METROMEDIA FIBER NETWORK INC
S-1/A, 1997-10-28
TELEPHONE COMMUNICATIONS (NO RADIOTELEPHONE)
Previous: TRANSCOASTAL MARINE SERVICES INC, S-1/A, 1997-10-28
Next: METROMEDIA FIBER NETWORK INC, S-1MEF, 1997-10-28



<PAGE>
   
   AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 28, 1997.
    
 
                                                      REGISTRATION NO. 333-33653
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
 
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------
                               AMENDMENT NO. 6 TO
 
                                    FORM S-1
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                            ------------------------
 
                         METROMEDIA FIBER NETWORK, INC.
             (Exact name of registrant as specified in its charter)
 
<TABLE>
<S>                                     <C>                                     <C>
               DELAWARE                                  4813                                 11-3168327
   (State or other jurisdiction of           (Primary Standard Industrial                  (I.R.S. Employer
    incorporation or organization)           Classification Code Number)                Identification Number)
</TABLE>
 
                              110 East 42nd Street
 
                                   Suite 1502
 
                               New York, NY 10017
 
                                 (212) 687-9177
 
  (Address, including zip code, and telephone number, including area code, of
                   registrant's principal executive offices)
                         ------------------------------
 
                              STEPHEN A. GAROFALO
 
                      CHAIRMAN AND CHIEF EXECUTIVE OFFICER
 
                         METROMEDIA FIBER NETWORK, INC.
 
                              110 EAST 42ND STREET
 
                                   SUITE 1502
 
                               NEW YORK, NY 10017
 
                                 (212) 687-9177
 
 (Name, address, including zip code, and telephone number, including area code,
                             of agent for service)
                         ------------------------------
 
                                   COPIES TO:
 
<TABLE>
<S>                                        <C>
          JAMES M. DUBIN, ESQ.                        JOHN W. WHITE, ESQ.
PAUL, WEISS, RIFKIND, WHARTON & GARRISON            CRAVATH, SWAINE & MOORE
       1285 AVENUE OF THE AMERICAS                      WORLDWIDE PLAZA
      NEW YORK, NEW YORK 10019-6064                    825 EIGHTH AVENUE
             (212) 373-3000                      NEW YORK, NEW YORK 10019-7475
                                                        (212) 474-1000
</TABLE>
 
                            ------------------------
 
    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, other than securities offered only in connection with dividend or interest
reinvestment plans, 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 delivery of the prospectus is expected to be made pursuant to Rule 434,
check the following box. / /
                            ------------------------
 
                        CALCULATION OF REGISTRATION FEE
 
   
<TABLE>
<CAPTION>
                                                                                              PROPOSED MAXIMUM
                                                                          PROPOSED MAXIMUM       AGGREGATE           AMOUNT OF
                TITLE OF EACH CLASS                     AMOUNT TO BE       OFFERING PRICE      OFFERING PRICE       REGISTRATION
          OF SECURITIES TO BE REGISTERED               REGISTERED(1)         PER SHARE             (1)(2)              FEE(3)
<S>                                                  <C>                 <C>                 <C>                 <C>
Class A Common Stock, par value $.01 per share.....   7,590,000 shares         $16.00           $121,440,000          $36,800
</TABLE>
    
 
(1) Includes shares which may be purchased by the Underwriters solely to cover
    over-allotments, if any.
 
(2) Estimated solely for purposes of calculating the registration fee.
 
   
(3) Calculated pursuant to Rule 457(a). $34,848.48 of the registration fee was
    wired to the Securities and Exchange Commission in connection with the
    initial filing. An additional registration fee of $1,951.52 is being wired
    to the Commission's account at Mellon Bank on the date of this filing.
    
                         ------------------------------
 
    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 THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(A) OF
THE SECURITIES ACT OF 1933, AS AMENDED, OR UNTIL THE REGISTRATION STATEMENT
SHALL BECOME EFFECTIVE ON SUCH DATE AS THE SECURITIES AND EXCHANGE COMMISSION,
ACTING PURSUANT TO SAID SECTION 8(A), MAY DETERMINE.
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>
                                    PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 13. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION
 
    The following table sets forth all expenses, other than underwriting
discounts and commissions, in connection with the issuance and distribution of
the securities registered hereby. All the amounts shown are estimates, except
for the Securities and Exchange Commission registration fee, the NASD filing fee
and the Nasdaq National Market listing fee. All of the following fees and
expenses will be paid by the Company.
 
   
<TABLE>
<S>                                                                              <C>
Securities and Exchange Commission registration fee............................  $   36,800
NASD filing fee................................................................      12,000
Nasdaq National Market listing fee.............................................      50,000
Printing and engraving expenses................................................     250,000
Legal fees and expenses........................................................     400,000
Accounting fees and expenses...................................................     198,049
Blue Sky fees and expenses (including counsel fees and expenses)...............      25,000
Transfer Agent and Registrar fees and expenses.................................      25,000
Miscellaneous..................................................................       3,151
                                                                                 ----------
    Total......................................................................  $1,000,000
                                                                                 ----------
                                                                                 ----------
</TABLE>
    
 
ITEM 14. INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
    Section 145(a) of the General Corporation Law of the State of Delaware
provides that a Delaware corporation may indemnify any person who was or is a
party or is threatened to be made a party to any threatened, pending or
completed action, suit or proceeding, whether civil, criminal, administrative or
investigative (other than an action by or in the right of the corporation) by
reason of the fact that he is or was a director, officer, employee or agent of
the corporation or is or was serving at the request of the corporation as a
director, officer, employee or agent of another corporation or enterprise,
against expenses, judgments, fines and amounts paid in settlement actually and
reasonably incurred by him in connection with such action, suit or proceeding if
he acted in good faith and in a manner he reasonably believed to be in or not
opposed to the best interests of the corporation, and, with respect to any
criminal action or proceeding, had no cause to believe his conduct was unlawful.
 
    Section 145(b) provides that a Delaware corporation may indemnify any person
who was or is a party or is threatened to be made a party to any threatened,
pending or completed action or suit by or in the right of the corporation to
procure a judgment in its favor by reason of the fact that such person acted in
any of the capacities set forth above, against expenses actually and reasonably
incurred by him in connection with the defense or settlement of such action or
suit if he acted under similar standards, except that no indemnification may be
made in respect of any claim, issue or matter as to which such person shall have
been adjudged to be liable to the corporation unless and only to the extent that
the court in which such action or suit was brought shall determine that despite
the adjudication of liability, such person is fairly and reasonably entitled to
be indemnified for such expenses which the court shall deem proper.
 
    Section 145 further provides that to the extent a director or officer of a
corporation has been successful in the defense of any action, suit or proceeding
referred to in subsections (a) and (b) or in the defense of any claim, issue, or
matter therein, he shall be indemnified against expenses actually and reasonably
incurred by him in connection therewith; that indemnification provided for by
Section 145 shall not be deemed exclusive of any other rights to which the
indemnified party may be entitled; and
 
                                      II-1
<PAGE>
that the corporation may purchase and maintain insurance on behalf of a director
or officer of the corporation against any liability asserted against him or
incurred by him in any such capacity or arising out of his status as such
whether or not the corporation would have the power to indemnify him against
such liabilities under such Section 145.
 
    Section 102(b)(7) of the General Corporation Law provides that a corporation
in its original certificate of incorporation or an amendment thereto validly
approved by stockholders may eliminate or limit personal liability of members of
its board of directors or governing body for breach of a director's fiduciary
duty. However, no such provision may eliminate or limit the liability of a
director for breaching his duty of loyalty, failing to act in good faith,
engaging in intentional misconduct or knowingly violating a law, paying a
dividend or approving a Stock repurchase which was illegal, or obtaining an
improper personal benefit. A provision of this type has no effect on the
availability of equitable remedies, such as injunction or rescission, for breach
of fiduciary duty. The Company's Charter contains such a provision.
 
    The Company's Charter further provides that the Company shall indemnify its
officers and directors and, to the extent authorized by the Board, employees and
agents of the Company, to the fullest extent permitted by and in the manner
permissible under the laws of the State of Delaware.
 
ITEM 15. RECENT SALES OF UNREGISTERED SECURITIES
 
    During the past three years, the Company has issued the following
securities, none of which have been registered under the Securities Act.
 
    As of December 31, 1995, the Company owed its majority shareholder $896,979.
Pursuant to an agreement dated May 21, 1996, the Company issued 152,100 shares
of its Class A Common Stock to the majority shareholder in consideration for the
cancellation of a portion of the outstanding balance.
 
    The Company engaged the services of an electrical contractor controlled by
the Company's majority shareholder in connection with the construction of the
fiber optic network. As of December 31, 1995, the entire $692,887 was owed to
this related company. In May 1996, the Company and the assignee of this related
party entered into an agreement whereby the full amount of this indebtedness was
satisfied by the issuance of 456,300 shares of the Company's Class A Common
Stock.
 
    On May 1, 1995, the Company issued Option Warrants to Realprop for 207,883
shares of Class A Common Stock at $.01 per share, exercisable prior to February
1, 1999. The warrants were redeemed by the Company as part of the Katz
Securities.
 
    On March 16, 1995, the Company entered into the Rubin Loan Agreement with
one of the Company's directors for $500,000 bearing interest at 10% per annum
due on March 16, 1996. As an inducement for entering into this loan agreement,
the Company issued to the director 155,994 shares of Class A Common Stock.
 
    On April 18, 1995, the Company entered into a loan agreement with a customer
for $500,000 bearing interest at 11% per annum, originally due 120 days from the
date of this loan. Pursuant to a supplemental agreement dated January 12, 1996,
the parties agreed to extend the maturity date of this loan to November 18,
1996. Pursuant to a second supplemental agreement dated March 1997, the parties
agreed to extend the maturity date to June 30, 1997. On February 16, 1995, the
Company issued to this party a warrant entitling the holder to purchase a total
of 669,167 shares of the Company's Class A Common Stock. This warrant was
cancelled and replaced by a new warrant issued on February 13, 1997 for 456,300
nonassessable shares of Class A Common Stock at a purchase price of $4.85 per
share. The new warrant expires on February 13, 2000.
 
    On April 16, 1996, the Company entered into an agreement with US ONE for the
lease of exclusive usage rights for 8 to 12 fibers on the Company's fiber optic
transmission network. On April 30, 1997, the Company amended this agreement.
Concurrent with the execution of the original lease agreement, the
 
                                      II-2
<PAGE>
Company and US ONE entered into a bridge financing agreement. Concurrent with
the execution of the aforementioned lease and bridge financing agreements, the
Company entered into a letter agreement with US ONE providing for the sale of a
warrant to purchase Class A Common Stock of the Company. Under this agreement,
the warrant is exercisable for a number of shares to be determined at the
Company's discretion subject to a minimum number of 76,050 shares and a maximum
number of 456,300 shares. The per share exercise price is to be determined
pursuant to a formula, but in no event shall the aggregate purchase price exceed
$1,250,000.
 
    On September 24, 1996, the Company entered into a loan agreement with
Sterling Capital, LLC ("Sterling") for $550,000. As an incentive for the loan,
MFN issued to Sterling warrants to purchase 94,302 shares of Class A Common
Stock at an exercise price of the lesser of $5.92 per share, the price at which
the Company shall issue its securities in the future less $5.92, or one half the
price at which the Class A Common Stock of the Company is offered in an initial
public offering. The warrants can be exercised at the later of (i) the third
anniversary or (ii) twelve months and 90 days after the Company has completed a
public offering.
 
    On February 13, 1996, the Company entered into an investment agreement with
an individual, Patrice Knobel (the "Investor"), pursuant to which the Company
borrowed $1,000,000 in consideration for the issuance of 12% senior subordinated
promissory notes maturing on November 1, 1996. The notes were convertible at a
price of $2.62 per unit for each $1,000 of principal outstanding. Each unit
consists of the following: (i) .507 shares of Class A Common Stock, and (ii) one
warrant to purchase one share of Class A Common Stock at $5.27 per share. As an
inducement for entering into the investment agreement, the Company issued to the
investor the following: (i) 381,087 paid shares of Class A Common Stock, and
(ii) a warrant to purchase 381,087 shares of Class A Common Stock at $5.27 per
share, exercisable for a five year period beginning August 15, 1997 and ending
August 15, 2002. On March 19, 1996, a supplemental investment agreement was
executed with the same investor providing for an additional advance of $500,000
with the same maturity date, interest rate, conversion rights, and guaranty
features as the initial $1,000,000 investment. This advance was subsequently
repaid, along with interest on April 16, 1996. In connection with this
supplemental agreement, the Company issued a warrant to purchase 190,543 shares
of Class A Common Stock at $5.27 per share, exercisable for a five year period
beginning on August 15, 1997 and expiring August 15, 2002. The Company also
issued a warrant to purchase an additional 190,543 shares at $.006 per share
(the "Penny Warrants"), exercisable for a period beginning August 15, 1997 and
expiring August 15, 2002. On April 11, 1996, a memorandum of understanding was
entered into between the parties pursuant to which the warrants issued on
February 13, 1996 to purchase 381,087 shares at $5.27 per share and the warrants
issued on March 19, 1996 to purchase 190,543 shares at $5.27 per share were
surrendered by the investor to the Company in consideration for the issuance of
228,150 shares of the Company's Class A Common Stock. In April and July 1996,
the investor purchased 152,100 and 38,443 shares of Class A Common Stock,
respectively, at $.006 per share in connection with an exercise of the Penny
Warrants. The Company granted the investor the right to exercise prior to the
stated exercise period. Further, in accordance with the investment agreement an
additional 38,025 shares of Class A Common Stock was issued to the investor in
compliance with the anti-dilutive requirements in the agreement.
 
    In August 1995, the Company initiated a $600,000 private offering of
subordinated notes. Those notes were scheduled to mature in March 1996 and bear
interest at an annual rate of 15%, payable quarterly in arrears. Concurrent with
the issuance of these notes, warrants were issued by the Company to the
noteholders which were exercisable for common shares of the Company in an amount
equal to 0.7% of the outstanding shares of Class A Common Stock immediately
following an initial public offering of the Company's Class A Common Stock, at
an exercise price equal to 60% of the initial public offering price. These
warrants are exercisable over a three-year period beginning on the effective
date of such initial public offering. In April 1996, the Company offered the
warrant holders fully paid shares of Class A Common Stock equal to 0.7% of the
Class A Common Stock then issued and outstanding, in exchange
 
                                      II-3
<PAGE>
for the surrender and cancellation of the outstanding warrants, and in
consideration for the extension of the maturity date of the notes through June
30, 1996. All of the warrant holders accepted this offer and accordingly, the
Company issued a total of 59,359 shares of the Company's Class A Common Stock.
 
    In October 1995, the Company initiated a private offering of $858,000 of
convertible subordinated notes. Through December, 1995, $783,000 of convertible
notes were sold pursuant to this offering, and an additional $75,000 of notes
were sold during January and February of 1996. These notes were scheduled to
mature during the period October 1996 through February 1997 and bear interest at
an annual rate of 15%, payable at maturity. The notes are convertible, at the
Company's option, at any time into shares of Class A Common Stock at a rate of
1.521 shares of Class A Common Stock per $1,000 of note principal, at a
conversion price equal to 60% of the per share price of an initial public
offering of the Company's Class A Common Stock. Concurrently with the issuance
of these notes, warrants were issued by the Company to the noteholders which are
exercisable at a rate of 15,210 shares of Class A Common Stock per $100,000 of
note principal. Such warrants, entitling the holders to purchase an aggregate of
130,502 shares, are exercisable at a price equal to 50% of the per share price
of an initial pubic offering of Class A Common Stock over a three-year period
beginning on the effective date of such public offering.
 
    In December 1996, the Company offered the private placement noteholders
Common Stock purchase warrants to purchase 107,078 shares of its Class A Common
Stock exercisable at one half of the price for which shares are sold in an
initial public offering for a period of three years following such offering in
exchange for the extension of the due dates of the notes. All of the noteholders
accepted this offer.
 
    In March 1997, the Company issued purchase warrants to private placement
noteholders to purchase 57,682 shares of common stock exercisable at one half of
the price for which shares are sold in an initial public offering for a period
of three years following such offering in exchange for the extension of the due
dates of the notes.
 
    On January 12, 1996, the Company entered into an agreement with its then
legal counsel which called for the issuance by the Company of Class A Common
Stock as additional consideration for legal services provided. Pursuant to this
agreement, and a subsequent amendment dated April 16, 1996, the Company issued a
total of 491,105 shares during March and April of 1996.
 
    In June 1996, the Company sold a total of 38,025 shares of Class A Common
Stock to two individuals for total proceeds of $100,000. Concurrent with the
issuance of these shares, warrants were issued by the Company to these
shareholders entitling the holders to purchase a total of 38,025 shares at $2.62
per share for a three year period. In the event of an initial public offering of
the Company's Class A Common Stock during the exercise period, the exercise
price will be reduced to the lesser of $2.62 or 50% of the per share price of
the initial public offering.
 
    In July 1996, the Company issued 12,168 shares of Class A Common Stock as
consideration for consulting services. In addition, the Company issued 150,579
shares to three employees for services rendered. The transaction was later
rescinded and the shares were returned to the Company.
 
    In August 1996, the Company issued 182,520 shares of Class A Common Stock
for consulting services to Marc Pelson.
 
    In September 1996, the Company sold 10,935 shares of Class A Common Stock to
three individuals for total proceeds of $23,500.
 
    On April 15, 1996, the Company entered into a stock purchase agreement with
VCNY. Pursuant to this agreement, the Company issued 1,521,000 shares of Class A
Common Stock to VCNY as consideration for services provided by VCNY.
 
                                      II-4
<PAGE>
    In June 1996, the Company granted 152,100 Class A Common Stock purchase
warrants to the Company's legal counsel exercisable at $.07 per share for a
period of four years as additional consideration for legal services provided.
This warrant was exercised in January 1997.
 
    On December 13, 1996, the Company issued and sold to Penny Lane Partners,
L.P. ("Penny Lane"), for aggregate cash consideration of $2,025,000, (i) 150,000
shares of 10% cumulative convertible preferred Stock (the "Series A Preferred
Stock") bearing dividends at a rate of $1.35 per share per annum, (ii) warrants
to purchase 114,075 shares of Class A Common stock at an exercise price of $4.93
per share (the "Penny Lane Warrants") and (iii) a contingent Stock subscription
warrant to purchase a number of shares of Class A Common Stock (such number to
be determined based on certain future events) at an exercise price of $.02 per
share (the "Contingent Warrants"), In March 1997, Penny Lane agreed to permit
the Series A Preferred Stock and the Contingent Warrants to be redeemed at an
aggregate redemption price of $2,115,000 (which includes accrued but unpaid
dividends on the Series A Preferred Stock) and in connection therewith the
number of Penny Lane Warrants was increased from 114,075 to 228,150.
 
    Through April 30, 1997, Metromedia loaned the Company an aggregate of
$4,000,000. The Metromedia Loan bore interest at the prime rate announced by The
Chase Manhattan Bank and was convertible into Class A Common Stock based on a
formula if the principal and interest was not repaid in full by August 31, 1997.
On April 30, 1997, the Metromedia Loan was repaid with a portion of the proceeds
from the Metromedia Investment.
 
    On April 30, 1997, the Company sold an aggregate of 8,403.325 shares of
Series B Preferred Stock to Metromedia and certain of its affiliates, for an
aggregate price of $32.5 million. The shares of Series B Preferred Stock were
exchanged for shares of Class B Common Stock in the Series B Reclassification.
 
    Each of the foregoing transactions was effected without registration under
the Securities Act in reliance on the exemption from registration provided
pursuant to Section 4(2) and Regulation D promulgated thereunder.
 
                                      II-5
<PAGE>
ITEM 16. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES
 
    (a) Exhibits.
 
   
<TABLE>
<CAPTION>
 EXHIBIT
 NUMBER                                                  DESCRIPTION
- ---------  -------------------------------------------------------------------------------------------------------
<S>        <C>
 
 1.1**     Form of Underwriting Agreement.
 
 3.1**     Form of Amended and Restated Certificate of Incorporation of Metromedia Fiber Network, Inc.
 
 3.2**     Form of Amended and Restated Bylaws of Metromedia Fiber Network, Inc.
 
 4.1**     Specimen Class A Common Stock Certificate of Metromedia Fiber Network,
 
 5.1**     Form of Opinion of Paul, Weiss, Rifkind, Wharton & Garrison.
 
10.1**     Form of Metromedia Fiber Network, Inc. 1997 Incentive Stock Plan.
 
10.2**     Employment Agreement by and between National Fiber Network, Inc. and Stephen A. Garofalo, dated as of
           February 26, 1997.
 
10.3**     Employment Agreement by and between National Fiber Network, Inc. and Howard Finkelstein, dated as of
           April 30, 1997.
 
10.4**     Agreement made as of April 30, 1997, to be amended by a Modification Agreement made as of October   ,
           1997 by and among Metromedia Company, Stuart Subotnick, Arnold Wadler, Silvia Kessel, Stephen A.
           Garofalo and National Fiber Network, Inc.
 
10.5**     Franchise Agreement between The City of New York and National Fiber Network, Inc., dated as of December
           20, 1993.
 
10.6**     Conduit Occupancy Agreement by and between New York Telephone Company and National Fiber Network, Inc.,
           dated as of May 1993.
 
10.7**     Consulting Agreement between National Fiber Network and Realprop Capital Corporation, dated as of
           February 1, 1996.
 
10.8**     Letter Agreement from National Fiber Network, Inc. to Peter Sahagen dated February 11, 1997.
 
10.9**     Office Lease by and between National Fiber Network, Inc. and 110 East 42nd Street Associates, dated as
           of March 19, 1997.
 
10.10**    Office Lease by and between National Fiber Network, Inc. and 110 East 42nd Street, dated as of June
           1997.
 
10.11**    Trademark License Agreement by and between Metromedia Company and Metromedia Fiber Network, Inc., dated
           as of August 14, 1997.
 
10.12      Fiber Optic Use Agreement between National Fiber Network, Inc. and NextLink New York, L.L.C., dated as
           of June 3, 1997 (portions of this exhibit are subject to a request to the Securities and Exchange
           Commission for confidential treatment, and omitted material has been separately filed with the
           Securities and Exchange Commission).
 
10.13      Amended and Restated Agreement for the Provision of a Fiber Optic Transmission Network dated as of the
           Effective Date by and between US ONE Communications of New York, Inc. and National Fiber Network, Inc.
           (portions of this exhibit are subject to a request to the Securities and Exchange Commission for
           confidential treatment, and omitted material has been separately filed with the Securities and Exchange
           Commission).
 
11.1**     Statement Re Computation of Per Share Earnings.
</TABLE>
    
 
                                      II-6
<PAGE>
   
<TABLE>
<CAPTION>
 EXHIBIT
 NUMBER                                                  DESCRIPTION
- ---------  -------------------------------------------------------------------------------------------------------
<S>        <C>
21.1**     List of Subsidiaries of Metromedia Fiber Network, Inc.
 
23.1**     Consent of Paul, Weiss, Rifkind, Wharton & Garrison (contained in the opinion filed as Exhibit 5.1
           hereto).
 
