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EXHIBIT 5.1
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January 11, 2001
Avici Systems Inc.
101 Billerica Avenue
North Billerica, MA 01862
Re: Registration Statement on Form S-8
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Ladies and Gentlemen:
We are acting as counsel for Avici Systems Inc., a Delaware corporation
(the "Company"), in connection with the registration on a Registration Statement
on Form S-8 (the "Registration Statement") under the Securities Act of 1933, as
amended, of (i) 200,000 shares of Common Stock, par value $.0001 per share
("Common Stock"), of the Company under the 2000 Non-Employee Director Stock
Option Plan (the "Non-Employee Director Plan"), and (ii) 57,304 shares of Common
Stock of the Company under the 2000 Employee Stock Purchase Plan (the "Purchase
Plan" and, collectively with the Non-Employee Director Plan, the "Stock Plans").
In rendering our opinion, we have examined, and are familiar with, and have
relied as to factual matters solely upon, originals or copies certified, or
otherwise identified to our satisfaction, of such documents, corporate records
or other instruments as we have deemed necessary or appropriate for the purposes
of the opinion set forth herein, including, without limitation, (a) the Stock
Plans, (b) the Company's Fourth Restated Certificate of Incorporation, (c) the
Company's By-laws, (d) a specimen of the form of Certificate evidencing the
shares of Common Stock of the Company and (e) the minute books of the Company.
We are members only of the Bar of the Commonwealth of Massachusetts and are
not experts in, and express no opinion regarding, the laws of any jurisdiction
other than the Commonwealth of Massachusetts and the United States of America,
and the General Corporation Law of the State of Delaware.
Based upon and subject to the foregoing, we are of the opinion that the
shares of Common Stock of the Company issuable pursuant to the Stock Plans are
duly authorized and, when issued pursuant to the terms of the Stock Plans and
the terms of any agreement relating to such issuance, will be validly issued,
fully paid and nonassessable.
We hereby consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement.
Very truly yours,
TESTA, HURWITZ & THIBEAULT, LLP
