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                                                                    Exhibit 10.5

                              STANDSTILL AGREEMENT

         This Standstill Agreement (the "Agreement"), dated as of August 29,
2000, is between Cabletron Systems, Inc., a Delaware corporation (the
"Company"), and each of the parties listed on Schedule I hereto (the
"Investors").

         WHEREAS, simultaneously with the execution of this Agreement, the
Investors and the Company are entering into the Amended and Restated Securities
Purchase Agreement dated as of the date hereof (as from time to time in effect,
the "Purchase Agreement"); and

         WHEREAS, the Company and each of the Investors desire to establish in
this Agreement certain conditions of such Investors' and such Investors'
Controlled Affiliates' relationship with Company;

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

                                    ARTICLE I

                                   DEFINITIONS

         SECTION 1.01 Definitions.

              (a)  "ACQUISITION PROPOSAL" shall mean a bona fide, written
         proposal, which proposal includes all material terms of a proposed
         transaction, received by the Board of Directors of the Company from any
         Person or Group proposing to enter into a transaction which, if
         effected, would constitute a Change of Control of the Company.

              (b)  "AFFILIATE" shall have the meaning given it in Rule 12b-2
         under the Exchange Act.

              (c)  "BENEFICIAL OWNER" shall have the meaning given it in Rule
         13d-3 under the Exchange Act; and "Beneficially Own" and "Beneficial
         Ownership" shall apply to securities held by a Beneficial Owner.

              (d)  "CHANGE OF CONTROL" shall mean (1) the acquisition by a Third
         Party of more than 50% of the Company's then outstanding Voting Stock,
         excluding however, a purchase agreement with an underwriter or group of
         underwriters in a registered public offering to the public; (2) the
         consummation of a merger, acquisition, consolidation or reorganization
         or series of such related transactions involving the Company, unless
         immediately after such
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         transaction or transactions, the stockholders of the Company
         immediately prior to such transaction shall Beneficially Own at least
         50% of the outstanding Voting Stock of the Company (or, if the Company
         shall not be the surviving company in such merger, consolidation or
         reorganization, the Voting Stock of the surviving corporation issued in
         such transaction or transactions in respect of Voting Stock of the
         Company shall represent at least 50% of the Voting Stock of such
         surviving company); (3) a change or changes in the membership of the
         Company's Board of Directors which represents a change of a majority or
         more of such membership during any twelve month period (unless such
         change or changes in membership are caused by the actions of the then-
         existing Board of Directors); (4) an Insolvency Proceeding (as defined
         below); or (5) the consummation of a sale of all or substantially all
         of the Company's assets unless immediately after such transaction, the
         stockholders of the Company immediately prior to such transaction shall
         beneficially own at least 50% of the Voting Stock of the acquiring
         company.

              (e)  "CLOSING" shall have the meaning given to it in the Purchase
         Agreement.

              (f)  "COMMON STOCK" shall mean the Common Stock of the Company,
         par value $.01 per share.

              (g)  "CONTROLLED AFFILIATE" means for any Investor, any Person
         that is controlled, directly or indirectly, by such Investor.

              (h)  "EXCHANGE ACT" shall mean the Securities Exchange Act of
         1934, as amended.

              (i)  "EXCLUDED AFFILIATES" means Morgan Stanley Dean Witter & Co.
         and its Affiliates, except to the extent that any of the foregoing is
         an Investor.

              (j)  "GROUP" shall mean any group within the meaning provided in
         Section 13(d)(3) of the Exchange Act.

              (k)  "INSOLVENCY PROCEEDING" shall mean (1) an assignment for the
         benefit of creditors, (2) the filing by the Company of a petition to
         have the Company adjudged insolvent, bankrupt or seeking a
         reorganization or liquidation under any law relating to bankruptcy,
         insolvency or receivership, (3) an appointment of a receiver or trustee
         for all or substantially all of the assets of the Company unless
         appointed without the Company's consent, in which case if after 60 days
         such appointment has not been vacated or stayed, (4) a public admission
         in writing of the Company's inability to pay its debts as they come
         due, or (5) the adoption of a plan of liquidation or dissolution by the
         Board of Directors of the Company.