23.2**     Consent of Ernst & Young, LLP
 
23.3**     Consent of M. R. Weiser & Co., LLP
 
23.4**     Consent of Richard A. Eisner & Company, LLP
 
23.5**     Consent of David Rockefeller.
 
23.6**     Consent of Leonard White.
 
24.1**     Power of Attorney from officers and directors (contained on signature page).
 
27.1**     Financial Data Schedule.
</TABLE>
    
 
- ------------------------
 
**  Previously filed.
 
    (b) Financial Statement Schedules.
 
                  None.
 
ITEM 17. UNDERTAKINGS
 
    Insofar as indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers and controlling persons of the
registrant pursuant to the provisions described under Item 15 above, 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 for 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 such director, officer or controlling person
in connection with the securities being registered, 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.
 
    The undersigned registrant hereby undertakes:
 
        (1) For purposes of determining any liability under the Securities Act
    of 1933, 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 of 1933, 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.
 
        (3) To provide to the Underwriters at the closing specified in the
    underwriting agreements certificates in such denominations and registered in
    such names as required by the Underwriters to permit prompt delivery to each
    purchaser.
 
                                      II-7
<PAGE>
                                   SIGNATURES
 
   
    Pursuant to the requirements of the Securities Act of 1933, as amended, the
registrant has duly caused this amendment to the registration statement to be
signed on its behalf by the undersigned, thereunto duly authorized, in the City
of New York, State of New York, on October 28, 1997.
    
 
<TABLE>
<S>                             <C>  <C>
                                By:           /s/ STEPHEN A. GAROFALO
                                     -----------------------------------------
                                                Stephen A. Garofalo
                                        CHAIRMAN, CHIEF EXECUTIVE OFFICER &
                                                     SECRETARY
</TABLE>
 
                                      II-8
<PAGE>
    Pursuant to the requirements of the Securities Act of 1933, as amended, this
amendment to the registration statement has been signed by the following persons
in the capacities and on the dates indicated.
 
   
          SIGNATURES                TITLE OR CAPACITIES             DATE
- ------------------------------  ---------------------------  -------------------
              *                 Chairman of the Board,
- ------------------------------    Chief Executive Officer     October 28, 1997
     Stephen A. Garofalo          and Secretary
 
  /s/ HOWARD M. FINKELSTEIN     President, Chief Operating
- ------------------------------    Officer and Director
    Howard M. Finkelstein                                     October 28, 1997
       Attorney-in-fact
 
              *                 Chief Financial Officer and
- ------------------------------    Chief Accounting Officer    October 28, 1997
       Stephen W. Ellis
 
              *                 Senior Vice President--
- ------------------------------    Business Development and    October 28, 1997
     Vincent A. Galluccio         Director
 
              *                 Director
- ------------------------------                                October 28, 1997
        John W. Kluge
 
              *                 Director
- ------------------------------                                October 28, 1997
        Silvia Kessel
 
              *                 Director
- ------------------------------                                October 28, 1997
       Stuart Subotnick
 
              *                 Director
- ------------------------------                                October 28, 1997
       Arnold L. Wadler
 
    
 
- ------------------------
 
<TABLE>
  <S>  <C>                                       <C>
               /s/ HOWARD M. FINKELSTEIN
       -----------------------------------------
                 Howard M. Finkelstein
  *By:              ATTORNEY-IN-FACT
</TABLE>
 
                                      II-9
<PAGE>
                               INDEX TO EXHIBITS
 
   
<TABLE>
<CAPTION>
 EXHIBIT
 NUMBER                                             DESCRIPTION
- ---------  ----------------------------------------------------------------------------------------------
<S>        <C>
 1.1**     Form of Underwriting Agreement.
 3.1**     Form of Amended and Restated Certificate of Incorporation of Metromedia Fiber Network, Inc.
 3.2**     Form of Amended and Restated Bylaws of Metromedia Fiber Network, Inc.
 4.1**     Specimen Class A Common Stock Certificate of Metromedia Fiber Network, Inc.
 5.1**     Form of Opinion of Paul, Weiss, Rifkind, Wharton & Garrison.
10.1**     Form of Metromedia Fiber Network, Inc. 1997 Incentive Stock Plan.
10.2**     Employment Agreement by and between National Fiber Network, Inc. and Stephen A. Garofalo,
           dated as of February 26, 1997.
10.3**     Employment Agreement by and between National Fiber Network, Inc. and Howard Finkelstein, dated
           as of April 30, 1997.
10.4**     Agreement made as of April 30, 1997, to be amended by a Modification Agreement made as of
           October   , 1997 by and among Metromedia Company, Stuart Subotnick, Arnold Wadler, Silvia
           Kessel, Stephen A. Garofalo and National Fiber Network, Inc.
10.5**     Franchise Agreement between The City of New York and National Fiber Network, Inc., dated as of
           December 20, 1993.
10.6**     Conduit Occupancy Agreement by and between New York Telephone Company and National Fiber
           Network, Inc., dated as of May 1993.
10.7**     Consulting Agreement between National Fiber Network and Realprop Capital Corporation, dated as
           of February 1, 1996.
10.8**     Letter Agreement from National Fiber Network, Inc. to Peter Sahagen dated February 11, 1997.
10.9**     Office Lease by and between National Fiber Network, Inc. and 110 East 42nd Street Associates,
           dated as of March 19, 1997.
10.10**    Office Lease by and between National Fiber Network, Inc. and 110 East 42nd Street, dated as of
           June 1997.
10.11**    Trademark License Agreement by and between Metromedia Company and Metromedia Fiber Network,
           Inc., dated as of August 14, 1997.
10.12      Fiber Optic Use Agreement between National Fiber Network, Inc. and NextLink New York, L.L.C.,
           dated as of June 3, 1997 (portions of this exhibit are subject to a request to the Securities
           and Exchange Commission for confidential treatment and omitted material has been separately
           filed with the Securities and Exchange Commission).
10.13      Amended and Restated Agreement for the Provision of a Fiber Optic Transmission Network dated
           as of the Effective Date by and between US ONE Communications of New York, Inc. and National
           Fiber Network, Inc. (portions of this exhibit are subject to a request to the Securities and
           Exchange Commission for confidential treatment and omitted material has been separately filed
           with the Securities and Exchange Commission).
11.1**     Statement Re Computation of Per Share Earnings.
21.1**     List of Subsidiaries of Metromedia Fiber Network, Inc.
23.1**     Consent of Paul, Weiss, Rifkind, Wharton & Garrison (contained in the opinion filed as Exhibit
           5.1 hereto).
23.2**     Consent of Ernst & Young, LLP
23.3**     Consent of M. R. Weiser & Co., LLP
23.4**     Consent of Richard A. Eisner & Company, LLP
23.5**     Consent of David Rockefeller.
23.6**     Consent of Leonard White.
24.1**     Power of Attorney from officers and directors (contained on signature page).
27.1**     Financial Data Schedule.
</TABLE>
    
 
- ------------------------
 
   
**  Previously filed.
    

<PAGE>
                                                               Exhibit 10.12 

                             CONFIDENTIAL TREATMENT (1)




                              Fiber Optic Use Agreement
                                    by and between
                             National Fiber Network, Inc.
                                         and
                              NEXTLINK New York, L.L.C.
                                     June 3, 1997











- ------------------
(1) Redacted portions have been marked with an asterisk (*).  The redacted 
material is subject to a request for confidential treatment and has been 
filed separately with the Securities and Exchange Commission.

<PAGE>

                              FIBER OPTIC USE AGREEMENT

         This AGREEMENT ("Agreement") made and entered into as of the ___ day 
of June, 1997, by and between National Fiber Network, Inc., a Delaware 
corporation ("NFN") and NEXTLINK, New York, L.L.C. ("NEXTLINK"), a Washington 
limited liability company (either NFN or NEXTLINK a "Party," and collectively 
the "Parties").

         WHEREAS NFN constructs and maintains a fiber optic cable network (the
"NFN System") and desires to provide NEXTLINK with long term exclusive use of a
portion of this network subject to the terms and conditions of this Agreement;

         WHEREAS NEXTLINK desires to acquire certain long term rights to use
portions of the NFN System as described herein, subject to the terms and
conditions of this Agreement;

         NOW, THEREFORE, in consideration of the mutual covenants and
agreements hereinafter contained, the Parties and the Guarantor hereby expressly
agree as follows.

                                      ARTICLE I

                                     DEFINITIONS

         For purposes of this Agreement words and phrases spelled with initial
capital letters (other than proper names, section headings, and the beginnings
of sentences) shall have the defined meanings set forth in the applicable
provisions of this Agreement or in this Article I.

         "Central Office" shall mean a NYNEX end office or tandem office
facility where traffic may, through the related entrance facility, be connected
to the NYNEX network.

         "Leased Fibers" shall mean the NEXTLINK Fibers together with any
additional fibers that NEXTLINK may lease from NFN pursuant to this Agreement. 
With regard to any NEXTLINK Extension, Leased Fibers shall terminate at the
point along such Extension at which NEXTLINK connects fibers or other facilities
of its own.

         "NEXTLINK Extension" shall mean a fiber optic cable leased from NFN
connecting the NEXTLINK Fibers and a NEXTLINK Location.

         "NEXTLINK Fibers" shall mean the fibers leased by NEXTLINK from NFN
pursuant to this Agreement, as described in Exhibit A hereto and more fully
defined in Subarticle 2.1 herein.


                                          
<PAGE>


         "NEXTLINK Locations" shall mean a building or buildings specified by
NEXTLINK and set forth in the initial Exhibit F hereto, which premises shall
begin at the exterior demising walls of such buildings, or specific "splice
points" as mutually agreed upon by the Parties on or before the second
anniversary of this Agreement.  A NEXTLINK Location may be a Central Office or
other commercial or residential building or a splice point not thin a building.

         "NFN System" shall mean the fiber optic network controlled and
operated by NFN in New York City with a connection to Jersey City, New Jersey,
on the date of this Agreement.

         "Pro Rata" shall mean the percentage of the total count of optical
fiber strands and other cables within relocated conduit under the control of NFN
that is represented by the Leased Fibers.


                                      ARTICLE II

                                    TERM AND LEASE

         2.1  Unless sooner terminated in accordance with the terms of this
Agreement, NFN hereby grants to NEXTLINK a lease of the exclusive use of *
fiber-miles of optical fiber, provided as those contiguous strands of fiber
within the NFN System as described in Exhibit A to this Agreement and as other
fibers (the "Banked Fiber") at locations within the NFN System in Manhattan as
NEXTLINK may choose to utilize up to the total of * fiber-miles of optical fiber
(such fiber together with NEXTLINK Extensions to those NEXTLINK Locations listed
in the initial Exhibit F hereto, hereinafter, "NEXTLINK Fibers"), for an initial
term commencing on the date of this Agreement and terminating on December 19,
2008 (the "Initial Term"), and a first additional term of one hundred and two
(102) months, commencing immediately upon the expiration of the Initial Term.

         2.2  Banked Fiber may be used from time to time during the term of
this Agreement pursuant to the provisions of this Subarticle. NEXTLINK shall
proposed the utilization of Banked Fiber by completing a Banked Fiber Request
Form as provided by NFN. Upon receipt of a completed Request Form, NFN shall
evaluate NEXTLINK's request and either (i) make such Banked Fiber available for
use by NEXTLINK within thirty (30) days or (ii) notify NEXTLINK within five (5)
days that Banked Fiber is not available at the location requested.  Banked Fiber
may also be used for new NEXTLINK Extensions pursuant to Subarticle 2.5(b), in
which case Additional Fiber Charges shall not be assessed to the extent that
fiber-miles of Banked Fiber are available; Monthly Recurring Charges pursuant to
Subarticle 3.2, however, shall be required for NEXTLINK Extensions employing
Banked Fiber.
                                          2
<PAGE>

         2.3  NEXTLINK may, at its sole discretion, elect a second additional
term of ten (10) years, commencing immediately upon the expiration of the first
additional term (either the first or the second additional terms hereinafter an
"Additional Term").  Any Additional Term shall be subject to such terms and
conditions that may be imposed by the franchise granted to NFN by the City of
New York for the period of such Additional Term.  NEXTLINK shall provide written
notice to NFN of its intention to exercise the option to make use of such second
Additional Term no later than six (6) months but no more than twelve (12) months
prior to the expiration of the first Additional Term.

         2.4  NFN shall, as soon as practicable, but no later than nine (9)
months after the date of this Agreement, provide access to NEXTLINK for the
installation of its originating and terminating equipment on the NEXTLINK
Extensions at the points listed in Exhibit F hereto.

              (a)  NFN shall test all Leased Fibers in accordance with the
procedures specified in Exhibit D ("Fiber Acceptance Testing") to verify that
the Leased Fibers are installed and operating in accordance with the
specifications described in Exhibit D.  Fiber Acceptance Testing shall progress
span by span along each segment as cable splicing progresses, so that test
results may be reviewed in a timely manner.  NFN shall provide NEXTLINK at least
five (5) days advance notice of the date and time of each Fiber Acceptance
Testing (each of which shall take place during normal business hours) such that
NEXTLINK shall have the right, but not the obligation, to have a person or
persons present to observe NFN Fiber Acceptance Testing.  When NFN has
determined that the results of the Fiber Acceptance Testing with respect to a
particular span show that the Leased Fibers so tested are installed and
operating substantially in conformity with the applicable specifications set
forth in Exhibit D, NFN shall promptly provide NEXTLINK with a copy of such test
results.

              (b)  When NFN reasonably determines the Leased Fibers with
respect to an entire segment are installed and operating substantially in
conformity with the applicable specifications set forth in Exhibit D, NFN shall
promptly provide written notice of completion to NEXTLINK (a "Completion
Notice").  NEXTLINK shall, within seven (7) days of receipt of the Completion
Notice, either reject the Completion Notice specifying the defect or failure in
such Fiber Acceptance Testing or give NFN written notice of acceptance of such
Fiber Acceptance Testing (the period from the date of NEXTLINK's receipt of the
Completion Notice to the date of NFN's receipt of NEXTLINK's notice of rejection
or acceptance being referred to herein as the "Review Period".  In the event
NEXTLINK rejects the Completion Notice, NFN shall promptly, and not later than
seven (7) days after receipt of NEXTLINK's notice of rejection, and at no cost
to NEXTLINK, commence to remedy the defect or failure.  Thereafter, NFN shall
again give NEXTLINK a Completion Notice with respect to such NEXTLINK Fibers. 
The foregoing procedure shall apply again and successively thereafter for a
total of two attempts to remedy the defect or failure.  If NFN fails to
adequately remedy or 

                                       3
<PAGE>

complete the defect or failure after two attempts, NEXTLINK shall have the right
to proceed promptly and in an economically efficient manner to cure such defects
or failures at NFN's cost and expense, which shall be paid by NFN to NEXTLINK
upon demand, or at the election of NEXTLINK offset from any payment by NEXTLINK
to NFN under this Agreement.  No acceptance of, or failure by NEXTLINK to
reject, the Completion Notice shall be deemed to be a waiver of any rights or
remedies of NEXTLINK under this Agreement; provided that, any failure by
NEXTLINK to timely reject as set forth above shall operate as a constructive
acceptance for purposes of this Agreement.  The date when NEXTLINK accepts or is
deemed to have accepted a Completion Notice or cures such defects at NFN'S cost
and expense as provided above with respect to any portion of the Leased Fibers
is herein defined as the "Acceptance Date".

         2.5  (a) During the first five (5) years of the Initial Term, at
NEXTLINK's request and to the extent available, NFN shall make available to
NEXTLINK additional fibers on the NFN System ("Additional Fiber") not including
the Banked Fiber, up to a maximum of * additional fiber miles, for NEXTLINK's
use during the time remaining in such Initial Term and any first Additional Term
subject to the payment of Additional Fiber Charges as set forth herein.  The
maximum of * additional fiber miles shall apply to the total of fiber provided
under this Subarticle and Subarticle 2.5(c).

              (b)  During the first five (5) years of the Initial Term, at
NEXTLINK's request and where technically and logistically feasible, NFN shall
construct and maintain NEXTLINK Extensions limited to a length of two miles or
less from the NFN fiber network as it exists at the time such NEXTLINK Extension
is requested, subject to Additional Fiber Charges and charges for construction
and installation as set forth herein.  Upon completion of the construction of a
NEXTLINK Extension to a NEXTLINK Location and subject to approval by the owners
of underlying property and rights-of-way and advance notice to NFN, NEXTLINK may
have access to that portion of such NEXTLINK Extension as shall begin with the
"negative-one manhole," with respect to a Central Office, and the "point of
entry" manhole, with respect to other NEXTLINK Locations, (as such terms are
commonly defined in the industry) to connect its equipment and fiber to such
NEXTLINK Extensions.  Beginning with the point on the fiber optic cable at which
NEXTLINK connects such equipment and fiber, NFN shall have no further obligation
to monitor or maintain such NEXTLINK Extension.

              (c)  During the first five (5) years of the Initial Term,
NEXTLINK, shall have the option to lease fiber on major expansions (greater than
two route miles) to NFN's fiber network in New York, at the then current
Additional Fiber Rate, as set forth in Exhibit B hereto, subject to adjustments
for expansion zones that will be disclosed at the time such major expansions are
undertaken, up to the maximum of * additional fiber miles.

                                       4
<PAGE>

              (d)  No other leases of fiber are covered under this Agreement.

              (e)  All commitments by NFN to provide fiber or services pursuant
to this Subarticle 2.4 shall expire on the earlier of (i) the expiration of the
period during which NFN has agreed to provide such fiber or services in this
Subarticle, (ii) the date on which NEXTLINK receives a franchise to provide high
capacity telecommunications services in the City of New York, or (iii) the date
on which NEXTLINK first begins construction (directly or through contractors or
agents) of fiber optic cables of its own other than construction of not more
than an aggregate of five (5) miles on private rights of way.

         2.6  NFN shall, at the request of NEXTLINK and to the extent
available, provide such construction and installation services as are necessary
or useful to the construction of NEXTLINK Extensions and the connection of
NEXTLINK's origination and termination equipment to the NEXTLINK Fibers or
NEXTLINK Extensions.  Such services shall be provided at rates set forth in
Exhibit B hereto, or, if no applicable rate is included in Exhibit B, at such
rates as the Parties may subsequently agree upon.  If the Parties fail to agree
upon rates for such services within six (6) months of the receipt by NFN of a
request for such services by NEXTLINK, the issue of such rates shall be
submitted for arbitration in accordance with Article XX herein.  Charges for
construction and installation services initiated by NFN contractors and
suppliers shall be due and payable thirty (30) days from the receipt by NEXTLINK
of invoices for such charges.  Charges for associated NFN management and
administration fees shall be due and payable ten (10) days from the Acceptance
Date for the NEXTLINK Location associated with such services.  NFN shall not be
obligated to furnish construction and installation services under this Agreement
at any time following the date that is the earlier of: (i) the fifth anniversary
of this Agreement, (ii) the date on which NEXTLINK receives a franchise to
provide high capacity telecommunications services in the City of New York, or
(iii) the date on which NEXTLINK first begins construction (directly or through
contractors or agents) of fiber optic cables of its own other than construction
of not more than an aggregate of five (5) miles on private rights of way.

         2.7  Exhibit F may be amended from time to time by agreement of the
Parties to add or remove NEXTLINK Locations.  Any such amended Exhibit F shall
be incorporated into this Agreement only when signed by the Parties.  NFN agrees
to consider in good faith amendments to Exhibit F proposed by NEXTLINK from time
to time after the date of this Agreement and to assent to such amendments unless
(i) it is prohibited from doing so by applicable law or binding agreement or
(ii) the proposed amendment would require the construction of an extension in a
manner that is not technically feasible.  The rates and charges for construction
and use of fiber associated with such amendments to Exhibit F shall be the same
as those set forth in Subarticles 2.6, 3.2, and 3.3 herein for such NEXTLINK
Locations.  No further amendments to Exhibit F shall be made following the date
that is the earlier 


                                        5
<PAGE>
of:  (i) the fifth anniversary of this Agreement, (ii) the date on which
NEXTLINK receives a franchise to provide high capacity telecommunications
services in the City of New York, or (iii) the date on which NEXTLINK first
begins construction (directly or through contractors or agents) of fiber optic
cables of its own other  construction of not more than an aggregate of five (5)
miles on private rights of way

         2.8  If, at the request of NEXTLINK NFN provides available space in
such cages, conduits, or buildings as may be necessary or useful to the
installation and operation of NEXTLINK equipment, NEXTLINK shall pay NFN an
annual rent for such space as set forth in Exhibit B hereto. or, if no
applicable rent is included in Exhibit B, at such rental rates as the Parties
may subsequently agree upon.  The payment of rent shall be subject to the terms
and conditions for such payments under this Agreement and the lease of spare
under this Subarticle shall be subject to all relevant terms and conditions of
this Agreement.

         2.9  Upon the expiration of the lease provided for in this Agreement,
or any earlier termination of this Agreement, NEXTLINK shall exercise
commercially reasonable efforts to remove all NEXTLINK property from the NFN
System and reroute NEXTLINK's traffic within (60) days from such expiration or
termination and shall complete such removal in a manner that does not interfere
with or damage the NFN System.  In the event that NEXTLINK fails to remove its
property within such period, NFN may remove and store the NEXTLINK property at
NEXTLINK's expense.

                                     ARTICLE III

                                   TERMS OF PAYMENT

         3.1  NEXTLINK shall pay NFN upfront payments as set forth in Exhibit B
hereto, as consideration for the Initial Term and the first Additional Term of
the lease of the NEXTLINK Fibers described in Exhibit A hereto (the "Upfront
Payments").  These Upfront Payments shall be due according to the payment
schedule set forth in Exhibit B.  Charges for a second Additional Term shall be
at market rates at the time NEXTLINK elects to secure such second Additional
Term pursuant to Subarticle 2.3 above.  If the Parties fail to reach an
agreement with regard to market rates for such second Additional Term, the
issues remaining open shall be submitted to arbitration pursuant to Article XX
of this Agreement.

         3.2  NEXTLINK shall Pay NFN a Monthly Recurring Charge per terminated
fiber and, as set forth in Exhibit B, for each NEXTLINK Extension other than
those extensions to the NEXTLINK Locations set forth in Exhibit F hereto.  The
Monthly Recurring Charge shall be adjusted for inflation annually as set forth
in Exhibit B hereto and shall be adjusted to accommodate new Taxes pursuant to
Subarticle 11.2 herein.  The first Monthly Recurring Charge, along with any rent
pursuant to Subarticle 2.8, shall be payable on the Acceptance Date for the 


                                        6
<PAGE>
NEXTLINK Location associated with such Monthly Recurring Charge and rent. 
Subsequent Monthly Recurring Charges and rent shall be due on the first day of
each month during the Initial Term and any Additional Term.

         3.3  Within five (5) days of the Acceptance Date for any Additional
Fiber, NEXTLINK shall pay a one-time Additional Fiber Charge as set forth in
Exhibit B hereto, which charge shall be based on the length and number of
strands that comprise the Additional Fiber and the number of months remaining in
the Initial Term and any first Additional Term.

