Form Of Restricted Stock Agreement

EXHIBIT (D)(4)


STOCK RESTRICTION AGREEMENT


AGREEMENT made this day of October, 2001 (the "Grant Date") between Avici Systems Inc., a Delaware corporation (the "Company"), and (the "Employee").


RECITALS:


1. The Employee has been granted shares (the "Shares") of the Common Stock, $.0001 par value per share (the "Common Stock"), of the Company pursuant to the Company's 2000 Stock Option and Incentive Plan (the "Plan") in exchange for tendering for cancellation certain previously granted options to purchase Common Stock of the Company (the "Tendered Options").


2. The Company wishes to continue to retain the Employee as an employee of the Company and the Employee wishes to continue to be retained by the Company.


In consideration of the mutual covenants contained herein and for other valuable consideration, receipt of which is hereby acknowledged, the parties hereto agree as follows:


1. Grant. Subject to the terms and conditions of the Plan, the Company hereby grants and issues to the Employee Shares in exchange for the Tendered Options. The Shares granted pursuant to the Plan shall be subject to forfeiture, if, in the discretion of the Board of Directors (the "Board") or any one or more committees or subcommittees of the Board (a "Committee"), the Employee has not, within a reasonable period of time following the grant of the Shares, executed any instrument required by the Board or a Committee to be executed in connection with such grant. The Shares will be evidenced by this Agreement and the Employee will not receive a stock certificate for the Shares. Initially, the Employee will have his or her ownership of the Shares registered only in book-entry form in the records of the transfer agent for the Company's Common Stock. Book-entry registration refers to a method of recording stock ownership in which no share certificates are issued to stockholders. After any date upon which the Shares have vested, the Employee may obtain a certificate for his or her vested Shares registered in his or her name in book-entry form upon request from the Company, provided that the Employee has signed this Agreement and the Irrevocable Standing Order to Sell Shares, attached hereto as Exhibit A (the "Standing Order") to facilitate payment of applicable Withholding Taxes (as defined in Section 4 below).


2. Vesting of Option if Business Relationship Continues.


(a) If the Employee has continued to serve the Company or any parent or subsidiary of the Company (a "Related Corporation") in the capacity of an employee, officer, director or consultant (such service is described herein as maintaining or being involved in a "Business Relationship" with the Company or any Related Corporation) on the following dates, the Shares granted to the Employee shall vest as indicated below:


On the First Anniversary [Insert a number that is 50% of the Shares]
of the Grant Date:


After the first anniversary of the [Grant Date], an additional Shares will vest on the last day of every three-month period (or with respect to the final installment such number of shares as shall remain unexercisable) such that it shall be fully exercisable, subject to the terms and conditions of this Agreement, on the date which is two years from [Insert Grant Date]]. In the event that the Grant Date occurs on the 29th, 30th or 31st day of a month and if vesting occurs within a month where there are fewer than those number of days, vesting shall occur on the last day of that month.


(b) In the event the Employee ceases to maintain a Business Relationship with the Company or any Related Corporation, no additional unvested Shares shall become vested Shares under any circumstances with


respect to the Employee. Any determination under this Agreement as to employment status or other matters referred to above shall be made in good faith by the Board of Directors of the Company, whose decision shall be binding on all parties. In addition, all unvested Shares shall be forfeited by the Employee and the Common Stock represented by the unvested Shares shall again be available for the grant of awards under the Plan.


3. Restrictions on Transfer. The Employee shall not sell, assign, transfer, pledge, encumber or dispose of all or any of his unvested Shares, either voluntarily or by operation of law, except that the Employee may transfer all or any of his unvested Shares as follows:


(a) As a gift to any member of his family or to any trust for the benefit
of any such family member or the Employee provided that any such
transferee shall agree in writing with the Company, as a condition
precedent to such transfer, to be bound by all of the provisions of
this Agreement to the same extent as if such transferee were the
Employee; or


(b) By court order, in which event each such transferee shall be bound by
all of the provisions of this agreement to the same extent as if such
transferee were the Employee. As used herein, the word "family" shall
include any spouse, lineal ancestor or descendant, brother or sister.


4. Taxes


(a) The Company's obligation to deliver ...