).  This
Proxy shall terminate, and be of no further force and effect, automatically upon
the Expiration Date.


Dated:  November 19, 1999


                Signature of Stockholder:   /s/ Robert A. Hoff, General Partner
                                         ---------------------------------------

                Print Name of Stockholder:    Crosspoint Venture Partners
                                          --------------------------------------

                         Shares beneficially owned:

                                 5,116,619  shares of the Purchaser Common Stock
                                -----------

                                            shares of the Purchaser Common Stock
                                -----------
                                issuable upon exercise of outstanding options or
                                warrants

                     [Signature Page to Irrevocable Proxy]
<PAGE>

     This Proxy is irrevocable (to the fullest extent permitted by law).  This
Proxy shall terminate, and be of no further force and effect, automatically upon
the Expiration Date.


Dated:  November 19, 1999


                         Signature of Stockholder:   /s/  Anthony Maher
                                                   --------------------------

                         Print Name of Stockholder:    Siemens AG
                                                   --------------------------

                         Shares beneficially owned:

                                 3,716,800  shares of the Purchaser Common Stock
                                -----------

                                            shares of the Purchaser Common Stock
                                -----------
                                issuable upon exercise of outstanding options or
                                warrants

                     [Signature Page to Irrevocable Proxy]
<PAGE>

     This Proxy is irrevocable (to the fullest extent permitted by law).  This
Proxy shall terminate, and be of no further force and effect, automatically upon
the Expiration Date.


Dated:  November 19, 1999


                         Signature of Stockholder:   /s/  Robert C. Hawk
                                                   -------------------------

                         Print Name of Stockholder:    Robert C. Hawk
                                                   -------------------------

                         Shares beneficially owned:

                                 150,000    shares of the Purchaser Common Stock
                                -----------

                                            shares of the Purchaser Common Stock
                                -----------
                                issuable upon exercise of outstanding options or
                                warrants

                     [Signature Page to Irrevocable Proxy]



<PAGE>

                                                                   EXHIBIT 10.23

                     EFFICIENT NETWORKS RESELLER AGREEMENT

The terms contained herein, along with the attachments and exhibits constitute
an AGREEMENT ("Reseller Agreement" or "Agreement") made this 21st day of
November, 1999 between Efficient Networks, Inc., a Delaware corporation with its
principal place of business at 4201 Spring Valley Road, Suite 1200, Dallas,
Texas, U.S.A., and its subsidiaries (collectively "Efficient") and Cabletron
Systems, Inc., a Delaware corporation, with its principle place of business at
35 Industrial Way, Rochester, New Hampshire, U.S.A. ("Reseller" or "Cabletron"),
and effective as of the closing of the merger contemplated by the Agreement and
Plan of Reorganization made and entered into as of even date herewith, among
Efficient, Reseller, Fire Acquisition Corporation, a California corporation and
a wholly-owned subsidiary of Efficient and Flowpoint Corporation, Inc., a
California corporation and a wholly-owned subsidiary of Reseller ("Flowpoint")
(such date referred to herein as the "Effective Date").


1.  DEFINITIONS:

1.1.  End User shall mean the ultimate customer that purchases Products for its
      --------
      internal use from Reseller.

1.2.  Exhibits to this Agreement are:

      Exhibit A  Products
      Exhibit B  Technical Support Guidelines
      Exhibit C  Limited Exclusivity
      Exhibit D  Marketing Principles

1.3.  Intellectual Property Rights shall mean all patents, copyrights,
      ----------------------------
      trademarks, mask works and other intellectual property rights relating to
      a Product.

1.4.  Orders shall mean purchase orders for Products submitted to Efficient by
      ------
      Reseller under the terms of this Agreement.

1.5.  Parties shall mean Efficient and Reseller.
      -------

1.6.  Products shall mean those products set forth in Exhibit A to this
      --------
      Agreement, together with any product introduced by Efficient during the
      term of this Agreement that enhances the functionality of, or replaces, a
      product set forth in Exhibit A.

1.7.  Product Specifications shall mean Efficient or Flowpoint's published
      ----------------------
      specifications for the Flowpoint product current on date Efficient accepts
      Reseller's Order and any additional specifications agreed to by the
      Parties in writing.

1.8.  Software shall mean software products and software or firmware
      --------
      incorporated in hardware Products.

1.9.  Territory - Unless otherwise specified or agreed by the Parties in
      ---------
      writing, the Territory is worldwide.

1.10. Warranty Period - Unless otherwise specified by Efficient or agreed by
      ---------------
      the Parties, the Warranty Period shall be the shorter of twelve (12)
      months from the date the Product is delivered to the End User or fifteen
      (15) months from the date the Product is shipped to Reseller.

2.  RELATIONSHIP:

2.1.  Appointment - Efficient appoints Reseller as a non-exclusive reseller of
      -----------
      Products to be sold under Efficient and Reseller brands to End Users
      within the Territory under the terms of this Agreement.

2.2.  Limited Exclusivity - The parties agree that the limited exclusivity
      -------------------
      provisions set forth in Exhibit C shall apply to this Agreement.

2.3.  Relationship Reviews - Efficient and Reseller will conduct reviews of
      --------------------
      their relationship and performance under this Agreement at least twice
      during each year following the Effective Date. These reviews will
      consider, among other things, new products, Product Specifications and
      pricing, and Reseller's Product forecasts, purchases and payments under
      this Agreement.

2.4.  Marketing Principles - The parties recognize the need to coordinate their
      --------------------
      efforts with respect to sales opportunities for the products. The parties
      agree that they shall act in good faith to follow their mutual intentions
      as set forth in the Marketing Principles attached hereto as Exhibit D, and
      further agree to abide by the issue resolution mechanisms set forth
      therein.

3.  PRODUCT BRANDING:

3.1   Existing Arrangements - Any Flowpoint product which Reseller, immediately
      ---------------------
      prior to the Effective Date, was reselling under a Reseller brand, may, at

                                                                          Page 1
<PAGE>

      Reseller's request, continue to be resold under such Reseller brand. For
      purposes of rebranding, upgraded and enhanced versions of Products
      rebranded prior to the Effective Date shall be deemed to be Products
      entitled to rebranding. Such Products shall continue to be rebranded
      substantially similarly to the way they were being rebranded prior to the
      Effective Date. Any changes to the rebranding specifications shall be
      agreed in writing by authorized representatives of each Party.

3.2   Rebranding of Additional Products - Provided that the parties agree to
      ---------------------------------
      minimum purchase volumes for a particular additional Product, Reseller may
      request that additional Products be rebranded to carry a Reseller brand.
      In the event that the parties are unable to agree on minimum purchase
      volumes, Reseller may require Efficient to rebrand such additional
      Products provided Reseller pays Efficient's fully-loaded cost to effect
      such rebranding.

3.3   Other Products - Except as provided in Sections 3.1 and 3.2, Reseller
      --------------
      agrees that all Products sold by Reseller hereunder shall bear the brand
      marking and other labeling provided by Efficient. Reseller shall not
      remove any such branding or labeling, nor shall Reseller add any Reseller
      (or other) branding or labeling to any Product without the prior written
      consent of Efficient.

4.  RESELLER RESPONSIBILITIES:

4.1.  Product Forecasts - On or before the Effective Date and during the first
      -----------------
      week of each calendar month after the Effective Date, Reseller shall
      provide Efficient with a forecast of Reseller's expected demand for each
      Product to be purchased and delivered during each month of the subsequent
      twelve (12) month period.

4.2.  Firm Orders - With respect to Products rebranded at Reseller's request,
      -----------
      the Product forecasts for the first two (2) months of each twelve (12)
      month period shall constitute firm Orders for Products under this
      Agreement that are subject to acceptance by Efficient and will be
      accompanied by a purchase order by such amount.

5. PRODUCTS AND PRICING:

5.1.  New Products - Products which constitute enhancements of or replacements
      ------------
      for products listed on Exhibit A shall be added to Exhibit A by a writing
      signed by the parties, and shall thereafter be deemed to be "Products" for
      purposes of this Agreement. The parties acknowledge that the term Products
      is intended to encompass only those products heretofore manufactured by
      Flowpoint and any enhancements thereto or replacements therefor. To the
      extent that the parties later agree to permit Reseller to sell any
      products which were heretofore manufactured by Efficient (or are hereafter
      developed by Efficient and do not fall within the definition of Products)
      the right to resell any such products shall be the subject of a separate
      written agreement between the parties.

5.2.  Withdrawal of Products - Efficient shall have the right to cease
      ----------------------
      production and withdraw any Product from Exhibit A, provided Efficient
      gives Reseller a written "Product Withdrawal Notice" at least ninety (90)
      days prior to the effective date of the withdrawal. Reseller may, within
      forty-five (45) days after receipt of a Product Withdrawal Notice, submit
      a single, non-cancelable "Last Buy" Order for the affected Product for
      delivery within the subsequent three (3) months. Efficient shall not be
      obligated to accept any Last Buy Order which exceeds fifty (50) percent of
      the Product units that Reseller ordered during the twelve (12) month
      period prior to the date of the relevant Product Withdrawal Notice.

5.3.  Software and Firmware - All Products consisting of Software and Software
      ---------------------
      incorporated in any Product shall not be sold but shall be provided to
      Reseller and its customers subject to a use license.

5.4.  Product Modifications - In the event Efficient intends to modify a Product
      ---------------------
      Specification affecting its form, fit, interoperability or function,
      Efficient shall notify Reseller of the modification in writing no later
      than ninety (90) days prior to the effective date of the modification.
      Based upon information from Reseller, Efficient will make reasonable
      efforts to mitigate the impact of any modification on Reseller, including
      consideration of changes to the modification and allowing Reseller to make
      a final purchase of the unmodified Products, provided that Efficient shall
      retain the sole right to make final decisions concerning the design of
      Products and Product Specifications, and that the Order for any final
      purchase of unmodified Products shall be placed at least thirty (30) days
      prior to the effective date of the modification for delivery within sixty
      (60) days.

5.5.  [Intentionally Left Blank]

                                                                          Page 2
<PAGE>

5.6.  Most Favored Pricing - During the term of this Agreement, Efficient will
      --------------------
      extend to Cabletron the best price it offers to third parties, for the
      same or lower volume of Products.

5.7.  Price Changes - Upon the written request of either Party, made at least
      -------------
      sixty (60) days prior to any anniversary of the Effective Date, Parties
      shall meet to consider and negotiate in good faith requested changes in
      Product prices.

5.8.  Price Decreases - The Parties agree that Product prices may require
      ---------------
      adjustment from time to time to allow Reseller to remain competitive, and
      Efficient will consider in good faith any request by Reseller for a
      reduction in the price of any Product. In the event Efficient determines
      to lower the price of a Product, the price decrease shall apply to all
      Products on order by Reseller but not shipped as of the effective date of
      the decrease.

5.9.  Price Terms - Prices for all Products are F.O.B. the shipping dock of the
      -----------
      Efficient manufacturing or distribution facility, with Reseller fully
      responsible for all costs of transportation, insurance, taxes, customs
      duties, landing, storage and handling fees, and documents or certificates
      required for exportation or importation.

6. ORDERING & SHIPMENT:

6.1.  No Conflicting Terms - No additional or different terms on the face or
      --------------------
      reverse side of any purchase order or other written or oral communications
      between the Parties shall supercede or amend the terms of this Agreement,
      unless such terms are agreed upon in advance, set forth in writing and
      signed by an authorized representative of each Party.

6.2.  Issuance and Acceptance - Each Order shall be dated, and shall contain:
      -----------------------
      (i) a complete list of the Products to be purchased specifying quantity,
      type, description and price; (ii) shipment and delivery instructions;
      (iii) branding requirements, where applicable; and (iv) any special terms
      and conditions agreed to in writing by the Parties. Efficient agrees to
      receive Orders placed by Reseller via electronic document transfer,
      facsimile, or hard copy only. Verbal or telephone orders must be followed
      promptly by one of the transmission means described above. All Orders are
      subject to acceptance by Efficient, and Efficient may reject Orders in its
      reasonable discretion.

6.3.  Right to Reschedule - Reseller may reschedule the date of the shipment of
      -------------------
      any Order once without penalty provided that Efficient receives written
      notice at least thirty (30) days prior to the scheduled shipment date
      requesting shipment on a date within ninety (90) days after the original
      shipment date.

6.4.  Delivery Schedule - Efficient will endeavor to deliver all Products in
      -----------------
      accordance with the Product delivery date specified in the Reseller's
      Order as accepted by Efficient, provided that Efficient reserves the
      right, at its sole discretion, to make partial shipments. When Products or
      component parts are in short supply, or on an industry wide allocation,
      Efficient will allocate its available inventory and make deliveries on a
      basis Efficient deems equitable, in its sole discretion, and without
      liability to Reseller on account of the method of allocation chosen or its
      implementation.

6.5.  Quantities - [Intentionally Left Blank]
      ----------

6.6.  No Right of Return - Reseller shall have no right to return and Efficient
      ------------------
      shall have no obligation to repurchase Products sold under this Agreement.

6.7.  Carrier & Risk of Loss - Products will be shipped by the carrier
      ----------------------
      designated in writing by Reseller. In the absence of specific shipping
      instructions from Reseller, Efficient may designate the carrier. In no
      event, however, shall Efficient be liable for the shipment, nor shall the
      carrier be deemed to be an agent or representative of Efficient. Title to
      Products and risk of loss shall pass to Reseller upon Efficient's delivery
      to the designated carrier.

6.8.  Packing - Products shipped by Efficient will be packed and packaged
      -------
      according to Efficient's then current packaging methods. Special packaging
      or packing requirements shall be quoted by Efficient and mutually agreed
      to in advance.

7. SOFTWARE LICENSE TERMS:

7.1.  License Grant - Efficient hereby grants Reseller a nontransferable,
      -------------
      nonexclusive license to use and distribute Software solely for use by End
      Users in and in connection with their use of Products.

7.2.  Protection of Software - Reseller agrees not to modify, decompile or
      ----------------------
      disassemble Software except as expressly permitted by applicable law and
      agrees not to lend, rent, lease, sublicense, or otherwise transfer
      Software in any form to any

                                                                          Page 3
<PAGE>

      person except in accordance with this Agreement. Reseller will use its
      best efforts to protect Software and any copies or portions thereof from
      unauthorized reproduction, publication, disclosure or distribution.

8.  PAYMENT:

8.1.  Payment Terms - Efficient's payment terms are net thirty (30) days from
      -------------
      the date of Efficient's invoice. Reseller shall promptly pay all invoices
      and amounts due and maintain satisfactory credit arrangements with
      Efficient. All payments shall be made in United States dollars.

8.2.  Delinquency - If Reseller is delinquent in payment, Efficient may refuse
      ----------
      to accept any new Orders, or may cancel or delay shipment on existing
      Orders. Efficient may also rescind Reseller's credit terms and demand
      payment on either a pre-paid or delivery basis. Unless there is a
      legitimate dispute concerning an invoice, interest will accrue on
      delinquent amounts at the lesser of the maximum rate permitted by law or
      one and one half percent (1 1/2 %) per month from the due date.

9.  WARRANTY TERMS:

9.1.  Product Warranty - Efficient warrants that Products purchased under this
      ----------------
      Reseller Agreement will conform to the Product Specifications applicable
      as of the date of Reseller's Order throughout the Warranty Period.

9.2.  Repair or Replacement - Efficient shall use commercially reasonable
      ---------------------
      efforts to, at its option, repair, replace or issue a credit equal to the
      purchase price for Products that fail to meet the applicable Product
      Specifications during the Warranty Period.

9.3.  Return, Repair or Replacement Procedures - Reseller shall pay all
      ----------------------------------------
      transportation charges for Products returned to Efficient under these
      product warranty terms, except that Efficient shall pay the transportation
      charges for return of any Product that failed within thirty (30) days of
      its initial use by an End User. Efficient will pay all transportation
      charges back to the Reseller or End User. In the event that no warranty
      repair or replacement is required, Efficient reserves the right to charge
      Reseller for the transportation incurred by Efficient in returning the
      Product.

9.4.  Warranty Disclaimer - EXCEPT AS EXPRESSLY PROVIDED HEREIN, NO OTHER
      -------------------
      WARRANTY, EXPRESS OR IMPLIED SHALL APPLY. EFFICIENT SPECIFICALLY DISCLAIMS
      ANY IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
      PURPOSE. NO REPRESENTATION OR WARRANTY, INCLUDING BUT NOT LIMITED TO
      STATEMENTS OF CAPACITY, SUITABILITY FOR USE OR PERFORMANCE, WHETHER MADE
      BY EFFICIENT PERSONNEL OR RESELLER PERSONNEL SHALL BE CONSIDERED A
      WARRANTY BY EFFICIENT, FOR ANY PURPOSE, OR GIVE RISE TO ANY LIABILITY OF
      EFFICIENT WHATSOEVER.

9.5.  Warranty Notice - All End Users shall be provided with a written notice of
      ---------------
      the foregoing Product Warranty and Warranty Disclaimer either in a
      contract or upon delivery of the Product. In the event that Reseller shall
      modify or supplement the foregoing Product Warranty, Reseller shall
      indemnify and hold Efficient harmless from all claims, damages and related
      expenses, including attorneys' fees, incurred by Efficient during or after
      the term of this Agreement as a result of any such modification.

10. SERVICE:

10.1. End User Support - Reseller shall provide all first and second level End
      ----------------
      User customer support for Products, as defined below, in the same manner
      Reseller provides similar support for other products. Efficient will
      provide third level support, according to the Technical Support Guidelines
      set forth in Exhibit B to this Agreement, solely to Reseller's designated
      engineering personnel who are trained in the technical operation of the
      Product. As used herein: (i) First Level Support shall mean the provision
      of general product information, configuration support, collection of
      technical problem identification information and screening of customer
      support requests; (ii) Second Level Support shall mean First Level Support
      plus problem isolation, defect determination and module or Product
      replacement, lab simulation, interoperability testing and action plan
      definition; and (iii) Third Level Support shall mean back-up technical
      support by telephone and, where appropriate, the provision of hardware and
      software "bug fixes" and work-arounds.