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              (l)  "MAJORITY IN INTEREST" means, prior to the closing of the
         transactions contemplated by the Purchase Agreement, Investors who have
         agreed to purchase more than 50% of the shares of Preferred Stock
         pursuant to the Purchase Agreement and, on and after the closing of the
         transactions contemplated by the Purchase Agreement, Investors holding
         more than 50% of the Voting Power of the shares of Preferred Stock
         originally purchased pursuant to the Purchase Agreement and then owned
         by the Investors (and related Underlying Shares, as defined in Section
         4.01 hereof).

              (m)  "OPERATING SUBSIDIARY" shall have the meaning set forth in
         the Purchase Agreement.

              (n)  "PARENT WARRANT" shall have the meaning set forth in the
         Purchase Agreement.

              (o)  "PERSON" shall mean an individual, corporation, partnership,
         limited liability company, association, trust, unincorporated
         organization or other entity.

              (p)  "PREFERRED STOCK" shall mean the Company's Series A and
         Series B Participating Convertible Preferred Stock, par value $.01 per
         share.

              (q)  "PRE-SPIN-OFF IPO" shall have the meaning set forth in the
         Purchase Agreement.

              (r)  "PROPRIETARY INFORMATION" shall mean all confidential
         information of the Company other than information that (i) is or
         becomes publicly available other than as a result of a breach by an
         Investor of its obligations hereunder, (ii) is or becomes available to
         an Investor on a nonconfidential basis from a source that is, to the
         Investor's actual knowledge, not prohibited from disclosing such
         information, (iii) is known to an Investor or its Representatives prior
         to disclosure by the Company, or (iv) has been independently developed
         by an Investor without reference to confidential information of the
         Company.

              (s)  "REPLACEMENT WARRANT" shall have the meaning set forth in the
         Purchase Agreement.

              (t)  "SECURITIES ACT" shall mean the Securities Act of 1933, as
         amended.

              (u)  "SUBSIDIARY STOCK PURCHASE RIGHT" shall have the meaning set
         forth in the Purchase Agreement.

              (v)  "SUBSIDIARY WARRANT" shall have the meaning set forth in the
         Purchase Agreement.

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              (w)  "THIRD PARTY" shall mean any Person (other than any Investor
         and its Controlled Affiliates) or Group (other than any Group that
         includes any Investor or its Controlled Affiliates).

              (x)  "TOTAL VOTING POWER" at any date, with respect to any Person,
         shall mean the total combined Voting Power of all the Voting Stock of
         such Person then outstanding and entitled to vote.

              (y)  "VOTING POWER" with respect to any Voting Stock of any Person
         on any date shall mean the voting power in the general election of
         directors of the relevant Person to which such Voting Stock would be
         entitled on such date.

              (z)  "VOTING STOCK" of any Person shall mean any securities
         entitled to vote generally in the election of directors of such Person,
         or any direct or indirect rights or options or warrants to acquire any
         such securities or any securities (including, without limitation, the
         Preferred Stock) convertible or exercisable into or exchangeable for
         such securities, whether or not such securities are so convertible,
         exercisable or exchangeable at the time of determination.

                                   ARTICLE II

                                      TERM

         SECTION 2.01 Term. The term of this Agreement (the "Term") shall
commence on the date hereof and shall continue until the earlier to occur of the
following:

              (a)  the fourth anniversary of the Closing; and

              (b)  the termination of the Purchase Agreement prior to the
         Closing in accordance with its terms.

