SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                                   FORM 8-A

               FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                   PURSUANT TO SECTION 12(b) OR 12(g) OF THE
                        SECURITIES EXCHANGE ACT OF 1934

                           RIVERSTONE NETWORKS, INC.
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            (Exact name of registrant as specified in its charter)

                   Delaware                                95-4596178
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(State or Other Jurisdiction of Incorporation)            (IRS Employer
                                                       Identification No.)

               5200 Great America Parkway, Santa Clara, CA 95054
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             (Address of principal executive offices)  (Zip Code)


   If this Form relates to the            If this Form relates to the
   registration of a class of             registration of a class of
   securities pursuant to Section         securities pursuant to Section 12(g)
   12(b) of the Exchange Act and is       of the Exchange Act and is effective
   effective pursuant  to General         pursuant to General Instruction
   Instruction A.(c), please check        A.(d), please check the following
   the following box. [_]                 box. [X]

Securities Act registration statement file number to which this form
relates:_____________
         (if applicable)

Securities to be registered pursuant to Section 12(b) of the Act:

            Title of Each                     Name of Each Exchange on Which
       Class to be so Registered              Each Class is to be Registered
-----------------------------------------    -----------------------------------

                None                                        None

Securities to be registered pursuant to Section 12(g) of the Act:

                   Series A Preferred Stock Purchase Rights
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                               (Title of class)

                                  Page 1 of 7


Item 1.    Description of Registrant's Securities to be Registered.
           -------------------------------------------------------

     On July 13, 2001, Riverstone Networks, Inc. (the "Company") declared a
dividend distribution of one preferred stock purchase right (collectively, the
"Rights", and individually, a "Right") for each outstanding share of the
Company's common stock, $.01 par value per share (the "Common Stock"). Each
Right entitles the registered holder to purchase from the Company after the
Distribution Date (described below) one one-thousandth of a share of the
Company's Series A Preferred Stock, $.01 par value per share (the "Preferred
Stock"). The exercise price is $115.00 for each one-thousandth of a share of
Preferred Stock. The distribution of Rights will be made on August 3, 2001 to
the record holders of Common Stock at the close of business on July 26, 2001.
One Right will also be issued for each share of Common Stock issued between July
26, 2001 and the Distribution Date.

     Exercisability of the Rights; Distribution Date.  The Rights are not
exercisable until the Distribution Date.  The Distribution Date would occur, if
ever, ten business days after either of the following events:

     .  A public announcement that a person or group other than certain exempt
persons (an "Acquiring Person") has acquired, or obtained the right to acquire,
beneficial ownership of 15% or more of the Company's outstanding Common Stock
(the "Stock Acquisition Date"); or

     .  The commencement or announcement of an intention to make a tender offer
or exchange offer that would result in a person or group, other than certain
exempt persons, owning 15% or more of the Company's outstanding Common Stock.

     Mergers, Asset Sales and Self-Dealing Transactions. If after the Stock
Acquisition Date the Company is acquired in a merger or other business
combination, or 25% or more of its assets or earning power is sold, proper
provision is to be made so that each holder of a Right would have the right to
receive, upon exercise of the Right, that number of shares of common stock of
the acquiring company which at the time has a market value of two times the
exercise price of the Right.

     In the event that:

     (1) the Company is the surviving corporation in a merger with an Acquiring
Person and its Common Stock is not changed or exchanged; or

     (2) an Acquiring Person engages in one of a number of self-dealing
transactions specified in the Rights Agreement described below; or

     (3) during such time as there is an Acquiring Person any recapitalization,
reorganization or other transaction involving the Company occurs which results
in such Acquiring Person's ownership interest being increased by more than 1%;

                                  Page 2 of 7


then each holder of a Right would have the right to receive, upon exercise of
the Right, that number of shares of Common Stock (or, in certain circumstances,
cash, property or other securities of the Company) having a market value of two
times the exercise price of the Right.

     Following the occurrence of any of the events described in this section,
any Rights beneficially owned by any Acquiring Person would immediately become
null and void.

     Exchange Option. The Board may, at its option, at any time after any person
becomes an Acquiring Person, exchange all or part of the then outstanding and
exercisable Rights for shares of Common Stock at an exchange ratio of one share
of Common Stock per Right. The Board, however, may not effect an exchange at any
time after any person (other than (i) the Company, (ii) any subsidiary of the
Company, (iii) any employee benefit plan of the Company or any such subsidiary
or any entity holding Common Stock for or pursuant to the terms of any such plan
or (iv) until the close of business on August 15, 2001, Cabletron Systems,
Inc.), together with all affiliates of such person, becomes the beneficial owner
of 50% or more of the Common Stock then outstanding. Immediately upon the action
of the Board ordering the exchange of any Rights and without any further action
and without any notice, the right to exercise such Rights will terminate and the
only right thereafter of a holder of such Rights will be to receive that number
of shares of Common Stock equal to the number of such Rights held by the holder.

     Transferability of Rights. Until the Distribution Date, the Common Stock
certificates will evidence the Rights, and the transfer of the Common Stock
certificates will constitute a transfer of the Rights. After the Distribution
Date, separate certificates evidencing the Rights would be mailed to holders of
record of the Company's Common Stock as of the close of business on the
Distribution Date, and such separate Rights certificates alone would evidence
the Rights.