                                                                          Page 4
<PAGE>

10.2.  Reseller's Efforts - Reseller shall use its best effort to resolve End
       ------------------
       User support problem without Efficient's assistance and insure that all
       Product problems and technical inquiries are reported in a standard
       format. Reseller shall cooperate with Efficient in identification of "bug
       fixes" and work-arounds and the provision of Level Three Support.

10.3.  Technical Information and Training - Efficient will provide technical
       ----------------------------------
       information and up to ___ days of training for ___ individuals with
       regard to each Product to allow Reseller to provide Level One and Level
       Two Support. Unless otherwise agreed by the Parties, all training shall
       take place at Efficient's facility in Dallas, Texas. All costs and
       expenses of Reseller's personnel in attending Efficient training shall be
       borne by the Reseller.

10.4.  Additional Support - Efficient may agree to provide Reseller with
       -------------------
       additional maintenance services and support pursuant to a separate
       agreement between the Parties.

10.5.  Non-Warranty Repair - Non-warranty repair services for Products may be
       -------------------
       provided by Efficient at a designated Efficient facility on a time and
       materials basis under Efficient's then standard prices, terms and
       conditions. Reseller shall also be responsible for all associated freight
       and insurance charges.

11.  INTELLECTUAL PROPERTY:

11.1.  Ownership - Unless expressly stated, nothing in this Agreement shall
       ---------
       grant Reseller a license to use or any other right, title or interest in
       any Efficient Intellectual Property Right, and all such Intellectual
       Property Rights shall remain the exclusive property of Efficient.
       Reseller acknowledges that its unauthorized use or assertion of ownership
       of any Efficient Intellectual Property Right will cause Efficient or its
       Affiliates immediate and irreparable harm and shall entitle Efficient or
       its Affiliates to obtain injunctive relief.

12.  DURATION AND TERMINATION:

12.1.  Term - The initial term of this Reseller Agreement shall be the three (3)
       ----
       year period commencing on the Effective Date and terminating on the date
       exactly three (3) years after the Effective Date unless earlier
       terminated pursuant to the terms of this Agreement. This Agreement may be
       renewed for additional one (1) year periods upon the same terms and
       conditions as set forth herein upon the mutual written agreement of the
       parties.

12.2.  Termination for Cause - This Agreement may be terminated upon the
       ---------------------
       occurrence of any of the following events: (i) by Efficient, upon ten
       (10) days written notice, should Reseller fail to pay any sums due
       hereunder within twenty (20) days of the due date thereof; or (ii) by
       either Party should the other Party commit a material breach of any
       obligation under this Agreement not specifically set out in this Section
       or any other Agreement between the parties and fail to cure such material
       breach within thirty (30) days after written notice to the defaulting
       party (hereinafter the "Default Notice"); or (iii) by either party,
       immediately, upon the insolvency of the other party, the appointment of a
       liquidator, receiver, administrative receiver or administrator.

12.3.  Termination on Change of Control - Notwithstanding the provisions of
       --------------------------------
       Section 18.4 (Assignment) of this Agreement, either party may, in its
       sole discretion, terminate this Agreement immediately upon a change of
       control of the other party; provided, however, that the election to
       terminate must be made within thirty (30) days of the time that the
       terminating party becomes aware of the change of control; and provided
       further that any such termination shall not be effective for ninety (90)
       days from the notice and that, during the ninety (90) day notice period,
       this Agreement will remain in full force and effect. This restriction in
       Exhibit C and D shall not apply to a person who acquires Reseller in a
       change of control but shall continue to apply to Reseller and its
       subsidiaries so long as Reseller and its subsidiaries continue using
       Reseller's brand name(s) or until they legally cease to exist.

12.4.  Effects of Termination - Upon any termination of this Agreement, Reseller
       ----------------------
       shall: (i) refrain from submitting additional Product Orders; (ii)
       promptly pay for any Products which Reseller has ordered but has not yet
       paid Efficient; and (iii) allow Efficient, at its discretion, to
       repurchase at the invoice price all or any portion of the Products in
       Reseller's inventory. Products to be repurchased must be unused, in new
       condition, and in Reseller's inventory (or in transit from Efficient) on
       the day this Reseller Agreement ends. Reseller shall pay all shipping
       charges for Products returned and for all Products rejected. If Efficient
       chooses not to repurchase products from Reseller, Reseller may sell such
       existing inventories to End Users.

                                                                          Page 5
<PAGE>

12.5.  Limits of Liability for Termination - In the event this Agreement is
       -----------------------------------
       terminated, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR COMPENSATION,
       REIMBURSEMENT OR DAMAGES ON ACCOUNT OF THE LOSS OF PROSPECTIVE PROFITS OR
       ANTICIPATED SALES, OR ON ACCOUNT OF EXPENDITURES, INVESTMENTS, LEASES OR
       COMMITMENTS IN CONNECTION WITH THE BUSINESS OR GOOD WILL OF EFFICIENT OR
       RESELLER, OR FOR ANY OTHER REASON RELATING TO OR ARISING FROM SUCH
       TERMINATION.

12.6.  Post Termination Support - The termination of this Agreement shall not
       ------------------------
       relieve Efficient of its Warranty obligations under Article 8 of this
       Agreement with regard to Products sold by Reseller to End Users prior to
       the date of termination, and Efficient shall continue to provide the
       technical support described Article 9 of this Agreement for one (1) year
       following the date of termination.

13.  CONFIDENTIAL AND PROPRIETARY INFORMATION:

13.1.  Disclosure of Information - It is expected that Efficient and Reseller
       -------------------------
       may each disclose to the other proprietary or confidential information.
       For purposes of the following, the Party disclosing the Confidential
       Information is the "Discloser" and the Party receiving the Confidential
       Information is the "Recipient".

13.2.  Confidential Information - "Confidential Information" shall mean any and
       ------------------------
       all information of the Discloser that is not generally known by others
       with whom it competes or does business, and any and all information,
       publicly known in whole or in part or not, which, if disclosed would
       assist in competition against Discloser. Confidential Information
       includes without limitation such information relating to: (i) the
       technical specifications of the Products; (ii) the development, research,
       testing, marketing and financial activities of the Discloser; (iii) the
       identity and special needs of the customers or suppliers of the
       Discloser; and (iv) the people and organizations with whom the Discloser
       has business relationships and those relationships.

13.3.  Ownership and Non-Disclosure - All Confidential Information acquired by
       ----------------------------
       Recipient or its employees or agents shall remain Discloser's exclusive
       property, and Recipient shall use its best efforts (which in any event
       shall not be less than the efforts Recipient takes to ensure the
       confidentiality of its own proprietary and other confidential
       information) to keep, and have its employees and agents keep, any and all
       such information and data confidential, and shall not copy or publish or
       disclose it to others, or authorize its employees, or agents or anyone
       else to copy, publish, or disclose it to others, without Discloser's
       prior written approval, and shall return such information and data to
       Discloser at its request. Recipient shall only use any Confidential
       Information in connection with its performance under this Agreement.

13.4.  Exception - The confidentiality provisions in this Section will not apply
       ---------
       to information which is or which becomes generally known to the public by
       publication or by any means other than a breach of duty on the part of
       the Reseller hereunder or is released by Efficient without restriction or
       is released pursuant to judicial or governmental decree.

13.5.  Post Termination - Except to the extent necessary to fulfill ongoing
       ----------------
       product support obligations or as otherwise provided herein, upon
       termination or expiration, the Reseller shall deliver to Efficient all
       material furnished by Efficient and pertaining to Products, which is then
       in the possession of Reseller, and shall not retain copies of the same.
       Except as provided herein, upon termination or expiration, Efficient
       shall deliver to Reseller all material furnished by Reseller, which is
       deemed confidential hereunder.

14.  INTELLECTUAL PROPERTY CLAIMS:

14.1.  Indemnification by Efficient - Efficient shall defend, at Efficient's
       ----------------------------
       expense, any claim brought against Reseller or End Users (a "Claim
       Defendant") alleging that any Efficient Product acquired or licensed
       under this Agreement infringes a U.S. patent, copyright, or mask work
       right (hereinafter a "Claim"). Efficient shall pay all costs and damages
       awarded or agreed to in settlement, provided that the Claim Defendant
       gave Efficient prompt written notice of the Claim, reasonable assistance
       and sole authority to defend or settle the Claim. Efficient shall obtain
       for the Claim Defendant, the right to continue using the Product, replace
       or modify the Product so it becomes non-infringing. If such remedies are
       not reasonably available, Efficient shall grant Reseller

                                                                          Page 6
<PAGE>

       a credit for the Product normally depreciated and have Reseller return
       the Product to Efficient. Efficient shall not have any liability if the
       alleged infringement is based upon the use, license or sale of the
       Product in combination with other products, including software not
       furnished by Efficient. This is Efficient's entire liability and
       Reseller's exclusive remedy for intellectual property Claims.

14.2.  Representation and Indemnification by Reseller - Reseller represents and
       ----------------------------------------------
       warrants that it is the owner or licensee of all Reseller brands and
       agrees that Efficient shall have no responsibility for the protection or
       maintenance of Reseller's rights in Reseller brands. Reseller shall hold
       Efficient harmless from and defend, at Reseller's expense, any claim
       brought against Efficient alleging that any Reseller brand infringes the
       trademark, trade name or any other intellectual property right of a third
       party (a "Brand Claim"). Reseller shall pay all costs and damages awarded
       or agreed to in settlement, provided that the Efficient gave Reseller
       prompt written notice of the Brand Claim, reasonable assistance and sole
       authority to defend or settle the Brand Claim.

15.  LIMITATION OF LIABILITY:

15.1.  Limitation of Liability - IN NO EVENT SHALL EITHER PARTY OR ITS
       -----------------------
       RESPECTIVE AFFILIATES, OFFICERS, DIRECTORS, AGENTS, OR EMPLOYEES BE
       LIABLE TO RESELLER OR END USERS FOR ANY INDIRECT, INCIDENTAL, OR
       CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOSS OF DATA OR
       PROFITS OR ATTORNEY'S FEES, WHETHER CLAIMED BY REASON OF BREACH OF
       WARRANTY, IN TORT OR OTHERWISE, AND WITHOUT REGARD TO THE FORM OF ACTION
       IN WHICH SUCH CLAIM IS MADE. IN ANY EVENT, EACH PARTY'S LIABILITY SHALL
       BE LIMITED TO ONE MILLION UNITED STATES DOLLARS ($1,000,000) OR THE
       EQUIVALENT IN FOREIGN CURRENCY; PROVIDED, HOWEVER, THAT THIS LIMITATION
       SHALL NOT APPLY TO RESELLER'S OBLIGATION TO PAY FOR PRODUCTS PURCHASED
       HEREUNDER.

16.  DISPUTE RESOLUTION:

16.1.  Consultation and Review - The Parties shall make good faith efforts to
       -----------------------
       resolve all disputes arising under this Agreement through consultations.
       If consultations are unsuccessful in resolving any dispute, either Party
       may request a senior management review. Within ten (10) business days of
       any such request, designated vice presidents of Efficient and Reseller
       will meet in a mutually acceptable fashion to exchange relevant
       information and attempt to resolve the dispute.

17.  TRANSACTION RELATED ITEMS:

17.1.  Merger Agreement.  Reseller and Efficient have entered into an Agreement
       -----------------
       and Plan of Merger and Reorganization, dated as of November 21, 1999 (the
       "Merger Agreement").

17.2.  Indemnity Obligation.  Under the Merger Agreement Reseller has agreed to,
       --------------------
       under certain circumstances, indemnify and hold Efficient harmless from
       certain claims. Reseller and Efficient agree and acknowledge that nothing
       express or implied in this Agreement (e.g. Article 14) shall limit or
       modify any of Reseller's obligations under the Merger Agreement.

18.  GENERAL TERMS:

18.1.  Commercial Use - Products are manufactured by Efficient for standard
       --------------
       commercial use and are accepted and approved by Efficient following
       qualified test procedures, processes and programs established by
       Efficient prior to delivery to Reseller. Special acceptance criteria
       established by Reseller shall be deemed by Efficient as a request for
       custom Product and will be quoted on a case by case basis. Efficient
       shall not be responsible for any damages caused by Products which are not
       intended for use in critical safety systems or nuclear facilities.

18.2.  Import and Export - Certain Products may be subject to export or import
       -----------------
       control laws and regulations of the U.S. government and other
       governments. Reseller assures that Reseller and Resellers will comply
       with those regulations at their expense whenever they export or re-export
       controlled products or technical data obtained from Efficient or any
       product produced directly from the controlled technical data. Reseller
       shall hold harmless and indemnify Efficient from any damages, including
       attorneys' fees, and any government sanctions resulting to Efficient from
       a breach of this Section.

18.3.  United States Government Restricted Rights - All Software shall be
       ------------------------------------------
       licensed to End Users subject to

                                                                          Page 7
<PAGE>

       the following: "The enclosed Product (a) was developed solely at private
       expense; (b) contains "restricted computer software" submitted with
       restricted rights in accordance with section 52.227-19 (a) through (d) of
       the Commercial Computer Software-Restricted Rights Clause and its
       successors, and (c) in all respects is proprietary data belonging to
       Efficient and/or its suppliers. For Department of Defense units, the
       Product is considered commercial computer software in accordance with
       DFARS section 227.7202-3 and its successors, and use, duplication, or
       disclosure by the government is subject to restrictions set forth
       herein."

18.4.  Assignment - This Agreement may not be assigned or transferred in whole
       ----------
       or in part by Reseller without the prior written consent of Efficient.
       Subject to each party's right to terminate this Agreement as provided in
       Section 12.3, either party may, however, assign this Agreement without
       the other party's consent to any person or entity that acquires
       substantially all of the stock, assets or any major division, unit, or
       subsidiary of the assigning party.

18.5.  Waiver and Severability - A Party's failure to enforce any provision of
       -----------------------
       this Agreement shall not be deemed a waiver of that or any other
       provision of this Agreement. If any provision of this Agreement has been
       declared illegal, invalid or unenforceable, the provision shall be
       construed to be enforceable to the maximum extent permitted and, if not,
       shall be deemed deleted from this Agreement, provided that if such
       construction or deletion substantially alters the commercial basis of
       this Agreement, the Parties shall negotiate in good faith to amend the
       provisions of this Agreement to give effect to their original intent.

18.6.  Force Majeure - Except in the case of Reseller's failure to pay any
       -------------
       amounts due hereunder, neither Party shall be liable for any damages or
       penalties for delay in delivery nor for failure to give notice when such
       delay is due to the elements, acts of God, acts of the other Party, acts
       of civil or military authority, fires, or floods, epidemics, quarantine
       restrictions, war, riots, strikes, lockouts or other labor disputes,
       delays in transportation, delays in delivery by vendors, or any other
       causes, without limitation, which are beyond the reasonable control of
       the delayed Party. The delivery date shall be considered extended by a
       period of time equal to the time lost because of any delay that is
       excusable under this provision.

18.7.  Survival - Appropriate provisions of this Agreement, including but not
       --------
       limited to the following, shall survive the expiration or termination of
       this Agreement: Definitions; Ordering and Shipment; Software Terms;
       Payment; Warranty Terms; Intellectual Property; Duration and Termination;
       Confidential and Proprietary Information; Limitation of Liability; Import
       and Export; Confidentiality of Agreement, Waiver and Severability and
       Laws.

18.8.  Laws -This Reseller Agreement shall be governed by the laws of the State
       ----
       of Texas, U.S.A., regardless of the laws that might otherwise govern
       under applicable conflicts and choice of laws principles. Any Action
       under this Agreement must be brought within twelve (12) months after the
       cause of action arises.

18.9.  Relationship of the Parties - Except as expressly provided in this
       ---------------------------
       Agreement, Reseller shall not be, and will not hold itself out as, the
       representative, agent, commission-sales agent, franchisee or employee of
       Efficient for any purpose. This Agreement creates no relationship of
       joint venture, franchise or partnership, and neither Party has any right
       or authority to assume or to create any obligation or responsibility on
       behalf of the other Party. All agreements relating to the sale of the
       Products and Services provided by Reseller to its customers are
       Reseller's exclusive responsibility. Reseller shall indemnify against and
       hold Efficient harmless from, any and all claims, damages or legal
       proceedings and associated costs of whatever nature, relating to the
       performance by Reseller of this Agreement arising out of the acts or
       omissions of Reseller, its employees, servants, Resellers or agents.

18.10. Entire Agreement - This Reseller Agreement, its Exhibits and
       ----------------
       attachments, including all documents which are incorporated by reference,
       constitute the entire and only understanding between the Parties with
       regard to the subject matter hereof and thereof. Unless otherwise
       provided herein, no modifications to this Agreement shall be binding on
       either Party unless made in writing and signed by duly authorized
       representatives of both Parties. In the event of any conflict between
       this Agreement, and any Addendum, Exhibits, or other attachments, the
       terms of this Agreement shall govern.

18.11. Third-Party Financing - In the event Reseller obtains financing in any
       ---------------------
       form whatsoever for the

                                                                          Page 8
<PAGE>

        purchase of Products under this Agreement and there is a conflict
        between the provisions of any such financing agreement and this
        Agreement, the terms of this Reseller Agreement (other than Payment)
        shall govern.

18.12.  Notices - Where electronic communication is available, Efficient and
        -------
        Reseller may communicate with each other by electronic means. Efficient
        and Reseller agree that when electronic communications are used, they
        are the equivalent of written and signed documents except for Notices
        given under this Agreement which if transmitted electronically, shall
        also be sent via facsimile transmission (with a copy by U.S. mail or
        overnight courier (signature required)). Notices shall be deemed
        effective upon receipt or refusal to accept delivery. Routine business
        communications shall not be deemed to be Notices. All such notices shall
        be in English and addressed as follows:

        If to Efficient:

        Efficient Networks, Inc.
        4201 Spring Valley Road, Suite 1200
        Dallas, Texas 75244
        Attention:  Jill Manning
        Facsimile Number:  972-991-8579

        If to Cabletron:

        Cabletron Systems, Inc.
        35 Industrial Way
        Rochester, NH
        Attention:  __________________________
        Facsimile Number: ____________________
<PAGE>

IN WITNESS WHEREOF, the Parties have caused this Reseller Agreement to be
executed by their duly authorized representatives.