                                   ARTICLE III

                              STANDSTILL PROVISIONS

         SECTION 3.01 Restrictions of Certain Actions. Each of the Investors
hereby severally agrees that during the Term, neither it nor any Controlled
Affiliate of such Investor, other than Excluded Affiliates, will, singly or as
part of a Group, directly or indirectly:

              (a) acquire or offer, make a proposal or agree to acquire (whether
         publicly or otherwise), in any manner, any material assets of the
         Company or its subsidiaries or any equity securities of the Company or
         its subsidiaries (or Beneficial Ownership thereof), except (1) for
         equity securities representing less than five percent (5%) of the
         issued and outstanding

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         Voting Stock of the Company or any of its subsidiaries and (2) pursuant
         to a stock split, stock dividend, recapitalization, reclassification or
         similar transaction not effected by such person pursuant to a violation
         of this Section 3.01;

              (b)  make or in any way propose or participate in any
         "solicitation" of "proxies" to vote (as such terms are defined in Rule
         14a-1 under the Exchange Act), solicit any consent or communicate with
         or seek to advise or influence any Person, other than the Company, the
         Investors and their Controlled Affiliates, with respect to the
         solicitation or voting of any Voting Stock of the Company in opposition
         to any matter that has been recommended by the Board or in favor of any
         matter that has not been approved by the Board, or become a
         "participant" in any "election contest" (as such terms are defined or
         used in Rule 14a-11 under the Exchange Act) with respect to the
         Company;

              (c)  form, be a member of, join or encourage the formation of, any
         Group (other than any Group consisting solely of Investors and their
         Controlled Affiliates) with respect to any Voting Stock of the Company
         or the acquisition of any assets of the Company or any of its
         subsidiaries;

              (d)  deposit any Voting Stock of the Company into a voting trust
         or subject any such Voting Stock to any arrangement or agreement with
         respect to the voting thereof (other than arrangements solely
         concerning the Investors and their Controlled Affiliates);

              (e)  seek election to or seek to place a representative on the
         Board of Directors of the Company (except pursuant to Section 5.7 of
         the Purchase Agreement) or seek the removal of any member of the Board
         of Directors of the Company (except pursuant to Section 5.7 of the
         Purchase Agreement);

              (f)  call or seek to have called any meeting of the stockholders
         of the Company other than participation as a director of the Company in
         calling, or seeking to have called, meetings of stockholders generally;

              (g)  initiate, propose or otherwise solicit stockholders of the
         Company for the approval of any stockholder proposal with respect to
         the Company as described in Rule 14a-8 under the Exchange Act, or
         induce or attempt to induce any Person to initiate any such stockholder
         proposal, in opposition to any matter that has been recommended by the
         Board or in favor of any matter that has not been approved by the
         Board;

              (h)  solicit, seek to effect, negotiate with or provide any
         information to any other party with respect to, or make any statement
         or proposal, whether written or oral, to the Board of Directors of the
         Company or otherwise make any public announcement or proposal
         whatsoever with respect to, a merger or acquisition of the Company, the
         sale of all or a substantial portion of the assets of the Company and
         its subsidiaries, the purchase of equity securities of the Company or
         any of its subsidiaries, liquidation of the Company,

                                       5
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         recapitalization of the Company or similar business transactions with
         respect to the Company or take any action which might require or result
         in a public announcement with respect to any such matters (the
         foregoing shall not limit the Investor from discussing any Third Party
         Acquisition Proposal with, or providing any information with respect
         thereto to, the Company, and shall not restrict communications among
         the Investors and their Controlled Affiliates);

              (i)  instigate or assist, or enter into any arrangements with, any
         Third Party to do any of the actions described in Sections 3.01(a)
         through (h); or

              (j)  If any Investor or any of its Controlled Affiliates owns or
         acquires any Voting Stock in violation of this Agreement, such Voting
         Stock shall immediately be disposed of to persons who are not
         Controlled Affiliates thereof but only in compliance with the
         provisions of this Section 3.01 and Section 4.01; provided, however,
         that Company may also pursue any other available remedy to which it may
         be entitled as a result of such violation.

         SECTION 3.02 Suspension of Restrictions. The limitations provided in
Section 3.01 shall immediately be suspended upon the occurrence of any of the
following events.