         3.4  If a first Additional Term is unavailable because NFN's franchise
is not renewed, NFN shall refund the upfront payment for such first Additional
Term within thirty (30) days of the expiration of the Initial Term.

         3.5  In any circumstances under this Agreement in which NFN contracts
with third parties for maintenance or construction services the charges for
which are to be passed through to NEXTLINK, with or without the addition of any
management, administration, or other fees as set forth herein, NFN shall secure
bids for such maintenance or construction services from not fewer than two and
not more than three independent contractors chosen by NFN and the amount
billable to NEXTLINK shall be the lowest of the bids submitted (plus any costs
necessary to the project that are not included in the bid and a 15% Management
and Administration fee), regardless of whether NFN actually selects the lowest
bidding contractor to perform the service.

         3.6  Escrow.  On the date of the execution of this Agreement the
Parties shall enter an Escrow Agreement substantially in conformance with the
form of agreement attached as Exhibit G hereto pursuant to which agreement
NEXTLINK shall deposit six million ($6,000,000) in an escrow account with First
National Association (the "Escrow Agent").  The escrow agreement shall authorize
the Escrow Agent to remit the Upfront Payments to NFN pursuant to the Schedule
of Rates and Charges in Exhibit B hereto, when the conditions precedent to such
payments, as provided herein, are satisfied.

                                   ARTICLE IV

                  MAINTENANCE AND REPAIR OF THE LEASED FIBERS

         4.1   Routine Maintenance.  Routine maintenance and repair of the
Leased Fibers described in this section ("Scheduled Maintenance") shall be
performed at NFN's expense by or under the direction of NFN, at NFN's reasonable
discretion or at NEXTLINK's request.  Scheduled Maintenance shall commence with
respect to each segment upon the Acceptance Date for such segment.

                                       7
<PAGE>

         4.2  Unscheduled Maintenance.  Non-routine maintenance and repair of
the Leased Fibers which is not included as Scheduled Maintenance ("Unscheduled
Maintenance"), shall be performed at NFN's expense (except To the extent caused
by the acts or omissions of NEXTLINK) by or under the direction of NFN. 
Unscheduled Maintenance shall commence with respect to each segment upon the
Acceptance Date for such segment.  Unscheduled Maintenance shall consist of:

              (a)  "Emergency Unscheduled Maintenance" in response to an alarm
identification by NFN's Operations Center, notification by NEXTLINK or
notification by any third party of any failure, interruption or impairment in
the operation of the Leased Fibers, or any event imminently likely to cause the
failure, interruption or impairment in the operation of the Leased Fibers.

              (b)  "Non-Emergency Unscheduled Maintenance" in response to any
potential service-affecting situation to prevent any failure, interruption or
impairment in the operation of the Leased Fibers.

         NEXTLINK shall immediately report the need for Unscheduled Maintenance
to NFN in accordance with procedures promulgated by NFN from time to time.  NFN
will log the time of NEXTLINK's report, verify the problem and will dispatch
personnel immediately to take corrective action.

         4.3   Operations Centers.  NFN shall operate and maintain one or more
Operations Centers ("OCs") staffed twenty-four hours a day, seven (7) days a
week by trained and qualified personnel beginning with the earliest Acceptance
Date under this Agreement.  Qualified maintenance personnel shall be available
for dispatch twenty-four (24) hours a day, seven (7) days week.  NFN shall use
its best efforts to have its first maintenance representative at the site
requiring Emergency Unscheduled Maintenance activity within two (2) hours after
the time NFN becomes aware of an event requiring Emergency Unscheduled
Maintenance.  NFN shall maintain a telephone number through which NEXTLINK may
contact personnel at an OC without toll from the New York metropolitan area. 
NFN's OC personnel shall dispatch maintenance and repair personnel along the
system to handle and repair problems detected in the Leased Fibers, (i) through
NEXTLINK's remote surveillance equipment and upon notification by NEXTLINK to
NFN, or (ii) upon notification by a third party.

         4.4  Cooperation and Coordination.  NEXTLINK shall utilize an
Operations Escalation List, as updated from time to time, to report and seek
immediate initial redress of exceptions noted in the performance of NFN in
meeting maintenance service objectives.  NEXTLINK will, as necessary, arrange
for escorted access for NFN to all sites of the Leased Fibers, subject to
applicable contractual underlying real property and other third-party
limitations and restrictions.  In performing its services hereunder, NFN shall
take workmanlike care to prevent impairment to the signal continuity and
performance of the Leased Fibers.  The 


                                       8
<PAGE>
precautions to be taken by NFN shall include notification to NEXTLINK.  In
addition, NFN shall reasonably cooperate with NEXTLINK in sharing information
and analyzing the disturbances regarding the cable and/or fibers.  In the event
that any Scheduled or Unscheduled Maintenance hereunder requires a traffic roll
or reconfiguration involving cable, fiber, electronic equipment or regeneration
or other facilities of NEXTLINK, then NEXTLINK shall, at NFN's reasonable
request, make such personnel of NEXTLINK available as may be necessary in order
to accomplish such maintenance, which personnel shall coordinate and cooperate
with NFN in performing such maintenance as required of NFN hereunder.  NFN shall
use its best efforts to notify NEXTLINK at least [five] business days prior to
the date of any Scheduled Maintenance on any NEXTLINK Extensions and as soon as
possible after becoming aware of the need for Unscheduled Maintenance.  NEXTLINK
shall have the right to be present during the performance of any Scheduled
Maintenance on any NEXTLINK Extensions or Unscheduled Maintenance so long as
this requirement does not interfere with NFN's ability to perform its
obligations under this Agreement.  In the even that Scheduled Maintenance is
canceled or delayed for whatever reason as previously notified, NFN shall notify
NEXTLINK at NFN's earliest opportunity, and will comply with the provisions of
the previous sentence to reschedule any delayed activity.

         4.5  Facilities.  NFN shall maintain the Leased Fibers in a manner
which will permit NEXTLINK's use, in accordance with the terms and conditions of
this Agreement, of the Leased Fibers and associated facilities required to be
provided under the terms of this Agreement.  Except to the extent otherwise
expressly provided in this Agreement, NEXTLINK will be solely responsible for
providing and paying for any and all maintenance of all electronic, optronic and
other equipment, materials and facilities used by NEXTLINK in connection with
the operation of the Leased Fibers, none of which is included in the maintenance
services to be provided hereunder.

         4.6  Cable/Fibers.  NFN shall perform appropriate Scheduled
Maintenance on the cable contained in the Leased Fibers in accordance with NFN's
then current preventative maintenance procedures as agreed to by NEXTLINK which
shall not substantially deviate from standard industry practice. NFN shall
maintain sufficient capability to teleconference with NEXTLINK during an
Emergency Unscheduled Maintenance in order to provide regular communication
during the repair process.  When correcting or repairing cable discontinuity or
damage, including but not limited to in the event of Emergency Unscheduled
Maintenance, NFN shall use reasonable efforts to repair traffic affecting
discontinuity within four (4) hours after the NFN maintenance employee's arrival
at the problem site.  In order to accomplish such objective, it is acknowledged
that the repairs so effected may be temporary in nature.  In such event, within
twenty-four (24) hours after completion of any such Emergency Unscheduled
Maintenance, NFN shall commence its planning for permanent repair, and
thereafter promptly shall notify NEXTLINK of such plans, and shall implement
such permanent repair within an appropriate time thereafter.  


                                      9
<PAGE>
Restoration of open fibers on fiber strands not immediately required for service
shall be completed on a mutually agreed-upon schedule.  If the fiber is required
for immediate service, the repair shall be scheduled for the next available
Planned Service Work Period ("PSWP").  In performing repairs, NFN shall comply
with the splicing specifications as set forth in Exhibit D. NFN shall provide to
NEXTLINK any modifications to these specifications as may be necessary or
appropriate in any particular instance for NEXTLINK's approval, which approval
shall not be unreasonably withheld.  NFN's representatives that are responsible
for initial restoration of a cut cable shall carry on their vehicles the
typically appropriate equipment that would enable a temporary splice, with the
objective of restoring operating capability in as little time as possible.  NFN
shall maintain and supply an inventory of spare cable in storage facilities
supplied and maintained by NFN at strategic locations to facilitate timely
restoration.

         4.7  Planned Service Work Period ("PSWP").  Scheduled Maintenance
which is reasonably expected to produce any signal discontinuity must be
coordinated between the parties.  Generally, this work should be scheduled after
midnight and before 6:00 a.m. local time.  Major system work such as fiber rolls
and hot cuts will be scheduled for PSWP weekends.  A calendar showing approved
PSWP will be agreed upon in the last quarter of every year for the year to come.
The intent is to avoid jeopardy work on the first and last weekends of the month
and high-traffic holidays.

         4.8  Restoration.  NFN shall use its best efforts to respond to any
interruption of service or a failure of the Leased Fibers to operate in
accordance with the specifications set forth in Exhibit D (in any event, an
"Outage") as quickly as possible in accordance with the procedures set forth
herein.  When restoring a cut cable in the Leased Fibers, the parties agree to
work together to restore all traffic as quickly as possible.  NFN, promptly upon
arriving on the site of the cut, shall determine the course of action to be
taken to restore the cable and shall begin restoration efforts.  NFN shall
splice fibers tube by tube or ribbon by ribbon, rotating between tubes or
ribbons operated by any fiber lessees or holders of IRUs (collectively,
"Interest Holders"), including NEXTLINK, in accordance with the following
described priority and rotation mechanics; provided that, lit fibers in all
buffer tubes or ribbons shall have priority over any dark fibers in order to
allow transmission systems to come back on line; and provided further that NFN
will continue such restoration efforts until all lit fibers in all buffer tubes
or ribbons are spliced and all traffic restored.  In general, priority among
Interest Holders affected by a cut shall be determined on a rotating
restoration-by-restoration and segment-by-segment basis, to provide fair
restoration to all Interest Holders.  However, NFN shall establish a Priority
Customer Grouping ("PCG") which will receive, whenever possible, priority in the
restoration of tubes or ribbons that affect their use of NFN facilities.  All
members of the PCG shall receive equal treatment.  NFN shall include NEXTLINK in
its PCG.  The goal of emergency restoration splicing shall be to restore service
as quickly as possible.  This requires the use of some  of mechanical 


                                       10
<PAGE>
splice, such as the "3M Fiber Lock" to complete the temporary restoration. 
Permanent restorations will take place as soon as possible after the temporary
splice is complete.

         4.9   Subcontracting.  NFN may subcontract any of the maintenance
services hereunder; provided that NFN shall require the subcontractor(s) to
perform in accordance with the requirement and procedures set forth herein.  The
use of any such subcontractor shall not relieve NFN of any of its obligations
hereunder.

         4.10 Fiber Replacement.  In the event all or any part of the Leased
Fibers shall require replacement during the term of this Agreement, such
replacement shall be made as soon as reasonably practical, at NFN's sole cost
and expense; except, however, if the replacement of the Leased Fibers is
required as a result of the acts or omissions of NEXTLINK, NFN shall make such
replacement at NEXTLINK's cost and expense on a time and materials basis.

         4.11  Outages.  During the Term of this Agreement, NFN shall credit to
NEXTLINK against the next due Monthly Recurring Charge, the amounts set forth in
Exhibit E hereto, as compensation for "Outages." For the purposes of this
Agreement, an Outage is the complete interruption of service over any fiber
circuit at any NEXTLINK Location, whether or not due to the physical damage or
severance of such fiber circuit; except that no interruption of service caused
in whole or in part by the negligent act or omission or willful misconduct of
NEXTLINK shall constitute an Outage.

         4.12 Replacement Maintenance.  For any isolated incident wherein NFN
has failed to cure an Outage Within twenty-four (24) hours of the onset of
service interruption at a specific location, NEXTLINK may secure the services of
the contractor selected in advance by NFN for the purposes of repairing and
maintaining the Leased Fibers at such location at NFN's expense.

                                   ARTICLE V

                  PERMITS, ACCESS, AND REQUIRED RIGHTS-OF-WAY

         5.1  NFN represents and warrants that it has obtained or will obtain
all regulatory approvals, franchises, permits, orders, consents, and
rights-of-way, either by contract or through a franchise, and all other rights
necessary to be obtained by NFN to enable its provision of the Leased Fibers
(all of which are herein collectively referred to as the "Rights-of-Way").  On
or before the Acceptance Date for each NEXTLINK Location NFN shall provide
NEXTLINK with a copy or a detailed summary of all Rights-of-Way applicable to
the segment of the NFN System or the NEXTLINK Extension associated with such
NEXTLINK Location.  NFN shall use commercially reasonable efforts to cause such
Rights-of-Way to remain effective through the Initial Term and the Additional
Term of this Agreement and in the event 


                                       11
<PAGE>
that any Rights-of-Way are discontinued and not replaced and the loss of such
Rights-of-Way adversely affects the use of the NEXTLINK Fibers, NFN shall issue
a rebate to NEXTLINK of a portion of the upfront payment for any Term of this
Agreement in which such loss of Right-of-Way has an effect, such rebate to be in
proportion to the number of fiber-miles affected and the duration of any
disruption in service caused by such loss of Right-of-Way.

         5.2  NEXTLINK shall provide, obtain, and maintain in full force and
effect, all necessary approvals, licenses, or leases for building entrance
facilities at NEXTLINK Locations and the placement of intra-building conduits
and equipment through which the Leased Fibers may pass into NEXTLINK's
Locations.  NEXTLINK shall provide NFN with 24-hour-per-day, 7-day-per-week
escorted access to fix NEXTLINK Locations with notice by NFN reasonable under
the circumstances for which access is required.  NEXTLINK shall provide at no
cost to NFN all electricity, sanitary facilities, and other utilities at the
NEXTLINK Locations as NFN may reasonably require to provide safe and convenient
working conditions during the construction and installation of NEXTLINK
Extensions.

                                   ARTICLE VI

                          RELOCATION OF THE NFN SYSTEM
                            AND THE NEXTLINK FIBERS

         6.1  If NFN receives notice of any request, intent, or plan by any
third party, including, but not limited to, a governmental entity, to relocate
any segment of NFN's fiber network used in the provision of the Leased Fibers,
NFN shall notify NEXTLINK of such request, intent, or plan and shall consult
with NEXTLINK regarding proceedings and negotiations involving such proposed
relocation and communicate with NEXTLINK regarding the status of such
proceedings and negotiations.  If NFN is required by any such third party to
relocate any segment of NFN's fiber network used in providing the Leased Fibers,
NFN shall give NEXTLINK at least sixty (60) days' (or such lesser period of
notice that NFN may have received) prior written notice of any such relocation
("Relocation Notice").  Along with the Relocation Notice, NFN shall provide an
estimate of the cost of such relocation, NFN shall relocate the Leased Fibers
and, to the extent NFN is not reimbursed for the cost of such relocation by a
third party, governmental entity or otherwise, NEXTLINK shall pay its Pro Rata
share of the costs associated with the relocation of the Leased Fibers; except,
however, to the extent that the factors causing such relocation are under NFN's
control.  NFN shall use its reasonable best efforts to secure an agreement for
reimbursement from any third party, governmental entity or otherwise, requiring
any relocation of the NFN System and the Leased Fibers.

                                  ARTICLE VII

                                  CONDEMNATION
                                       12
<PAGE>

         7.1  In the event any portion of the NFN System and/or the Leased
Fibers, or the Rights-of-Way in or upon which they shall have been installed,
become the subject of a condemnation proceeding which is not dismissed within
one hundred eighty (180) days of the date of filing of such proceeding and which
could reasonably be expected to result in a taking by any governmental agency or
other party cloaked with the power of eminent domain for public purpose or use,
both parties shall be entitled to the extent permitted under applicable law, to
participate in any condemnation proceedings to seek to obtain compensation by
either joint or separate awards for the economic value of their respective
interests in the portion of the NFN System subject to such condemnation.

         7.2  Upon its receipt of a formal notice of condemnation or taking,
NFN shall notify  NEXTLINK immediately of any condemnation proceeding filed
against the NFN System, including the Leased Fibers, or the Rights-of-Way in or
upon which the Leased Fibers shall have been installed.  NFN shall also notify
NEXTLINK of any similar threatened condemnation proceeding and agrees not to
sell the Leased Fibers or Rights-of-Way to such acquiring agency, authority or
other party in lieu of condemnation without prior written notice of five (5)
business days to NEXTLINK.

                                  ARTICLE VIII

                            USE OF THE LEASED FIBERS

         8.1  NEXTLINK shall not, by itself or by or through any agent or
contractor, make any repair or replacement of the Leased Fibers or any other
equipment owned by NFN except as provided in Subarticle 4.12 herein.

         8.2  NEXTLINK shall not use the Leased Fibers in any way which fails
to comply with any applicable federal, state or local code, ordinance, law,
rule, regulation or restriction or any policy of insurance.

         8.3  NEXTLINK shall not, directly or indirectly, sublease, condo,
sublicense, or wholesale to any third party dark fiber optic capacity on any
Leased Fiber.  NEXTLINK shall no directly or indirectly, sublease, condo,
sublicense, or wholesale to any third party lit fiber optic capacity on any
Leased Fiber unless such lit fiber optic capacity is distributed through
NEXTLINK's transmission and switching equipment.

                                   ARTICLE IX

                         OWNERSHIP OF THE LEASED FIBERS

                                       13
<PAGE>

         9.1  NEXTLINK shall have an undivided exclusive leasehold interest in
the Leased Fibers.  NFN shall have undivided, absolute legal title to ownership
in the NFN System, including the Leased Fibers.

         9.2  Except as otherwise provided in this Agreement, NEXTLINK shall
not represent to any third party that any party other than NFN is the legal
owner of the Leased Fibers.

                                   ARTICLE X

                         REPRESENTATIONS AND WARRANTIES

         10.1  NFN represents that the Leased Fibers have been constructed
substantially as represented in Exhibit A hereto and warrants that for the Term
of this Agreement, the NFN System shall, at all times during the Term of this
Agreement: (a) be in full compliance with and operate within the parameters of
the specifications set forth in Exhibit D hereto, and (b) be fit to perform as
an optical fiber system; provided, however, that such warranties shall in no way
be deemed to be a limitation on or in derogation of NFN's obligations under
Article IV herein.

         10.2 EXCEPT AS EXPRESSLY PROVIDED IN THE FOREGOING SUBARTICLE 10.1,
NFN MAKES NO WARRANTY, EXPRESS OR IMPLIED, INCLUDING ANY WARRANTY OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE WITH RESPECT TO THE FIBER
OPTIC SYSTEM AND THE LEASED FIBERS, DEMAND MAINTENANCE, AND SCHEDULED
MAINTENANCE THEREON.  IN NO EVENT SHALL EITHER PARTY HERETO BE LIABLE TO THE
OTHER PARTY OR TO ANY THIRD PARTY FOR ANY INDIRECT, SPECIAL, CONSEQUENTIAL, OR
PUNITIVE DAMAGES, INCLUDING THOSE BASED ON LOSS OF REVENUES, PROFITS, OR
BUSINESS OPPORTUNITIES, WHETHER OR NOT SUCH PARTY HAD OR SHOULD HAVE HAD ANY
KNOWLEDGE, ACTUAL OR CONSTRUCTIVE, THAT SUCH DAMAGES MIGHT BE INCURRED.

         10.3 NFN represents and warrants to NEXTLINK that it has full
corporate power and authority to execute and deliver this Agreement and to
consummate the transactions contemplated hereby.  The execution and delivery of
this Agreement and the consummation of the transactions contemplated hereby by
NFN have been duly and validly authorized by all necessary corporate action on
the part of NFN.

         10.4  NEXTLINK represents and warrants to NFN that it has full
corporate power and authority to execute and deliver this Agreement and to
consummate the transactions contemplated hereby.  The execution and delivery of
this Agreement and the consummation of the transactions contemplated hereby by 


                                       14
<PAGE>
NEXTLINK have been duly and validly authorized by all necessary corporate action
on the part of NEXTLINK.

         10.5 NFN represents and warrants to NEXTLINK that NFN is in compliance
in all material respects with all laws and regulations applicable to its
operation of the NFN System, including its franchise to operate within the City
of New York.  NFN has obtained and holds all permits, licenses, and approvals
necessary to conduct the operation of the NFN System as presently conducted and
as contemplated by this Agreement, in accordance with applicable law.  Neither
the execution or performance of this Agreement nor the delivery of the leased
fibers contemplated hereby conflict with or result in a breach or violation of
any provision of NFN's franchise or applicable law.  There is no action, suit,
investigation, claim, arbitration, or litigation pending, or to NFN's knowledge,
threatened against, affecting, or involving NFN or the operation of the NFN
System at law or in equity or before any court, arbitrator, or governmental
authority that is reasonably likely to result in a material adverse effect on
the operation of the NFN System.  NFN is not in default in any material respect
of any contract with a third party that is reasonably likely to result in a
material adverse effect upon the operation of the NFN System.

         10.6 NEXTLINK represents and warrants to NFN that NEXTLINK is in
compliance in all material respects with all laws and regulations applicable to
the operation of the business it intends to pursue through the use of the NFN
Fiber.  NEXTLINK has obtained or intends to obtain all permits, licenses, and
approvals necessary to conduct its business as contemplated by this Agreement,
in accordance with applicable law.  Neither the execution or performance of this
Agreement nor the acceptance of the leased fibers contemplated hereby conflict
with or result in a breach or violation of any provision of applicable law. 
There is no action, suit, investigation, claim, arbitration, or litigation
pending, or to NEXTLINK's knowledge, threatened against, affecting, or involving
NEXTLINK at law or in equity or before any court, arbitrator, or governmental
authority that is reasonably likely to result in a material adverse effect on
NEXTLINK's performance under this Agreement.  NEXTLINK is not in default in any
material respect of any contract with a third party that is reasonably likely to
result in a material adverse effect upon NEXTLINK's performance under this
Agreement.

                                   ARTICLE XI
                                           
                                     TAXES
                                           
         11.1 NEXTLINK shall be responsible for and shall timely pay any and
all Taxes imposed with respect to this Agreement upon NEXTLINK.  For the
purposes of this Agreement, Taxes shall include license, permit, or franchise
fees imposed by a government entity, including any New York City or New York
State Sales and Use Taxes or any Taxes assessed on the Monthly Recurring Charge
payable by NEXTLINK to NFN.  NFN shall be responsible for and shall timely pay
any and 


                                       15
<PAGE>
all Taxes imposed with respect to this Agreement upon NFN including any fees
assessed by the City of New York on NFN as compensation for its Franchise for
Local High Capacity Telecommunication Service.

         11.2 If at any time during the Initial Term a federal, state or local
governmental authority seeks to impose any new Taxes on NFN because of NFN's
provision of the Leased Fibers pursuant to this Agreement, NFN shall be
responsible, at its sole expense, for paying such Taxes either with or without a
protest to the appropriate administrative jurisdiction or administrative forum;
provided, however that if the amount of such new Taxes exceeds ten percent (10%)
of the amount of the Monthly Recurring Charge (on an annualized basis) during
any year of the Term of this Agreement, the Monthly Recurring Charge for the
next year shall be increased by the amount of such new Taxes that exceeds ten
percent (10%) of such Monthly Recurring Charge in addition to the adjustment for
inflation set forth in Exhibit B hereto.