Efficient Networks, Inc.                Cabletron Systems, Inc.

      /s/ JILL MANNING                        /s/ PIYUSH PATEL
By:  _______________________________    By:  __________________________________

        Jill Manning                            Piyush Patel
Name:  _____________________________    Name:  ________________________________

         Chief Financial Officer                President
Title:  ____________________________    Title  ________________________________

         December 17, 1999                      December 17, 1999
Date:  _____________________________    Date:  ________________________________
<PAGE>

                     EFFICIENT NETWORKS RESELLER AGREEMENT

                              Exhibit A - Products

- -------------------------------------------------------------------------
Product No.               Description
- -------------------------------------------------------------------------
FP128                     ISDN Router SSR - 105 SSR - 103
- -------------------------------------------------------------------------
FP144                     IDSL Router
- -------------------------------------------------------------------------
FP2025                    ATM25 Router
- -------------------------------------------------------------------------
FP2200                    SDSL Router
- -------------------------------------------------------------------------
FP2200V                   SDSL IAD
- -------------------------------------------------------------------------
SSR245                    Dual Ethernet Router
- -------------------------------------------------------------------------
SSR250                    ADSL Router
- -------------------------------------------------------------------------
SSR255                    ADSL Router
- -------------------------------------------------------------------------
<PAGE>

                     EFFICIENT NETWORKS RESELLER AGREEMENT

                    Exhibit B - Technical Support Guidelines

Nature of Technical Support - During the term of this Agreement, Efficient will
assist Reseller in the identification and resolution of Product performance
problems and errors.  Efficient's technical support shall be Level 3 Support to
the Reseller in connection with its support of its Resellers and End Users.
Level 1 Support and Level 2 Support shall be the sole and exclusive
responsibility of the Reseller and its resellers.  Level 3 Support shall be
provided by Efficient only to engineering personnel designated by the Reseller
who are trained in the technical operation of the Product.  Efficient's support
will be provided in accordance with the following guidelines:

I.   Technical Support

     1.   Availability - Efficient shall provide Level 3 Support via telephone,
          ------------
          facsimile and electronic mail twenty-four hours per day, seven days
          per week.

     2.   Response - Reseller shall use reasonable efforts to attempt to resolve
          --------
          End User support requirements for the Products. If Reseller cannot
          successfully resolve an issue within a reasonable period of time,
          Efficient's technical support staff will provide assistance. Efficient
          will provide an initial response to all Reseller support requests
          within two (2) hours, and Reseller and Efficient will mutually agree,
          in good faith, what additional information or documentation will be
          required for resolution of the problem. Efficient will provide a
          problem report form for Reseller's use in reporting problems.

II.  Error Correction

     1.   Error Definitions - "Error" means a reproducible that causes a Product
          -----------------
          not to function substantially in conformance with its specifications.
          Errors are classified as follows:

          Category 1: End User's network segment or management application is
          down or experiencing a consistent, measurable performance impact with
          no immediate resolution available.

          Category 2: End User is experiencing intermittent failure, performance
          degradation, or functionality of network or management applications.

          Category 3: Issues that do not affect customer's normal network or
          management application operation or questions concerning Product
          functionality or usage.

      2.  Non-Emergency Technical Support - For End User or Reseller problems
          -------------------------------
          not deemed by Reseller to be an emergency, Efficient will use its best
          efforts to address and resolve the problems as quickly as practicable
          during normal business hours. If a particular problem is not resolved
          within two (2) business days following the initial call to Efficient,
          technical support managers and engineers for each Party, will discuss
          and work in good faith to devise and implement a satisfactory
          resolution. Problems regarded as non-emergencies include: (i)
          installation and operation problems, i.e., routine questions that can
          be resolved by following documentation; and (ii) deviations from
          documentation, omissions and known workarounds, i.e. problems that
          cannot be resolved by following the documentation or result from
          reasonable misinterpretation of the documentation.

      3.  Emergency Technical Support - Efficient acknowledges that Category 1
          ---------------------------
          and Category 2 Errors should be resolved quickly. During the
          applicable Warranty Period, Efficient shall replace any defective
          Products or correct Errors promptly following receipt of notice from
          Reseller, not to exceed the following:

          .  Efficient shall provide an initial response to Errors reported by
             Reseller during normal business hours within four (4) hours and
             Reseller and Efficient shall promptly agree in good faith to any
             additional information and documentation that may be required to
             permit Efficient to resolve such errors. The error
<PAGE>

             correction period begins after Reseller has enough information to
             profile the error and can recreate the error or has access to a
             facility where the error can be recreated.

          .  Efficient shall use its best efforts to resolve Category 1 Errors
             within two (2) working days of receipt of notice of such Error.

          .  Efficient shall use its best efforts to resolve Category 2 Errors
             within five (5) working days of receipt of notice of such Error.

          .  Efficient shall use its best efforts to resolve Category 3 Errors
             within fifteen (15) working days of receipt of notice of such
             Error.

          The prescribed Error correction periods above may be extended by
          agreement of the Parties, e.g., if resolution of problem requires
          hardware certification or test, or if resolution represents
          significant risk to the primary Product functions.

      4.  Support Reports and Evaluation - Efficient shall provide a reporting
          ------------------------------
          mechanism by which Reseller will regularly receive a detailed list of
          the status of all Errors reported and resolved, including a list of
          workarounds and bug-fixes. At least once during each calendar quarter,
          the Parties shall hold management-level meetings to discuss
          improvements in support.

III.  Technical Support Hotline

Reseller shall make all requests for technical support to the following hotline
telephone or facsimile number, or via the Internet to the address indicated:

     Efficient Technical Hotline contacts as follows:

     Telephone No. __________________________
     Facsimile No. ___________________________
     Electronic Mail: ___________@______.com

Efficient may change contact telephone numbers, facsimile numbers, or Internet
addresses on ten day's notice.
<PAGE>

                     EFFICIENT NETWORKS RESELLER AGREEMENT

                        Exhibit C - Limited Exclusivity

I.        Reseller Non Exclusive Reseller - Reseller's appointment by Efficient
          -------------------------------
          as a Reseller under the Reseller Agreement is on a non-exclusive
          basis. Efficient may appoint additional parties to sell Products and
          may sell Products itself to all parties throughout the Territory.

II.       Efficient Exclusive Supplier - Reseller agrees that it shall acquire
          DSL and ISDN customer premises equipment ("CPE") for resale from
          Efficient as provided herein.

          .  First Twelve Months - Reseller agrees that, for a period of twelve
             (12) months from the Effective Date, it shall purchase for resale
             CPE exclusively from Efficient. Reseller shall be relieved of this
             obligation, and may purchase CPE for resale from other parties, in
             the event that: (A) Efficient is unable to meet Reseller's
             reasonable delivery requirements for CPE; or (B) Efficient CPE does
             not substantially meet the specifications of Reseller or Reseller's
             customer for the CPE and, after reasonable notice, Efficient is
             unable or unwilling to modify its products to meet Reseller or the
             customer requirements in the required timeframe; or (C) a third
             party manufacturer of CPE is able to supply comparable CPE to
             Reseller at prices which are equal to or less than ninety-five
             percent (95%) of the price at which Efficient is offering
             comparable CPE to Reseller; or (D) Reseller's customer makes a
             specific request not solicited by Reseller for CPE manufactured by
             a third party. Any exception to the general rule of exclusivity
             will apply to the specific product or order presented by Reseller,
             but will not result in a general release from the foregoing
             exclusivity provisions.

          .  Subsequent Periods - Following the initial twelve month period of
             the Reseller Agreement and for so long as the Reseller Agreement
             remains in effect, Reseller agrees that Efficient shall be its
             preferred supplier of CPE for resale and that Reseller shall
             feature Efficient CPE as its lead CPE products.

III.      Branding - For so long as the Reseller Agreement remains in effect,
          --------
          Reseller agrees that it will not rebrand any CPE as Reseller CPE,
          other than (i) CPE so branded by Efficient pursuant to the Reseller
          Agreement and (ii) CPE purchased from third parties as permitted by
          paragraph II. To the extent that Reseller acquires a third party which
          makes or sells CPE that is comparable to the Flowpoint CPE, Reseller
          will not rebrand any such CPE as Reseller CPE for the longer of (A)
          twelve (12) months from the date it acquires such third party; or (B)
          that date on which it otherwise generally ceases to use the branding
          of the acquired entity.

IV.       Sales Force Training and Incentives - Reseller agrees that, for so
          long as the Reseller Agreement remains in effect:

          .  Reseller shall provide Efficient with access to its sales personnel
             on a regular basis in conjunction with regularly scheduled Reseller
             sales force training events so that Efficient may provide training
             on the Flowpoint CPE;

          .  Reseller shall not permit any third party CPE manufacturer to offer
             similar training to Reseller sales personnel; provided, however,
             that Reseller may permit third party manufacturers supplying CPE as
             permitted by paragraph II to conduct limited training as reasonably
             required;

          .  Reseller shall utilize marketing material provided by Efficient, or
             jointly developed by Reseller and Efficient, as its exclusive
             marketing material relating to CPE except with respect to third
             party CPE permitted by paragraph II above;

          .  To the extent that Reseller elects to feature CPE at trade shows or
             in general product marketing material, it shall feature Flowpoint
             CPE substantially more predominantly at such shows or in such
             material than it features any other third party CPE;

          .  Reseller shall include in Flowpoint CPE its product/commission
             lists made available to its sales personnel and shall pay customary
             commissions to its sales personnel on sales of Flowpoint CPE;
<PAGE>

          .  Reseller shall not compensate (through commissions, rebates,
             special incentives or any other means) its sales personnel for the
             sale of third party CPE at rates more favorable than the rates at
             which Reseller compensates its sales personnel for sales of
             Flowpoint CPE; and

          .  Reseller shall not disseminate any press releases or similar
             announcements relating to any non-Efficient CPE which Reseller may
             sell nor with respect to any strategic relationship, joint or
             cooperative marketing or similar arrangement with any third-party
             supplier of CPE.
<PAGE>

                     EFFICIENT NETWORKS RESELLER AGREEMENT

                        Exhibit D - Marketing Principles

These Marketing Principles set forth the intentions of the parties as it relates
to opportunities which may arise to sell DSL and ISDN customer premises
equipment (DSL and ISDN customer premises equipment are referred to herein as
"CPE.").  In particular, the parties recognize that situations are likely to
arise where the sales force of each party may be presented with the same
business opportunity, or different opportunities within a single customer
enterprise.  It is the parties intention that any such conflicts be resolved
through good faith discussions between the parties taking into account the
guidelines set forth herein.

I.        General Statement - Efficient is primarily in the business of
          -----------------
          developing and selling CPE. Reseller is not primarily in the business
          of developing or selling CPE, and intends to sell CPE only in
          situations which may lead to sales by Reseller of other Reseller
          products and services. It is the general intention and marketing
          strategy of the parties that: (1) sales which primarily involve CPE
          will be handled by Efficient and (2) sales which primarily involve
          non-CPE Reseller products and services will be handled by Reseller. It
          is the mutual goal of the parties to increase the level of CPE being
          sold through all available sales channels and to optimize the use of
          their respective sales resources.

II.       Specific Accounts - In furtherance of the General Statement, the
          -----------------
          parties acknowledge that there are certain customers which require a
          more specific statement of intention. These are as set forth in this
          Article II.

         1.  Efficient Key Accounts - Efficient has existing customer
             ----------------------
             relationships with each of the following parties and/or their
             purchasing affiliates (the "Efficient Key Accounts"): America
             Online; Concentric Networks; Covad Communications; Northpoint;
             Rhythms; and SBC. The parties agree that Efficient will be the
             preferred vendor of CPE into these accounts. Absent unusual
             circumstances, Reseller will refrain from selling CPE into these
             accounts, and will refer sales leads to Efficient.

         2.  Common Key Accounts - Efficient and Reseller each have existing
             -------------------
             customer relationships with the following parties and/or their
             purchasing affiliates (the "Common Key Accounts"): AT&T; Bell
             Atlantic; Bell South; Mindspring; and MCI/Worldcom. Both Efficient
             and Reseller expect to continue to sell their respective products
             and services into each of the Common Key Accounts. In order to
             mitigate the potential for the inefficient duplication of sales
             efforts with respect to the Common Key Accounts, promptly following
             the Effective Date, representatives of Efficient and Reseller shall
             meet and (1) inform the other party about the status of current and
             prospective sales activities in each of the Common Key Accounts;
             and (2) work in good faith to develop a plan of action to mitigate
             any duplications of effort or other inefficiencies which may then
             exist or may arise in the future. Efficient and Reseller further
             agree that, for so long as the Reseller Agreement remains in
             effect, they will keep the other party informed of current and
             prospective sales activities in the Common Key Accounts and will
             meet periodically to discuss any issues that may have arisen.

         3.  Other Accounts - Efficient and Reseller recognize that they are
             --------------
             likely to engage in selling activities with respect to customers or
             potential customers that are not Efficient Key Accounts or Common
             Key Accounts. As to all such other customers or potential
             customers, it is the intention that the General Statement shall
             apply.

III.      Contacts and Dispute Resolution - The parties agree to appoint primary
          -------------------------------
          contact persons and to attempt to resolve in good faith any issues
          that may arise under these Marketing Principles.

         1.  Contacts - The following persons shall be the initial contacts for
             --------
             resolving any issues under these Marketing Principles: for
             Efficient, David Stefan; for Reseller, Romulus Pereira; for
             Flowpoint, Dano Ybarra. Although the parties are free to change
             their contact person in their discretion by notice to the other
             parties, each party acknowledges and agrees that maintaining
             continuity of the contacts and relationship will be beneficial to
             all parties, and will make decisions to keep or change contact
             persons with this in mind.
<PAGE>

         2.  Dispute Resolution - Each party shall put into place appropriate
             ------------------
             mechanisms such that conflicts that arise among their respective
             sales forces will be brought to the attention to their contact
             persons. In the event of any such dispute, the contact persons
             shall promptly meet (in person or by phone) and shall attempt in
             good faith to resolve any such controversies following the
             principles set forth in these Marketing Principles. If, after
             making reasonable efforts to resolve the controversy, the contact
             persons are unable to arrive at a mutually satisfactory resolution,
             the matter shall be elevated to the second level contacts within
             the organizations. The second level contacts shall be: for
             Efficient, [Mark Floyd]; for Reseller, [________________]; and for
             Flowpoint, [Chuck Waggoner]. Each party is free to designate a
             different second level contact. The second level contacts shall
             attempt to resolve any controversies in the same manner as the
             initial contacts act under these Marketing Principles.

<PAGE>

                                                                   EXHIBIT 10.24

                                                                  EXECUTION COPY
                                                                  --------------

                     STANDSTILL AND DISPOSITION AGREEMENT

                                   Between

                           EFFICIENT NETWORKS, INC.

                                      and

                            CABLETRON SYSTEMS, INC.

                         Dated as of December 17, 1999
<PAGE>

                              TABLE OF CONTENTS

<TABLE>
<S>                                                                               <C>
                                                                                  Page
                                                                                  ----
ARTICLE 1 DEFINITIONS...........................................................     1
     1.1  Certain Definitions...................................................     1

ARTICLE 2 STANDSTILL AND RELATED COVENANTS......................................     5
     2.1  Cabletron Ownership of Efficient Securities...........................     5
     2.2  Standstill Provisions.................................................     5
     2.3  Voting................................................................     6
     2.4  Voting Trust..........................................................     6
     2.5  Solicitation of Proxies...............................................     6
     2.6  Acts in Concert with Others...........................................     6
     2.7  Termination...........................................................     7

ARTICLE 3 RESTRICTIONS ON TRANSFER OF SECURITIES; COMPLIANCE WITH
     SECURITIES LAWS............................................................     7
     3.1  Restrictions on Transfer of Voting Securities of Efficient............     7
     3.2  Restrictive Legends...................................................     8
     3.3  Procedures for Certain Transfers......................................     9
     3.4  Covenant Regarding Exchange Act Filings...............................    10
     3.5  Termination...........................................................    10

ARTICLE 4 REGISTRATION RIGHTS...................................................    11
     4.1  Demand Registration...................................................    11
     4.2  Shelf Registration....................................................    11
     4.3  Piggyback Registration................................................    12
     4.4  Demand and Shelf Registration Procedures, Rights and Obligations......    14
     4.5  Expenses..............................................................    18
     4.6  Indemnification.......................................................    18
     4.7  Issuances by Efficient or Other Holders...............................    19
     4.8  Information by Cabletron..............................................    19
     4.9  Market Standoff Agreements............................................    19
     4.10 Additional Registration Rights Covenants..............................    20
     4.11 Termination...........................................................    20

ARTICLE 5 MISCELLANEOUS.........................................................    21
     5.1  Governing Law.........................................................    21
     5.2  Successors and Assigns................................................    21
     5.3  Entire Agreement; Amendment...........................................    21
     5.4  Notices and Dates.....................................................    21
     5.5  Language Interpretation...............................................    22
     5.6  Table of Contents; Titles; Headings...................................    23
     5.7  Counterparts..........................................................    23
     5.8  Severability..........................................................    23
     5.9  Injunctive Relief.....................................................    23
     5.10 Automatic Adjustments to Share Numbers................................    23
</TABLE>

                                      -i-
<PAGE>

                     STANDSTILL AND DISPOSITION AGREEMENT

     THIS STANDSTILL AND DISPOSITION AGREEMENT (this "Agreement") is made as of
December 17, 1999, between Cabletron Systems, Inc., a Delaware corporation
("Cabletron"), and Efficient Networks, Inc., a Delaware corporation
("Efficient").

                                   RECITALS
                                   --------

     A.   Pursuant to the terms of the Agreement and Plan of Reorganization,
dated as of November 21, 1999 (the "Merger Agreement"), by and among Efficient,
Cabletron, Fire Acquisition Corporation, a California corporation and Flowpoint
Corporation, a California corporation, Cabletron will receive 7,200,000 shares
of Efficient's Common Stock, par value $0.01 per share (the "Shares") and 6,300
shares of Efficient's Series A Non-Voting Convertible Stock (the "Preferred
Stock").