              (a)  any Third Party commences a tender or exchange offer seeking
         to acquire Beneficial Ownership of 50% or more of the outstanding
         shares of Voting Stock, but only if (i) the Company has not within 10
         days after commencement of such offer (or such longer period as may
         then be permitted under applicable law for the Company's initial
         recommendation with respect to such offer) publicly recommended that
         such offer not be accepted, and (ii) all of the material conditions to
         such offer relating to the elimination or satisfaction of the material
         defensive provisions established by the Company, including any rights
         plan or similar defensive provision of the Company, have been satisfied
         or waived;

              (b)  any Third Party publicly announces an Acquisition Proposal
         from any Third Party but only if (i) the Company has not, within 15
         days after such announcement, rejected such Acquisition Proposal, and
         (ii) all of the material conditions to such offer relating to the
         elimination or satisfaction of the material defensive provisions
         established by the Company, including any rights plan or similar
         defensive provision of the Company, have been satisfied or waived;

              (c)  the occurrence of a Change of Control of the Company;

              (d)  the public announcement by the Company that it is "for sale";

              (e)  the execution of a definitive agreement which, if
         consummated, would result in a Change of Control of the Company;

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              (f)  the public announcement by or on behalf of any Third Party of
         the commencement of a bona fide proxy or consent solicitation subject
         to Section 14 of the Exchange Act (or any successor provision) to elect
         or remove a majority of the directors of the Company which is not,
         within 10 days after the announcement of such proxy or consent
         solicitation (or such longer period as may then be permitted under
         applicable law for the Company's initial recommendation with respect to
         such contest if such a period is specified), publicly opposed by the
         Company's Board of Directors and which would, if successful, result in
         a change in the composition of a majority of the Board of Directors of
         the Company; or

              (g)  the adoption by the Board of Directors of a plan of
         liquidation or dissolution.

         The Company shall provide the Investors with prompt written notice of
the occurrence of any of the events set forth in this Section 3.01. Upon any (i)
withdrawal or lapsing of any such tender or exchange offer referred to in
Section 3.02(a) in which such Third Party does not acquire more than 15% of the
outstanding Voting Stock of the Company, (ii) withdrawal, rejection or
termination of an Acquisition Proposal referred to in Section 3.02(b), (iii) the
public withdrawal of any "for sale" notice referred to in Section 3.02(d), (iv)
the termination of the agreement referred in Section 3.02(e) without
consummation thereof, (v) the withdrawal or termination or failure of the
solicitation referred to in Section 3.02(f) or (vi) the termination of the plan
of liquidation referenced in Section 3.02(g), as the case may be, the
limitations provided in Sections 3.01 (except to the extent then suspended as a
result of any other event specified in Section 3.02) shall again be applicable
for so long as and only to the extent provided therein without any extension of
the term thereof.

                                   ARTICLE IV

                              TRANSFER RESTRICTIONS


         SECTION 4.01 Transfer Restrictions.

              (a)  For a period of one year from the date of the Closing under
         the Purchase Agreement, each of the Investors agrees not to sell,
         assign, grant, put, call, pledge or hypothecate (other than in
         connection with a bona fide credit facility established with third-
         party lenders), or grant, without the Company's prior written consent,
         other similar rights with respect to or otherwise transfer (each, a
         "Transfer"): (i) any shares of the Preferred Stock or any interest
         therein; (ii) any Parent Warrant, Subsidiary Warrant, Replacement
         Warrant, IPO Valuation Warrant or other securities issued pursuant to
         the Purchase Agreement (other than shares of capital stock issuable
         upon exercise of any Subsidiary Stock Purchase Rights) or any interest
         therein; (iii) any shares of or interest in the Common Stock issuable
         upon conversion of the Preferred Stock or exercise of the Parent
         Warrants, Subsidiary Warrants, Replacement Warrants, IPO Valuation
         Warrants or other securities issued pursuant to the Purchase Agreement
         (other than shares of capital stock issuable upon exercise of any
         Subsidiary Stock Purchase Rights) (the "Underlying Shares") or (iv) any
         Subsidiary Stock Purchase Rights or any interest therein; provided,
         however, that the