         11.3 If at any time during the Term of this Agreement, any Taxes are
imposed on or assessed against NEXTLINK, directly or through NFN, on the basis
of revenue received by NEXTLINK or on the basis of its use of the Leased Fibers,
NEXTLINK shall have the right to protest, by appropriate proceedings, the
imposition or assessment of any such Taxes.  In such event, NEXTLINK shall be
responsible for such payments and shall indemnify and hold NFN harmless from any
expense, legal action or cost, including reasonable attorney's fees, resulting
from the exercise of its rights under this Subarticle 11.3.  In the event of any
refund, rebate, reduction, or abatement to NEXTLINK of any such Taxes, NEXTLINK
shall be entitled to receive the entire benefit of such refund, rebate,
reduction, or abatement.

                                  ARTICLE XII
                                           
                                   LIABILITY
                                           
         12.1 Neither NEXTLINK nor NFN shall be liable to the other for any
indirect, special, punitive, or consequential damages (including, but not
limited to, any claim from any customer for loss of services) arising under this
Agreement or from any breach or partial breach of the provisions of this
Agreement or arising out of any act or omission of either Party hereto, its
employees, servants, contractors and/or agents.  Both NFN and NEXTLINK shall use
their reasonable best efforts to include in any agreement with any third party
relating to the use of the NFN System or the Leased Fibers a waiver by such
third party of any claim for indirect, special, punitive, or consequential
damages (including, but not limited to, any claim from any client or customer
for loss of services) arising out of or as a result of any act or omission by
either Party hereto, its employees, servants, contractors and/or agents.

         12.2 Each Party agrees to indemnify, defend, protect and save the
other harmless from and against any claim, damage, loss, liability, cost and
expense 


                                       16
<PAGE>
(including reasonable attorney's fees) in connection with any personal injury,
including death, loss, or damage to any property or facilities of any party
(including NFN, NEXTLINK, or any other party operating or using any part of the
NFN System or the Leased Fibers) arising out of or resulting in any way from the
acts or omissions to act, negligent or otherwise, of such party, its employees,
servants. contractors, and/or agents in connection with the exercise of its
rights and obligations under the terms of this Agreement or any breach by such
party of any obligation contained herein.

         12.3 Nothing contained herein shall operate as a limitation on the
right of either Party hereto to bring an action for damages, including
consequential damages, against any third party based on any acts or omissions of
such third party as such acts or omissions may affect the construction,
operation, or use of the NFN System or the Leased Fibers; provided ' however,
that each Party hereto shall assign such rights or claims, execute such
documents, and do whatever else may be reasonably necessary to enable the
injured Party to pursue any such action against such third party.

                                  ARTICLE XIII

                                   INSURANCE

         13.1 Each Party shall, at its own expense, secure and maintain in
force, throughout the term of this Agreement, general liability insurance, with
competent and qualified issuing insurance companies, such that the total
available limits to all insureds will not be less than three million dollars
($3,000,000.00) in respect of injuries to or death of any one person and not
less than five million dollars ($5,000,000.00) in respect of injuries to or
death of any number of persons aggregated for any one occurrence and not less
than three million dollars ($3,000,000.00) in respect of damage to or loss of
use of property in any one occurrence, and worker's compensation and employer's
liability insurance as required by the laws of the State of New York and any
other applicable governmental entity.  Such insurance may be provided in policy
or policies, primary and excess, including the so-called umbrella or catastrophe
forms.  The undertaking with respect to insurance shall not relieve either Party
of its obligation in Article XII.


                                  ARTICLE XIV

                                 FORCE MAJEURE

         14.1 The obligations of the Parties hereto are subject to force
majeure and neither Party shall be in default under this Agreement if any
failure or delay in performance is caused by strike or other labor problems;
accidents; acts of God; fire; flood; adverse weather conditions; material or
facility shortages or 


                                       17
<PAGE>
unavailability not resulting from such Party's failure to timely place orders
therefor; lack of transportation; the imposition of any governmental codes,
ordinances, laws, rules, regulations or restrictions; condemnation or the
exercise of rights of eminent domain; war or civil disorder; or any other cause
beyond the reasonable control of either Party hereto.

                                   ARTICLE XV
                                           
                                    DEFAULT
                                           
         15.1 Neither Party shall be in default under this Agreement, or in
breach of any provision hereof unless and until the other Party shall have given
it written notice of such breach and it shall have failed to cure the same
within thirty (30) days after receipt of such notice; provided, however, that
where such breach cannot reasonably be cured ,within such thirty (30) day
period, if the defaulting Party shall proceed promptly to cure the same and
prosecute such curing with due diligence, the time for curing such breach shall
be extended for such period of time as may be necessary to complete such curing.
Upon the failure by the defaulting Party to timely cure any such breach after
notice thereof from the other Party, the non-defaulting Party shall have the
right, in its sole discretion, to take such action is it may determine to be
necessary to cure the breach or to terminate this Agreement upon written notice
to the defaulting Party.  If this Agreement is terminated by NFN pursuant to the
preceding sentence prior to the end of the Initial Term pursuant to Article II,
NEXTLINK shall immediately pay to NFN an amount equal to the present value of
the aggregate unpaid Monthly Recurring Charges payable to NFN for the remainder
of the Initial Term (calculated using a discount rate equal to ten percent
(10%)).  NFN shall refund to NEXTLINK the portion of the Monthly Recurring
Charges paid pursuant to this Subarticle that relates to fiber that NFN is
subsequently able to lease to a third party for the remainder of the Initial
Term.  If this Agreement is terminated by NEXTLINK pursuant to this Subarticle,
NEXTLINK may cease payment of any charges that would thereafter become payable
under this Agreement.

         15.2 No remedy provided for herein is intended to be exclusive, but
each remedy shall be cumulative and in addition to and may be exercised
concurrently with any other remedy available to NFN or NEXTLINK at law or in
equity.

                                  ARTICLE XVI

                                CONFIDENTIALITY

         16.1 The Parties acknowledge and agree that the information each Party
has provided or will provide in connection with this Agreement, including,
without limitation, the terms and conditions of this Agreement, are and shall be
confidential and proprietary to the Party providing such information (the
"Providing Party").  The Party in receipt of confidential information (the
"Receiving Party") 


                                       18
<PAGE>
agrees not to use or disclose to any third party the confidential information of
the Providing Party except as required for performance of its obligations under
this Agreement.  Each Party shall restrict dissemination of confidential
information to only those persons in its respective organization who must have
access to such confidential information in order to perform its obligations
under this Agreement.  Neither Party shall be required to hold confidential any
information which becomes publicly available other than through the Receiving
Party; which is independently developed by the Receiving Party; which becomes
available to the Receiving Party without restriction from a third party; with
respect to which the Providing Party consents to the disclosure by the Receiving
Party; or with respect to which a court, administrative agency, or other
governmental body with jurisdiction over the Receiving Party orders the
disclosure, provided that in such circumstances the Receiving Party first
provides the Providing Party with notice of such required disclosure and takes
reasonable steps to allow the Providing Party to seek a protective order with
respect to the confidential information.  The Receiving Party will cooperate and
assist the Providing Party in connection with such protective order at the
Providing Party's request.

         16.2 The provisions of this Article XVI shall be subject to and
superseded by any separate confidentiality agreement between the Parties,
whether now existing or later entered into.

         16.3 Notwithstanding the other provisions of this Article XVI and
without waiver of any obligations hereunder, NFN may disclose the identity of
NEXTLINK as a customer of NFN and NEXTLINK may disclose the identity of NFN as a
supplier of NEXTLINK, and each Party may disclose the length of the term of this
Agreement, the number of fibers and route miles provided pursuant to this
Agreement, and the fact that such fibers are being provided in Manhattan or the
New York metropolitan area, all without any additional consent from the other.

                                  ARTICLE XVII
                                           
                                    NOTICES
                                           
         17.1 Unless otherwise provided herein, all notices and communications
concerning this Agreement shall be in writing and addressed as follows:

         IF to NFN:

              National Fiber Network, Inc.
              110 East 42nd Street
              New York, New York  10018
              Fax:  (212) 687-9188
              Attention:  Chief Executive Officer
                                       19
<PAGE>


         If to NEXTLINK

              NEXTLINK New York, L.L.C.
              155 108th Avenue, N.E.
              Bellevue, Washington
              Fax: (206) 519-8910 


or at such other address as may be designated in writing to the other Party.

         17.2 Unless otherwise provided herein, notices shall be sent by
certified U.S. Mail, return receipt requested, or by commercial overnight
delivery service, or by facsimile, and shall be deemed delivered: if sent by
U.S. Mail, five (5) days after deposit; if sent by facsimile, upon verification
of receipt; or, if sent by commercial overnight delivery service, one (1)
business day after deposit.

                                 ARTICLE XVIII
                                           
                             ASSIGNMENT; SUCCESSION
                                           
         18.1 Except as provided in this Subarticle 18.1, NEXTLINK shall not
assign or otherwise transfer this Agreement in whole or in part to any other
party without the prior written consent of NFN, which consent shall not be
unreasonably withheld or delayed.  NEXTLINK shall remain secondarily liable for
all payments due under this Agreement after assignment.  Without such consent,
NEXTLINK shall have the right to assign, sublet, or otherwise transfer this
Agreement, in whole or in part, to any parent, subsidiary or affiliate of
NEXTLINK which shall control, be under the control of, or be under common
control with NEXTLINK, any entity that purchases all or substantially all of the
assets of NEXTLINK, or any entity formed by the merger of NEXTLINK and another
entity.

         18.2 NFN shall retain the right to assign this Agreement, in whole or
in part, to any other party subject to the prior written consent of NEXTLINK,
which consent shall not be unreasonably withheld or delayed; provided, however,
that without such consent, NFN shall have the right to assign or otherwise
transfer this Agreement to any parent, subsidiary or affiliate of NFN which
shall control, be under the control of, or be under common control with NFN, any
entity which purchases all or substantially all of the assets of NFN, or any
entity formed by the merger of NFN and another entity.

         18.3 Subject to the provisions of this Article XVIII, this Agreement,
and each of the Parties' respective rights and obligations hereunder, shall be
binding upon and shall inure to the benefit of the Parties hereto and each of
their respective permitted successors and assigns.

                                       20
<PAGE>


                                  ARTICLE XIX
                                           
                                 GOVERNING LAW
                                           
         19.1 This Agreement shall be interpreted and construed in accordance
with the internal laws of the State of New York without giving effect to its
principles of conflicts of laws.

                                   ARTICLE XX
                                           
                               DISPUTE RESOLUTION
                                           
         20.1  Any claims or disputes arising under the terms and provisions of
this Agreement, or any claims or disputes which the Parties are unable to
resolve to their mutual satisfaction within thirty (30) calendar days (or such
longer period as may be mutually agreed upon) from the date that either Party
notifies the other in writing that such claim or dispute exists, shall be
settled in New York, New York, in accordance with the Commercial Arbitration
Rules of the American Arbitration Association in effect at the time of the
dispute.  The written notice shall contain a concise statement of the claim or
issue in dispute, together with relevant facts and data to support the claim. 
The arbitrator(s) shall be bound by the limits on damages set forth in this
Agreement.  The decision of the arbitrator(s) shall be final and binding upon
the Parties if based upon written findings of law and fact.  The arbitrator(s)
shall be empowered to order injunctive relief and judgment may be obtained on
the decision of the arbitrator(s) by either Party in a court of competent
jurisdiction.  Each Party shall bear the cost of preparing and presenting its
own case.  The cost of the arbitration, including the fees and expenses of the
arbitrator(s), will be shared equally by the parties hereto unless the award
otherwise provides.

         20.2 During arbitration proceedings under this Article, NFN shall
continue to provide the Leased Fibers pursuant to this Agreement and NEXTLINK
shall continue to make payments in accordance with this Agreement.

                                  ARTICLE XXI

                                ENTIRE AGREEMENT

         21.1 This Agreement, and any Exhibits attached hereto or to be
attached hereto, constitute the entire agreement between the parties hereto with
respect to the subject matter hereof and supersede any and all prior
negotiations, understandings, and agreements with respect hereto, whether oral
or written.

                                  ARTICLE XXII
                                           
                                 MISCELLANEOUS

                                       21
<PAGE>
                                           
         22.1 The headings of the Articles in this Agreement are strictly for
convenience and shall not in any way be construed as amplifying or limiting any
of the terms, provisions, or conditions of this Agreement.

         22.2 In the event any term of this Agreement shall be held invalid,
illegal, or unenforceable in whole or in part, neither the validity of the
remaining part of such term nor the validity of the remaining terms of this
Agreement shall in any way be affected thereby.

         22.3 This Agreement may be amended only by a written instrument
executed by the Parties.

         22.4 No failure to exercise and no delay in exercising, on the part of
either party hereto, any right, power, or privilege hereunder shall operate as a
waiver hereof, except as expressly provided herein.

         22.5 This Agreement may be executed in two or more counterparts, each
of which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

         IN WITNESS WHEREOF the Parties hereto have executed this Agreement the
day and year fist above written.

NATIONAL FIBER NETWORK, INC.           NEXTLINK New York, L.L.C.



- ------------------------------         ------------------------------
Howard Finkelstein                     James F. Voelker
President                              President


                                       22
<PAGE>


Exhibit A - The NEXTLINK Fibers


                                       23
<PAGE>
                                   Exhibit A

                        NEW YORK NETWORK - FIBER SIZING



                             [Insert graphic - map]


                                       24
<PAGE>

Exhibit B - Schedule of Rates and Charges

Upfront Payment for the Initial Term:                 $ 10,000,000.00
Upfront Payment for the first Additional Term:        $  1,000,000.00

Schedule for Upfront Payments

Within five (5) business days of the date of the execution of this Agreement, a
payment of $5,000,000.00 shall be due and payable by NEXTLINK and NEXTLINK shall
deposit the amount of $6,000,000 into the Escrow Account, from which account the
following Upfront Payments shall be made.

A payment of $950,000 for each of three groups of NEXTLINK Locations, as set
forth in Exhibit F, shall be due and payable by NEXTLINK within five (5) days of
the date at which NFN completes construction to the "negative one manhole" (for
Central Offices) or the "point of entry manhole" (for other NEXTLINK Locations)
of all NEXTLINK Locations within such group.

A fourth payment of $950,000 shall be due and payable on the date that is nine
(9) months following the date of the execution of this Agreement; provided,
however, that NFN has performed all construction obligations under this
Agreement to the extent that NEXTLINK has made NEXTLINK Locations available to
NFN.  In the event that NFN has not fully performed its construction obligations
nine months after the execution of this Agreement, NEXTLINK shall pay this
fourth payment within five (5) days of the completion of such construction;
except, however, that if NFN has not fully performed its construction
obligations because NEXTLINK has not made NEXTLINK Locations available to NFN,
NEXTLINK shall pay the fourth payment as scheduled and NFN's construction
obligations shall continue until all such construction has been completed.

Seventeen (17) payments of $129,412 each shall be due and payable by NEXTLINK
within five business days of the Acceptance Date for each of the seventeen (17)
NEXTLINK Locations listed in Exhibit F hereto; except, however, that any of
these seventeen payments that have not been paid prior to the first anniversary
of the date of this Agreement shall be due and payable on that first
anniversary.


Initial Monthly Recurring Charge for Terminated Fibers

         Monthly Recurring Charge is based on the number of fiber strands
terminated at NEXTLINK Locations other than those NEXTLINK Locations set forth
in the initial Exhibit F hereto.  (See Exhibit B, Figure #2)


                                       25
<PAGE>

         For each month in the year beginning with the date of Agreement:

                      Strands        Cost per Strand

                      1                   $500.00
                      2                   $250.00
                      4                   $200.00
                      6                   $175.00
                      8                   $150.00
                      10                  $125.00
                      12                  $100.00


Annual Adjustment to Monthly Recurring Charge

         For each subsequent year of the Initial Term or any Additional Term of
this Agreement ("Term"), the Monthly Recurring Charge from the previous year for
each NEXTLINK Location, other than those NEXTLINK Locations set forth in the
initial Exhibit F hereto, shall be increased by a factor equal to the difference
between the Consumer Price Index ("CPI" as defined below) from the month
preceding by two months the beginning of the next year of the Term and the CPI
for the month preceding by one year and two months the beginning of the next
year of the Term.

    Example:  Acceptance Date:                   April 1, 1996
              second year of Term begins:        April 1, 1997
              CPI for February, 1997:            166.2
              CPI for February, 1996:            161.7
              Difference:                        4.5
              Monthly Recurring Charge for year 
                   ending March 1997             $350,000
              Monthly Recurring Charge for year
                   beginning April 1997
                   ($350,000 x 104.5%)           $365,750


         CPI shall mean the Consumer Price Index published by the Bureau of
Labor Statistics ("BLS") of the United States Department of Labor for Urban Wage
Earners and Clerical Workers for All Items for the New York Metropolitan Area
(New York - Northern New Jersey - Long Island), or shall mean the successor
thereto.  In the event the BLS Consumer Price Index is converted to a different
standard reference base (current base period: 1982-84 = 100) or otherwise
revised, the determination of Monthly Recurring Charge increase shall be made
with the use of such conversion factor, formula, or table 


                                       26
<PAGE>
for converting the BLS Consumer Price Index as may be published by the BLS, or
if the BLS should fail to publish the BLS Consumer Price Index, then with the
use of such conversion factor, formula, or table for converting the BLS Consumer
Price Index as may be published by Prentice Hall, Inc. or any other nationally
recognized publisher of similar statistical information.  If the BLS Consumer
Price Index ceases to be published and there is no successor thereto, such other
index as NFN and NEXTLINK may agree upon shall be substituted for the BLS
Consumer Price Index.  If the Parties are unable to agree upon such
substitution, the dispute shall be settled pursuant to Article XX of this
Agreement.


Additional Fiber Charge

         NFN shall provide Additional Fiber (Fiber other than that described in
Exhibit A hereto, made available for NEXTLINK's use on a date after the date of
this Agreement) for a one-time charge that shall be calculated by multiplying
the number of fiber miles (rounded off to the nearest hundredth of a mile) by
the number of months remaining in the Initial Term, by the Additional Fiber
Rate, which rate shall depend upon the year of the Initial Term in which the
Additional Fiber is made available to NEXTLINK according to the schedule below,
and adding the total of the monthly first Additional Term Fiber Charges for the
entire first Additional Term. (See Exhibit B, Figure #3).

            Year of Initial Term     Additional Fiber Rate

                      1                        *
                      2    
                      3    
                      4    
                      5    
                      6    
                      7    
                      8    
                      9    
                      10   
                      11   
                      12   
            First Additional Term    
            Fiber Charge
            (Per Month, Per Fiber-
            Mile of Additional Fiber)

                                       27
<PAGE>

Construction and Installation Services

         NFN shall construct NEXTLINK Extensions at the actual cost to NFN of
materials and services provided by NFN's vendors for such construction plus a
Management and Administration Fee of fifteen percent (15%) thereof.

         The construction charges for the NEXTLINK Extensions to the seventeen
(17) NEXTLINK Locations set forth in Exhibit F hereto shall not exceed five
hundred seventy-three thousand dollars ($573,000), including Management and
Administration Fees.


                                       28
<PAGE>

Exhibit C - Notification Procedures for Emergency Maintenance

Any trouble with the Leased Fibers should be promptly reported to:

                                 (212) 566-2444

This number will be answered 24 hours per day, 7 days per week.

NFN may, from time to time, change this notification procedure with advance
notice to NEXTLINK.


                                       29
<PAGE>

Exhibit D - Technical Specifications


                                 DOCUMENTATION

Not later than ninety (90) days after the Acceptance Date for each segment, NFN
shall provide NEXTLINK with the following documentation:

              (a)  As built drawings for such segment in accordance with the
following requirements:

              Survey information (either from existing data or new information)
              will be put on drawings.

              Drawing will contain cable information, splice locations, assist
              point locations with permanent structures, landowner information,
              conduit information, regen locations and optical distances to
              each regen from each splice location.

              Drawings will be updated with actual field data during and after
              construction.

              Metro areas scale shall not exceed 1 inch = 200 feet.

              Cable information shall include manufacturer and type of fiber,
              and manufacturer and style of cable.

              Red line drawings will be provided at the time of acceptance.

              (b)  Technical specifications of the optical fiber cable and
associated splices and other equipment placed in that segment.

                              FIBER CABLE SPLICING

         1.   All splices will be performed with an industry accepted fusion
splicing machine.  NFN will perform two stages of testing during the
construction of a new fiber cable route.  Initially, OTDR tests will be taken
from one direction.  As soon as fiber connectivity has been achieved to both
regen sites, NFN will verify and record the continuity of all fibers.  NFN will
take and record power level readings on all fibers at both wavelengths in both
directions.  NFN will perform bidirectional OTDR tests on all Leased Fibers.

         2.   If during the initial construction it is only possible to measure
the fiber from one direction, splices will be qualified during initial
construction with an OTDR from only one direction.  The profile alignment system
or light injection 


                                       30
<PAGE>
detection system on the fusion splicer may be used to qualify splices as long as
a close correlation to OTDR is established.  All measurements at this stage in
construction will be taken at 1550 nm.  As splice joints are completed,
unidirectional OTDR measurements of the splice losses will be made and recorded.

         3.   After NFN has provided end-to-end connectivity on the fibers,
bidirectional end-to-end testing will be done.  These measurements must be made
after the splice manhole or handhole is closed in order to check for
macro-bending problems.  Continuity tests will be done to verify that no fibers
have been "frogged" or crossed in any of the splice points.  Once the pigtails
have been spliced, loss measurements will be recorded using an industry accepted
laser source and a power meter.  OTDR traces will be taken and splice loss
measurements will be recorded.  NFN will also store OTDR traces on diskette and
on data sheets.  Laser Precision format will be used on all traces.  NFN will
provide three copies of all data sheets and tables, and one set of diskettes
with all traces.

              (a)  The power loss measurements shall be made at both 1310 nm
and 1550 nm, and performed bi-directionally.

              (b)  OTDR traces shall be taken in both directions at both 1310
nm and 1550 nm.

         4.   The splicing standards are as follows:

              (a)  The loss value of the pigtail connector and its associated
splice will not exceed 0.5 dB.  This value does not include the inherent loss in
the pigtail or its connector, nor the insertion loss from its connection to the
FDP.  For values greater than this, the splice will be broken and respliced
until an acceptable loss value is achieved.  If, after five attempts, NEXTLINK
is not able to produce a loss value less than 0.5 dB, the splice will be marked
as Out-of-Space ("OOS") on the data sheet.  Each splicing attempt shall be
documented on the data sheet.

              (b)  During initial unidirectional OTDR testing, the objective
for each splice is a loss of 0.15 dB or less.  If, after three attempts, NFN is
not able to produce a loss value of less than 0.15 dB, then 0.25 dB will be
acceptable.  If, after two additional attempts, a value of less than 0.25 dB is
not achievable, then the splice will be marked as OOS on the data sheet.  Each
splicing attempt shall be documented on the data sheet.