     B.   The Merger Agreement provides for the execution and delivery of this
Agreement.

     NOW, THEREFORE, in consideration of the representations, warranties,
covenants and conditions herein and in the Merger Agreement, the parties hereto
hereby agree as follows:

                                   ARTICLE 1

                                  DEFINITIONS



     1.1  Certain Definitions.  As used in this Agreement:
          -------------------

          (a) "Affiliate" shall have the meaning set forth in Section 3.3(c).

          (b) "Available Shares" shall have the meaning set forth in Section
4.3(c)(ii).

          (c) "Base Shares" means the number of shares of Efficient equal to ten
percent (10%) of Efficient's Voting Securities.

          (d) "Beneficial ownership" or "beneficial owner" has the meaning
provided in Rule 13d-3 promulgated under the Exchange Act. References to
ownership of Voting Securities hereunder mean record and/or beneficial
ownership.

          (e) "Change in Control of Efficient" shall mean a merger,
consolidation or other business combination or the sale of all or substantially
all of the assets of Efficient (other than a transaction pursuant to which the
holders of the voting stock of Efficient outstanding immediately prior to such
transaction have the entitlement to exercise, directly or indirectly, fifty
percent (50%) or more of the Total Voting Power of the continuing, surviving
entity or transferee immediately after such transaction).
<PAGE>

          (f) "Cabletron" has the meaning set forth in the recitals hereto and
includes any Person controlling Cabletron.

          (g) "Cabletron Competitor" is any of the top five (5) data networking
companies, as measured by revenues from time to time.

          (h) "Cabletron Conflict of Interest Transaction" means any transaction
requiring the approval of Efficient's Stockholders (i) between Efficient and one
(or more) Persons in which Cabletron owns or controls a five percent (5%) equity
interest or (ii) a Change of Control of Efficient with a Cabletron Competitor.

          (i) "Cabletron Pooling Transaction Lock-Up" has the meaning set forth
in Section 4.9(a).

          (j) "Cabletron Public Offering Lock-Up" has the meaning set forth in
Section 4.9(a).

          (k) "Controlled Affiliate" means, with respect to any Person, any
Person directly or indirectly controlled by such other Person where, for
purposes of this definition, "control" or "controlled by" means the possession,
directly or indirectly, of the power to direct or cause the direction of the
management and policies of such Person, whether through the ownership of Voting
Securities, by contract or otherwise.

          (l) "Conversion Stock" shall mean the Efficient Common Stock received
upon conversion of the Preferred Stock.

          (m) "Demand Breathing Period" means (x) 180 days after the closing of
the offering related to a prior Demand Request or (y) 90 days after the closing
of the last public offering of securities by Efficient for its own account.

          (n) "Demand Registration Statement" has the meaning set forth in
Section 4.1(a).

          (o) "Demand Request" has the meaning set forth in Section 4.1(a).

          (p) "Demand Managing Underwriters" has the meaning set forth in
Section 4.4(c).

          (q) "Demand Market Cut-Back" has the meaning set forth in Section
4.4(d).

          (r) "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

          (s) "Exclusive Demand Period" means the period between the date hereof
and December 31, 2000; provided, that, the Exclusive Demand Period shall be
extended day per day for the duration of any Suspension Condition in effect
prior to December 31, 2000.

                                      -2-
<PAGE>

     (t)  "Exclusive Demand Period Offering" means a public offering of Voting
Securities for cash by Efficient for its own account (excluding the First
Offering) during the Exclusive Demand Period.

     (u)  "First Offering" means the first underwritten public offering of
Voting Securities for cash by Efficient for its own account following the date
hereof.

     (v)  "Group" or "group" shall have the meaning provided in Section 13(d)(3)
of the Exchange Act and the rules and regulations promulgated thereunder, but
shall exclude any institutional underwriter purchasing Voting Securities of
Efficient in connection with an underwritten registered offering for purposes of
a distribution of such securities.

     (w)  "Indemnified Party" has the meaning set forth in Section 4.6(c).

     (x)  "Indemnifying Party" has the meaning set forth in Section 4.6(c).

     (y)  "Investors" shall have the meaning set forth in the Investors" Rights
Agreement.

     (z)  "Investors" Rights Agreement" shall mean that certain Investors"
Rights Agreement of Efficient dated July 30, 1993, as amended (or any successor
to such agreement).

     (aa) "Minimum Demand Portion" shall have the meaning set forth in Section
4.4(d)(i).

     (bb) "Passive Investor" means a bank, a qualified pension trust or a
registered mutual fund which reports its ownership of securities under and
utilizing Section 13(G) of the Exchange Act (and Form 13(G) under the Exchange
Act) and which has not, within the two (2) year period prior to the time of
determination, participated in a solicitation of proxies against a portfolio
company or filed a Form 13(d) or converted from a Form 13(G) filer to a Form
13(d) filer with respect to any portfolio company.

     (cc) "Person" shall mean any person, individual, corporation, partnership,
trust, limited liability company or other non-governmental entity or any
governmental agency, court, authority or other body (whether foreign, federal,
state, local or otherwise).

     (dd) "Piggyback Market Cut-Back" has the meaning set forth in Section
4.3(c).

     (ee) "Piggyback Registrable Securities" has the meaning set forth in
Section 4.3(a).

     (ff) "Piggyback Registration Statement" has the meaning set forth in
Section 4.3(a).

     (gg) "Piggyback Request" has the meaning set forth in Section 4.3(a).

     (hh) "Piggyback Underwriting Agreement" has the meaning set forth in
Section 4.3(b).

                                      -3-
<PAGE>

     (ii) "Preferred Stock" has the meaning set forth in Section A of the
Recitals.

     (jj) "Proportionately" has the meaning set forth in Section 2.3.

     (kk) "Register," "registered" and "registration" refer to a registration
effected by preparing and filing a registration statement in compliance with the
Securities Act, and the declaration or ordering of the effectiveness of such
registration statement.

     (ll) "Registrable Securities" means (i) the Shares, (ii) Conversion Stock
and (iii) any securities issued in respect of the foregoing as a result of any
stock split, stock dividend, recapitalization, or similar transaction.

     (mm) "Registration Expenses" shall mean all expenses incurred in connection
with a registration hereunder, including, without limitation, all registration
and filing fees, listing fees, printing and automated document preparation
expenses, custody fees, fees and disbursements of counsel for Efficient, blue
sky fees and expenses, and the expenses of Efficient's independent accountants,
including any special audits or comfort letters incident to or required by any
such registration, but excluding the expenses of regular employees of Efficient,
which shall be paid in any event by Efficient.

     (nn) "Reserved Portion" shall mean (i) with respect to the First Offering,
provided the preliminary prospectuses with respect to such offering are printed
and distributed prior to May 1, 2000 and such offering closes by June 1, 2000
(the "Criteria"), 35% of the number of shares to be distributed in such
offering; (ii) with respect to an Exclusive Demand Period Offering (or the First
Offering if the Criteria are not met), the greater of 40% of the shares to be
distributed in such offering or 3,000,000 shares.

     (oo) "Reserved Shares" shall have the meaning set forth in Section
4.4(d)(ii).

     (pp) "Securities" has the meaning set forth in Section 3.2(a).

     (qq) "Securities Act" means the Securities Act of 1933, as amended.

     (rr) "SEC" means the Securities and Exchange Commission or any other
federal agency at the agency administering the Securities Act.

     (ss) "Selling Expenses" shall mean with respect to any registration
pursuant to this Agreement, all underwriting discounts and selling commissions
applicable to the sale of shares and all fees and disbursements of counsel to
any Person other than the Company.

     (tt) "Shares" has the meaning set forth in Section A of the recitals above;
provided, however, if not capitalized, "shares" shall mean shares of Efficient's
common stock generally.

     (uu) "Shelf Registrable Securities" has the meaning set forth in Section
4.2(a).

     (vv) "Shelf Registration Statement" has the meaning set forth in Section
4.2(a).

                                      -4-
<PAGE>

     (ww) "Suspension Condition" has the meaning set forth in Section 4.4(f).

     (xx) "Total Consideration Shares" shall mean the aggregate of (x) the total
number of Shares held by Cabletron and (y) the total number of shares of
Efficient Common Stock which the Preferred Stock has been converted into or is
convertible into.

     (yy) "Voting Securities" means all securities of Efficient, entitled, in
the ordinary course, to vote in the election of directors of Efficient. Voting
Securities shall not include stockholder rights or other comparable securities
having Voting Power only upon the happening of a trigger event or comparable
contingency and which can only be transferred together with the Voting
Securities to which they attach. References herein to meetings of holders of
Voting Securities shall include meetings of any class or type thereof.

     (zz) "Voting Power" or "Total Voting Power" of Efficient (or any other
corporation) refer to the votes or total number of votes which at the time of
calculation may be cast in the election of directors of Efficient (or such
corporation) at any meeting of stockholders of Efficient (or such corporation)
if all securities entitled to vote in the election of directors of Efficient (or
such corporation) were present and voted at such meeting; provided that for
purposes of references herein made to any Person's "Voting Power" or percentage
beneficial ownership of "Total Voting Power," any rights (other than rights
referred to in any rights plan of Efficient (or any such other corporation) or a
successor to such rights plan so long as such rights can only be transferred
together with the Voting Securities to which they attach) of such Person to
acquire Voting Securities (whether or not the exercise of any such right shall
be conditioned upon any contingency) shall be deemed to have been exercised in
full.

     All capitalized terms used and not defined herein shall have the respective
meanings assigned to such terms in the Merger Agreement.

                                   ARTICLE 2

                       STANDSTILL AND RELATED COVENANTS


     2.1  Cabletron Ownership of Efficient Securities. On the date hereof, and
          -------------------------------------------
without giving effect to the transactions contemplated by the Merger Agreement,
neither Cabletron nor any Controlled Affiliate of Cabletron beneficially owns
any Voting Securities of Efficient.

     2.2  Standstill Provisions. Cabletron shall not acquire, directly or
          ---------------------
indirectly, and shall not cause or permit any Controlled Affiliate of Cabletron
to acquire, directly or indirectly (through market purchases or otherwise),
record or beneficial ownership of any Voting Securities of Efficient without the
prior written consent of the Board of Directors of Efficient; provided, however,
that the prior written consent of the Board of Directors of Efficient shall not
be required for the acquisition of any Voting Securities of Efficient directly
from Efficient or resulting from a stock split, stock dividend or similar
recapitalization by Efficient. Nothing contained in this Section 2.2 shall
adversely affect any right of Cabletron or any Controlled Affiliate of Cabletron
to acquire record or beneficial ownership of Voting Securities of Efficient
pursuant to any rights plan instituted by Efficient.

                                      -5-
<PAGE>

     2.3  Voting. Unless the Board of Directors of Efficient otherwise consents
          ------
in writing in advance, Cabletron shall take such action (and shall cause each
Controlled Affiliate of Cabletron that beneficially owns Voting Securities of
Efficient to take such action) as may be required so that all Voting Securities
of Efficient beneficially owned by Cabletron (or any such Controlled Affiliate
of Cabletron) from time to time, other than the Base Shares, are voted on all
matters to be voted on by holders of Voting Securities of Efficient in the same
proportion (for, against and abstain, with lost, damaged or disfigured ballots
counting as abstentions to the extent that they cannot be counted as for or
against under applicable law) as the votes cast by the other holders of Voting
Securities of Efficient with respect to such matters ("Proportionately");
provided, however, that on any matter that constitutes, involves or is part of,
a Cabletron Conflict of Interest Transaction, Cabletron and any Controlled
Affiliate of Cabletron must vote all Voting Securities, including the Base
Shares, Proportionately. Cabletron (or any Controlled Affiliate of Cabletron),
as the holder of Voting Securities of Efficient, shall be present, in person or
by proxy, at all meetings of the stockholders of Efficient so that all Voting
Securities of Efficient beneficially owned by Cabletron (or such Controlled
Affiliate of Cabletron) from time to time may be counted for the purposes of
determining the presence of a quorum at such meetings. The foregoing provision
shall also apply to the execution by Cabletron of any written consent in lieu of
a meeting of holders of Voting Securities of Efficient or any class thereof.

     2.4  Voting Trust. Cabletron shall not, and shall not cause or permit any
          ------------
Controlled Affiliate of Cabletron to, deposit any Voting Securities of Efficient
in a voting trust or, except as otherwise provided herein, subject any Voting
Securities of Efficient to any arrangement or agreement with respect to the
voting of such Voting Securities of Efficient.

     2.5  Solicitation of Proxies. Without the prior written consent of the
          -----------------------
Board of Directors of Efficient, Cabletron shall not, and shall not cause or
permit any Controlled Affiliate of Cabletron to, directly or indirectly (i)
initiate, propose or otherwise solicit Efficient stockholders for the approval
of one or more stockholder proposals with respect to Efficient or induce or
attempt to induce any other Person to initiate any stockholder proposal, (ii)
make, or in any way participate in, any "solicitation" of "proxies" (as such
terms are defined or used in Regulation 14a-1 under the Exchange Act) with
respect to any Voting Securities of Efficient, or become a "participant" in any
"election contest" (as such terms are used in Rule 14a-11 of Regulation 14A
under the Exchange Act), with respect to Efficient or (iii) call or seek to have
called any meeting of the holders of Voting Securities of Efficient.

     2.6  Acts in Concert with Others. Except as contemplated herein, Cabletron
          ---------------------------
shall not, and shall not cause or permit any Controlled Affiliate of Cabletron,
to participate in the formation, or encourage the formation, of any Person which
owns or seeks to acquire beneficial ownership of, or otherwise acts in concert
in respect of the Voting or disposition of, Voting Securities of Efficient.
Without limiting the generality of the foregoing, and except as contemplated
herein, Cabletron shall not, and shall not cause or permit any Controlled
Affiliate of Cabletron to: (i) join a partnership, limited partnership,
syndicate or other group, or otherwise act in concert with any third person, for
the purpose of acquiring, holding, or disposing of Voting Securities of
Efficient; (ii) seek election to or seek to place a representative on the Board
of Directors of Efficient; (iii) seek the removal of any member of the Board of
Directors of Efficient; (iv) otherwise seek control of the management, Board of
Directors or policies of Efficient; (v) solicit, propose, seek to effect or
negotiate with any other Person with respect to any form of business combination
transaction with Efficient or any Controlled

                                      -6-
<PAGE>

Affiliate thereof, or any restructuring, recapitalization or similar transaction
with respect to Efficient or any Controlled Affiliate thereof; (vi) solicit,
make or propose or encourage or negotiate with any other Person with respect to,
or announce an intent to make, any tender offer or exchange offer for any Voting
Securities of Efficient; (vii) disclose an intent, purpose, plan or proposal
with respect to Efficient or any Voting Securities of Efficient inconsistent
with the provisions of this Agreement, including an intent, purpose, plan or
proposal that is conditioned on or would require Efficient to waive the benefit
of or amend any provision of this Agreement; or (vii) assist, participation in,
facilitate, encourage or solicit any effort or attempt by any Person to do or
seek to do any of the foregoing. Cabletron shall not, and shall not cause or
permit any Controlled Affiliate of Cabletron to, encourage or render advice to
or make any recommendation or proposal to any Person to engage in any of the
actions covered by Section 2.5 and this Section 2.6 hereof.

     2.7  Termination. The provisions of this Article 2 shall terminate at such
          -----------
time as (i) Cabletron (together with all Controlled Affiliates of Cabletron)
beneficially owns in the aggregate Voting Securities of Efficient representing
less than five percent (5%) of the Total Voting Power of Efficient or (ii) upon
a Change in Control of Efficient.

                                   ARTICLE 3

    RESTRICTIONS ON TRANSFER OF SECURITIES; COMPLIANCE WITH SECURITIES LAWS


     3.1  Restrictions on Transfer of Voting Securities of Efficient. Cabletron
          ----------------------------------------------------------
shall not, and shall not cause or permit any Controlled Affiliate of Cabletron
to, directly or indirectly, offer to sell, contract to sell, make any short sale
of, or otherwise sell, dispose of, loan, gift, pledge or grant any options or
rights with respect to, any Securities, now or hereafter acquired, or with
respect to which Cabletron or any Controlled Affiliate of Cabletron has or
hereafter acquires the power of disposition or enter into any agreement or
understanding with respect to the foregoing, except as set forth below (for
purposes of the following, the Preferred Stock shall be deemed converted into
Conversion Stock):

          (a)  to Efficient, or any Person or group approved in writing in
advance by the Board of Directors of Efficient;

          (b)  subject to Section 3.3(a) below, to any Controlled Affiliate of
Cabletron, so long as such Controlled Affiliate agrees in writing, in form
reasonably acceptable to counsel for Efficient, to hold such Voting Securities
or Preferred Stock of Efficient subject to all the provisions of this Agreement,
and so agrees to transfer such Voting Securities or Preferred Stock of Efficient
to Cabletron or another Controlled Affiliate of Cabletron if it ceases to be a
Controlled Affiliate of Cabletron;

          (c)  pursuant to a firm commitment, underwritten public offering of
Securities registered under the Securities Act;

          (d)  subject to Section 3.3(b) below, through a sale of Securities
pursuant to Rule 144 under the Securities Act or pursuant to the Shelf
Registration Statement; provided, however, that any such sale complies with the
manner of sale provisions under paragraph (f) of Rule

                                      -7-
<PAGE>

144 or the plan of distribution set forth in the Shelf Registration Statement,
as applicable and is not made to: (A) any Person or group which has theretofore
filed a Schedule 13D with the SEC with respect to any class of "equity security"
(as defined in Rule 13a11-1 under the Exchange Act) of Efficient and which, at
the time of such sale, continues to reflect beneficial ownership in excess of
five percent (5%) of the Total Voting Power of Efficient; (B) any Person or
group which, after giving effect to the sale and to the actual knowledge of
Cabletron (with no duty of investigation), will beneficially own in excess of
five percent (5%) of any Voting Securities of Efficient or to be accumulating
stock on behalf of or acting in concert with any such Person or group or a
Person or group contemplated by clause (A) above, provided however, that this
clause (B) shall not apply with respect to transfers less than 100,000 shares;
or (C) any Person or group that has announced or commenced an unsolicited offer
for any Voting Securities or Preferred Stock of Efficient or publicly initiated,
proposed or otherwise solicited Efficient stockholders for the approval of one
or more stockholder proposals with respect to Efficient or publicly made, or in
any way participated in, any "solicitation" of "proxies" (as such terms are
defined or used in Regulation 14A under the Exchange Act) with respect to any
Voting Securities or Preferred Stock of Efficient, or become a "participant" in
any "election contest" (as such terms are used in Rule 14a-11 of Regulation 14A
under the Exchange Act);

          (e)  (i) subject to Section 3.3(a) below, pursuant to any private sale
of Securities exempt from the registration requirements under the Securities
Act; provided, however, that (i) no such sale may be made to any Person or group
which, to the knowledge of Cabletron after reasonable inquiry and after giving
effect to such sale, will beneficially own or have the right to acquire Voting
Securities or Preferred Stock of Efficient with aggregate Voting Power of more
than five percent (5%) of the Total Voting Power of Efficient or group, except,
however, if such Person or group is a Passive Investor, such limitation shall be
ten percent (10%) of the Total Voting Power of Efficient; and (ii) in any event
any such purchaser shall agree to take and hold such Securities subject to the
provisions and upon the conditions specified in Sections 2 and 3 of this
Agreement, and it will be a condition precedent to the effectiveness of any such
transfer that Cabletron shall have delivered to Efficient a written agreement of
such purchaser to that effect in form and substance reasonably satisfactory to
Efficient; or

          (f)  in response to an offer to purchase or exchange for cash or other
consideration any Voting Securities or Preferred Stock, which in any case is not
opposed by the Board of Directors of Efficient within the time such Board is
required, pursuant to Regulations under the Exchange Act, to advise the
stockholders of Efficient of such Board's position with respect to such offer,
or, if no such Regulations are applicable, within ten (10) business days of the
commencement of such offer, or pursuant to a merger, consolidation or other
business combination involving Efficient approved by the Board of Directors of
Efficient.