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         restrictions contained in this Section 4.01 shall not apply to
         Transfers (A) among the Investors or (B) to any Controlled Affiliate of
         an Investor that has agreed to be bound by the terms and conditions of
         this Agreement applicable to the Investors; and provided, further, that
         with respect to any shares of capital stock of any Operating Subsidiary
         issuable upon exercise of any Subsidiary Stock Purchase Rights, (x)
         each Investor agrees to enter into any lock-up agreement entered into
         by management of an Operating Subsidiary in connection with the Pre-
         Spin-Off IPO of such Operating Subsidiary, which agreement shall
         provide for a lock-up period of not longer than 180 days for the
         initial date of release and shall provide that after such initial
         period, such Investor shall not transfer more than one-third of such
         shares held by such Investor during any 30-day period unless the
         executive management of such Operating Subsidiary is permitted to sell
         25% of their shares under such lock-up agreement, in which case such
         lock-up agreement shall not place any transfer restrictions on such
         Investor after such initial period), and (y) until the date that is one
         year from the Closing, such Investor may Transfer such shares through a
         sale in the open market pursuant to Rule 144 under the Securities Act,
         provided that any such sale complies with the manner of sale
         requirements of Rule 144 and is not made to (I) any Person or Group
         that has theretofore filed a Schedule 13D with the Commission with
         respect to any class of equity security (as defined in Rule 13a11-1
         under the Exchange Act) of the Company and that, at the time of such
         sale, continues to reflect beneficial ownership in excess of 5% of the
         Total Voting Power of the Company or (II) any Person or Group that,
         after giving effect to the sale and to the actual knowledge of such
         Investor (with no duty of investigation), will beneficially own in
         excess of 5% of any Voting Securities of the Company or be accumulating
         stock on behalf of or acting in concert with any such Person or Group
         or a Person or Group contemplated by clause (I) above.

              (b)  After the first anniversary of the Closing, prior to any
         transfer of shares of Preferred Stock, the Parent Warrants, the
         Subsidiary Warrants, the Replacement Warrants, the IPO Valuation
         Warrants, the Underlying Shares, the Subsidiary Stock Purchase Rights
         and the shares of capital stock issuable upon exercise of the
         Subsidiary Stock Purchase Rights (collectively, the "Restricted
         Securities"), in each case, that have not been registered under an
         effective registration statement under the Securities Act, the holder
         thereof will give written notice to the Company of such holder's
         intention to effect such transfer and to comply in all other respects
         with this Section 4.01(b). Each such notice shall describe the manner
         and circumstances of the proposed transfer and shall designate counsel
         for the holder giving such notice (who may be house counsel for such
         holder). The holder giving such notice will submit a copy thereof to
         the counsel designated in such notice. The following provisions shall
         then apply:

                   (1)   in the written opinion of such counsel addressed to the
                         Company (which opinion and counsel are reasonably
                         acceptable to the Company), the proposed transfer may
                         be effected without registration of such Restricted
                         Securities under the Securities Act, such holder shall
                         thereupon be entitled to transfer such Restricted
                         Securities in accordance with the terms of the notice
                         delivered by such holder to the Company.

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                   (2)   in the opinion of such counsel, the proposed transfer
                         may not legally be effected without registration of
                         such Restricted Securities under the Securities Act
                         (such opinion to state the basis of the legal
                         conclusions reached therein), thereafter, such holder
                         shall not be entitled to transfer such Restricted
                         Securities until either (x) receipt by the Company of a
                         further notice from such holder pursuant to the
                         foregoing provisions of this Section 4.01(b) and
                         fulfillment of the provisions of clause (1) above or
                         (y) such Restricted Securities have been effectively
                         registered under the Securities Act.

              (c)  The restrictions imposed by Section 4.01(b) on the
         transferability of Restricted Securities shall cease and terminate as
         to any particular Restricted Securities upon the earlier of (a) when
         such Restricted Securities shall have been effectively registered under
         the Securities Act and (b) when, in the opinions of both counsel for
         the holder thereof and counsel for the Company, such restrictions are
         no longer required in order to insure compliance with the Securities
         Act. Whenever such restrictions shall cease and terminate as to any
         Restricted Securities, the holder thereof shall be entitled to receive
         from the Company, without expense (other than applicable transfer
         taxes, if any), new securities of like tenor not bearing the applicable
         legends required by Section 4.02.