              (c)  During the end-to-end testing of a span (a span shall be FDP
to FDP), the objective for each splice is a bidirectional average of 0.10 dB or
less.

              (d)  The objective for all splices of all fibers within a span
shall be an average loss of 0.10 dB or less.


                                       31
<PAGE>

         5.   The entire NFN fiber-optic cable system shall be properly
protected from foreign voltage and grounded with an industry accepted system.

         6.   Leased Fibers will be consecutive in count and in a separate
buffer tube (or ribbon) from others.  The maximum number of fibers within a
single buffer tube shall be 12,



                                       32
<PAGE>

Exhibit E - Outage Credits

NEXTLINK shall receive a credit against the Monthly Recurring Charges for
Outages according to the following schedule:


For each Outage at a site:

Less than or equal to 4 hours                    1 day

greater than 4 hours but less than 24 hours      1 day per hour of Outage

greater than or equal to 24 hours                1 month


All Outages shall be rounded to the nearest hour.



                                       33
<PAGE>

Exhibit F - Initial NEXTLINK Locations


                                       34


<PAGE>

<TABLE>
                                                                                          Exhibit F - Initial NEXTLINK Locations

<CAPTION>

MAP_KEY  SWITCH    ADDRESS               CITY      OCN_NAME                  NXX_BLKS DESCRIPTION    CD MFS TCG TWC NFN TOT_LINE
<S>      <C>       <C>                   <C>       <C>                       <C>      <C>            <C><C> <C> <C> <C> <C>
199.5    NYCMNY56  228 E. 56th St.       Manhattan New York Telephone Company    57   Homing Sw      X   X   X   X   X  194510
237.9    NYCMN     140 West St.          Manhattan New York Telephone Company    72   Homing Sw      X   X   X   X   X  173145
169.3    NYCMN     204 Second Ave.       Manhattan New York Telephone Company    31   Homing Sw          X       X   X  166595
212.5    NYCMN     104 Broad St.         Manhattan New York Telephone Company    47   Homing Sw      X   X   X   X   X  146899
182.7T   NYCMN     221 E. 37th St.(T)    Manhattan New York Telephone Company    53   Homing Sw          X   X       X  142053
193.5T   NYCMN     435 W. 50th St.       Manhattan New York Telephone Company    68   Homing Sw          X   X   X   X  153045
172.3    NYCMN     210 W. 18th St.       Manhattan New York Telephone Company    32   Homing Sw          X   X   X   X  108231
190.4    NYCMN     1095 Ave of Americas  Manhattan New York Telephone Company    39   Homing Sw          X   X   X   X  100781
179.3    NYCMN     230 W. 36 St.         Manhattan New York Telephone Company    33   Homing Sw              X           88406
176.3    NYCMN     227 E. 30 St.         Manhattan New York Telephone Company    21   Homing Sw          X   X   X      115619
217.5    NYCMN     33 Thomas St.         Manhattan New York Telephone Company    88   Homing Sw/Tandem
         NYCMN     811 10th Ave.         Manhattan AT&T
         NYCMN     1155 Ave of Americas  Manhattan MCI
         NYCMN     60 Hudson St.         Manhattan Nextlink
         NYCMN     111 8th Ave.          Manhattan Nextlink
         NYCMN     1515 Broadway         Manhattan Wiltel/LDDS
***      NYCMN     Midtown (on-net/NFN)  Manhattan Nextlink


         **     AT&T Colocated w/ New York Tel. Assuming, counted as one set of manholes
         ***    Nextlink is planning a Transport Node in Midtown, could be on "NFN" network
</TABLE>

                                                                     1

<PAGE>

                                      EXHIBIT G

                                   ESCROW AGREEMENT


         THIS ESCROW AGREEMENT (this "Agreement") is made as of                
               , 1997, by and among NEXTLINK New York, L.L.C., a Washington
limited liability company ("NEXTLINK") and National Fiber Network, Inc., a
Delaware corporation, ("NFN"), and First Trust National Association, as escrow
agent (the "Escrow Agent").

                                      BACKGROUND

         NFN and NEXTLINK entered into a Fiber Optic Use Agreement, dated June
  , 1997 (the "Fiber Agreement"), relating to the long-term lease of certain
fiber optic cable and related matters.

         The terms of the Fiber Agreement contemplate that NEXTLINK shall place
in escrow $6,000,000 (collectively, the "Escrow Deposit"), the Escrow Deposit to
be released upon satisfaction of certain terms and conditions stated in the
Fiber Agreement.  The parties wish to specify the terms and conditions on which
the Escrow Deposit, together with all interest accrued thereon will be held,
invested and disbursed.

         THEREFORE, in consideration of the mutual undertakings and covenants
contained in this Agreement, the parties agree as follows:

                                    AGREEMENTS

         Section 1.  Definitions.  All terms used and not otherwise defined in
this Agreement shall have the meanings given to them in the Fiber Agreement.

         Section 2.  Obligation of Escrow Agent.  Promptly after the execution
of this Agreement by NEXTLINK, NFN and Escrow Agent, NEXTLINK shall deposit in
escrow with the Escrow Agent the Escrow Deposit.  The Escrow Agent agrees to
hold and dispose of the Escrow Deposit pursuant to the terms and conditions of
this Agreement.  Any additional deposits shall constitute part of the Escrow
Deposit and shall be held and disbursed by Escrow Agent in accordance with the
terms of this Agreement.

         Section 3.  Payment of Interest; Investment.  The Escrow Agent shall
distribute the interest received on all amounts held by Escrow Agent under this
Agreement, less the fees paid to Escrow Agent pursuant to Section 14, to
NEXTLINK unless NEXTLINK otherwise instructs the Escrow Agent in writing.  The
payment of accrued interest to date shall be made at the time all or any portion
of the Escrow Deposit is disbursed under this Agreement.  The Escrow Agent shall
invest all funds held by Escrow Agent under this Agreement as directed in
writing by the NEXTLINK in one or more of the following:  (a) in marketable
direct obligations issued or unconditionally guaranteed by the United States of
America or any agency thereof; (b) in open market commercial paper currently
having the highest rating obtainable from either Standard & Poors Corporation or
Moody's Investors Service, Inc.; (c) in certificates of deposit issued by
commercial banks or savings institutions incorporated under the laws of the
United States of 

                                       2
<PAGE>

America, having total assets of not less than $100,000,000.00; (d) any money
market fund which invests exclusively in direct obligations of the United States
of America; or (e) in such other investments or interest bearing accounts as
shall be directed in writing to the Escrow Agent signed by NEXTLINK.  If there
are insufficient funds held by Escrow Agent to make the disbursements to NFN
that are required under this Agreement, NEXTLINK shall pay to NFN and it shall
have no duty to review investments to determine if they are eligible or
permitted under this paragraph.  Escrow Agent shall not be liable for any loss
resulting from the selection or sale of any investment directed by NEXTLINK. 
All entities entitled to receive interest from the escrow shall provide Escrow
Agent with a W-8 or W-9 prior to disbursement of interest.  If voting rights
apply to any investment hereunder, NEXTLINK shall be responsible for exercising
such voting rights.

         Section 4.  Disposition of Documents and Escrow Deposit.  Promptly
upon receipt by Escrow Agent of a certificate in the form attached to this
Agreement as Exhibit A (the "Escrow Release Certificate"), executed by NEXTLINK,
Escrow Agent shall deliver to NFN the Upfront Payments pursuant to the terms and
conditions of Exhibit B to the Fiber Agreement; provided, however, that Escrow
Agent shall not disburse any amount identified by NEXTLINK as being subject to a
good faith dispute, in a certificate in the form attached to this Agreement as
Exhibit B (the "Holdback Certificate"), unless and until Escrow Agent either
receives joint written instructions from NEXTLINK and NFN or receives written
payment instructions from an arbitrator pursuant to Section 22.  Escrow Agent
shall comply with such joint written instructions of the parties or such written
direction from the arbitrator. With respect to any subsequent deposits of funds
in escrow by NEXTLINK under this Agreement, Escrow Agent shall comply with
NEXTLINK's written directions for disbursement.

         Section 5.  Conditions to Execution and Delivery of Escrow Release
Certificate.  NEXTLINK agrees to execute and to deliver to Escrow Agent the
Escrow Release Certificate upon satisfaction (or waiver by NEXTLINK) of the
conditions set forth in the Fiber Agreement.

         Section 6.  Termination of Escrow.  If the Escrow Agent has not
received all of the executed Escrow Release Certificates by June 1, 1998, the
Escrow shall terminate, Escrow Agent shall wire transfer to NEXTLINK the full
amount of the Escrow Deposit and wire transfer to NEXTLINK the interest on the
Escrow Deposit less the amount of Escrow Agent's fees.  After doing so, Escrow
Agent shall have no further obligations under this Escrow Agreement.

         Section 7.  Payment of Escrow Deposit.  

              a.   The Escrow Agent shall make no disbursements of the Escrow
Deposit, except as permitted pursuant to Sections 4 or 6 above.

              b.   Any amounts payable by the Escrow Agent hereunder shall be
paid by wire transfer of immediately available funds, unless otherwise
designated in a written notice to the Escrow Agent by the payee.

              c.   Upon disbursement in full of the Escrow Deposit, and
interest thereon, this Agreement shall terminate and the Escrow Agent shall be
released and discharged from any further obligations or liability hereunder.


                                       3
<PAGE>

         Section 8.  Wire Transfer Instructions.  Wire transfers by the Escrow
Agent under this Agreement shall be directed to an account designated in writing
to the Escrow Agent by NEXTLINK with respect to funds it is to receive and by
NFN with respect to funds it is to receive.  All wire transfer fees shall be
deducted from the amount of the transfer.  The parties hereto agree that the
wire transfer security procedures identified on the attached Exhibit C to this
Agreement are commercially reasonable.  The parties hereto further agree that
Escrow Agent should use these procedures to detect unauthorized wire transfer
payment requests prior to executing such requests and further agree that any
request acted upon by the Escrow Agent in compliance with these security
procedures, whether or not authorized, shall be treated as an authorized
request.  The parties hereto agree that the Escrow Agent has the right to change
the wire transfer security procedures from time to time and that use of any
changed procedures evidences the acceptance of the commercial reasonability of
such change.

         Section 9.  Duties of Escrow Agent.  This Agreement states the entire
agreement between the parties hereto and merges all prior negotiations,
agreements and understandings, if any, and states in full the representations
and warranties which have induced the agreement, there being no representations
or warranties, other than those herein stated, with respect to the escrow
property (except as stated in the Fiber Agreement as between NEXTLINK and NFN). 
Escrow Agent's rights, duties and obligations are strictly limited to those
expressly set forth in this Agreement and Escrow Agent shall be under no implied
obligation or subject to any implied liability hereunder.  Escrow Agent shall
not be required to take notice of any default or any other matter, nor be bound
nor required to give notice or demand, nor required to take any action whatever
except as herein expressly provided.  Escrow Agent shall not be liable for any
loss or damage unless caused by its own gross negligence or willful misconduct. 
Escrow Agent may act in reliance upon any instrument of signature believed to be
genuine and may assume that any person purporting to give any notice or make any
statement in connection with the provisions hereof has been duly authorized to
do so.  Escrow Agent is requested and authorized, but not obligated, to rely
upon and act in accordance with any communication which may be given by
telephone, facsimile, telex, or other electronic transmission.  Escrow Agent
shall be entitled, but not bound, to treat such communication as fully
authorized by and binding and shall be entitled to take such steps in connection
with or in reliance on such communication.

         Section 10.  Indemnification.  In consideration of its acceptance of
the appointment as the Escrow Agent, NEXTLINK and NFN jointly and severally
agree to indemnify and hold the Escrow Agent harmless from any loss, damages,
claims or liability incurred by it to any person, firm or corporation by reason
of its having accepted the same or in carrying out any of the terms of this
Agreement, and to reimburse the Escrow Agent for all its reasonable expenses,
including, among other things, counsel fees and court costs, including
reasonable attorneys' fees and costs at trial and on any appeal, incurred by
reason of its position hereunder or actions taken pursuant to this Agreement. 
This indemnity shall survive the termination of this Agreement for any reason.

         Section 11.  No Additional Duties.  The Escrow Agent shall have no
duties except those which are expressly set forth herein, and it shall not be
bound by any notice of a claim for payment, or demand with respect thereto, or
any waiver, modification, amendment, termination or rescission of this
Agreement, unless received by it in writing.


                                       4
<PAGE>

         Section 12.  Amendments.  This Agreement may be amended, and
observance of any term of the Agreement may be waived, with (and only with) the
written consent of the parties hereto.

         Section 13.  Resignation of Escrow Agent.  The Escrow Agent, and any
successor Escrow Agent, may resign at any time as Escrow Agent by giving at
least  (30) calendar days written notice to NFN and NEXTLINK.  Upon such
resignation and the appointment of a successor Escrow Agent, the resigning
Escrow Agent shall be absolved from any and all liability in connection with the
exercise of its powers and duties as Escrow Agent.  Upon their receipt of notice
of resignation from the Escrow Agent, NEXTLINK and NFN shall use their best
efforts jointly to designate a successor Escrow Agent.  In the event NEXTLINK
and NFN do not agree upon a successor Escrow Agent within thirty (30) calendar
days after the receipt by NEXTLINK and NFN of such notice, the Escrow Agent so
resigning may petition any court of competent jurisdiction for the appointment
of a successor Escrow Agent or other appropriate relief, including delivery of
any assets to a court in an interpleader action, and any such resulting
appointment shall be binding upon all parties to this Agreement.  By mutual
agreement, NEXTLINK and NFN shall have the right at any time upon not less than
seven (7) calendar days written notice to terminate their appointment of the
Escrow Agent or successor Escrow Agent, as Escrow Agent.  The Escrow Agent or
successor Escrow Agent shall continue to act as Escrow Agent until a successor
is appointed and qualified to act as Escrow Agent; provided Escrow Agent shall
have the right to interplead the Escrow Deposit as provided in this Agreement,
if NEXTLINK and NFN do not jointly appoint a successor escrow agent within 30
days after Escrow Agent's receipt of such notice.

         Section 14.  Fees of the Escrow Agent.  The Escrow Agent shall be
entitled to compensation in accordance with the schedule set forth in Exhibit D.
The cost of such compensation and expenses shall be paid out of the interest
earned on amounts held by Escrow Agent under this Agreement.  In the event that
the interest earned (but not yet distributed under Section 3 above) on the funds
held by Escrow Agent under this Agreement is insufficient to pay the
compensation and expenses owing to the Escrow Agent, the excess of such
compensation and expenses over the interest earned but unpaid shall be paid by
NEXTLINK, upon demand.  In the event that Escrow Agent brings an action in
interpleader or in the event the conditions of this Agreement are not promptly
fulfilled, or Escrow Agent is required to render any service not provided for in
the Agreement or in Exhibit D, or there is any assignment of the interest of
this escrow or any modification hereof, Escrow Agent shall be entitled to
reasonable compensation for such extraordinary services and reimbursement for
all fees, costs, liability and expenses, including attorney fees.  Such
compensation and reimbursement shall be paid by NEXTLINK.

         Section 15.  Miscellaneous.  The Escrow Agent may execute any of its
powers or responsibilities hereunder and exercise any rights hereunder either
directly or by or through its agents or attorneys.  Nothing in this Agreement
shall be deemed to impose upon the Escrow Agent any duty to qualify to do
business or to act as fiduciary or otherwise in any jurisdiction other than the
State of Washington.  The Escrow Agent shall not be responsible for and shall
not be under a duty to examine or pass upon the validity, binding effect,
execution or sufficiency of this Agreement, of any agreement or document
deposited in escrow, or of any agreement amendatory or supplementary hereto.  If
any controversy arises between the parties to this Agreement or with a third
person relating to this Agreement, Escrow Agent shall not be required to resolve
the controversy but may, at its discretion, institute an interpleader or other
proceeding as it reasonably deems proper.  Escrow Agent may rely on any joint
written instructions as to the disposition of funds or documents held in escrow.

                                       5
<PAGE>

         Section 16.  Counterparts.  This Agreement may be executed in one or
more counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

         Section 17.  Notices.  Any notices to be given hereunder shall be
sufficiently given if in writing and delivered personally, or mailed by
registered or certified mail, return receipt requested, postage prepaid, to the
following addresses or to such other addresses as the parties may from time to
time designate in writing delivered in accordance with this Section 17:

              a.   If to NEXTLINK:

                   NEXTLINK New York, L.L.C.
                   155 - 108th Avenue NE, Suite 810
                   Bellevue, WA 98004
                   Attention: General Counsel

                   With a copy to:

                   Jay D. Hull
                   Davis Wright Tremaine LLP
                   2300 First Interstate Center
                   1300 S.W. Fifth Avenue
                   Portland, OR 97201

              b.   If to NFN:

                   National Fiber Network, Inc.
                   110 East 42nd Street
                   New York, New York  10018
                   Attn:  Chief Executive Officer

                   With a copy to:

                   Gregory A. Fernicola
                   Skadden Arps Slate Meagher & Flom
                   919 Third Avenue
                   New York, New York  10022

              c.   If to Escrow Agent:

                   First Trust National Association
                   Global Escrow Depository Services
                   PO Box 24425
                   Seattle, WA  98124

                                       6
<PAGE>

Any notices to be given hereunder shall be deemed received (a) on the date
delivered, if delivered personally or (b) on the third business day after the
date such notice was sent, if sent by registered or certified mail.

         Section 18.  Binding Effect.  This Agreement shall be binding upon and
inure to the benefit of the parties hereto and their respective successors and
permitted assigns.  NEXTLINK and NFN may not assign their respective obligations
hereunder without the prior written consent of the other parties.  Any
assignment in contravention of this provision shall be void.  No assignment
shall release NEXTLINK or NFN from any obligation or liability under this
Agreement.

         Section 19.  Applicable Law.  This Agreement shall be construed in
accordance with and governed by the laws of the State of New York, without
giving effect to its principles of conflict of laws.

         Section 20.  Dispute Resolution.  NEXTLINK and NFN desire to resolve
disputes arising out of this Agreement without litigation.  Accordingly, except
for action seeking a temporary restraining injunction related to the purposes of
this Agreement, or suit to compel compliance with this dispute resolution
process, NEXTLINK and NFN agree to use the dispute resolution procedures set
forth in Sections 20 through 22 as their sole remedy with respect to any
controversy or claim arising out of or relating to this Agreement or its breach.
Escrow Agent shall not be subject to the provisions of Sections 20 through 22.

         At the written request of either NEXTLINK or NFN, the parties will
appoint a knowledgeable, responsible representatives to meet and negotiate in
good faith to resolve any dispute arising under this Agreement.  The parties
intend that these negotiations be conducted by non-lawyer, business
representatives.  The location, format, frequency, duration and conclusion of
these discussions shall be left to the discretion of the representatives. 
Discussion and correspondence among the representatives for purposes of these
negotiations shall be treated as confidential information developed for purposes
of settlement, exempt from discovery and production, which shall not be
admissible in the arbitration described below.  Documents identified in or
provided with such communications, which are not prepared for purposes of the
negotiations, are not so exempted and may, if otherwise admissible, be admitted
in evidence in the arbitration or lawsuit.

         Section 21.  Mediation.  If the negotiations set forth in Section 20
do not resolve the dispute within sixty (60) days of the initial written
request, the parties agree to work in good faith to settle the dispute by
mediation under the commercial mediation rules of the American Arbitration
Association.  The parties will attempt to agree on a mediator.  If they are
unable to do so, the mediation will be referred to the New York office of the
American Arbitration Association for mediation which will appoint a qualified
mediator to serve.  The mediation shall take place in New York.  Unless the
parties agree otherwise, the first mediation session shall take place no later
than ninety (90) days after the initial written request to negotiate.  The
mediation shall continue until the dispute is resolved or until such time as the
mediator makes a good faith determination that the likelihood of resolution is
sufficiently remote that continuation of the mediation is not warranted.

         Section 22.  Arbitration.  If a determination is made pursuant to
Section 21 that continuation of the mediation process is not warranted, the
dispute shall be submitted to binding arbitration by a panel of 


                                       7
<PAGE>

three arbitrators pursuant to the Commercial Arbitration Rules of the American
Arbitration Association.  Either NEXTLINK or NFN may demand such arbitration in
accordance with the procedures set out in those rules.  Each party shall have
the right to take the deposition of one individual, and any expert witness
designated by the other party.  Each party shall also have the right to request
production of relevant documents, the scope and enforcement of which shall be
governed by the arbitrator.  Additional discovery may be only by order of the
arbitrator, and only upon a showing of substantial need.  The arbitrator shall
rule on the dispute by issuing be authorized to issue subpoenas for the purpose
of requiring attendance of witnesses at depositions.  The arbitration hearing
shall be commenced within sixty (60) days of the determination that mediation is
not going to be successful.  The arbitration shall be held in New York, New
York, or such other location as mutually agreed upon by the parties.  The
arbitrator shall control the scheduling so as to process the matter
expeditiously.  The parties may submit written briefs.  The arbitrator shall
rule on the dispute by issuing a written opinion within thirty (30) days after
the close of hearings. The times specified in this section may be extended upon
mutual agreement of the parties or by the arbitrator upon a showing of good
cause.  The award rendered by arbitration shall be final, binding and
nonappealable judgment and the award may be entered in any court of competent
jurisdiction in the United States.  No special consequential or punitive damages
shall be awarded by the arbitrator.

         Section 23.  Confidentiality.  NEXTLINK and NFN agree that all
communications and negotiations between the parties during the dispute
resolution process, any settlements agreed upon during the dispute resolution
process and any information regarding the other party obtained during the
dispute resolution process (that are not already pubic knowledge) are
confidential and may be disclosed only to employees and agents of NEXTLINK and
NFN who shall have a "need to know" the information and who shall have been made
aware of the confidentiality obligations set forth in this Section, unless the
party is required by law to disclose such information. 

         Section 24.  Fees and Expenses.  NEXTLINK and NFN shall equally split
the fees of the mediator and the arbitrator. Any party found by the arbitrator
to have breached this Agreement shall pay all other cost and expenses, including
reasonable attorneys' fees and expenses, of the other party incurred in
connection with the dispute resolution process.  The costs and expenses shall
also include the attorneys' fees and other reasonable costs and expenses
incurred by the Escrow Agent arising from the dispute.  If the arbitrator does
not find that any party has reached this Agreement, then each party shall bear
its own costs and expenses, including attorneys' fees and expenses.

         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date first above written.

                        NEXTLINK NEW YORK, L.L.C.


                        By:

                        Its:

                                       8
<PAGE>

                        NATIONAL FIBER NETWORK, INC.


                        By:

                        Its:


                        FIRST TRUST NATIONAL ASSOCIATION


                        By:

                        Its:


                                       9
<PAGE>

                                      EXHIBIT A

                              ESCROW RELEASE CERTIFICATE



              To:  First Trust National Association
                   Global Escrow Depository Services
                   PO Box 24425, 5th Floor
                   Seattle, WA 98124


         The undersigned hereby certifies that all conditions set forth in the
Fiber Agreement have been satisfied, or waived by NEXTLINK, and you are
authorized to make disbursements and deliveries as provided in the Escrow
Agreement among NEXTLINK New York, L.L.C., National Fiber Network, Inc. and
First Trust National Association.