     3.2  Restrictive Legends.
          -------------------

                                      -8-
<PAGE>

          (a)  The certificate or certificates representing the (i) the Shares,
(ii) the Preferred Stock, (iii) the Conversion Stock and (iv) any securities
issued in respect of the foregoing as a result of any stock split, stock
dividend, recapitalization, or similar transaction (collectively, the
"Securities") shall be stamped or otherwise imprinted with a legend
substantially in the following form (in addition to any legend required under
applicable state Securities laws):

          THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE BEEN
          ACQUIRED FOR INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER
          THE SECURITIES ACT OF 1933. SUCH SHARES MAY NOT BE SOLD OR
          TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR AN
          OPINION OF COUNSEL SATISFACTORY TO THE ISSUER AS TO THE
          AVAILABILITY OF AN EXEMPTION FROM REGISTRATION.

          (b)  In addition to the legend provided for in Section 3.2 (a), the
certificate or certificates representing the Securities and any other securities
of Efficient hereafter acquired (for example, in compliance with Section 2.2)
shall be stamped or otherwise imprinted with a legend substantially in the
following form:

          THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO
          RESTRICTIONS ON TRANSFER, INCLUDING ANY SALE, PLEDGE OR
          OTHER HYPOTHECATION, WHICH RESTRICTIONS ARE SET FORTH IN AN
          AGREEMENT BETWEEN THE ISSUER AND CABLETRON SYSTEMS, INC., A
          COPY OF WHICH MAY BE OBTAINED AT NO COST BY WRITTEN REQUEST
          MADE BY THE HOLDER OF RECORD OF THIS CERTIFICATE TO THE
          SECRETARY OF THE ISSUER AT THE ISSUER'S PRINCIPAL EXECUTIVE
          OFFICES.

     3.3  Procedures for Certain Transfers.
          --------------------------------

          (a)  Prior to any proposed transfer of any Securities pursuant to
Sections 3.1(b) and 3.1(e)(i) hereof, Cabletron shall give written notice to
Efficient of Cabletron's intention to effect such transfer. Each such notice
shall describe the manner and circumstances of the proposed transfer in
sufficient detail, and shall be accompanied by either: (i) a written opinion of
legal counsel (including in-house counsel), who shall be reasonably satisfactory
to Efficient, addressed to Efficient and reasonably satisfactory in form and
substance to Efficient's counsel, to the effect that the proposed transfer of
the Securities may be effected without registration under the Securities Act; or
(ii) a "no action" letter from the SEC and a copy of any request by Cabletron
(together with all supplements or amendments thereto), which shall have been
provided to Efficient at or prior to the time of first delivery to the SEC's
staff, to the effect that the transfer of such Securities without registration
will not result in a recommendation by the staff of the SEC that action be taken
with respect thereto, whereupon Cabletron shall be entitled to transfer such
Restricted Securities in accordance with the terms of the notice delivered by
Cabletron to Efficient.

                                      -9-
<PAGE>

          (b)  In connection with any proposed transfer of Securities pursuant
to Rule 144 as provided in Section 3.1(d) above, Cabletron shall comply with the
reasonable requirements of Efficient's transfer agent with respect to sales of
restricted securities pursuant to Rule 144.

          (c)  Each certificate evidencing the Securities transferred as herein
provided (other than a transfer pursuant to Section 3.1(c) or pursuant to the
Shelf Registration Statement) shall bear the appropriate restrictive legend set
forth (or described) in Section 3.4(a) above, except that such certificate shall
not bear such restrictive legend if: (i) in the opinion of counsel for
Efficient, such legend is not required in order to establish compliance with any
provisions of the Securities Act; (ii) the Securities have been held by the
holder for more than two years, and the holder represents to counsel for
Efficient that it has not been an "Affiliate" (as such term is defined for
purposes of Rule 144) of Efficient during the three-month period prior to the
sale and shall not become an affiliate (as such term is defined for purposes of
Rule 144) of Efficient without resubmitting the Securities for reimposition of
the legend; or (iii) the Securities have been sold pursuant to Rule 144 and in
compliance with Section 3.1(d). In addition, each certificate evidencing the
Securities transferred pursuant to this Article 3 (other than transfers pursuant
to Sections 3.1(c) or pursuant to the Shelf Registration Statement) shall bear
the legend set forth in Section 3.2(b) above. The restrictive legend specified
in Section 3.2(a) shall promptly be removed in connection with a sale pursuant
to Section 3.1(c) or the Shelf Registration Statement or the satisfaction of
subclause (i), (ii) or (iii) above. The restrictive legend specified in Section
3.2(b) shall be removed upon termination of Article 3 as set forth in Section
3.5 below or in connection with a transfer of securities which does not require
the transferee to be bound by this Section 3.

     3.4  Covenant Regarding Exchange Act Filings. With a view to making
          ---------------------------------------
available to Cabletron the benefits of Rule 144 promulgated under the Act and
any other rule or regulation of the SEC that may any time permit Cabletron to
sell securities of Efficient to the public without registration. Efficient
agrees to:

               (i)   Make and keep public information available, as those terms
are understood and defined in SEC Rule 144;

               (ii)  File with the SEC in a timely manner all reports and other
documents required of the Company under the Act and the 1934 Act; and

               (iii) Furnish to Cabletron, so long as Cabletron owns any Voting
Securities, forthwith upon request (i) a written statement by Efficient that it
has complied with the reporting requirements of SEC Rule 144; (ii) a copy of the
most recent annual or quarterly report of Efficient and such other reports and
documents so filed by Efficient and (iii) such other information as may be
reasonably requested in availing Cabletron of any rule or regulation of the SEC
which permits the selling of any such securities without registration.

     3.5  Termination. The provisions of this Article 3 shall terminate (other
          -----------
than insofar they relate to general application of securities laws) upon the
later to occur of: (i) the tenth anniversary date of this Agreement and (ii)
such time as Cabletron (together with all Controlled Affiliates of Cabletron)
beneficially owns in the aggregate Voting Securities of Efficient representing
less than five percent (5%) of the Total Voting Power of Efficient or upon the
closing or other completion of a Change in Control of Efficient.

                                      -10-
<PAGE>

                                   ARTICLE 4

                              REGISTRATION RIGHTS


     4.1  Demand Registration.
          -------------------

          (a)  If at any time after July 21, 2000, Efficient shall receive from
Cabletron a written request (a "Demand Request") that Efficient register on Form
S-1 or Form S-3 under the Securities Act (or if such form is not available, any
registration statement form then available to Efficient) Registrable Securities
equal to at least 2,000,000 shares of the Voting Securities of Efficient
outstanding on the date of such Demand Request, then Efficient shall use
commercially reasonable efforts to cause the Registrable Securities specified in
such Demand Request (the "Demand Registrable Securities") to be registered as
soon as reasonably practicable so as to permit the offering and sale thereof
and, in connection therewith, shall prepare and file with the SEC as soon as
practicable, and in any event within thirty (30) days, after receipt of such
Demand Request, a registration statement (a "Demand Registration Statement") to
effect such registration; provided, however, that each such Demand Request
shall: (i) specify the number of Demand Registrable Securities intended to be
offered and sold by Cabletron pursuant thereto (which number of Demand
Registrable Securities shall not be less than 2,000,000 of the Voting Securities
of Efficient outstanding on the date of such Demand Request); (ii) express the
present intention of Cabletron to offer or cause the offering of such Demand
Registrable Securities pursuant to such Demand Registration Statement, (iii)
describe the nature or method of distribution of such Demand Registrable
Securities pursuant to such Demand Registration Statement (including, in
particular, whether Cabletron plans to effect such distribution by means of an
underwritten offering); and (iv) contain the undertaking of Cabletron to provide
all such information and materials and take all such actions as may be required
in order to permit Efficient to comply with all applicable requirements of the
Securities Act, the Exchange Act and the rules and Regulations of the SEC
thereunder, and to obtain any desired acceleration of the effective date of such
Demand Registration Statement.

          (b)  The procedures to be followed by Efficient and Cabletron, and the
respective rights and obligations of Efficient and Cabletron, with respect to
the preparation, filing and effectiveness of Demand Registration Statements and
the distribution of Demand Registrable Securities pursuant to Demand
Registration Statements under this Section 4.1 are set forth in Section 4.4
hereof.


     4.2  Shelf Registration.
          ------------------

          (a)  By July 21, 2000, Efficient shall use its commercially reasonable
efforts to register pursuant to Rule 415(a)(1)(i) under the Securities Act (or
any successor rule with similar effect) a continuous or delayed offering of
Registrable Securities (the "Shelf Registrable Securities") to be registered as
soon as reasonably practicable so as to permit the sale thereof and, in
connection therewith, shall prepare and file with the SEC a shelf registration
statement on Form S-3 relating to the Shelf Registrable Securities, if such Form
S-3 is available for use by Efficient (or any successor form of registration
statement to such Form S-3), to effect such registration (the "Shelf
Registration Statement"), to enable the distribution of the Shelf Registrable
Securities. In

                                      -11-
<PAGE>

connection with the Shelf Registration Statement, Cabletron shall undertake to
offer or cause the offering of such Shelf Registrable Securities in accordance
with the plan of distribution described in the Shelf Registration Statement
which shall include, to the extent allowable on such form, exchange transactions
or the over-the-counter market transactions; private transactions other than
exchange or over-the-counter market transactions; pledge to secure debts and
other obligations; writing of non-traded and exchange-traded call options, hedge
transactions and in settlement of other transactions in standardized or
over-the-counter options, or a combination of the above transactions; and
provide all such information and materials and take all such actions as may be
required in order to permit Efficient to comply with all applicable requirements
of the Securities Act, the Exchange Act and the rules and Regulations of the SEC
thereunder, and to obtain any desired acceleration of the effective date of the
Shelf Registration Statement.

          (b)  The aggregate number of shares sold by Cabletron pursuant to this
Section 4.2 hereof and pursuant to the resale allowances under Rule 144 may not
exceed an aggregate of 2,000,000 shares during any calendar quarter.

          (c)  The procedures to be followed by Efficient and Cabletron, and the
respective rights and obligations of Efficient and Cabletron, with respect to
the preparation, filing and effectiveness of the Shelf Registration Statement
and the distribution of Registrable Securities pursuant to the Shelf
Registration Statement under this Section 4.2 are set forth in Section 4.4
hereof.

     4.3  Piggyback Registration.
          ----------------------

          (a)  If at any time after the date of this Agreement, Efficient shall
determine to register any of its equity or equity-linked Securities, including
registration of shares in a so-called unallocated or universal shelf
registration, whether for sale for its own account or for the account of any
other Person, other than registration statements relating to (i) employee,
consultant or distributor compensation or incentive arrangements, including
employee benefit plans, or (ii) acquisitions or any transaction or transactions
under Rule 145 under the Securities Act or any successor rule with similar
effect, then Efficient will promptly give Cabletron written notice thereof and
include in such registration statement (a "Piggyback Registration Statement")
and in any underwriting involved therein, all Registrable Securities (the
"Piggyback Registrable Securities") specified in a written request made by
Cabletron (a "Piggyback Request") within five (5) business days (or such later
time as the underwriters may allow in writing) after receipt of such written
notice from Efficient.

          (b)  If the Piggyback Registration Statement of which Efficient gives
notice is for an underwritten offering or Efficient proposes to do an
underwritten take down from an unallocated or universal shelf registration,
Efficient shall so advise Cabletron as a part of the written notice given
pursuant to Section 4.3(a). In such event, the right of Cabletron to
registration pursuant to this Section 4.3 (or participate in an underwritten
take down in the case of an unallocated or universal shelf registration) shall
be conditioned upon the agreement of Cabletron to participate in such
underwriting and in the inclusion of such Piggyback Registrable Securities in
the underwriting to the extent provided herein. Cabletron shall (together with
Efficient and any other holders distributing Securities in such Piggyback
Registration Statement, if any) enter into an underwriting agreement (the
"Piggyback Underwriting Agreement") in customary form with the underwriter or
underwriters selected for such underwriting by Efficient. If Cabletron
disapproves of the terms of

                                      -12-
<PAGE>

any such underwriting, it may elect to withdraw therefrom by written notice to
Efficient and the managing underwriters. Any Piggyback Registrable Securities
excluded or excluded from such underwriting shall be excluded from such
Piggyback Registration Statement.

          (c)  Notwithstanding any other provision of this Agreement, if the
managing underwriters of any underwritten offering pursuant to a Piggyback
Request determine, in their sole discretion that, after including all the shares
proposed to be offered by Efficient and all the shares of any other Persons
entitled to registration rights with respect to such Piggyback Registration
Statement (pursuant to other agreements with Efficient), marketing factors
require a limitation of the number of Piggyback Registrable Securities to be
underwritten, Efficient may exclude Piggyback Registrable Securities (a
"Piggyback Market Cut-Back"), subject to the following:

               (i)   Cabletron shall, in any event, have the right to include in
the First Offering or an Exclusive Demand Period Offering, as the case may be, a
number of shares of Piggyback Registrable Securities equal to the Reserved
Portion, (to the exclusion of shares to be included by Efficient or any other
Person); and

               (ii)  With respect to shares in excess of the Reserve Portion in
the case of the First Offering or an Exclusive Demand Period Offering, or in
other offerings, the Piggyback Market Cut-Back shall be made among Cabletron and
the Investors pro-rata relative to the shares to be included in the offering
other than (a) any shares to be issued and sold by Efficient, or (b) any
Reserved Portion (the "Available Shares"); provided that other than in
connection with the First Offering or an Exclusive Demand Period Offering, the
Available Shares shall not be less than thirty percent (30%) of the shares to be
sold in the offering. An Investor's pro-rata portion of the Available Shares
shall be a fraction, the numerator of which is (a) the total number of shares of
Efficient common stock held by such Investor, and the denominator of which is
(b) the aggregate number of shares of common stock beneficially owned by all
Investors and the Total Consideration Shares then beneficially owned by
Cabletron (excluding the Reserved Portion). Cabletron's pro-rata portion of the
Available Shares shall be a fraction, the numerator of which is (a) the number
of Total Consideration Shares then beneficially owned by Cabletron (excluding
the Reserved Portion), and the denominator of which is (b) the aggregate number
of shares of common stock beneficially owned by all Investors and the number of
Total Consideration Shares then beneficially owned by Cabletron (excluding the
Reserved Portion).

          (d)  Except to the extent specifically provided in this Section 4.3
hereof, the procedures to be followed by Efficient and Cabletron, and the
respective rights and obligations of Efficient and Cabletron, with respect to
the distribution of any Piggyback Registrable Securities by Cabletron pursuant
to any Piggyback Registration Statement filed by Efficient shall be as set forth
in the Piggyback Underwriting Agreement, or any other agreement or agreements
governing the distribution of such Piggyback Registrable Securities pursuant to
such Piggyback Registration Statement.

          (e)  Notwithstanding the foregoing, however, nothing in this Section
4.3, or any other provision of this Agreement, shall be construed to limit the
absolute right of Efficient, for any reason and in its sole discretion: (i) to
delay, suspend or terminate the filing of any Piggyback Registration Statement;
(ii) to delay the effectiveness of any Piggyback Registration Statement; (iii)
reduce the number of securities to be distributed pursuant to any Piggyback
Registration

                                      -13-
<PAGE>

Statement (except below the 3,000,000 share minimum of the Reserve Portion in
either (a) an Exclusive Demand Period Offering or (b) if the First Offering has
not met the Criteria, then the First Offering, as the case may be); or (iv) to
withdraw such Piggyback Registration Statement.