         SECTION 4.02 Legends. The Investors acknowledge that the certificates
evidencing the Restricted Securities will bear, unless the restrictions imposed
by Section 4.01(a) and (b) shall have ceased and terminated as to such
Restricted Securities pursuant to Section 4.01, in addition to any legend
required by other agreements among the parties hereto and by the laws of any
applicable jurisdiction, substantially the following legend:

                  "The holder of the securities represented by this certificate
                  is subject to certain obligations contained in a Standstill
                  Agreement dated as of August , 2000, a copy of which is
                  available for inspection at the principal office of the issuer
                  hereof, and will be furnished without charge to the holder of
                  such securities upon written request."

         SECTION 4.03 Impermissible Transfers. Except as otherwise provided by
law, any Transfer in contravention of the provisions of Section 4.01 shall be
null and void, and the Company or other issuer of the applicable security or
instrument shall not in any way give effect to any such impermissible Transfer.

                                       9
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                                    ARTICLE V

                     APPLICABILITY TO SPIN-OFF SUBSIDIARIES

         Each of the Investors shall be bound by the terms of this Agreement
with respect to each Operating Subsidiary as if the Operating Subsidiary were a
party hereto, and in each such case, all references herein to the Company and to
securities of the Company shall instead be deemed to be references to the
applicable Operating Subsidiary and to the securities of the applicable
Operating Subsidiary; provided, however, that, insofar as this Article VI makes
the terms of Section 3.01(a) applicable to any Operating Subsidiary or the
securities of any Operating Subsidiary, the percentage specified therein shall
be ten percent (10%) (it being understood that this proviso shall not change the
percentage stated in Section 3.01(a) insofar as such percentage applies to the
Company or securities of the Company). Each of the Investors shall confirm its
agreements set forth in this Article V in a separate agreement with any
Operating Subsidiary if requested by the Company or such Operating Subsidiary.
Whether or not any such separate agreement is executed and delivered, each
Operating Subsidiary is an intended third party beneficiary of this Agreement
and shall be entitled to enforce this Agreement as if it were a party hereto
insofar as this Agreement applies to such Operating Subsidiary or any of its
securities.

                                   ARTICLE VI

                                  MISCELLANEOUS


         SECTION 6.01 Confidentiality.

              (a) Each Investor agrees that such Investor and its Controlled
         Affiliates (i) will keep all Proprietary Information confidential, (ii)
         will not, except as required by applicable law, regulation or legal
         process (and after compliance with paragraph (b) below), without the
         Company's prior written consent, disclose any Proprietary Information
         in any manner whatsoever to any Person, provided that the Proprietary
         Information may be revealed to officers, employees, representatives
         (including, without limitation, financial advisors, attorneys and
         accountants) or agents (collectively, "Representatives") of such
         Investor or Controlled Affiliate who need to know the Proprietary
         Information and who agree to act in accordance with the terms of this
         Section 6.01, and (iii) will cause Representatives of such Investor or
         Controlled Affiliates (other than any Representative that is not one of
         its members, partners, directors, officers or employees and that has
         agreed to be bound by the provisions of this Section 6.01) to observe
         the terms of this Section 6.01 and will be responsible for any breach
         of this Section 6.01 by any such Representative.

              (b) In the event that an Investor, any of its Controlled
         Affiliates or any Representative of an Investor or its Controlled
         Affiliates are requested pursuant to, or required by, applicable law,
         regulation or legal process to disclose any of the Proprietary

                                       10
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         Information or any other information the disclosure of which is
         prohibited by this Section 6.01, such Investor will notify the Company
         promptly so that the Company may seek a protective order or other
         appropriate remedy or, in its sole discretion, waive compliance with
         the terms of this Section 6.01. In the event that no such protective
         order or other remedy is obtained, or that the Company does not waive
         compliance with the terms of this letter agreement, such Investor will
         furnish only that portion of the Proprietary Information or such other
         information that such Investor is advised by outside counsel is legally
         required and will exercise all reasonable efforts to obtain reliable
         assurance that confidential treatment will be accorded the Proprietary
         Information or such other information.