                        NEXTLINK NEW YORK, L.L.C.


                        By:
                        Its:
                        Date:


                                       10
<PAGE>

                                      EXHIBIT B

                                 HOLDBACK CERTIFICATE


              To:  First Trust National Association
                   Global Escrow Depository Services
                   PO Box 24425, 5th Floor
                   Seattle, WA 98124


         The undersigned hereby certifies that NEXTLINK New York, L.L.C. claims
in good faith that a dispute exists with respect to the disbursement of
$                from the Escrow Deposit held by you pursuant to the Escrow
Agreement among NEXTLINK New York, L.L.C., National Fiber Network, Inc. and
First Trust National Association.  Consequently, you are hereby directed to
continue to hold such amount in escrow pending receipt of joint written
instructions from NEXTLINK and NFN or receipt of written direction from an
arbitrator pursuant to Section 22 of the Escrow Agreement.


                        NEXTLINK NEW YORK, L.L.C.


                        By:
                        Its:
                        Date:


                                       11
<PAGE>

                                      EXHIBIT C

                          Wire Transfer Security Procedures

                                    [See Attached]


                                       12
<PAGE>

                                      EXHIBIT D
                             Escrow Agent's Compensation
                                    [See Attached]



                                       13


<PAGE>
                                                                  Exhibit 10.13

                                                      CONFIDENTIAL TREATMENT (1)

                            AMENDED AND RESTATED AGREEMENT
               FOR THE PROVISION OF A FIBER OPTIC TRANSMISSION NETWORK
                                           

         This AMENDED AND RESTATED AGREEMENT FOR THE PROVISION OF A FIBER OPTIC
TRANSMISSION NETWORK (this "Agreement") is made and entered into effective as of
the Effective Date (as hereinafter defined), by and between National Fiber
Network, Inc., a Delaware corporation ("NFN"), and US ONE Communications of New
York, Inc., a Delaware corporation ("US ONE").


                                      RECITALS:

         A.   US ONE and NFN entered into that certain Agreement for the
Provision of a Fiber Optic Transmission Network, dated as of April 16, 1996 (the
"Original Agreement"), whereby NFN agreed to, among other things, provide US ONE
exclusive long-term use, as described below, of certain dedicated capacity on
NFN's fiber optic cable network and certain extensions thereof, as more
particularly described below;

         B.   US ONE and NFN have agreed to amend and restate the Original
Agreement pursuant to the terms hereof;

         C.   US ONE desires to use such dedicated capacity on such fiber optic
cable network upon the terms and subject to the conditions set forth in this
Agreement;

         D.   NFN is the holder of a franchise (the "Franchise") granted
pursuant to that certain Franchise Agreement between the City of New York (the
"City") and National Fiber Network, Inc., dated as of December 20, 1993, as
amended (the "Franchise Agreement"), pursuant to which NFN has the right to
install, operate, repair, maintain, remove and replace cable, wire, fiber or
other transmission medium in order to provide telecommunications services and
high capacity fiber optic transmission facilities in the City;

- --------------------
(1) Redacted portions have been marked with an asterisk (*).  The redacted
portions are subject to a request for confidential treatment and have been 
filed separately with the Securities and Exchange Commission.

<PAGE>


         E.   NFN, through its wholly-owned subsidiary, National Fiber Network
of New Jersey, Inc., is the holder of a license granted by the City of Jersey
City to construct a fiber optic system within the City of Jersey City; and

         F.   Pursuant to the terms of the Franchise Agreement, NFN has
constructed a fiber optic cable transmission network consisting of 47 route
miles of fiber optic cable in and around the City (as set forth on the map
attached hereto as Exhibit A, the "Existing Network") and plans the construction
of additional route miles of fiber optic cable and other construction
constituting the Extended Network (as hereinafter defined).

         NOW, THEREFORE, in consideration of the foregoing and of the mutual
covenants contained herein, the parties hereto agree as follows:

    1.   DEFINITIONS

         As used in this Agreement, the following terms have the respective
meanings set forth below:

         "Additional Fiber" shall have the meaning set forth in Section 3.2 of
this Agreement.

         "Affected Party" shall have the meaning set forth in Section 14 of
this Agreement.

         "Affiliate" shall mean, with respect to any Person, any other Person
who, directly or indirectly, controls, is controlled by, or is under common
control with that Person.  As used in this definition, "control" means the
possession, directly or indirectly, of the power to direct or cause the
direction of the management and policies of a Person, whether by way of equity
ownership, contract or otherwise.

         "Colocation Point" shall mean a point designated by US ONE that is
physically in, or virtually colocated in, a particular NYNEX serving wire center
or central office and at which US ONE will interconnect the portion of the US
ONE network to be provided over the facilities leased hereunder from NFN to the
NYNEX local loops or other NYNEX communications network facilities.

         "Colocation Agreements" shall mean colocation agreements between NYNEX
and US ONE allowing US ONE to establish Colocation Points for the purposes of
this Agreement.

                                          2
<PAGE>

         "Common Stock Equivalents" shall have the meaning assigned to such
term in the Warrant.

         "Consumer Price Index" as used herein shall mean the Consumer Price
Index published by the bureau of Labor Statistics of the United States
Department of Labor for Urban Wage Earners and Clerical Workers for All Items
for the New York/Metropolitan area, or shall mean the successor thereto.

         "CLEC" shall mean a certified local exchange company other than a LEC.

         "Current Market Value" shall mean, with respect to a share of common
stock, par value $.01 per share (the "Common Stock"), of NFN as of any date (i)
the fair market value per share of Common Stock, as reasonably determined in
good faith by the Board of Directors of NFN, using an appropriate valuation
method, assuming an arms' length sale to an independent party of all of the
Common Stock of NFN, without giving regard to the lack of liquidity of the
Common Stock or any discount for minority interests and assuming the conversion
or exchange of all Common Stock Equivalents, including the Warrants, then
outstanding and exercisable (whether at the time of determination or with the
passage of time), or (ii) if there shall be a public market for the Common
Stock, the average of the daily market prices for each day during the 30
consecutive trading days commencing 45 business days before such date as of
which such a price can be established in the manner set forth below.  The market
price for each such business day shall be the last sale price on such day as
reported in the Consolidated List Sale Reporting System or as quoted in the
National Association of Securities Dealers Automated Quotation System, or if
such last sale price is not available, the average of the closing bid and asked
prices as reported in either such system, or in any other case the higher bid
price quoted for such day as reported by The Wall Street Journal (or any
successor publication) and the National Quotation Bureau pink sheets.

         "Effective Date" shall mean the date on which NFN shall complete the
sale of common stock and/or other securities convertible into common stock for
an aggregate purchase price of $30,000,000 or more.

         "Existing Central Offices" shall mean the Colocation Points located at
140 West Street and East 38th Street, New York, New York (which have been
completed as of the date hereof).

         "Existing Network" shall have the meaning set forth in the recitals
hereto.

         "Expiration Date" shall have the meaning set forth in Section 3.1 of
this Agreement.

         "Extended Network" shall mean collectively the Existing Network, plus
the fiber loops to the Existing Central Offices that have been extended off of
the Network, and the Network Buildout.


                                          3
<PAGE>

         "Extended Term" shall mean an extension of the Initial Term for an
additional term of 13 years, commencing on December 21, 2008 and ending on
December 20, 2021.

         "Fiber Mile" shall mean one fiber strand transversing one linear mile.

         "Force Majeure" shall have the meaning set forth in Section 14 of this
Agreement.

         "Initial Term" shall mean the term of this  Agreement, commencing  on
April 16, 1996 and ending on December 20, 2008.

         "LEC" shall mean an incumbent local exchange carrier or operating
telephone company.

         "Lump Sum Payment Option" shall have the meaning set forth in Section
4.2 of this Agreement.

         "Lump Sum Price" shall have the meaning set forth in Section 4.2 of
this Agreement.

         "More Favorable Terms" shall have the meaning set forth in Section
16.18 of this Agreement.

         "Most Favored Nations" shall mean the most favorable terms and lowest
price offered to any customer on the relevant system at the time of
determination.

         "Network Affiliate" shall mean any Person who, directly or indirectly,
controls, is controlled by, or is under common control with NFN.  As used in
this definition, "control" means (i) the possession, directly or indirectly, of
the power to elect at  a majority of the board of directors or other similar
governing body of such Person or (ii) the beneficial ownership of at least a
majority of the voting capital stock or other beneficial interests with voting
rights of such Person; provided, that notwithstanding  the foregoing, a Network
Affiliate shall be deemed to include any Person as to which NFN and/or Stephen
Garofalo have the effective ability, directly or indirectly, to cause such
Person to lease or otherwise grant the right to use such Person's fiber optic
cable network to another Person.

         "Network Buildout" shall mean such expansion of the Existing Network
as NFN may in its sole discretion build through the counties of Westchester, New
York, Nassau, New York, and Suffolk, New York.

         "Note" shall have the meaning set forth in Section 4.1(b)(i) of this
Agreement.

                                          4
<PAGE>

         "NYNEX Cages" (sometimes referred to as "Cage") shall mean Colocation
Points.

         "Other Party" shall have the meaning set forth in Section 14 of this
Agreement.  

         "Outage" shall have the meaning set forth in Section 12 of this
Agreement.

         "Person" shall mean any individual, sole proprietorship, partnership,
joint venture, corporation, trust, unincorporated organization, association,
institution, public benefit corporation, entity, or government (whether federal,
state, county, city, municipal or otherwise, including, without limitation, any
instrumentality, division, agency, body or department thereof) and shall for all
purposes include Stephen A. Garofalo and members of his immediate family,
including his parents, siblings, spouse and children.  

         "Term" shall mean the Initial Term and, if this Agreement is extended,
the Extended Term.

         "Termination Point" shall mean any location where US ONE facilities
begin and NFN facilities end.

         "US ONE POP" shall mean a specific geographical location designated by
US ONE at which customers of US ONE may, through the related entrance facility,
connect to the portion of the US ONE network to be provided over the facilities
leased hereunder from NFN.

         "US ONE 12 Fiber Network" shall have the meaning set forth in Section
4.1(a) of this Agreement.

         "Warrant" shall mean a warrant to be dated April 16, 1996
substantially in the form of Exhibit A attached to that certain Amended and
Restated Letter Agreement regarding Purchase and Sale of Warrant dated as of the
date hereof by and between NFN and US ONE Communications Corp., a Delaware
corporation.

    2.   LEASE

         2.1  NFN shall lease to US ONE, for the exclusive use of US ONE and
its customers, an aggregate of * Fiber Miles, of which (i) * Fiber Miles
represent current availability of * strands of dark fiber per linear mile on the
Existing Network and (ii) * additional Fiber Miles may be designated by US ONE
at any time during the Initial Term, either within the Existing Network or in
any part of the Extended Network, in each case pursuant to technical
specifications which will meet or exceed those attached hereto as Exhibit B.

                                          5
<PAGE>

         2.2  The lateral extension policy attached hereto as Exhibit C shall
be utilized to afford US ONE Most Favored Nations treatment with respect to
fiber loops off of the Extended Network to commercial sites and to Colocation
Points in addition to the Existing Central Offices requested by US ONE during
the Term.  US ONE shall be entitled to the benefits of any subsequent lateral
extension policy so that it will always be afforded Most Favored Nations
treatment with respect to such fiber loops.  Notwithstanding the foregoing, in
the event US ONE elects to install any additional Colocation Points which are
designated in Section C of Schedule I attached hereto, NFN shall complete
construction of such Colocation Points at the prices set forth on such schedule.
Linear mileage comprising such fiber loops shall be counted for purposes of
calculating the * Fiber Miles provided for in Section 2.1 and the * Fiber Miles
provided for in Section 5.1.

         2.3  NFN shall cause the buildout, if any, of the Extended Network to
be performed in compliance with technical specifications that meet or exceed the
technical specifications set forth on Exhibit B attached hereto.

    3.   TERM

         3.1  Initial Term.  Subject to Section 4, NFN leases, grants and
conveys to US ONE the exclusive use of (i) * Fiber Miles (that is, the * Fiber
Miles on the Existing Network as currently constituted plus * Fiber Miles that
may be designated by US ONE from time to time pursuant to Section 2.1 hereof)
plus any Option Fiber (as hereinafter defined) as to which the Option (as
hereinafter defined may be exercised (as determined pursuant to Section 5.1),
plus (ii) the fiber loops that have been extended off of the Existing Network to
the Existing Central Offices on the Extended Network for a term commencing as of
April 16, 1996 and terminating on December 20, 2008 (the "Expiration Date"),
unless extended as provided in this Agreement.  All rights and privileges
granted to US ONE under this Agreement shall be irrevocable until the Expiration
Date (unless extended).

         3.2  Extended Term.  US ONE shall have the option to extend the
Initial Term for an additional term of up to 13 years, which option shall be
exercised by notice to NFN at least six months, but not more than 12 months,
prior to the end of the Initial Term.  In the event the Franchise is not
extended for the entire Extended Term and US ONE has exercised its option to
extend the Initial Term for the entire Extended Term, NFN shall, for such
portion of the Extended Term as the Franchise shall not be in effect, provide US
ONE, with an equivalent number of strands of additional fiber (Fiber Mile for
Fiber Mile) ("Additional Fiber") on such portion of the Extended Network (or, at
the option of US ONE, on any other NFN networks (including networks belonging to
or controlled by Network Affiliates) which have been developed as of that point
in time) outside the Franchise territory as shall be designated by US ONE for
the Extended Term to compensate US ONE for the loss of its twelve strands of
fiber in the Franchise territory.


                                          6
<PAGE>

    4.   LEASE PAYMENTS

         4.1  Payment for Initial Term.  In consideration of the exclusive
right to the long term use of * Fiber Miles on the Extended Network (as
determined pursuant to Section 2.1 hereof), plus the fiber loops to the Existing
Central Offices, US ONE shall prepay its lease payments for the Initial Term to
NFN in accordance with the following:

              (a)  As of April 16, 1996, US ONE has paid an advance lease
payment to NFN in the sum of $100,000.

              (b)  Upon written notification from NFN that the conditions
precedent for the determination of the Effective Date have taken place, such
written notification to be delivered to US ONE at least one business day prior
to the Effective Date, on the date which shall be two business days after the
Effective Date, US ONE shall (A) prepay additional lease payments aggregating
$3,400,000 and (B) pay $130,000 for the cost of installation of fiber loops to
Colocation Points at 140 West Street and East 38th Street, New York, New York. 
Such payments shall be made and satisfied by the simultaneous delivery and
exchange of the following:

                   (i)  US ONE shall deliver to NFN (A) that certain promissory
note (the "Note") dated April 16, 1996 from NFN to US ONE in the principal
amount of $4,900,000, marked "Canceled," together with delivery and release of
all security instruments pledged or filed with respect thereto and (B) that
certain stock subscription warrant (the "Subscription Warrant") dated December
13, 1996 from NFN to US ONE for the purchase of up to 25,000 Warrant Shares (as
defined in the Subscription Warrant); and

                   (ii)  NFN shall return to US ONE the balance of $1,370,000
in cash by wire transfer of immediately available funds to an account designated
in writing by US ONE.

              (c)  Payments to be made by US ONE pursuant to Section 4.l(b)
above shall be applied as a prepayment of this Agreement entitling US ONE to the
full and unfettered use, pursuant to this Agreement for the Initial Term (and
the Extended Term to the extent US ONE exercises its right to so extend), of *
Fiber Miles on the Extended Network, plus the fiber loops to the Existing
Central Offices as set forth in Section 2.1 hereto, without any further
obligation by US ONE in respect of such portion of the network whatsoever,
whether under the terms of this Agreement or otherwise.

         4.2  Payments for Extended Term.  Lease payments for the Extended Term
shall be payable, at the option of US ONE, either (i) monthly at a rate per
fiber mile equal to the lowest rate per fiber mile charged by NFN to any lessee
of "dark" fiber optic capacity on the Extended Network at the time US ONE
exercises its option 


                                          7
<PAGE>
to extend for the Extended Term, or, alternatively, if US ONE shall opt to lease
fiber on other NFN networks (including networks owned or controlled by Network
Affiliates) in the Extended Term pursuant to Section 3.2 hereof, the lowest
lease rate per fiber mile then charged to any lessee of dark fiber optic
capacity on such network, or (ii) in a lump sum payment (the "Lump Sum Payment
Option") equal to the present value of the lease payments described in Section
4.2(i) (which present shall be based upon discounting in accordance with
standard financial procedures at an implied interest rate of 15% per annum,
calculated monthly) (the "Lump Sum Price"); provided, that such present value
payment shall not exceed an amount equal to $8,750,000 plus the percentage by
which the Consumer Price Index as of December 2008 shall have increased over the
Consumer Price Index as of April 1996 (the "Lump Sum Cap"); provided, further,
that in the event NFN has not completed a minimum of 55 route miles of the
Network Buildout at such time as US ONE elects to pay the Lump Sum Price, then
the Lump Sum Cap shall be reduced to an amount equal to $8,750,000 times a
fraction, the numerator of which is the number of Fiber Miles which are leased
by US ONE as of the end of the Initial Term and the denominator of which is
2508.  In the event US ONE elects to make payments pursuant to Section 4.2(i)
hereof, the Extended Term shall continue for the entire Extended Term unless
terminated by US ONE upon 30 days written notice to NFN.  In the event US ONE
elects the Lump Sum Payment Option, US ONE shall have the option, within 30 days
after the exercise of such Lump Sum Payment Option, to put the Warrant or the
securities issuable thereunder to NFN (assuming the Warrant has been issued) for
a price equal to the greater of the Lump Sum Price or the Current Market Value
of the securities underlying such Warrant.  In the event US ONE elects to
exercise the put option and the Current Market Value of the securities
underlying the Warrant exceeds the Lump Sum Price, US ONE shall be entitled to
receive from NFN in cash any excess of the Current Market Value over the Lump
Sum Price.  In the event the Consumer Price Index is converted to a different
standard reference base or otherwise revised, the determination of the Lump Sum
Price shall be made with the use of such conversion factor, formula or table for
converting the Consumer Price Index as may be published by the Bureau of Labor
Statistics, or if the Bureau of Labor Statistics should fail to publish same,
then with the use of such conversion factor, formula or table for converting the
Consumer Price Index as may be published by Prentice Hall, Inc., or any other
nationally recognized publisher of similar statistical information.  If the
Consumer Price Index ceases to be published and there is no successor thereto,
such other index as NFN and US ONE may agree upon shall be substituted for the
Consumer Price Index.  If the parties hereto are unable to agree, then such
matter shall be submitted to arbitration.

         4.3  Maintenance and Repair.  NFN shall be responsible for, and shall
provide directly, all maintenance and repair on the Existing Network and the
Extended Network in a diligent, expeditious, good and workmanlike manner, using
first class workmanship and materials, and NFN shall use its best efforts to
cause the Extended Network to remain in good working order and condition at all
times.  US ONE shall always be entitled to the benefit of the highest standard
of redundancy, 



                                          8
<PAGE>
surveillance, maintenance and repair, including, without limitation, in regard
to response time, alarm  and monitoring and other surveillance systems, network
redundancy and technical innovation, then provided to any customer of NFN. 
Notwithstanding the prior sentence, US ONE shall at a minimum be entitled to the
surveillance, maintenance and repair standards set forth on Exhibit D hereto. 
No charge shall be made by NFN for maintenance, surveillance, general system
redundancy or repair on the NFN fiber optic network.  NFN agrees that it shall
at all times maintain remote monitoring of the fiber cable for surveillance
purposes in substantial compliance with the specifications set forth on Exhibit
D hereto and to ensure the integrity of such cable.  The monitoring shall be
accomplished through a remote optical test system connected to the fiber
strands.  Any fiber strands necessary for such fiber monitoring program shall be
in addition to, and not deducted from, the fiber strands leased by US ONE
hereunder.

    5.   ADDITIONAL FIBER CAPACITY

         5.1  In addition to the * Fiber Miles described in Section 2.1, US ONE
shall have the option (the "Option") to lease from NFN, at any time during the
Initial Term, up to * Fiber Miles (the "Option Fiber") on the Extended Network
(pursuant  to  technical specifications which will meet or exceed those attached
hereto as Exhibit B) for a term which will commence upon the date the Option is
exercised and terminate on the last day of the Initial Term.  US ONE shall
exercise the Option by delivery of (i) a written notice to NFN and (ii) a
prepayment of the lease for any such additional Fiber Miles as to which the
Option is being exercised at the rate of *  per Fiber Mile for each Option Fiber
Mile that has been constructed and is operational.  Notwithstanding the prior
sentence, US ONE may exercise the Option for Option Fiber Miles that have not
yet been constructed but as to which NFN offers, in its discretion, to US ONE as
a result of a planned build-out (the "Offer"), but shall not be required to
prepay for any such Fiber Mile until it has been constructed and is operational.
US ONE may rescind an exercised Option for any unconstructed Option Fiber Mile
unless construction has begun in respect of such Option Fiber Mile or is
irrevocably scheduled to begin within 90 days of the date of rescission, as
certified by an executive officer of NFN.  Notwithstanding anything to the
contrary herein contained, in the event that (i) NFN notifies US ONE that
construction on any such Option Fiber Miles subject to the Offer has been halted
or terminated or (ii) construction on any such Option Fiber Miles subject to the
Offer is not substantially completed on the date which is 180 days after US ONE
elects to purchase such Option Fiber Miles from NFN (each, a "Triggering
Event"), then such number of Option Fiber Miles shall be subject to the Option
for a period of 120 days after the occurrence of any such Triggering Event.  Any
Fiber Miles as to which the Option may be exercised pursuant to this Section 5.1
shall consist of a minimum of eight fibers and a maximum of 48 fibers per route
mile, which number of fibers and location on the Extended Network of such Fiber
Miles shall be designated by US ONE upon its exercise of the Option.  The Option
shall expire on November 1, 1998.  Notwithstanding the foregoing, in the event
that NFN has not completed a minimum 


                                          9
<PAGE>
of 55 route miles of the Network Buildout (the "Minimum Condition") by
November 1, 1998, the term of the Option shall be extended until such time as US
ONE receives written notice from NFN that NFN has satisfied the Minimum
Condition and for a period of 30 days thereafter.

         5.2  Commencing on the earlier of (i) the date on which US ONE
exercises the Option in full pursuant to Section 5.1 hereof or (ii) November 1,
1998 if NFN has not completed the Minimum Condition and continuing for a period
of 18 months thereafter, US ONE may, at its option, acquire additional fiber
optic capacity on any NFN network (including networks belonging to or controlled
by Network Affiliates), and NFN shall provide US ONE with such additional fiber
optic capacity on a Most Favored Nations basis on such NFN network.  Upon
commencement of the installation by NFN of other fiber optic networks (including
networks belonging to or controlled by Network Affiliates) during the Term, NFN
shall, upon the request of US ONE, negotiate in good faith a lease to US ONE for
a portion of such network, such lease to be provided for on a basis
substantially the same as the lease provided under this Agreement.  NFN agrees
that it will not, nor will any of its Affiliates, take any action the purpose or
effect of which would be to contravene the benefits which would otherwise accrue
to US ONE from this Section 5.