     4.4  Demand and Shelf Registration Procedures, Rights and Obligations. The
          ----------------------------------------------------------------
procedures to be followed by Efficient and Cabletron, and the respective rights
and obligations of Efficient and Cabletron, with respect to the preparation,
filing and effectiveness of Demand Registration Statements and the Shelf
Registration Statement, respectively, and the distribution of Demand Registrable
Securities and Registrable Securities, respectively, pursuant thereto, are as
follows:

               (i)   Cabletron shall not be entitled to make a Demand Request
until expiration of the Demand Breathing Period, and shall not be entitled to
make more than two (2) Demand Requests; provided, however, that any Demand
Request that: (A) does not result in the corresponding Demand Registration
Statement being declared effective by the SEC; (B) is withdrawn by Cabletron
following the imposition of an order by the SEC with respect to the
corresponding Demand Registration Statement; (C) is withdrawn by Cabletron as a
result of the exercise by Efficient of its suspension rights pursuant to
Sections 4.4(e) or (f) hereof; (D) is withdrawn by Cabletron as a result of a
Demand Market Cut-Back in violation of Section 4.4(d)(i) below, (E) is withdrawn
if Cabletron shall have learned of a material adverse change in the condition,
business or prospects of Efficient different than that known to Cabletron at the
time of Cabletron shall have initiated the Demand Request (other than a decline
in Efficient's stock price since such time unless, however, Cabletron agrees to
pay, or otherwise reimburse Efficient, for all Registration Expenses) that makes
the proposed offering unreasonable in the good faith judgment of Cabletron; or
(F) is withdrawn because the terms of the underwriting agreement, as
contemplated by Section 4.4(c) below, are not reasonably customary, such Demand
Request in the event of any of (A) through (F) shall not count as one of the two
(2) Demand Requests. Any Demand Request that is withdrawn by Cabletron for any
reason other than as set forth in the previous sentence shall count as a Demand
Request.

          (b)  Efficient shall use commercially reasonable efforts to cause each
Demand Registration Statement and the Shelf Registration Statement to be
declared effective promptly and to keep such Demand Registration Statement and
the Shelf Registration Statement continuously effective until the earlier to
occur of: (i) the sale or other disposition of the Registrable Securities so
registered; (ii) in the case of Demand Registration Statements, one hundred
twenty (120) days after the effective date of any such Demand Registration
Statement; (iii) in the case of the Shelf Registration Statement, until
September 30, 2002; and (iv) the termination of Cabletron's registration rights
pursuant to Section 4.10 hereof. Efficient shall prepare and file with the SEC
such amendments and supplements to each Demand Registration Statement and the
Shelf Registration Statement and each prospectus used in connection therewith as
may be necessary to make and to keep such Demand Registration Statement and the
Shelf Registration Statement effective and to comply with the provisions of the
Securities Act with respect to the sale or other disposition of all Registrable
Securities proposed to be distributed pursuant to such Demand Registration
Statement and the Shelf Registration Statement until the earlier to occur of:
(i) the sale or other disposition of such Registrable Securities so registered;
(ii) in the case of Demand Registration Statements, one hundred twenty (120)
days after the effective date of any such Demand Registration Statement; (iii)
in the case of the Shelf Registration Statement, until September 30, 2002; and
(iv) the termination of Cabletron's registration rights pursuant to Section 4.10
hereof.

                                      -14-
<PAGE>

          (c)  In connection with any underwritten offering pursuant to a Demand
Registration Statement or the Shelf Registration Statement, Efficient shall
select and Cabletron shall approve, which approval shall not be unreasonably
withheld, one investment banking firm to serve as manager of such offering. The
manager is hereinafter referred to as the "Demand Managing Underwriter."
Efficient shall, together with Cabletron, enter into an underwriting agreement
with the Demand Managing Underwriter, which agreement shall contain
representations, warranties, indemnities and agreements then customarily
included by an issuer in underwriting agreements with respect to secondary
distributions under demand registration statements or shelf registration
statements, as the case may be, and shall stipulate that the Demand Managing
Underwriter will receive commissions and fees and other remuneration in
connection with the distribution of any Demand Registrable Securities or
Registrable Securities thereunder.

          (d)  Notwithstanding any other provision of this Agreement, the number
of shares proposed to be distributed by Cabletron pursuant to any underwritten
offering may be limited by and at the discretion of the Demand Managing
Underwriter (a "Demand Market Cut-Back"), subject to the following:

               (i)  The number of shares to be distributed by Cabletron may not
be limited to less than the greater of (x) 50% of the total number of shares
proposed to be distributed in the offering, (y) 4,000,000 shares, or (z) the
total number of shares proposed to be offered if such total proposed offering
size is less than 4,000,000 shares (the "Minimum Demand Portion"); and

               (ii) With respect to shares in excess of the Minimum Demand
Portion, the Demand Market Cut-Back shall be made among Cabletron and the
Investors pro-rata relative to the shares to be included in the offering other
than (a) any shares to be issued and sold by Efficient or (b) any Minimum Demand
Portion (the "Remaining Shares"). An Investor's pro-rata portion shall be a
fraction, the numerator of which is (a) the total number of shares of Efficient
Common Stock held by such Investor, and the denominator of which is (b) the
aggregate number of shares of common stock beneficially owned by all Investors
and the Total Consideration Shares then beneficially owned by Cabletron
(excluding the Minimum Demand Portion). Cabletron's pro-rata portion of the
Remaining Shares shall be a fraction, the numerator of which is (a) the Total
Consideration Shares then beneficially owned by Cabletron (excluding the Minimum
Demand Portion) and the denominator of which is (b) the aggregate number of
shares of common stock beneficially owned by all Investors and the Total
Consideration Shares then beneficially owned by Cabletron (excluding the Minimum
Demand Portion).

          (e)  Notwithstanding any other provisions of this Agreement, in the
event that Efficient receives a Demand Request, or Cabletron proposes an
underwritten offering utilizing the Shelf Registration Statement at a time when
Efficient (i) shall have filed, or has a bona fide intention to file, a
registration statement with respect to a proposed public offering of equity or
equity-linked Securities or (ii) has commenced, or has a bona fide intention to
commence, a public offering of equity or equity-linked Securities pursuant to an
existing effective shelf or other registration statement, then Efficient shall
be entitled to suspend, for a period of up to ninety (90) days after the receipt
by Efficient of such Demand Request or Cabletron proposal, the filing of any
Demand Registration Statement or the implementation of such proposal under the
Shelf Registration Statement; provided that if Efficient does not file and make
effective a primary registration statement with respect to such offering within
such 90 day period, Cabletron shall have a period of at least 90

                                      -15-
<PAGE>

consecutive days during the twelve (12) month period commencing with the
expiration of such 90 day period to effect a Cabletron Demand Request without
preemption or suspension.

          (f)  Notwithstanding any other provision of this Agreement, in the
event that Efficient determines that: (i) non-public material information
regarding Efficient exists, the immediate disclosure of which would be
significantly disadvantageous to Efficient; (ii) the prospectus constituting a
part of any Demand Registration Statement or the Shelf Registration Statement
covering the distribution of any Demand Registrable Securities or Registrable
Securities contains an untrue statement of a material fact or omits to state a
material fact required to be stated therein or necessary to make the statements
therein, in the light of the circumstances under which they were made, not
misleading; or (iii) an offering of Demand Registrable Securities or Registrable
Securities would materially interfere with any proposed material acquisition,
disposition or other similar corporate transaction or event involving Efficient
(each of the events or conditions referred to in clauses (i), (ii) and (iii) of
this sentence is hereinafter referred to as a "Suspension Condition"), then
Efficient shall have the right to suspend the filing or effectiveness of any
Demand Registration Statement or to suspend any distribution of Demand
Registrable Securities or Registrable Securities pursuant to any effective
Demand Registration Statement or the Shelf Registration Statement for so long as
such Suspension Condition exists; provided that Efficient shall have suspended
the filing or effectiveness of all other registration statements registering
securities for the account of Efficient or any other Person or suspended the
distribution of any securities under such registration statements and; provided
further, that in the case of (ii) above, Efficient shall be obligated to use
best efforts to amend such registration statement to correct such material
misstatement or omission in the Registration Statement and related prospectus.
Efficient will as promptly as practicable provide written notice to Cabletron
when a Suspension Condition arises and when it ceases to exist. Upon receipt of
notice from Efficient of the existence of any Suspension Condition, Cabletron
shall forthwith discontinue efforts to: (i) file or cause any Demand
Registration Statement or the Shelf Registration Statement to be declared
effective by the SEC (in the event that such Demand Registration Statement or
the Shelf Registration Statement has not been filed, or has been filed but not
declared effective, at the time Cabletron receives notice that a Suspension
Condition has arisen); or (ii) offer or sell Demand Registrable Securities or
Registrable Securities (in the event that such Demand Registration Statement or
the Shelf Registration Statement has been declared effective at the time
Cabletron receives notice that a Suspension Condition has arisen). In the event
that Cabletron had previously commenced or was about to commence the
distribution of Demand Registrable Securities or Registrable Securities pursuant
to a prospectus under an effective Demand Registration Statement or the Shelf
Registration Statement, then Efficient shall, as promptly as practicable after
the Suspension Condition ceases to exist, make available to Cabletron (and to
each underwriter, if any, participating in such distribution) an amendment or
supplement to such prospectus. If so directed by Efficient, Cabletron shall
deliver to Efficient all copies, other than permanent file copies then in
Cabletron's possession, of the most recent prospectus covering such Demand
Registrable Securities or Registrable Securities at the time of receipt of such
notice.

          (g)  Notwithstanding any other provision of this Agreement, Efficient
shall not be permitted to postpone (i) the filing or effectiveness of any Demand
Registration Statement or the Shelf Registration Statement or (ii) the
distribution of any Demand Registrable Securities or Registrable Securities
pursuant to an effective Demand Registration Statement or the Shelf Registration
Statement pursuant to Sections 4.4(e) or 4.4(f) hereof more than four (4) times
in any 360 day period provided that the aggregate of such suspensions may not
exceed a total of sixty (60)

                                      -16-
<PAGE>

days in any 360 day period (excluding any market standoff periods applicable to
Cabletron pursuant to Section 4.9(a) hereof).

          (h)  Efficient shall promptly notify Cabletron of any stop order
issued or, to Efficient's knowledge, threatened, to be issued by the SEC with
respect to any Demand Registration Statement or the Shelf Registration
Statement, and will use its best efforts to prevent the entry of such stop order
or to remove it if entered at the earliest possible date.

          (i)  Efficient shall furnish to Cabletron (and any underwriter in
connection with any underwritten offering) such number of copies of any
prospectus (including any preliminary prospectus and any amended or supplemented
prospectus), in conformity with the requirements of the Securities Act, as
Cabletron (and such underwriters) shall reasonably request in order to effect
the offering and sale of any Demand Registrable Securities or the Registrable
Securities to be offered and sold, but only while Efficient shall be required
under the provisions hereof to cause the Demand Registration Statement or the
Shelf Registration Statement pursuant to which such Demand Registrable
Securities or Registrable Securities are intended to be distributed to remain
current.

          (j)  Efficient shall use commercially reasonable efforts to register
or qualify the Demand Registrable Securities and Registrable Securities covered
by each Demand Registration Statement and the Shelf Registration Statement,
respectively, under the state Securities or "blue sky" laws of such states as
Cabletron shall reasonably request, maintain any such registration or
qualification current, until the earlier to occur of: (i) the sale of such
Demand Registrable Securities or Registrable Securities so registered; (ii) in
the case of Demand Registration Statements, one hundred twenty (120) days after
the effective date of any such Demand Registration Statement; (iii) in the case
of the Shelf Registration Statement, until September 30, 2002; and (iv) the
termination of Cabletron's registration rights pursuant to Section 4.10 hereof;
provided, however, that Efficient shall not be required to take any action that
would subject it to the general jurisdiction of the courts of any jurisdiction
in which it is not so subject or to qualify as a foreign corporation in any
jurisdiction where Efficient is not so qualified.

          (k)  Efficient shall furnish to Cabletron and to each underwriter
engaged in an underwritten offering of Demand Registrable Securities or
Registrable Securities, a signed counterpart, addressed to Cabletron or such
underwriter, of (i) an opinion or opinions of counsel to Efficient (with respect
to Efficient and Securities law compliance by Efficient) and (ii) a comfort
letter or comfort letters from Efficient's independent public accountants, each
in customary form and covering such matters of the type customarily covered by
opinions or comfort letters, as the case may be, as Cabletron or the managing
underwriters may reasonably request.

          (l)  Efficient shall use commercially reasonable efforts to make
appropriate members of its management reasonably available for due diligence
purposes, "road show" presentations and analyst presentations in connection with
any distributions of Demand Registrable Securities pursuant to a Demand
Registration Statement.

          (m)  Efficient shall use commercially reasonable efforts to cause all
Demand Registrable Securities and Registrable Securities to be listed on each
Securities exchange on which similar Securities of Efficient are then listed,
or, if Efficient does not have a class of equity securities listed on a national
securities exchange, apply for qualification and use commercially reasonable

                                      -17-
<PAGE>

efforts to qualify the Demand Registrable Securities and Registrable Securities
being registered for inclusion on the Nasdaq Stock Market.

          (n)  Efficient shall take all such other actions either reasonably
necessary or desirable to permit the Registrable Securities held by Cabletron to
be registered and disposed of in accordance with the methods of disposition
described herein.

     4.5  Expenses. Subject to Section 4.6, Cabletron, Efficient and any other
          --------
Person whose securities are included in any registration statements that are
initiated pursuant to Sections 4.1, 4.2 or 4.3 of this Agreement shall pay their
respective Selling Expenses, and, in the case of Sections 4.1 and 4.2, shall pay
the proportion of all Registration Expenses incurred in connection with any such
registration that the aggregate number of securities included in such
registration on behalf of such Cabletron or such Person bears to the aggregate
of number of all securities included in such registration. Efficient shall pay
all Registration Expenses incurred in connection with any registration statement
that is initiated pursuant to Section 4.3 of this Agreement.

     4.6  Indemnification.
          ---------------

          (a)  In the case of any offering registered pursuant to this Section
4, Efficient hereby indemnifies and agrees to hold harmless Cabletron (and its
officers and directors), any underwriter (as defined in the Securities Act) of
Registrable Securities offered by Cabletron, and each Person, if any, who
controls Cabletron or any such underwriter within the meaning of Section 15 of
the Securities Act against any losses, claims, damages or liabilities, joint or
several, to which any such Persons may be subject, under the Securities Act or
otherwise, and to reimburse any of such Persons for any legal or other expenses
reasonably incurred by them in connection with investigating any claims or
defending against any actions, insofar as such losses, claims, damages or
liabilities arise out of or are based upon any untrue statement or alleged
untrue statement of a material fact contained in the registration statement
under which such Registrable Securities were registered under the Securities Act
pursuant to this Section 4, the prospectus contained therein (during the period
that Efficient is required to keep such prospectus current), or any amendment or
supplement thereto, or the omission or alleged omission to state therein (if so
used) a material fact required to be stated therein or necessary to make the
statements therein, in the light of the circumstances in which they were made,
not misleading, except insofar as such losses, claims, damages or liabilities
arise out of or are (i) based upon any such untrue statement or omission or
alleged untrue statement or omission made in reliance upon information furnished
to Efficient in writing by Cabletron or any underwriter for Cabletron
specifically for use therein, or (ii) made in any preliminary prospectus, and
the prospectus contained in the registration statement as declared effective or
in the form filed by Efficient with the SEC pursuant to Rule 424 under the
Securities Act shall have corrected such statement or omission and a copy of
such prospectus shall not have been sent or otherwise delivered to such Person
at or prior to the confirmation of such sale to such Person.

          (b)  By requesting registration under this Section 4, Cabletron
agrees, if Registrable Securities held by Cabletron are included in the
Securities as to which such registration is being effected, and each underwriter
shall agree, in the same manner and to the same extent as set forth in the
preceding paragraph, to indemnify and to hold harmless Efficient and its
directors and officers and each Person, if any, who controls Efficient within
the meaning of the Securities Act against any losses, claims, damages or
liabilities, joint or several, to which any of such Persons may

                                      -18-
<PAGE>

be subject under the Securities Act or otherwise, and to reimburse any of such
Persons for any legal or other expenses incurred in connection with
investigating or defending against any such losses, claims, damages or
liabilities, but only to the extent it arises out of or is based upon an untrue
statement or alleged untrue statement or omission or alleged omission of a
material fact in any registration statement under which the Registrable
Securities were registered under the Securities Act pursuant to this Section 4,
any prospectus contained therein, or any amendment or supplement thereto, which
was based upon and made in conformity with information furnished to Efficient in
writing by Cabletron or such underwriter expressly for use therein.

          (c)  Each party entitled to indemnification under this Section 4.6
(the "Indemnified Party") shall give notice to the party required to provide
indemnification (the "Indemnifying Party") promptly after such Indemnified Party
has actual knowledge of any claim as to which indemnity may be sought, and shall
permit the Indemnifying Party to assume the defense of any such claim or any
litigation resulting therefrom, provided that counsel for the Indemnifying
Party, who shall conduct the defense of such claim or litigation, shall be
approved by the Indemnified Party (whose approval shall not be unreasonably
withheld), and the Indemnified Party may participate in such defense at its own
expense, and provided further that the failure of any Indemnified Party to give
notice as provided herein shall not relieve the Indemnifying Party of its
obligations under this Section 4 unless such failure resulted in actual
detriment to the Indemnifying Party. No Indemnifying Party, (i) in the defense
of any such claim or litigation, shall, except with the consent of each
Indemnified Party, which consent shall not be unreasonably withheld, consent to
entry of any judgment or enter into any settlement which does not include as an
unconditional term thereof the giving by the claimant or plaintiff to such
Indemnified Party of a release from all liability in respect to such claim or
litigation, or (ii) shall be liable for amounts paid in any settlement if such
settlement is effected without the consent of the Indemnifying Party, which
consent shall not be unreasonably withheld.

     4.7  Issuances by Efficient or Other Holders. As to each registration or
          ---------------------------------------
distribution referred to in Section 4.1, additional shares of the Common Stock
to be sold for the account of Efficient or the Investors may be included
therein, provided that the inclusion of such Securities in such registration or
distribution shall be subject to and governed by the provisions of Sections
4.3(c) and 4.4(d).

     4.8  Information by Cabletron. Cabletron shall furnish to Efficient such
          ------------------------
information regarding Cabletron in the distribution of Registrable Securities
proposed by Cabletron as Efficient may reasonably request in writing and as
shall be required in connection with any registration, qualification or
compliance referred to in this Article 4.