         SECTION 6.02 Enforcement. Each of the Investors, on the one hand, and
the Company, on the other, acknowledge and agree that irreparable damage would
occur if any of the provisions of this Agreement were not performed in
accordance with their specific terms or were otherwise breached. Accordingly,
the parties will be entitled to an injunction or injunctions to prevent breaches
of this Agreement and to enforce specifically its provisions in any court having
jurisdiction, this being in addition to any other remedy to which they may be
entitled at law or in equity.

         SECTION 6.03 Entire Agreement; Waivers. This Agreement, the Purchase
Agreement and the other agreements specifically contemplated by the Purchase
Agreement constitute the entire agreement among the parties hereto pertaining to
the subject matter hereof and thereof and supersede all prior and
contemporaneous agreements, understandings, negotiations and discussions,
whether oral or written, of the parties with respect to such subject matter
(including without limitation that certain letter agreement dated May 1, 2000).
No waiver of any provision of this Agreement shall be deemed or shall constitute
a waiver of any other provision hereof (whether or not similar), shall
constitute a continuing waiver unless otherwise expressly provided nor shall be
effective unless in writing and executed (i) in the case of a waiver by the
Company, by the Company and (ii) in the case of a waiver by the Investors, by a
Majority In Interest of the Investors.

         SECTION 6.04 Amendment or Modification . The parties hereto may not
amend or modify this Agreement except in such manner as may be agreed upon by a
written instrument executed by the Company and a Majority in Interest of the
Investors; provided, however, that no such amendment shall increase any
Investor's obligations hereunder or otherwise adversely affect such Investor
without its written consent thereto.

         SECTION 6.05 Successors and Assigns . All the terms and provisions of
this Agreement shall be binding upon and shall inure to the benefit of the
parties hereto and their respective successors, and each successor shall be
deemed to be a party hereto for all purposes hereof. The terms and provisions of
this Agreement shall not be binding upon any transferee (other than a Controlled
Affiliate of an Investor) that purchases any securities subject to this
Agreement without violation of any provision of this Agreement. An Investor may
not assign

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or transfer any of its rights or obligations hereunder without the prior written
consent of the Company, and no transfer or assignment by any party shall relieve
such party of any of its obligations hereunder.

         SECTION 6.06 Severability. If any provision of this Agreement is held
by a court of competent jurisdiction to be unenforceable, the remaining
provisions shall remain in full force and effect. It is declared to be the
intention of the parties that they would have executed the remaining provisions
without including any that may be declared unenforceable.

         SECTION 6.07 Headings. Descriptive headings are for convenience only
and will not control or affect the meaning or construction of any provision of
this Agreement.

         SECTION 6.08 Counterparts. For the convenience of the parties, any
number of counterparts of this Agreement may be executed by the parties, and
each such executed counterpart will be an original instrument.

         SECTION 6.09 Notices. Any notices or other communications required or
permitted hereunder shall be sufficiently given if in writing (including
telecopy or similar teletransmission), addressed as follows:

                         If to the Company, to:

                         Cabletron Systems, Inc.
                         35 Industrial Way - Bldg. 36
                         P.O. Box 5005
                         Rochester, NH 03867-5005
                         with a copy to:

                         Ropes & Gray
                         One International Place
                         Boston, MA  02110
                         Attn: John B. Ayer, Esq.
                         Telecopier No: (617) 951-7050
                         Telephone No: (617) 951-7937

              (a) if to the Investors, to such address listed on Schedule I to
         the Purchase Agreement, with a copy to:

                         Simpson, Thatcher & Bartlett
                         425 Lexington Avenue
                         New York, NY 10017
                         Attn:  Alan Schwartz, Esq.
                         Telecopier No.:  (212) 455-2502
                         Telephone No.:  (212) 455-3629