    6.   TERMINATION OF FRANCHISE

         NFN shall use its best efforts to enter into an agreement with the
City whereby, in the event of the termination of the Franchise for any reason,
the City will agree to honor, and will cause (i) any subsequent holder or
holders of the Franchise, or (ii) any entity that purchases substantially all of
NFN's hard assets to honor, this Agreement.  NFN agrees to use its best efforts
to enter into such an agreement with the City within six months after
commencement of the Initial Term.

    7.   PROHIBITION ON RESALE

         During the Term, US ONE shall not, directly or indirectly, sublease,
condo, sublicense or wholesale to any third party fiber optic capacity on NFN's
network unless such fiber such fiber optic capacity is distributed through US
ONE's transmission system.

    8.   REMEDIES ON DEFAULT

         In the event (i) NFN defaults materially under this Agreement
including, without limitation, any representations or warranties set forth in
Section 15 hereof, and (ii) such default or defaults results in the loss or
substantial diminution of effective use of the Extended Network to US ONE as
contemplated by this Agreement, then after notice from US ONE and the expiration
of any applicable grace periods, NFN shall provide US ONE with additional fiber
optic capacity on NFN's then existing Extended Network (and/or, at US ONE's
option, other NFN networks, 


                                          10
<PAGE>
including networks belonging to or controlled by Network Affiliates) equivalent
to the aggregate number of fiber miles US ONE would have been entitled to
receive had no default occurred.  In addition to the relief specified in the
preceding sentence, NFN shall provide US ONE with two dedicated fiber strands to
each commercial or residential property then accessed by any of NFN's networks. 
Attached hereto as Exhibit E is a list of ten office complexes into which NFN
currently has spur connections.

         Notwithstanding anything contained in the first paragraph of this
Section 8, NFN shall not be deemed to be in default under this Agreement if such
default is the result of an event of Force Majeure (as hereinafter defined),
provided, however, that NFN shall use its best efforts to resume and/or provide
service to US ONE as soon as reasonably practicable after the occurrence of an
event of Force Majeure.

    9.   TAXES

         US ONE agrees to pay any customer sales, use, gross receipts, excise,
excess, bypass, or any other local, state, or federal taxes or charges to the
extent such charges are imposed upon or based upon US ONE's purchase and use of
the services and products provided herein.  US ONE shall not pay any amounts to
the extent such amounts are related to (i) NFN or the Extended Network, (ii)
employees, contractors, subcontractors, agents, or representatives of NFN, or
(iii) the Franchise Agreement, all of which shall remain the sole responsibility
of NFN.

    10.  INSURANCE

         Each of NFN, any contractor and any subcontractor shall procure and
maintain, at its own cost and expense, the following types of insurance and
coverage during the Term of this Agreement:




Type of Insurance                           Minimum Amount

(1) Worker's compensation and all           As required by State law
    occupational disease

(2) Employer's liability including all      $100,000 per occurrence
    occupational disease when not
    so covered by Worker's compensation
    above

(3) Commercial General Liability            $1,000,000 per occurrence

                                          11
<PAGE>

    (comprehensive) including contractual   and annual aggregate
    liability, product and completed
    operations, business interruption,
    bodily injury and property damage
    combined


Type Of Insurance                           Minimum Amount

(4) Automobile liability (comprehensive),   $1,000,000 per occurrence
    bodily injury and property damage
    combined

(5) Umbrella liability                      $2,000,000 per occurrence and
                                            annual aggregate

NFN shall issue US ONE an insurance certificate and a copy of such policies,
naming US ONE as an additional insured as to (3) and (5) above.  All such
insurance policies shall be issued by an insurer duly licensed and authorized to
conduct insurance business in New York and having a policyholder's and financial
rating of "AIX" or better.  At least thirty (30) days prior to the expiration of
any policy, NFN shall furnish paid receipts and other evidence satisfactory to
US ONE that such policy has been renewed or replaced.  In addition, all policies
shall be written so as to require ten (10) days' prior written notice delivered
to US ONE for any cancellation or termination.

         US ONE shall maintain Commercial General Liability Insurance
(comprehensive) of at least $1,000,000 per occurrence and annual aggregate,
which shall name NFN as an additional insured.

    11.  INSTALLATION OF DARK FIBER OPTIC CABLE NETWORK

         If NFN's use of the Existing Network and the Extended Network results
in the necessity of additional construction, installation, maintenance or repair
in order to comply with NFN's obligations hereunder, NFN at all times shall
remain responsible for all costs and expenses of same and shall proceed with
such additional construction promptly and in a diligent and workmanlike manner
consistent with the technical and engineering standards contemplated herein.

         NFN shall terminate the fiber at an identified fiber termination panel
at each Termination Point and shall not be responsible in any manner whatsoever,
including for maintenance, repair or replacement for any extensions into US ONE
facilities from any Termination Point.  NFN shall in no way be responsible for
any damages or losses caused by its fiber cable except as a result of the
negligent act or 


                                          12
<PAGE>
omission or deliberate misconduct of NFN or NFN's employees, agents, contractors
or subcontractors.

    12.  MAINTENANCE OF FIBER OPTIC CABLE NETWORK

         As used in this Agreement, in supplement to the standard of care
described in Section 4.3 hereof, NFN's obligation to maintain fiber cable and
transmission equipment in good working order and condition shall mean in
accordance with best industry practices but in any event the fiber optic cable
splice loss shall not exceed .1 dB.  Projected dB losses for each route are
presented on Exhibit F attached hereto.

         In the event of physical damage or severance to, or a break in, any
Fiber Span, NFN shall respond directly, promptly, diligently and as
expeditiously as practicable, not to exceed two (2) hours, and shall restore
such Fiber Span within four (4) hours.  Service will be provided seven (7) days
a week, twenty-four (24) hours a day.  "Fiber Span" as used herein shall mean
the fiber optic cable originating from a fiber patch panel and terminating at
another fiber patch panel.  "Outage" as used herein means Complete Interruption
of Service for one (1) or more particular circuits.  A "Complete Interruption of
Service" as used herein shall mean an interruption of US ONE's traffic over any
circuit resulting from the interruption of US ONE's traffic over any Fiber Span,
whether or not due to the physical damage or severance of, or breaks in, such
Fiber Span, which is not prevented within 50 milliseconds by means of physical
or electronic protection that reroutes such traffic over another Fiber Span. 
NFN shall pay to US ONE the sum of (i) $1,000 per hour for each Outage of
greater than four (4) but less than or equal to 12 hours; (ii) 5,000 per hour
for each Outage of greater than 12 but less than or equal to 24 hours; and (iii)
$10,000 per hour for each Outage of greater than 24 hours.  NFN shall remit such
payments to US ONE within five business days of the end of the month in which
such Outage occurs; provided, that until July 1, 1997, NFN may defer the payment
of any such amounts by crediting to the account of US ONE an amount equal to the
payments otherwise required to be made, which shall be used by US ONE to offset
any amounts owed by US ONE or its Affiliates to NFN whether under this Agreement
or otherwise and on July 1, 1997, any amounts so credited to the account of US
ONE that have not been offset shall be paid in cash to US ONE by NFN.

         If NFN is required to relocate any section of the Existing Network or
the Extended Network, NFN will be solely responsible for the cost and
implementation of such relocation.  NFN will give US ONE a minimum of six months
written notice of any such relocation.  Any such relocation will not cause any
change in the performance of the network to US ONE.  Any US ONE Outages caused
by such relocation will not exceed one hour.

         NFN will maintain a reasonable and customary inventory of spare cable
in the event cable repair is needed.
                                          13
<PAGE>

         Upon prior written request a reasonable time in advance, NFN shall
have the right to inspect US ONE's use of the fiber cable during normal business
hours (9 a.m. to 5 p.m.) on business days.  Such inspection shall be conducted
only to comply with applicable regulatory requirements or as part of maintenance
or repair related to this Agreement, and NFN shall use its best efforts to
effectuate inspection urgently, expeditiously and with no interruption of US
ONE's operations and security.

         It is expressly understood, acknowledged and  agreed  that  NFN  is 
and  remains the owner of the Extended Network, except in the event that NYNEX
policies toward CLEFs or regulatory authorities require ownership of cable
inside the NYNEX wire centers, the parties hereto agree that US ONE shall obtain
ownership of such cable from NFN as joined at a theoretical splice point to be
determined in accordance with the applicable policy or regulation.  It shall be
the responsibility of US ONE to maintain all cable that it shall be required to
own as provided in immediately preceding sentence; provided, that NFN shall
incorporate such US ONE owned portions of the Extended Network into its full
network control fault isolation and diagnostic system and shall cooperate fully
with US ONE in detection, fault isolation and diagnosis of cable within the US
ONE owned portions of the Extended Network.  Except as set forth in the
immediately preceding sentence, nothing in this Agreement shall be construed as
conveying to US ONE any ownership right, title or ownership interest in the
fiber.

    13.    TERMINATION OF AGREEMENT

         If one or more of the following events of default shall occur, US ONE
shall have the right to immediately terminate this Agreement:

         (a)  NFN materially breaches its obligations under the second
paragraph of Section 12 of this Agreement dealing with Outages; or

         (b)  NFN breaches any other material term or condition of this
Agreement in any material respect with the exception of a breach for which a
remedy is available under Section 8 hereof, and such breach remains uncured (i)
as to maintenance and repair obligations, three (3) days, and (ii) otherwise
twenty (20) days after NFN has received notice of such uncured breach; provided,
however, that if the breach is of a nature or involves circumstances reasonably
taking more than three (3) days or twenty (20) days, respectively, to cure, the
time period shall be extended for so long as may be required, as long as NFN
shall proceed urgently and expeditiously to cure same; or

         (c)  NFN becomes insolvent or applies for or consents to the
appointment of a receiver, trustee or similar officer for it or any substantial
part of its property or assets, or any such appointment is made without such
consent by NFN and remains undischarged for a period of sixty (60) days; or

                                          14
<PAGE>


         (d)  NFN consents to the institution of a petition, application,
answer, consent, default or otherwise of any bankruptcy, insolvency or
reorganization, or any such proceeding is involuntarily instituted against NFN
and remains undischarged for a period of sixty (60) days.

         Notwithstanding any other remedies available to US ONE upon the
occurrence of an event of default by NFN, US ONE, its officers, attorneys,
accountants and other authorized representatives, upon reasonable notice to NFN,
shall be afforded reasonable access during normal business hours to the
employees, assets, facilities and the books and records of NFN so as to afford
US ONE full opportunity to make such review, examination and investigation of
the business as US ONE may desire to make in verifying that it has been afforded
Most Favored Nations treatment in accordance herewith.  US ONE will be permitted
to make extracts from or to make copies of such books and records as may be
reasonably necessary in connection therewith.

    14.  FORCE MAJEURE

         Neither NFN nor US ONE shall be considered in breach of this Agreement
or liable for any expense, loss or damage resulting from delay or prevention of
performance caused by any act attributable to an occurrence of an event of Force
Majeure.  Neither party shall, however, be relieved of liability for failure of
performance due to a claimed Force Majeure hereunder if such failure is due to
causes arising out of its own negligence or to removable or remediable causes
that it fails to remove or remedy with reasonable dispatch.

         The term "Force Majeure" shall mean any cause beyond the control of
the party affected which by exercise of due foresight such party could not
reasonably have been expected to avoid and, which by exercise of due diligence,
such party shall be unable to overcome during the period while such party shall
continue to exercise such due diligence, including, but not limited to, failures
of facilities, changes in laws except tax laws, rules, regulations, etc., flood,
earthquake, storm except for weather conditions normal to the area, fire,
lightning, epidemic, war, riot, civil disturbance, sabotage, inability due to
the previously mentioned conditions to obtain material, fuel or supplies in
adequate quantities, or restraint by court order or public authority.  Nothing
contained herein, however, shall be construed to require either party to prevent
or settle a strike (other than a strike by employees of a contractor) against
its will.

         Any party affected by an event of Force Majeure (the "Affected Party")
shall notify such other party (the "Other Party") promptly of any occurrence or
condition which in the Affected Party's opinion warrants an extension of time. 
Such notice must be submitted in writing to the Other Party within five days or
such sooner date as is practicable after such delay is known to the Affected
Party, or shall, in the exercise of reasonable diligence, become known.  Such
notice shall specify in detail 


                                          15
<PAGE>
the anticipated length of delay, the cause of the delay, and a timetable by
which any remedial measures shall be implemented.  Failure to provide such
notice within such period shall constitute a waiver by the Affected Party of any
request for extension applicable to any period prior to the date such notice is
actually received by the Other Party.  The Other Party shall acknowledge receipt
of the Affected Party's notice within ten (10) days of its receipt advising of
its acceptance or rejection or further consideration.  If the Other Party
reasonably requires further information in order to consider the request, the
Affected Party shall supply such information within ten (10) days and, if the
Affected Party fails to provide such information, the Affected Party's original
notice shall be deemed not to have been given.

    15.  WARRANTIES AND INDEMNITIES

         NFN represents and warrants to US ONE that

         (a)  NFN has obtained or will obtain, when and if required by any
regulatory agency or court of law, all regulatory approvals, permits, orders or
consents necessary to be obtained by NFN to timely effectuate the terms and
provisions of this Agreement, including the timely completion of the Network
Buildout; and

         (b)  NFN shall comply with all applicable laws, rules and regulations
related to the performance of its obligations under this Agreement; and

         (c)  NFN is bound hereunder through its duly authorized signatory
below and is duly formed, validly existing and in good standing under the laws
of the State of Delaware; and

         (d)  this Agreement is not prohibited or in violation of or
inconsistent with the charter or bylaws of NFN or any other agreement signed by
NFN or which binds NFN and no such agreement will adversely affect US ONE's use
and enjoyment of the fiber for US ONE's purposes; and

         (e)  a default by NFN under this Agreement will cause trouble harm and
loss to US ONE for which US ONE may lack an adequate remedy at law (e.g., money
damages).  Consequently, NFN agrees that US ONE may seek, and be entitled to
obtain, restraints and/or injunctions against NFN from any court of competent
jurisdiction to protect US ONE's business operations without same constituting
an election of remedies available hereunder or otherwise at law or in equity. 
In addition, NFN acknowledges and agrees that in the event of a default by NFN
hereunder, US ONE shall be entitled to specific performance; and

         (f)  NFN acknowledges and agrees that this Agreement, to the  extent
it is subject to regulation by the Federal Communications Commission, is an
agreement that is not subject to the filing requirements of Section 211 (a) of
the Local 


                                          16
<PAGE>
Telephone Network Act of 1934 (47 U.S.C. Section 211 (a)) as implemented in 47
C.F.R. Section 43.51, and NFN is not a carrier as such term is used in such Act;

         (g)  no representation or warranty by NFN contained in this  
Agreement, and no statement in any document (included, without limitation, all
documents executed in connection with any other transaction or transactions
consummated substantially concurrently with this Agreement), list, certificate
or other instrument or to be furnished by or on behalf of NFN or any Affiliate
thereof to US ONE or any of its representatives in connection with the
transactions contemplated hereby, contains or will contain any untrue statement
of a material fact, or omits or will omit to state any material fact necessary,
in light of the circumstances under which it was or will be made, in order to
make the statements herein or therein not misleading or necessary in order fully
and fairly to provide the information required to be provided in any such
document, list, certificate or other instrument.  NFN has not failed to disclose
to US ONE any fact which would reasonably be determined to have a material
adverse effect on the business, financial condition, results of operations or
prospects of the business, or which is otherwise material to the business; and

         (h)  there are no presently existing federal, state or local
regulatory fees or penalties, including fees under the Franchise, to which US
ONE will be subjected as a result of the execution and delivery of this
Agreement and the related transactions.

         US ONE shall indemnify, defend and hold NFN, its directors, officers,
agents, representatives and employees ("NFN Parties") harmless from and against
any claims, demands, losses, costs, damages, expenses and foes of any kind or
nature whatsoever arising from or related to death, personal injury or property
damage, and for reasonable legal fees to the extent asserted by persons other
than the NFN Parties arising from or out of US ONE's performance of or failure
to perform any term, condition or obligation of US ONE under this Agreement.

         NFN hereby agrees to indemnify, defend and hold harmless US ONE and US
ONE's partners, directors, officers, agents, representatives and employees from
and against any and all claims, demands, losses, costs, damages, expenses and
fees of any kind or nature whatsoever arising from or related to death, personal
injury or property damage, and for reasonable legal fees arising from or out of
NFN's obligations or NFN's performance of or failure to perform any term,
condition or obligation of NFN under this Agreement or any related act or
omission of NFN.  This Indemnity includes, without limitation, acts or omissions
of NFN's officers, agents, contractors, subcontractors, licensees, invitees,
representatives and employees.

         The above indemnities shall survive the expiration or earlier
termination of this Agreement.


                                          17
<PAGE>

    16.  MISCELLANEOUS

         16.1 Status of Parties.  The parties to this Agreement expressly
state, and understand, that the obligations and rights hereunder in no way
constitute them as partners, joint venturers or otherwise related in any way,
and that neither has any power under this Agreement to bind or commit the other
in any way to any third party or parties.

         16.2  Amendments, Alterations and Modifications.  Agreement shall not
be amended, altered or modified except by an instrument in writing duly executed
by both parties.

         16.3  Successors and Assigns.  This Agreement shall be binding upon
and shall inure to the benefit of the parties hereto and their respective
successors and permitted assigns.  It is the explicit intention of the parties
hereto that no person or entity, other than the parties hereto, is or shall be
entitled to bring any action to enforce any provision of this Agreement against
either of the parties hereto, and that the covenants, undertakings, and
agreements set forth in this Agreement shall be solely for the benefit of, and
shall be enforceable only by, the parties hereto or their respective successors
or permitted assigns.

         16.4 Special and Consequential Damages.  In no event shall either
party be liable to the other for special or consequential damages as a result of
its performance or nonperformance of this Agreement, and each party hereby
waives and releases the other from those specific types of damages.

         16.5 Confidentiality.  Each of NFN and US ONE reaffirms and
rememorializes its respective confidentiality obligations related to this
Agreement as set forth on Exhibit G attached hereto.

         16.6 Subsidiaries. NFN consents to the exercise by any subsidiary of
US ONE of the rights, and the performance by any such subsidiary of the
obligations, of US ONE hereunder.

         16.7  Leasing other Facilities.  This Agreement shall not prevent US
ONE from leasing the facilities of any other network provider, whatever the
location and whatever the terms thereof.

         16.8 Notices.  All demands, reports, approvals or other communications
which may be or are required to be given, served or sent pursuant to this
Agreement shall be in writing and shall be hand delivered or sent by recognized
overnight carrier or mailed by first-class, registered or certified mail, return
receipt requested, postage prepaid, addressed as follows:

              If to NFN, to:
                                          18
<PAGE>



                   National Fiber Network, Inc.
                   110 East 42nd Street
                   New York, New York 10017
                   Attn:   Stephen A. Garofalo
                        Howard Finkelstein

              with a copy to:

                   Skadden, Arps, Slate, Meagher & Flom
                   919 Avenue, 32nd Floor
                   New York, New York 10022
                   Attn:  Greg Fernicola

              If to US ONE, to:

                   US ONE Communications of New York, Inc.
                   One Lincoln Centre
                   5400 LBJ Freeway, Suite 700
                   Dallas, Texas 75240
                   Attn: James H. Sturges

         with a copy to:

                   Weil, Gotshal & Manges LLP
                   100 Crescent Court, Suite 1300
                   Dallas, Texas  75201
                   Attn: Mary R. Korby

Notices shall be effective when properly sent and received, refused or returned
undeliverable.  Either party can notify the other of an address change pursuant
to this notice provision.

         16.9 Severability. If any provision of this Agreement or any other
agreement, document or writing given pursuant to or in connection with this
Agreement shall be invalid or unenforceable under any applicable law, same shall
be ineffective to the extent of such invalidity only, without in any way
affecting the remaining parts of said provision or the remaining provisions of
said Agreement.  In such event, the parties shall negotiate in good faith to
amend this Agreement to comply with applicable law while preserving, to the
maximum extent feasible, the mutual benefits of this Agreement.

         16.10     Further Assurances.  To the extent that any statute,
regulation or policy passed or adopted after the date hereof materially alters
in a negative manner the practical realization of the value of this Agreement to
US ONE, NFN 


                                          19
<PAGE>
agrees to modify this Agreement so as to preserve the practical realization by
US ONE of the value of this Agreement.

         16.11     Exhibits.  Exhibits are an integral part  of  this 
Agreement.  "Will" and "shall" have the same meaning in this Agreement. 
"Including" or "include" shall mean "including without limitation."

         16.12     Waiver.  No failure or delay on the part of either party
hereto in exercising any right, power or privilege hereunder and no course of
dealing between the parties shall operate as a waiver thereof, nor shall any
single or partial exercise of any right, power or privilege hereunder preclude
any other or further exercise thereof or the exercise of any other right, power
or privilege.

         16.13     Entire Agreement.  This Agreement constitutes the entire
agreement between the parties with respect to the transactions contemplated
herein, and it supersedes all prior oral or written agreements, commitments or
understandings with respect to the matters provided herein.

         16.14     Titles and Headings.  Section headings contained in this
Agreement are inserted for convenience of reference only.  Such headings shall
not be deemed to be a part of this Agreement for any purpose and shall not in
any way define or affect the meaning, construction, or scope of any of the
provisions hereof.

         16.15      Governing Law.  This Agreement shall be governed by the
laws of the State of New York without regard to any other state's choice of law
principles.

         16.16     Execution in Counterparts.  To facilitate execution, this
Agreement may be executed in as many counterparts as may be required.

         16.17     Publication.  Neither NFN nor US ONE shall publicize or
disclose any aspect or contents of this Agreement or its relationship with the
other party to this Agreement, in any way, without the other party's prior
written consent and specific approval, in such party's sole discretion, except
as required by law, rule or regulation or to a lender or prospective lender or
bona fide investment banker.  Such consent shall not be unreasonably withheld as
to a bona fide investor, partner or joint venturer.

         16.18     Most Favored Nations.  Notwithstanding anything in this
Agreement, NFN agrees to treat US ONE to Most Favored Nations status for the
Term of this Agreement.  NFN warrants that all financial terms, warranties and
provisions regarding termination or expiration provided in this Agreement are
equivalent to or better, as a whole, than the terms and provisions offered by
NFN to its current customers.  In addition, if during the Term of this Agreement
NFN enters into any other agreement(s) with any other customer(s) providing such
customer(s) 


                                          20
<PAGE>
with more favorable financial terms, warranties or provisions regarding
termination or expiration, taken as a whole, then this Agreement shall be deemed
appropriately amended to provide such better terms ("More Favorable Terms") to
US ONE, unless US ONE elects, in writing, to reject such new term(s) or
provision(s).  NFN shall promptly provide US ONE with any refund or credits
thereby created.

         16.19     Assignment.  Neither NFN nor US ONE may assign this
Agreement, in whole or in part except by operation of law, without the prior
written consent of the other party, which consent shall not be unreasonably
withheld or delayed, and except as consistent with regulatory authorizations.