     Redemption. The Board of Directors, by a majority vote, may redeem the
Rights at a redemption price of $.01 per Right at any time before the earlier of
the Distribution Date or the close of business on the Expiration Date described
below. Immediately upon such redemption, the right to exercise the Rights will
terminate, and the Rights holders will become entitled only to receive the
redemption price.

     Expiration of Rights.  If not previously exercised or redeemed, the Rights
will expire on July 13, 2011.

     Anti-Dilution Adjustment. The exercise price, the redemption price, the
exchange ratio and the number of shares of the Preferred Stock or other
securities or property issuable upon exercise of the Rights are subject to
adjustment from time to time to prevent dilution under the following
circumstances:

     .  in the event of a stock dividend on, or a subdivision, combination or
reclassification of the Preferred Stock, or

     .  upon the grant to holders of the Preferred Stock of certain rights or
warrants to subscribe for shares of the Preferred Stock or convertible
securities at less than the current market price, or

                                  Page 3 of 7


     .  upon the distribution to holders of the Preferred Stock of evidences of
indebtedness or assets (excluding regular quarterly cash dividends out of the
earnings or retained earnings of the Company and dividends payable in shares of
Preferred Stock) or of subscription rights or warrants (other than those
referred to above).

     With certain exceptions, no adjustment in the exercise price will be
required until cumulative adjustments require an adjustment of at least 1% in
such price. At the Company's option, cash (based on the market price on the last
trading date prior to the date of the exercise) will be paid instead of issuing
fractional shares of any securities (other than fractional shares of Preferred
Stock in integral multiples of one-thousandth of a share).

     No Shareholder Rights.  A Right holder, as such, has no rights as a
shareholder of the Company, including, without limitation, the right to vote or
receive dividends.

     Amendments. Any of the provisions of the Rights Agreement (described below)
may be amended by the Board of Directors prior to the Distribution Date without
the approval of any holders of the Rights. After the Distribution Date, the
Board of Directors may amend the Rights Agreement to cure any ambiguity, to make
changes which do not adversely affect the interests of holders of Rights
(excluding the interests of any Acquiring Person) or to shorten or lengthen any
time period under the Rights Agreement. A majority vote of the Board of
Directors is required.

     Tax Consequences. Although the Company believes that neither the
distribution of the Rights nor the subsequent separation of the Rights on the
Distribution Date should be taxable to the stockholders or the Company,
stockholders may, depending upon the circumstances, realize taxable income upon
the occurrence of an event described under "Mergers, Asset Sales and Self-
Dealing Transactions."

     Rights Agreement.  The terms of the Rights are set forth in a Rights
Agreement between the Company and Mellon Investor Services LLC, as Rights Agent.
A copy of the Rights Agreement is an Exhibit to this Form 8-A.  A copy of the
Rights Agreement is available free of charge from the Rights Agent at the
following address:

     Mellon Investor Services LLC
     400 S. Hope Street, 4/th/ Floor
     Los Angeles, California 90071

This summary does not purport to be complete and is qualified in its entirety by
reference to the Rights Agreement, which is incorporated in this summary by
reference.

                                  Page 4 of 7


Item 2.    Exhibits.
           --------

     4.1   Rights Agreement dated as of July 16, 2001 ("Rights Agreement")
           between the Company and Mellon Investor Services LLC, as Rights
           Agent.

     4.2   Form of Certificate of Designation with respect to the Series A
           Preferred Stock, $.01 par value per share, of the Company (attached
           as Exhibit A to the Rights Agreement).

     4.3   Form of Rights Certificate (attached as Exhibit B to the Rights
           Agreement). Pursuant to the Rights Agreement, printed Rights
           Certificates will not be mailed until the Distribution Date (as
           defined in the Rights Agreement).

     4.4   Summary of Rights (attached as Exhibit C to the Rights Agreement).

                                  Page 5 of 7


                                   SIGNATURE

     Pursuant to the requirements of Section 12 of the Securities Exchange Act
of 1934, the registrant has duly caused this registration statement to be signed
on its behalf by the undersigned, thereto duly authorized.

                              RIVERSTONE NETWORKS, INC.



Date: July 20, 2001           By: /s/ Romulus Pereira
                                  ----------------------
                              Name:     Romulus Pereira
                              Title:    President and Chief Executive
                                        Officer

                                  Page 6 of 7


                                 EXHIBIT INDEX


     The following designated exhibits are filed herewith:

     4.1  Rights Agreement dated as of July 16, 2001 ("Rights Agreement")
          between the Company and Mellon Investor Services LLC, as Rights Agent.

     4.2  Form of Certificate of Designation with respect to the Series A
          Preferred Stock, $.01 par value per share, of the Company (attached as
          Exhibit A to the Rights Agreement).

     4.3  Form of Rights Certificate (attached as Exhibit B to the Rights
          Agreement). Pursuant to the Rights Agreement, printed Rights
          Certificates will not be mailed until the Distribution Date (as
          defined in the Rights Agreement)

     4.4  Summary of Rights (attached as Exhibit C to the Rights Agreement).

                                  Page 7 of 7