     4.9  Market Standoff Agreements. In connection with the underwritten public
          --------------------------
offering by Efficient of at least 1,000,000 shares for its own account or
$50,000,000, whichever is lesser, Cabletron agrees that, upon the request of
Efficient or the underwriters managing any underwritten offering of Efficient's
Securities, Cabletron shall agree in writing (the "Cabletron Public Offering
Lock-Up") that neither Cabletron (nor any director, executive officer or
Controlled Affiliate of Cabletron) will, directly or indirectly, offer to sell,
contract to sell, make any short sale of, or otherwise sell, dispose of, loan,
gift, pledge or grant any options or rights with respect to, any Securities of
Efficient (other than those included in such registration statement, if any) now
or hereafter acquired by Cabletron (or any director, executive officer or
Controlled Affiliate of

                                      -19-
<PAGE>

Cabletron) or with respect to which Cabletron (or any director, executive
officer or Controlled Affiliate of Cabletron) has or hereafter acquires the
power of disposition without the prior written consent of Efficient and such
underwriters for such period of time (not to exceed fourteen (14) days prior to
the date such offering is expected to commence and ninety (90) days after the
date of the final prospectus delivered to the underwriters for use in confirming
sales in such offering) as may be requested by Efficient and the underwriters
provided that (i) the directors, executive officers (ii) all holders of more
than five percent (5%) of Efficient's Voting Securities which are an "affiliate"
of Efficient for purposes of the accounting rules governing pooling of interest
transactions and (iii) any Investor or other Person participating in such
offering enter into a public offering lock-up containing the same terms as the
Cabletron Public Offering Lock-Up; provided, however, that neither Cabletron
(nor any director, executive officer or Controlled Affiliate of Cabletron) shall
be bound by such Cabletron Public Offering Lock-Up more than once during any
twelve month period. Furthermore, Cabletron agrees that, at the request of
Efficient, Cabletron shall agree in writing (the "Cabletron Pooling Transaction
Lock-Up") that neither Cabletron (nor any director, executive officer or
Controlled Affiliate of Cabletron) shall, directly or indirectly, offer to sell,
contract to sell, make any short sale of, or otherwise sell, dispose of, loan,
pledge or grant any options or rights with respect to, any Securities of
Efficient now or hereafter acquired directly by Cabletron (or any director,
executive officer or Controlled Affiliate of Cabletron) or with respect to which
Cabletron (or any director, executive officer or Controlled Affiliate of
Cabletron) has or hereafter acquires the power of disposition without the prior
written consent of Efficient for such period of time as shall be necessary for
Efficient to complete any business combination transaction in the form of a
pooling of interests; provided that Efficient's independent accountants shall
have reasonably concluded, after reasonable inquiry, that, at the relevant time
with respect to such proposed pooling of interests transaction, Cabletron is or
was an "affiliate" of Efficient for purposes of the accounting rules governing
pooling of interests transactions. Cabletron agrees that Efficient may instruct
its transfer agent to place stop-transfer notations in its records to enforce
the provisions of the Cabletron Public Offering Lock-Up and the Cabletron
Pooling Transaction Lock-Up contained in this Section 4.9(a).

     4.10 Additional Registration Rights Covenants.
          ----------------------------------------

          (a)  First Offering. Efficient shall use its commercially reasonable
               --------------
efforts to conduct and close the First Offering as promptly as is practicable
after the date hereof with a target date for completion of such First Offering
of no later than March 31, 2000; provided, however, Efficient shall have no
obligation to so conduct and close such First Offering if the Efficient Board of
Directors concludes in good faith that so doing would be materially detrimental
to Efficient or its shareholders.

          (b)  Exclusive Demand Period. Without Cabletron's consent, during the
               -----------------------
Exclusive Demand Period and any other period during which Cabletron is
prohibited from effecting a Demand Registration or distributing securities under
the Shelf Registration Statement, Efficient will not file or cause or allow to
become effective a registration statement pursuant to Section 1.2 of the
Investors' Rights Agreement.

     4.11 Termination. The provisions of this Article 4 shall terminate upon the
          -----------
earlier to occur of: (i) five years after the date of the closing of
transactions contemplated by the Merger Agreement; and (ii) such time as
Cabletron and any Affiliates of Cabletron beneficially own, in the aggregate,
less than 5% of the Total Voting Power of Efficient.

                                      -20-
<PAGE>

                                   ARTICLE 5

                                 MISCELLANEOUS

     5.1  Governing Law. This Agreement shall be governed in all respects by the
          -------------
laws of the State of Delaware as applied to contracts entered into solely
between residents of, and to be performed entirely within, such state.

     5.2  Successors and Assigns. This Agreement shall be binding upon and shall
          ----------------------
inure to the benefit of the parties hereto and their respective successors and
assigns. This Agreement may not be assigned by a party without the prior written
consent of the other party; provided that, without the consent of Efficient,
Cabletron may assign this Agreement (and the rights and obligations hereunder)
to any wholly-owned subsidiary in connection with a transfer of Voting
Securities of Efficient to such Affiliate of Cabletron pursuant to Section
3.1(b), and without the consent of Cabletron, Efficient may assign all or part
of this Agreement (and the rights and obligations hereunder) to the successor or
an assignee of all or substantially all of Efficient's business; provided that,
in each case, such assignee expressly assumes the relevant obligations of this
Agreement (by a written instrument delivered to the other party, in form and
substance reasonably acceptable to it) and, notwithstanding such assignment, the
parties hereto shall each continue to be bound by all of their respective
obligations hereunder. This Agreement is not intended and shall not be construed
to create any rights or remedies in any parties other than Cabletron and
Efficient and no Person shall assert any rights as third party beneficiary
hereunder.

     5.3  Entire Agreement; Amendment. This Agreement contains the entire
          ---------------------------
understanding and agreement between the parties with regard to the subject
matter hereof and thereof and supersedes all prior agreements and understandings
among the parties relating to the subject matter hereof. Neither this Agreement
nor any term hereof may be amended, waived, discharged or terminated other than
by a written instrument signed by the party against whom enforcement of any such
amendment, waiver, discharge or termination is sought.

     5.4  Notices and Dates.
          -----------------

          (a)  All notices, requests, demands, and other communications under
this Agreement shall be in writing and shall be delivered personally (including
by courier) or given by facsimile transmission to the parties at the following
addresses (or to such other address as a party may have specified by notice
given to the other pursuant to this provision) and shall be deemed given when so
received:

                                      -21-
<PAGE>

               (i)  if to Efficient, to:
                    Efficient Networks, Inc.
                    4201 Spring Valley Road, Suite 1200
                    Dallas, Texas 75244
                    Attention: Jill Manning, CFO
                    Telephone: 972-991-3884
                    Facsimile: 972-991-3887

                    with a copy to:

                    Wilson Sonsini Goodrich & Rosati
                    650 Page Mill Road
                    Palo Alto, California 94304
                    Attention: Kenneth Siegel, Esq.
                    Telephone: (650) 493-9300
                    Facsimile: (650) 493-6811

                    if to Cabletron, to:
                    Cabletron Systems Inc.
                    35 Industrial Way
                    Rochester, NH 03867
                    Attention: General Counsel
                    Telephone: 630-332-9400
                    Facsimile:

                    with a copy to:

                    Ropes & Gray
                    One International Place
                    Boston, MA 02110
                    Attention: David A. Fine, Esq.
                    Telephone No.: (617) 951-7000
                    Telecopy No.: (617) 951-7050

All such notices, requests and other communications shall be deemed received on
the date of receipt by the recipient thereof if received prior to 5 p.m. in the
place of receipt and such day is a business day in the place of receipt.
Otherwise, any such notice, request or communication shall be deemed not to have
been received until the next succeeding business day in the place of receipt.

          (b)  In the event that any date provided for in this Agreement falls
on a Saturday, Sunday or legal holiday, such date shall be deemed extended to
the next business day.

     5.5  Language Interpretation. In the interpretation of this Agreement,
          -----------------------
unless the context otherwise requires, (a) words importing the singular shall be
deemed to import the plural and vice versa, (b) words denoting gender shall
include all genders, (c) references to persons shall include corporations or
other entities and vice versa, and (d) references to parties, Sections,
schedules, paragraphs and exhibits shall mean the parties, Sections, schedules,
paragraphs and exhibits of and to this Agreement, unless otherwise indicated by
the context.

                                      -22-
<PAGE>

     5.6  Table of Contents; Titles; Headings. The table of contents and
          -----------------------------------
Section headings of this Agreement are for reference purposes only and are to be
given no effect in the construction or interpretation of this Agreement. All
references herein to Articles and Sections, unless otherwise identified, are to
Articles and Sections of this Agreement.

     5.7  Counterparts. This Agreement may be executed in one or more
          ------------
counterparts, all of which shall be considered one and the same agreement, and
shall become a binding agreement when one or more counterparts have been signed
by each party and delivered to the other party.

     5.8  Severability. If any provision of this Agreement or portion thereof is
          ------------
held by a court of competent jurisdiction to be invalid, void or unenforceable,
the remainder of the terms, provisions, covenants and restrictions of this
Agreement shall remain in full force and effect and shall in no way be affected,
impaired or invalidated.

     5.9  Injunctive Relief. Cabletron, on the one hand, and Efficient, on the
          -----------------
other, acknowledge and agree that irreparable damage would occur in the event
that any of the provisions of this Agreement were not performed in accordance
with their specific terms or were otherwise breached. It is accordingly agreed
that the parties shall be entitled to an injunction or injunctions to prevent or
cure breaches of the provisions of this Agreement and to enforce specific
performance of the terms and provisions hereof in any court of the United States
or any state thereof having jurisdiction, this being in addition to any other
remedy to which they may be entitled at law or equity.

     5.10 Automatic Adjustments to Share Numbers. All numbers regarding the
          --------------------------------------
number of shares of Efficient (e.g., 2,000,000) shall be appropriately and
automatically adjusted to take into account any stock splits occurring after the
date hereof.


                           [Signature page follows]

                                      -23-
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed by their respective authorized officers as of the date set forth in the
introduction to this Agreement.

EFFICIENT NETWORKS, INC.,                 CABLETRON SYSTEMS, INC.,
a Delaware corporation                    a Delaware corporation

        /s/ JILL MANNING                          /s/ PIYUSH PATEL
By:    _______________________________    By:    _______________________________

        Jill Manning                              Piyush Patel
Name:  _______________________________    Name:  _______________________________

        Chief Financial Officer                   President
Title: _______________________________    Title: _______________________________

<PAGE>

                                                                   EXHIBIT 10.25


================================================================================


                            CROSS LICENSE AGREEMENT

                                by and between

                           Efficient Networks, Inc.

                                      and

                            Cabletron Systems, Inc.


================================================================================
<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            Page
                                                                            ----
<S>                                                                         <C>
1.   CONSTRUCTION AND DEFINITIONS.........................................   1

     1.1  Definitions.....................................................   1
     1.2  Construction....................................................   3

2.  LICENSE GRANTS........................................................   3

     2.1  License to Efficient............................................   3
     2.2  License to Cabletron............................................   3
     2.3  Reservation of Rights...........................................   4
     2.4  Delivery and Assistance.........................................   4
     2.5  Further Assurances..............................................   4

3.  CONFIDENTIAL INFORMATION..............................................   4

     3.1  Confidential Information........................................   4
     3.2  Confidential Information Exclusions.............................   4
     3.3  Confidentiality Obligation......................................   5
     3.4  Confidentiality of Cross License Agreement......................   5
     3.5  No Confidential Information of Other Parties....................   5
     3.6  Required Disclosure.............................................   5

4.  REPRESENTATIONS AND WARRANTIES........................................   6

     4.1  Efficient Warranties............................................   6
     4.2  Cabletron Warranties............................................   6
     4.3  Warranty Disclaimers............................................   6

5.  LIMITATIONS OF LIABILITY..............................................   6

     5.1  Exclusion of Damages............................................   6
     5.2  Failure of Essential Purpose....................................   7

6.  GENERAL...............................................................   7

     6.1  Term............................................................   7
     6.2  Notices.........................................................   7
     6.3  Amendments and Waivers..........................................   8
     6.4  Successors and Assigns..........................................   8
     6.5  Governing Law/Dispute Resolution................................   8
     6.6  Counterparts; Third Party Beneficiaries.........................   8
     6.7  Entire Agreement; Severability..................................   8
     6.8  Captions........................................................   9
     6.9  Representation by Counsel; Interpretation.......................   9
     6.10 Injunctive Relief...............................................   9
</TABLE>
<PAGE>

Exhibits:
- ---------

Exhibit A - Efficient Licensed Technology

Exhibit B - Cabletron Licensed Technology

                                     -ii-
<PAGE>

                            CROSS LICENSE AGREEMENT

     This Cross License Agreement (this "Cross License Agreement" or
                                         -----------------------
"Agreement") is made and entered into by and between Efficient Networks, Inc., a
 ---------
Delaware corporation with its principal place of business at 4201 Spring Valley
Road, Suite 1200, Dallas, Texas, U.S.A., and its Affiliates (collectively,
"Efficient") and Cabletron Systems, Inc., a Delaware corporation, with its
 ---------
principle place of business at 35 Industrial Way, Rochester, New Hampshire,
U.S.A., and its Affiliates (collectively, "Cabletron"), (each, a "Party";
                                           ---------              -----
together, the "Parties"), and effective as of the closing of the merger
               -------
contemplated by the Agreement and Plan of Reorganization (the "Merger
                                                               ------
Agreement") dated November 21, 1999, as amended, among Efficient, Cabletron,
- ---------
Flowpoint Acquisition Corporation, a California corporation and a wholly-owned
subsidiary of Efficient, and Flowpoint Corporation, a California corporation and
a wholly-owned subsidiary of Cabletron ("Flowpoint") (such date referred to
                                         ---------
herein as the "Effective Date").
               --------------

                                    RECITAL
                                    -------

     WHEREAS, in connection with the merger transaction contemplated in the
Merger Agreement, each Party desires to obtain from the other Party a license to
certain technology and intellectual property rights that shall be licensable by
the other Party as of the close of such merger transaction, on the terms and
conditions set forth herein.

     NOW, THEREFORE, in consideration of the foregoing and of the mutual
promises contained in this Cross License Agreement, the Parties hereby agree as
follows:

     1.   CONSTRUCTION AND DEFINITIONS

          1.1  Definitions.   The following capitalized terms have the meanings
               -----------
set forth below:

               (a)  "Affiliate" means any entity which controls, is controlled
                     ---------
by or is under common control with another entity. For purposes of this
definition, "control" shall mean beneficial ownership of more than fifty percent
(50%) of the shares of the subject entity entitled to vote in the election of
directors (or, in the case of an entity that is not a corporation, for the
election of the corresponding managing authority).

               (b)  "Derivative Work" has the meaning ascribed to it under the
                     ---------------
United States Copyright Law, Title 17 U.S.C. Sec. 101 et. seq., as the same may
be amended from time to time.

               (c)  "Improvement" means any adaptation, improvement, upgrade,
                     -----------
update, enhancement, new version, bug-fix, patch, extension, Derivative Work, or
add-on of or to any Technology. Without limiting the foregoing, any invention
(whether patented or not) that would infringe another patented invention will be
considered an "Improvement" to such first patented invention.
<PAGE>

               (d)  "Intellectual Property Rights" means any or all of the
                     ----------------------------
following, in any and all jurisdictions throughout the world, and all rights in,
arising out of, or associated with: (i) all patents and applications therefor,
including provisional applications, and all reissues, divisionals, renewals,
extensions, continuations and continuations-in-part thereof ("Patents"); (ii)
                                                              -------
all rights (other than Patents) in inventions (whether patentable or not),
invention disclosures, trade secrets, proprietary information, know-how,
technology and technical data ("Trade Secrets"); (iii) all copyrights, copyright
                                -------------
registrations and applications therefor and all other rights corresponding
thereto ("Copyrights"); (iv) all mask works, mask work registrations and
          ----------
applications therefor; (v) all industrial designs and any registrations and
applications therefor; (vi) any other rights in databases and data collections;
(vii) any other rights in computer software including all source code, object
code, firmware, development tools, files, records and data, and all media on
which any of the foregoing is recorded; (viii) all know-how and show-how,
whether or not protectible by Patents, Copyrights or Trade Secrets; and (ix) any
similar, corresponding or equivalent rights to any of the foregoing and any
other intellectual property or proprietary rights, whether or not registrable;
provided that all of the foregoing shall expressly exclude any and all
                                                   -------
trademarks, trade names, logos and service marks and any similar indications of
origin or branding.

               (e)  "Technology" means all technology, including all know-how,
                     ----------
show-how, techniques, design rules, inventions (whether or not patented or
patentable), ideas, concepts, methods, algorithms, routines, software, files,
databases, works of authorship, processes, prototypes, devices and hardware, and
including all Intellectual Property Rights therein or thereto.

               (f)  "Efficient Licensed Technology" means all Technology set
                     -----------------------------
forth in Exhibit A and any Improvements to such Technology owned by, or
developed and licensable by Flowpoint within one (1) year after the Effective
Date.

               (g)  "Cabletron Licensed Technology" means all Technology set
                     -----------------------------
forth in Exhibit B and any Improvements to such Technology owned by, or
otherwise developed and licensable by Cabletron within one (1) year after the
Effective Date.

               (h)  "CPE" means customer premises equipment; i.e., equipment
                     ---
residing at the site of an end user of a communications network, rather than at
the central office, headend or other central distribution point.

               (i)  "Cable Modem" means CPE computer peripheral devices for
                     -----------
bidirectional data communications with the headend of a cable television
distribution network, over the coaxial or HFC (hybrid fiber-coax) cables of the
cable television distribution network, including cable modem routers.

               (j)  "DSL" means digital subscriber line, a technology for
                     ---
delivering digital data over twisted-pair copper wire telephone lines. For
purposes of this Agreement, "DSL" shall include ADSL, CDSL, DSL Lite, HDSL,
IDSL, RADSL, SDSL, UDSL, VDSL and ISDN.

                                      -2-
<PAGE>

               (k)  "Efficient Field of Use" means all CPE products, software,
                     ----------------------
services and applications.

               (l)  "Cabletron Field of Use" means all Cable Modem products,
                     ----------------------
software, services and applications.

          1.2  Construction.
               ------------

               (a)  For purposes of this Cross License Agreement, whenever the
context requires: the singular number will include the plural, and vice versa;
the masculine gender will include the feminine and neuter genders; the feminine
gender will include the masculine and neuter genders; and the neuter gender will
include the masculine and feminine genders.