         Notwithstanding the immediately preceding paragraph, US ONE may assign
this Agreement to any Affiliate or as a security interest to a lender without
NFN's consent.  In addition, NFN shall be permitted to assign this Agreement
without US ONE's consent to a corporation of which it owns at least a majority
of the voting stock and controlling interest or any Affiliate.  Upon any
assignment under this Section 16.19, the assignor shall remain responsible for
performance under this Agreement and shall guaranty any and all continuing
financial obligations hereunder.  This guaranty shall be primary, joint and
several.  Any assignee shall expressly assume all liabilities hereunder prior to
the effectiveness of such assignment.



[REMAINDER OF PAGE  INTENTIONALLY LEFT BLANK]



                                          21
<PAGE>
         IN WITNESS WHEREOF, the undersigned have caused this Agreement to be
duly executed as of the Effective Date.


NATIONAL FIBER NETWORK, INC.      US ONE COMMUNICATIONS OF NEW YORK, INC.



By:                                     By:
   ---------------------------             --------------------------------
     Stephen A. Garofalo,                    James H. Stugres,
     President                               President


                                          22
<PAGE>

                                      Exhibit A


                  Map of Manhattan, Brooklyn, Queens and New Jersey


                                          
<PAGE>
                                      EXHIBIT B

                               Optical Fiber Properties

Fiber Type:        Single Mode Dispersion Unshifted Optical Fiber

Manufacturer: Sumitomo Electric Lightwave Corporation

Construction

              Glass Fiber                            Coating
    Cure                    Cladding

Diameter      Typically     Diameter  125=1.0 um     Material  UV-Acrylate
              8.3 um
    
Non-          LESS THAN     Non          < 1.0%   Inked 250 PLUS MINUS 15 um
Circularity   MINUS 5%      Circularity           Diameter

Core/Clad-    < 0.8 um
ding Offset  

Optical Characteristics

         Property                                     Specification

Point Discontinuities at 1310/1550 nm               LESS THAN MINUS 0.10 dB
Water Peak Attenuation at 1383 nm                   LESS THAN MINUS 2.0 dB/km
Attenuation Change vs. Wavelength  1285 to 1330 nm  < 0.10 dB/km
                                   1525 to 1575 nm  LESS THAN MINUS 0.05 dB/km

Attenuation Change vs. Bending     100 wraps/75 nm  LESS THAN MINUS 0.10 dB
                                   1 wrap/32 nm     LESS THAN MINUS 0.50 dB

Zero Dispersion Wavelength                          1300-1322 nm

Maximum Dispersion at 1310/1500 nm                  LESS THAN MINUS 3.2/18.0
                                                          ps/nm.km 
Zero Dispersion Slope                               LESS THAN MINUS 0.092 
                                                          ps/nm(2)
Mode Field Diameter                  1310 nm        9.3 PLUS MINUS 0.5 um
                                     1550 nm

Cabled Fiber Cutoff Wavelength                      < 1260 nm


                                          
<PAGE>
Group Index of Refraction         1310 nm             1.466
                                  1550 nm             1.467



                                          
<PAGE>
                                        DRAFT


Mechanical Characteristics

              Property                                Specification

              Proof-test Stress                     100 kpsi
              Fiber Curl Radius                     GREATER THAN MINUS 2 meters
Minimum Bend Radius                         Short   16.0 mm
Term                                                37.5 mm

Term                             Long

                        System Constituents and Designations

                                            RNB-System 1

Span 1 (Primary)                            Span 2 (Secondary)

Routing:                                    Routing:
111 Pavonia to 1 W39th St.                  1 W39th St to 111 Pavonia
via Holland Tunnel (north tube)             via Holland Tunnel (south tube)

Number of Fibers = 1                        Number of Fibers = 1


                                         
<PAGE>
         It is important to note that NFN's Fiber Monitoring Program will
consider the attached fiber trace with its associated attenuation, length, etc.,
as the reference for surveillance purposes, thereby reacting to variations from
this reference for alarming and restoration notification.  The degree of
variation from the reference trace necessary to generate an alarm will be
specified in this report.  Fiber monitoring is conducted via maintenance
fiber(s) that emulate customer systems completely from one Customer Fiber
Distribution Panel (CFDP) to the next.

         It is critical that the customer only utilize the ports on the CFDP
that are specified in this report as other ports may be under use by NFN's
monitoring program and for future provisioning.  The use of these ports by the
customer would jeopardize NFN's ability to conduct surveillance on the system
under use and possibly other systems in the surrounding area.

         NFN has provided patchcords for connection from the CFDP to the end
equipment as per the customer's request.  These jumpers are of a length and with
specific end connector-types as specified in this report.  While these
connectors have been supplied in the original packaging in which they were
received from the manufacturer, shipping and handling may cause dust and dirt to
accumulate on the connector endface, adversely affecting optical performance. 
Therefore, prior to using any fiber connector, NFN recommends cleaning with
isopropyl alcohol of purity 95% or higher, via the following procedure:  wipe
the ferrule sides and endface of the connector with an alcohol-dampened
lint-free cloth; wipe again with a dry lint-free cloth and finally, blow across
the ferrule with compressed air.

         This report contains the following pertinent information:

         -    properties of the optical fiber.

         -    geographical map detailing each fiber system pictorially.

         -    routing and footages of each fiber system.

         -    OTDR trace of each fiber system with a table of optical events en
              route.

         -    End-to-end attenuation for each fiber at both 1310nm and 1550nm
              wavelengths.

         -    Loss thresholds that would generate alarming and notification
              procedures.

         -    Specification of ports to be utilized by the customer at the
              CFDP.

         -    Patchcord lengths provided with type of end connectors.


                                         
<PAGE>
                                        DRAFT


                             System 1 - Span 1 - Fiber 1


Summary: Total route length = 30271

         Attenuation    = 3.35 dB @ 1310 nm
                        = 2.53 dB @ 1550 nm



<PAGE>


                                        DRAFT


                            OTDR Trace (1310 nm)- Fiber 1

Note:    Trace generated from 1 W.39th St. location.






                                        GRAPH

                                    Trace Analysis
                                           
    Feature   Location (feet)     Reflection (dB)     Loss (dB)
    Launch    0                   -                        
    Fusion    20784               -                   0.315
    Fusion    28461               -                   -0.08
    End       30271               -                        

Results: End of fiber found at 30271 ft
         Fiber under test loss: 3.35 dB







<PAGE>


                             OTDR Trace (1550 nm) Fiber 1

Note:    trace generated from 1 W39th St location









                                        GRAPH







Trace Analysis

    Feature   Location (feet)     Reflection(dB)      Loss(dB)
    Launch    0                   -              
    Fusion    10091               -                   0.115
    Fusion    20851               -                   0.547
    End       30271               -              

Result:  End of fiber found at 30271 ft.
         Fiber under test loss:  3.35 dB



<PAGE>


                             System 1 - Span 1 - Fiber 1

Summary: Total route length = 38962 feet

         Attentuation   = 5.38 dB @ 1310 nm
                        = 3.87 dB @ 1550 nm

                        OTDR Trace (1310 nm) - Fiber 1








                                        GRAPH

                                    Trace Analysis
                                           
Feature  Location (feet)     Reflection (dB)     Loss (dB)
Launch   0                   -              
Fusion   16066               -                   0.065
Fusion   24916               >31.73              -0.771
End      38962               -              

Results: End of fiber found at 38962 ft
         Fiber under test loss: 5.38 dB



<PAGE>







                             OTDR Trace (1550 nm) Fiber 1

Note:    trace generated from 1 W 39th St location





                                        GRAPH

                                    Trace Analysis
                                           
Feature  Location (feet)     Reflection (dB)     Loss (dB)
Launch            0                 -              
Fusion         7937                 -              0.215
Fusion        15924                                0.097
Mechanical    24925          > 35.06               0.726
Fusion        28972                                0.126
End           38971

Results: End of fiber found at 38971 ft
         Fiber under test loss: 3.87 dB



<PAGE>






Loss Thresholds

This table represents the attenuation values that would generate an alarm on
each fiber as per NFN's Fiber Monitoring Program.

                              Deviations from Reference

                                  Span 1 - Fiber 1         Span 2 - Fiber 1

End to end fiber loss             3.0 dB                   3.0 dB
Fusion splice loss                0.15 dB                  0.15 dB
Mechanical/Grouped Event loss     0.20 dB                  0.20 dB
Reflectance                       5.00 dB                  5.00 dB

                                   Absolute Values
                                           
                                  Span 1 - Fiber 1         Span 2 - Fiber 1

Fusion splice loss                1.00 dB                  1.00 dB
Mechanical splice loss            3.00 dB                  3.00 dB
Reflectance                       20.00 dB                 20.00 dB

Customer Fiber Distribution Panel - Port Assignment

Location: 111 Pavonia

Port Assignment:   Span 1 - Fiber 1 : port 1
                   Span 2 - Fiber 1 : port 8

                                  Shaded ports are for customer use

                                        GRAPH
                                           



<PAGE>
Port Assignment:   Span 1 - Fiber 1 : port 1
                   Span 2 - Fiber 1 : port 8

                                  Shaded ports are for customer use

                                        GRAPH
                                           
Patchcords

    Length         End Connectors      Number
    30 feet        SC/SC               2
    45 feet        SC/FC               2




<PAGE>


                             EXHIBIT C TO LEASE AGREEMENT
                                       BETWEEN
                             NATIONAL FIBER NETWORK, INC.
                                         AND
                             US ONE COMMUNICATIONS CORP.

LATERAL EXTENSION POLICY OF NATIONAL FIBER NETWORK, INC.

         The policy of NFN with respect to construction cost reimbursement and
monthly charges for extension from its Network Backbone to locations requested
by a customer is as follows

         (i)  The NFN customer requesting a fiber connection from the NFN
              Network Backbone to a specific location shall pay to NFN the cost
              which it incurs for such construction plus 20% thereof measured
              from the Splice Point off of the Network Backbone to the point at
              which the connection terminates (the "Termination Point") at the
              subject premises (the "Lateral Extension").  The cost paid by the
              customer for such construction is referred to herein as the
              "Lateral Extension Cost";

        (ii)  Upon lease of fiber in the Lateral Extension to additional NFN
              customers, each such additional customer shall pay to NFN a
              portion of the Lateral Extension Cost equal to its pro rata
              portion thereof (based upon the total number of customers leasing
              fiber in the Lateral Extension).  Such payments shall be
              distributed equally by NFN to each prior NFN customer which has
              already contributed to the construction of the Lateral Extension;

       (iii)  Customers utilizing the Lateral Extension shall pay to NFN a
              monthly lease per fiber mile at the rate of $250 per fiber mile
              with a minimum of two fibers measured from the Splice Point
              on the Network Backbone to the Termination Point at the
              subject premises;

        (iv)  All customers leasing fiber on the Lateral Extension shall pay
              their respective pro rata cost of any easement, right of way, or
              other similar charge incurred by NFN for the right to maintain
              the Lateral Extension, as and when such charges are incurred.




<PAGE>

                                      EXHIBIT D

                                    ADMINISTRATION

         NFN's Monitoring Program will provide standard procedures, such as the
cable and specific fiber IDs within each sheath and origin and destination of
each fiber, and OTDR traces of each fiber path (at both 1310 nm and 1550 nm
wavelengths) will be recorded along with the locations of all optical events
(splices, connection points, etc...) en route.  The database will maintain a
manhole progression for each route which correlates optical distances obtained
via the OTDR to physical landmarks such as manholes, buildings, bridges, etc. 
Locations of slack coils and ring cuts will also be indicated which facilitates
expeditious response to maintenance requirements.

                               CABLE MONITORING SYSTEM

         NFN's monitoring system will at all times be based on state-of-the-art
OTDR technology with the capability of actively examining multiple fibers, each
with its own set of test parameters.  The resultant traces will be linked to
physical landmarks in their path via a geographical graphical user interface
which facilitates a visual depiction of fiber routings.

         NFN will monitor the complete routing of each customer system by
emulating its path in a maintenance fiber in the same sheath as the active
fiber.  The full complement of maintenance fibers will be set in surveillance
mode at the OTDR, as described below, which entails continuous monitoring.

Testing of fibers will be conducted in three modes:

1.  On-Demand Testing - This test will be used by a particular user
    (Maintenance Center Analyzer) to exercise a test of a select fiber ID and
    will return an OTDR trace and summary report of all pertinent information
    in regard to the select fiber.  The test results will be then be referenced
    to an "as-built" trace.  The On-Demand test will be performed in either
    Fault Locate or Maintenance mode.  The fault locate mode will be used to
    locate "gross" problems (cable cuts) while Maintenance mode will be used to
    perform a detailed analysis of selected fibers referenced to established
    NFN thresholds.

2.  Auto-Routining - This function will be used to execute a test of select
    fibers at programmable times and dates.  The scheduling time frames will be
    hours, days or weeks with a multitude of scheduling parameters.  This
    function will be used to observe any degradation in the fiber under test
    and will issue alarms if analysis indicates differences from threshold
    settings.



<PAGE>

3.  Local Surveillance - Will execute repetitive tests of selected fibers
    (Maintenance fibers) continuously, comparing the resultant trace to the
    stored reference trace, thereby establishing "full-time surveillance".

                           FAULT ISOLATION AND RESTORATION

    NFN's Cable Monitoring System will immediately identify the location and
nature of a fault.  This information will be automatically depicted on the
geographical interface of the system along with the nearest physical landmarks
surrounding the problem.  NFN's restoration parameters will require a response
time of 2-4 hours.  Within the 2-4 hour corridor, analysis, restoration
requirements and internal and external escalation notification procedures will
be completed.  The following details the procedures:

1.  Analysis - Once an alarm is received at the Maintenance Center, the
    Analyzer will review the fiber in alarm and determine the nature of the
    problem.  The determination will either reflect a degradation or
    catastrophic (cable cut) event.  Degradation Alarm - the Analyzer will
    determine the cause and the service affecting potential.  If the trouble is
    deemed service affecting, the Analyzer will contact his immediate
    Supervisor and Maintenance personnel of the alarm and direct the
    maintenance personnel to the fault location.  Maintenance personnel will
    ascertain the nature of the trouble and the Analyzer/Supervisor will be
    notified of repair requirements and time required by the Field Supervisor. 
    The Maintenance Center Supervisor will apprise the Customer
    Telecommunications Operations Supervisor of the nature of the trouble and
    the proposed time frame for restoration.  The NFN Maintenance Supervisor
    will maintain continual communications with the Customer Telecommunications
    Operations Supervisor until completion of final repair and acceptance to
    the Customer.  In the event the Degradation Alarm is not service affecting,
    full time surveillance will be maintained for a period of 4 hours to
    ascertain the conditions of the deterioration.  Following the full time
    surveillance period if degradation continues to exist, the Analyzer will
    contact Maintenance personnel for dispatch to clear alarm generation. 
    Catastrophic Alarm - the Analyzer will retrieve the fiber under alarm and
    determine trouble and location.  The system at this juncture has initiated
    multiple notification alarms (internally) to various levels of Supervision
    within NFN.  The Analyzer will be additionally responsible to ensure alarms
    have been received by contacting the various designated personnel.  The
    Analyzer will inform the designated individuals of location, size and
    number of Customers affected.  Maintenance personnel will be dispatched
    immediately to the location in order to determine cause and restoration
    time frames.  Maintenance Center Supervisor will contact all affected
    Customers to apprise them of our efforts and determination of anticipated
    time for restoration.

    NOTE:  ALL RESTORED FIBERS WILL CONFORM TO SPECIFICATION OF THE ORIGINAL
    DESIGN.




<PAGE>


                                      EXHIBIT E

                             NATIONAL FIBER NETWORK, INC.
                               POINT OF PRESENCE (POP)

                                  NFN BLDG.

    NFN BUILDING ADDRESS          ID#       STATUS

1.  150 Broadway                  252       Installed

2.  111 Pavonia Ave.              455       Installed

3.  140 E. 28th St.               463       Installed

4.  333 W. 52nd St.               487       Installed

5.  461 E.47th St.                493       Installed

6.  444 E. 10th St.               495       Installed

7.  810 7th Ave.                  597       Installed

8.  525 Washington Ave.           515       Installed

9.  1 W. 39th St.                 516       Installed

10. 8 E. 40th St.                 517       Installed


<PAGE>




                                      EXHIBIT F


Network Properties and Statistics


Great care has been taken in selecting fiber & cable types so as to provide high
flexibility in cable deployment while allowing for rapid restorative ability. 
Fusion splicing is the sole method of fiber connection used in the network with
strategically located slack loops for future provisioning and maintenance
purposes.  Every attempt has been made to locate the cable in the lowest and
most central possible duct bank position in order to minimize the effect of any
disruptive activity from street work.

The technical parameters of customer systems that are currently on-line reflect
the impressive results that are attainable using the topology employed by NFN. 
The average consumer system loss is 0.54 dB/km which includes cable loss, splice
loss and cross-connection insertion loss.  It should be kept in mind that the
cable loss itself is rated at 0.40 dB/km with each system averaging over 23 km
in end-to-end length.  The splice loss of these systems through their total
lengths reveal an average of 0.06 dB/splice with 0.15 dB being specified as the
maximum absolute splice loss with our contractors.

Customer systems may have either point-to-point or a ring-type configuration
depending on the specific requirements identified.  NFN provides and encourages
complete route diversity if requested by a customer.  This entails not only
identifying two separate street routings to link the customer locations, but
also providing two separate building entrances with independent risers so as to
achieve true redundancy in the fiber system.  Thus, the only point of
commonality between the two routings would be at the termination, not at the
customer site.



<PAGE>




                                      EXHIBIT G


                                   CONFIDENTIALITY


Definitions

Parties:           National Fiber Network, Inc. ("NFN")
                   US ONE Communications of New York, Inc. ("US ONE New York")
                   US ONE Communications Corp. ("US ONE")

Disclosing Party:  The party providing Confidential Material to another party.

Receiving Party:   The party receiving Confidential Material from a Disclosing
                   Party.

Loan
Documents:    The "Loan Documents" as defined in a certain Amended and Restated
              Master Agreement dated as of April 15, 1996 between NFN and US
              ONE.

Confidential
Material:     Information and documents exchanged between Parties in connection
              with the performance of their respective obligations pursuant to
              the Loan Documents with the exception of information which (i) is
              or becomes generally available to the public other than as the
              result of a disclosure by the Receiving Party or its directors,
              officers, employees, agents or representatives in violation of
              this agreement, (ii) was available to the Receiving Party prior
              to its disclosure to that party by the Disclosing Party, or
              (iii) becomes available to the Receiving Party from a source
              other than the Disclosing Party providing such information,
              provided that such source is not bound by a confidentiality
              agreement with respect to such confidential material.

         A Receiving Party will not use Confidential Material received for any
purpose except as shall be necessary to fulfill its respective obligations and
exercise its rights in accordance wit the terms of the Loan Documents.  A
Receiving Party will not disclose (except as expressly provided herein) any
portion of the Confidential Material to any person without the prior written
consent of the Disclosing Party; provided, however, that any Receiving Party may
disclose any Confidential Material to its directors, officers, employees, agents
or representatives, it being understood that they shall be informed by the
Receiving Party of the confidential nature of such information and that by
receiving such information they shall agree with the Receiving Party to treat
the Confidential Material accordance with this agreement.



<PAGE>

         In the event that a Party is requested or required by law, judicial or
governmental order, discovery request or other legal process or pronouncement to
disclose any Confidential Material which it has received from a Disclosing
Party, it will give the Disclosing Party prompt notice of such request so that
either Party may seek an appropriate protective order.  If in the absence of a
protective order a Party is nonetheless required to disclose Confidential
Material, it may disclose such information without liability hereunder;
provided, however, that it gives the Disclosing Party written notice of the
information to be disclosed as far in advance of its disclosure as is
practicable and, upon request and at the Disclosing Party's expense, reasonably
cooperate with the Disclosing Party's efforts to obtain assurances that
confidential treatment will be accorded to such information.

         The Parties agree that money damages would not be sufficient remedy
for any breach of this agreement, and that in addition to all such remedies, the
Parties shall be entitled (upon proof of all other necessary elements for such
relief) to specific performance and injunctive or other equitable relief as a
remedy for any such breach.

         IN WITNESS WHEREOF, the undersigned have caused this Agreement to be
duly executed as of the Effective Date.

NATIONAL FIBER NETWORK, INC. US ONE COMMUNICATIONS OF NEW
                                  YORK, INC.



By:                          By:
    Stephen A. Garofalo,               James H. Sturges,
    President                          President


                                       2


<PAGE>


                                      SCHEDULE I

                              US ONE CONTRACT AMENDMENT
                          (PREPAYMENT REDUCED TO $3,530,000)

A.  CURRENT * MILE NETWORK                                 US ONE COST
    1.   * - Fiber Miles (FM)          PREPAID
    2.   Credit for additional * Fiber Miles (FM)          PREPAID
         i.   existing network = no minimum # strands
         ii.  future network = minimum of 8 strands

B.  CENTRAL OFFICES ALREADY BUILT
    1.   (2) 140 West Street                               PREPAID
    2.   East 38th Street                                  PREPAID

C.  CO'S TO BE BUILT @ US ONE'S SOLE OPTION

    CENTRAL OFFICE      AVAILABLE

    1. Broad St.                                 (3)$58,000
    2. W. 50th St.                               "
    3. W. 36th St.                               "
    4. Ave of the Americas                       "
    5. E 56th St                                 "
    6. Bridge St. (Bklyn)                        "
    7. W 73rd St.                                "
    8. E 79th St                                 "
    9. E 30th St                                 "
    10. W 18th St.                               "
    11. 204 Second Ave                           "
    12. Varick St.                               "
    13. E 97th St                                "
    14. Bway & Elm (Queens)                      "
    15. 2/Messerole St (Bklyn)

D.  CO's TO BUILD UPON US ONE'S REQUEST, BUT AT NFN'S SOLE OPTION

    CENTRAL OFFICE

    1. Main Street (White Plains)                T.B.D.
    2. Zeckendorf Blvd. (Nassau)                 T.B.D.
    3. Brentwood (Suffolk)                       T.B.D.
    4. 69 Cherry St. (Hicksville)                T.B.D.
    5. 7 Grant St. (Tuckahoe)                    T.B.D.

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

(2)  Single point of entry and non diverse path.
(3)  Average cost per C.O. (individual cost per C.O. may vary)

<PAGE>

    6. 7 Washington St. (Lynbrook)               T.B.D.
    7. 50 W. 4th St (Huntington)                 T.B.D.
    8. 60 Main St. (Mineola)                     T.B.D.
    9. 199 Fulton St. (Hempstead)                T.B.D.
    10. 50 Broad St (Port Chester)               T.B.D.
    11. 159 Lowell Ave (Floral Park)                  T.B.D.

E.  OPTION FOR ADDITIONAL * FIBER MILES     * PER STRAND PER FM 
                                            (* STRAND MINIMUM
                                            PREPAID 10 YEAR TERM

                                       2





© 2022 IncJournal is not affiliated with or endorsed by the U.S. Securities and Exchange Commission