                                       12
<PAGE>

Unless otherwise specified herein, such notices or other communications shall be
deemed received (a) in the case of any notice or communication sent other than
by mail, on the date actually delivered to such address (evidenced, in the case
of delivery by overnight courier, by confirmation of delivery from the overnight
courier service making such delivery, and in the case of a telecopy, by receipt
of a transmission confirmation form or the addressee's confirmation of receipt),
or (b) in the case of any notice or communication sent by mail, three business
days after being sent, if sent by registered or certified mail, with first-class
postage prepaid. Each of the parties hereto shall be entitled to specify a
different address by giving notice as aforesaid to each of the other parties
hereto.

         SECTION 6.10 Governing Law . This Agreement shall be governed by and
construed in accordance with the domestic substantive law of the State of
Delaware, without giving effect to any choice or conflict of law provision or
rule that would cause the application of the law of any other jurisdiction.

         SECTION 6.11 Termination . This Agreement will terminate at the end of
the Term or earlier upon the written approval of the Company and a Majority In
Interest of the Investors.


                     [Remainder of Page Intentionally Blank]

                                       13
<PAGE>

                                                          [Standstill Agreement]

         IN WITNESS WHEREOF, the Company and the Investors have caused this
Agreement to be executed as of the date first above written by their respective
officers thereunto duly authorized.



The Company:                             CABLETRON SYSTEMS, INC.


                                         By: /s/ Piyush Patel
                                             ------------------------------
                                             Name: Piyush Patel
                                             Title: Chief Executive Officer

                                       14
<PAGE>

                                                          [Standstill Agreement]

The Investors:                           SILVER LAKE PARTNERS, L.P.

                                         By: Silver Lake Technology Associates,
                                             L.L.C., its general partner


                                         By: /s/ James A. Davidson
                                             ------------------------------
                                             Name: James A. Davidson
                                             Title: Managing Member

                                       15
<PAGE>

                                                          [Standstill Agreement]


                                          MORGAN STANLEY DEAN WITTER EQUITY
                                          FUNDING, INC.

                                          By: /s/ Thomas A. Clayton
                                              ------------------------------
                                              Name: Thomas A. Clayton
                                              Title: Vice President

                                       16
<PAGE>

                                                          [Standstill Agreement]


                                          SILVER LAKE INVESTORS, L.P.

                                          By: Silver Lake Technology Associates,
                                              L.L.C., its general partner


                                          By: /s/ James A. Davidson
                                              -----------------------------
                                              Name: James A. Davidson
                                              Title: Managing Member

                                       17
<PAGE>

                                                          [Standstill Agreement]


                                          SILVER LAKE TECHNOLOGY INVESTORS,
                                          L.L.C.

                                          By: Silver Lake Technology Associates,
                                              L.L.C., its managing member


                                          By: /s/ James A. Davidson
                                              ------------------------------
                                              Name: James A. Davidson
                                              Title: Managing Member

                                       18
<PAGE>

                                                          [Standstill Agreement]


                                          INTEGRAL CAPITAL PARTNERS V, L.P.

                                          By: ICP Management V, LLC, its general
                                              partner


                                          By: /s/ Pamela K. Hagenah
                                              ----------------------------------
                                              Name: Pamela K. Hagenah
                                              Title: Manager

                                       19
<PAGE>

                                                          [Standstill Agreement]


                                          INTEGRAL CAPITAL PARTNERS V SIDE
                                          FUND, L.P.

                                          By: ICP Management V, LLC, its
                                              general partner


                                          By: /s/ Pamela K. Hagenah
                                              ----------------------------------
                                              Name: Pamela K. Hagenah
                                              Title: Manager

                                       20
<PAGE>

Investors

Silver Lake Partners, L.P.
Morgan Stanley Dean Witter Equity Funding, Inc.
Silver Lake Investors, L.P.
Silver Lake Technology Investors, L.L.C.
Integral Capital Partners V, L.P.
Integral Capital Partners V-MS Side Fund, L.P.

                                       21