               (b)  The Parties hereto agree that any rule of construction to
the effect that ambiguities are to be resolved against the drafting Party will
not be applied in the construction or interpretation of this Cross License
Agreement.

               (c)  As used in this Cross License Agreement, the words "include"
and "including," and variations thereof, will not be deemed to be terms of
limitation, but rather will be deemed to be followed by the words "without
limitation."

               (d)  Except as otherwise indicated, all references in this Cross
License Agreement to "Sections" and "Schedules" are intended to refer to
Sections of this Cross License Agreement and Schedules to this Cross License
Agreement.

               (e)  The headings in this Cross License Agreement are for
convenience of reference only, will not be deemed to be a part of this Cross
License Agreement, and will not be referred to in connection with the
construction or interpretation of this Cross License Agreement.

          2.   LICENSE GRANTS

               2.1  License to Efficient. Subject to the terms and conditions of
                    --------------------
this Cross License Agreement, Cabletron hereby grants to Efficient, under the
Cabletron Licensed Technology, a worldwide, non-exclusive, perpetual,
irrevocable, non-terminable, non-transferable, non-sublicensable, paid-up and
royalty-free license, solely for the Efficient Field of Use, to make, have made,
use, sell, reproduce, create derivative works of and distribute products,
provide services, practice processes or methods, and exercise all other rights
under the Cabletron Licensed Technology.

               2.2  License to Cabletron. Subject to the terms and conditions of
                    --------------------
this Cross License Agreement, Efficient hereby grants to Cabletron, under the
Efficient Licensed Technology, a worldwide, non-exclusive, perpetual,
irrevocable, non-terminable, non-transferable, non-sublicensable, paid-up and
royalty-free license, solely for the Cabletron Field of Use, to make, have made,
use, sell, reproduce, create derivative works of and distribute

                                      -3-
<PAGE>

products, provide services, practice processes or methods, and exercise all
other rights under the Efficient Licensed Technology. In addition, upon request
by Cabletron, Efficient and Cabletron shall negotiate in good faith to determine
reasonable royalty rates under which Efficient would license the Efficient
Licensed Technology to Cabletron for use in other Cabletron non-DSL CPE router
products and, subject to reaching agreement on such royalty rates, Efficient
will license the Efficient Licensed Technology for such other uses.

               2.3  Reservation of Rights. Each Party hereby reserves all rights
                    ---------------------
in and to such Party's Technology not expressly granted hereunder, and no other
licenses are granted by either Party hereunder, whether by implication, estoppel
or otherwise.

               2.4  Delivery and Assistance. Within ____ days after the
                    -----------------------
Effective Date: (i) Efficient shall deliver to Cabletron at least one copy of
each tangible item of Efficient Licensed Technology set forth in Exhibit A; and
(ii) Cabletron shall deliver to Efficient at least one copy of each tangible
item of Cabletron Licensed Technology set forth in Exhibit B. Upon the request
by either Party, the other Party shall provide reasonable additional information
or assistance in connection with such Party's use of the Technology licensed to
such Party hereunder.

               2.5  Further Assurances. Subject to the terms and conditions of
                    ------------------
this Cross License Agreement, each Party will, at the other Party's request and
expense, take all reasonable actions and do all things reasonably necessary,
proper, or advisable in order to consummate and make effective the ownership,
license grants and other transactions contemplated by this Cross License
Agreement, including without limitation appropriately documenting such
transactions and assisting the other Party in every proper way to secure and
maintain the other Party's Intellectual Property Rights in any and all
jurisdictions.

          3.   CONFIDENTIAL INFORMATION

               3.1  Confidential Information. "Confidential Information" means
                    ------------------------   ------------------------
any information: (i) disclosed by one Party (the "Disclosing Party") to the
                                                  ----------------
other (the "Receiving Party"), which, if written, graphic, machine-readable or
            ---------------
other tangible form is marked as "Confidential" or "Proprietary," or which, if
disclosed orally or by demonstration, is identified at the time of initial
disclosure as confidential or proprietary, and is summarized in writing and
similarly marked and delivered to the Receiving Party within thirty (30) days of
initial disclosure; (ii) which at the time it is disclosed is or should
reasonably be known by the Receiving Party to be proprietary or confidential
information of the Disclosing Party, or (iii) which is embodied in or learned
from the Disclosing Party's Technology licensed or disclosed hereunder, whether
or not so marked.

               3.2  Confidential Information Exclusions.  Confidential
                    -----------------------------------
Information will exclude information that the Receiving Party can demonstrate
is: (i) now or hereafter, through no unauthorized act or failure to act on
Receiving Party's part, in the public domain; (ii) known to the Receiving Party
from a source other than the Disclosing Party (including former employees of the
Disclosing Party) without an obligation of confidentiality at the time Receiving
Party receives the same from the Disclosing Party, as evidenced by written
records; (iii) hereafter furnished to the Receiving Party by a third party as a
matter of right and without restriction on
                                      -4-
<PAGE>

disclosure; (iv) furnished to others by the Disclosing Party without restriction
on disclosure; or (v) independently developed by the Receiving Party without use
of the Disclosing Party's Confidential Information. Nothing in this Cross
License Agreement shall prevent the Receiving Party from disclosing Confidential
Information to the extent the Receiving Party is legally compelled to do so by
any governmental investigative or judicial agency pursuant to proceedings over
which such agency has jurisdiction; provided, however, that prior to any such
disclosure, the Receiving Party shall (a) assert the confidential nature of the
Confidential Information to the agency; (b) immediately notify the Disclosing
Party in writing of the agency's order or request to disclose; and (c) cooperate
fully with the Disclosing Party in protecting against any such disclosure and/or
obtaining a protective order narrowing the scope of the compelled disclosure and
protecting its confidentiality.

          3.3  Confidentiality Obligation.  The Receiving Party shall treat as
               --------------------------
confidential all of the Disclosing Party's Confidential Information and shall
not use such Confidential Information except for the purposes of exercising its
rights and performing its obligations under this Cross License Agreement.
Without limiting the foregoing, the Receiving Party shall use the same degree of
care and means that it utilizes to protect its own information of a similar
nature, but in any event not less than reasonable care and means, to prevent the
unauthorized use or the disclosure of such Confidential Information to third
parties. The Receiving Party shall have appropriate written agreements with
employees or contractors with access to the Confidential Information sufficient
to comply with the provisions of this Cross License Agreement.

          3.4  Confidentiality of Cross License Agreement.  Each Party agrees
               ------------------------------------------
that the terms and conditions of this Cross License Agreement will be treated as
the other Party's Confidential Information and that no reference to this Cross
License Agreement or to activities pertaining thereto may be made in any form of
press release or public statement without first consulting with the other Party;
provided, however, that each Party may disclose the terms and conditions of this
- --------  -------
Cross License Agreement: (i) as may be required by law or in connection with any
governmental filing; (ii) to legal counsel of the Parties; (iii) in connection
with the requirements of an initial public offering or securities filing; (iv)
in confidence, to accountants, banks, and financing sources and their advisors;
(v) in confidence, in connection with the enforcement of this Cross License
Agreement or rights under this Cross License Agreement; or (vi) in confidence,
in connection with a merger or acquisition or proposed merger or acquisition, or
the like.

          3.5  No Confidential Information of Other Parties. Each Party
               --------------------------------------------
represents and warrants to the other that it has not used and shall not use in
the course of its performance hereunder, and shall not disclose to the other,
any confidential information of any third party, unless it is expressly
authorized in writing by such third party to do so.

          3.6  Required Disclosure.  In the event the Receiving Party is
               -------------------
required to disclose the Disclosing Party's Confidential Information pursuant to
the order or requirement of a court, administrative agency, or other
governmental body, the Receiving Party shall provide prompt notice thereof to
the Disclosing Party and shall use its reasonable efforts to obtain a protective
order or otherwise prevent public disclosure of such information.

                                      -5-
<PAGE>

     4.   REPRESENTATIONS AND WARRANTIES

          4.1  Efficient Warranties. Efficient represents, warrants and
               --------------------
covenants to Cabletron that (i) it has the full right and authority to enter
into this Cross License Agreement and grant the rights and licenses granted
herein; and (ii) it has not previously granted and will not grant any rights in
conflict with the rights and licenses granted herein.

          4.2  Cabletron Warranties.  Cabletron represents, warrants and
               --------------------
covenants to Efficient that (i) it has the full right and authority to enter
into this Cross License Agreement and grant the rights and licenses granted
herein; and (ii) it has not previously granted and will not grant any rights in
conflict with the rights and licenses granted herein.

          4.3  Warranty Disclaimers. Nothing set forth in this Cross License
               --------------------
Agreement will be construed to be:

               (a)  a warranty, representation or admission by either Party as
to the validity, enforceability or scope of any Technology licensed hereunder;

               (b)  a warranty or representation by either Party that the use of
such Party's Technology for the manufacture, use, licensing, sale, importation
or other exploitation of the Technology or the exercise of any license granted
to the other Party hereunder will be free from infringement of any Intellectual
Property Right of any third party; or

               (c)  an obligation on either Party to file any Patent application
or to secure any Patent or to maintain any Patent through the payment of patent
maintenance fees or otherwise.

               (d)  EXCEPT AS EXPRESSLY SET FORTH IN THIS CROSS LICENSE
AGREEMENT, (1) ALL TECHNOLOGY AND INTELLECTUAL PROPERTY RIGHTS, AND ALL OTHER
ITEMS OR RIGHTS PROVIDED, SOLD, TRANSFERRED OR LICENSED HEREUNDER ARE PROVIDED
"AS IS" AND WITHOUT WARRANTY OF ANY KIND, AND (2) EACH PARTY MAKES NO, AND
HEREBY DISCLAIMS ALL OTHER WARRANTIES, WHETHER EXPRESS, STATUTORY, OR IMPLIED,
INCLUDING WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE WITH RESPECT THERETO.

     5.   LIMITATIONS OF LIABILITY

          5.1  Exclusion of Damages. EXCEPT FOR A BREACH OF SECTION 3, IN NO
               --------------------
EVENT WILL EITHER PARTY BE LIABLE TO THE OTHER PARTY FOR LOST PROFITS, COST OF
PROCUREMENT OF SUBSTITUTE GOODS, OR FOR ANY OTHER INDIRECT, SPECIAL, RELIANCE,
INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF OR RELATED TO THIS CROSS
LICENSE AGREEMENT, WHETHER BASED ON BREACH OF CONTRACT, TORT (INCLUDING
NEGLIGENCE), PRODUCT LIABILITY, OR OTHERWISE, AND WHETHER OR NOT SUCH PARTY HAS
BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

                                      -6-
<PAGE>

          5.2  Failure of Essential Purpose. The limitations specified in this
               ----------------------------
Section 5 shall survive and apply even if any limited remedy specified in this
Cross License Agreement is found to have failed of its essential purpose.

     6.   GENERAL

          6.1  Term. The term of this Cross License Agreement shall commence on
               ----
 the Effective Date and shall continue in perpetuity thereafter.

          6.2  Notices. All notices, requests and other communications to any
               -------
Party hereunder shall be in writing (including facsimile transmission) and shall
be given,

     if to Efficient, to:
          Efficient Networks, Inc.
          4201 Spring Valley Road, Suite 1200
          Dallas, TX 75244
          Attention: Jill Manning
          Telecopy: 972-991-3887
          Telephone: 972-991-3884

          with a copy to:

          Wilson Sonsini Goodrich & Rosati
          650 Page Mill Road
          Palo Alto, California 94304
          Attention: Kenneth Siegel, Esq.
                     Michael Kennedy, Esq.
          Telecopy:  650-493-6811
          Telephone  650-493-9300

  if to Cabletron, to:
          Cabletron Systems, Inc.
          35 Industrial Way
          Rochester, NH
          Attention: General Counsel
          Telecopy: ________________
          Telephone: 630-332-9400

          with a copy to:

          Ropes & Gray
          One International Place
          Boston, MA 02110
          Attention: David A. Fine, Esq.
          Telecopy: 617-951-7000
          Telephone: 617-951-7050

                                      -7-
<PAGE>

All such notices, requests and other communications shall be deemed received on
the date of receipt by the Receiving Party thereof if received prior to 5 p.m.
in the place of receipt and such day is a business day in the place of receipt.
Otherwise, any such notice, request or communication shall be deemed not to have
been received until the next succeeding business day in the place of receipt.

          6.3  Amendments and Waivers.
               ----------------------

               (a)  Any provision of this Cross License Agreement may be amended
or waived if, but only if, such amendment or waiver is in writing and is signed,
in the case of an amendment by each Party to this Cross License Agreement, or in
the case of a waiver by the Party against whom the waiver is to be effective.

               (b)  No failure or delay by any Party in exercising any right,
power or privilege hereunder shall operate as a waiver thereof nor shall any
single or partial exercise thereof preclude any or other further exercise
thereof or the exercise of any other right, power or privilege. The rights and
remedies herein provided shall be cumulative and not exclusive of any rights or
remedies provided by law.

          6.4  Successors and Assigns.  The provisions of this Cross License
               ----------------------
Agreement shall be binding upon and inure to the benefit of the Parties hereto
and their respective successors and assigns; provided that neither Party may
assign, delegate or otherwise transfer any of its rights or obligations under
this Cross License Agreement without the consent of the other Party hereto,
except that either Party may assign this Cross License Agreement in connection
with a merger or acquisition of such Party or the sale or transfer of all or
substantially all of the business, stock or assets of such Party.

          6.5  Governing Law/Dispute Resolution.  This Cross License Agreement
               --------------------------------
shall be governed by and construed in accordance with the law of the State of
Texas, without regard to its conflicts of law rules. All disputes arising out of
this Agreement shall be subject to the exclusive jurisdiction and venue of the
Texas state courts in Dallas, Texas (or, if there is exclusive federal
jurisdiction, the United Stated District Court for the Northern District of
Texas), and the parties consent to the personal and exclusive jurisdiction of
these courts.

          6.6  Counterparts; Third Party Beneficiaries.  This Cross License
               ---------------------------------------
Agreement may be signed in any number of counterparts, each of which shall be an
original, with the same effect as if the signatures thereto and hereto were upon
the same instrument. This Cross License Agreement shall become effective when
each Party hereto shall have received a counterpart hereof signed by the other
Party hereto. No provision of this Cross License Agreement is intended to confer
upon any Person other than the Parties hereto any rights or remedies hereunder.

          6.7  Entire Agreement; Severability.  This Cross License Agreement
               ------------------------------
constitutes the entire agreement between the Parties with respect to the subject
matter of this Cross License Agreement and supersedes all prior agreements and
understandings, both oral and written, between the Parties with respect to the
subject matter of this Cross License Agreement. If at any time subsequent to the
date hereof any term or provision of this Cross License

                                      -8-
<PAGE>

Agreement shall be determined to be partially or wholly illegal, void or
unenforceable, such provision shall be of no force and effect to the extent so
determined, but the illegality or unenforceability of such term or provision
shall have no effect upon and shall not impair the legality or enforceability of
any other term or provision of this Cross License Agreement.

          6.8  Captions. The captions herein are included for convenience of
               --------
reference only and shall be ignored in the construction or interpretation
hereof.

          6.9  Representation by Counsel; Interpretation. The Parties
               -----------------------------------------
acknowledge that each Party to this Cross License Agreement has been represented
by counsel in connection with this Cross License Agreement and the transactions
contemplated by this Cross License Agreement. Accordingly, any rule of law or
any legal decision that would require interpretation of any claimed ambiguities
in this Cross License Agreement against the Party that drafted it has no
application and is expressly waived. The provisions of this Cross License
Agreement shall be interpreted in a reasonable manner to effect the intent of
the Parties.

          6.10 Injunctive Relief.  It is understood and agreed that,
               -----------------
notwithstanding any other provision of this Cross License Agreement, either
Party's breach of confidentiality obligations or provisions relating to
proprietary rights may cause irreparable damage for which recovery of money
damages would be inadequate, and that the other Party will therefore be entitled
to seek timely, injunctive relief to protect such Party's rights under this
Cross License Agreement in addition to any and all remedies available at law.
Each Party further agrees that no bond or other security shall be required in
obtaining such equitable relief, nor will proof of actual damages be required
for such equitable relief. Each Party hereby expressly consents to the issuance
of such injunction and to the ordering of such specific performance.

     IN WITNESS WHEREOF, the Parties, by their duly authorized representatives,
have executed this Cross License Agreement as of the Effective Date.

Efficient Networks, Inc.                Cabletron Systems, Inc.


    /s/ JILL MANNING                        /s/ PIYUSH PATEL
By:________________________________     By:________________________________

      Jill Manning                            Piyush Patel
Name:______________________________     Name:______________________________

       Chief Financial Officer                 President
Title:_____________________________     Title:_____________________________

                                      -9-
<PAGE>

                                   EXHIBIT A

                         EFFICIENT LICENSED TECHNOLOGY

All Flowpoint software source code for making and implementing routing decisions
for data packets.
<PAGE>

                                   EXHIBIT B

                         CABLETRON LICENSED TECHNOLOGY

All software source code and related documentation for:

 .    IPSEC

 .    DES

 .    TripleDES

 .    IKE

 .    L2TP

 .    Diffie-Hellman Key Exchange

 .    IP Flowointwall technology

 .    Virtual Private Network technology

In each case, that is incorporated in or is currently planned to be incorporated
in Flowpoint products.

<PAGE>

                                                                    EXHIBIT 23.1

                        Consent of Independent Auditors

The Board of Directors
Efficient Networks, Inc.

   We consent to the use of our reports included herein and to the reference to
our firm under the heading "Experts" in the prospectus.

                                          /s/ KPMG LLP

                                          KPMG LLP

Dallas, Texas
January 7, 2000

<PAGE>

                                                                    EXHIBIT 23.2

                        Consent of Independent Auditors

The Board of Directors
Efficient Networks, Inc.:

   We consent to the use of our report included herein and to the reference to
our firm under the heading "Experts" in the prospectus.

                                          /s/ KPMG LLP

                                          KPMG LLP

Boston, Massachusetts
January 7, 2000


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