<PAGE>

                                                                  Exhibit 10.19

                            CABLETRON SYSTEMS, INC.

                      Change-in-Control Severance Benefit
                            Plan for Key Employees
                     Amended and Restated __________, 2001

     Cabletron Systems, Inc. (including any "Successor Entity" as defined in
Section 8, the "Company") adopts this plan (the "Plan") with the intent of
assuring that it and its direct and indirect subsidiaries (together with the
Company, the "Employer") will have the benefit of continuity of management in
the event of any actual or threatened change in control.

     1.   Eligibility. The Board of Directors of the Company (the "Board") shall
          -----------
from time to time designate participants in the Plan ("Participants") from among
the Employer's key employees. An employee once designated a Participant shall
continue to be a Participant (subject to satisfaction of the requirements set
forth in Section 2 below) until the earlier of (a) the date (not later than the
180th day preceding a "Change in Control" as hereinafter defined) on which the
Board determines that he or she is no longer eligible to participate in the
Plan, and (b) the date he or she ceases to be employed by the Employer;
provided, that a Participant who ceases to be employed by the Employer under
circumstances giving rise to benefits under the Plan shall continue to be
treated as a Participant with respect to such benefits until they have been paid
or provided in full.

     2.   Agreement of Participants. As a precondition to participation in the
          -------------------------
Plan, each individual who is designated a Participant must enter into a written
agreement (each, a "Plan Agreement") in accordance with procedures prescribed by
and in a form acceptable to the Board. Each Plan Agreement shall contain:

          (a)  the Participant's binding commitment to the effect that once any
     Person other than the Company, a direct or indirect subsidiary of the
     Company, or an employee benefit plan of the company or any such subsidiary
     begins a tender or exchange offer or a solicitation of proxies from the
     Company's security holders or takes other actions to effect a "Change in
     Control" as hereinafter defined, the Participant will not voluntarily
     terminate his or her employment with the Employer until such Person has
     abandoned or terminated such efforts to effect a Change in Control or until
     a Change in Control has occurred (for purposes of the Plan, a "Person"
     means any individual, entity or other person, including a group within the
     meaning of Sections 13(d) or 14(d)(2) of the Securities Exchange Act of
     1934 ("Exchange Act")); and

          (b)  such other terms, if any, as the Board may specify, which may (if
     the Board so provides) deviate from the terms generally set forth in the
     Plan. As applied to any Participant, the term "Plan" means the terms and
     provisions of the Plan set forth herein as modified by the terms and
     provisions of the Participant's Plan Agreement.
<PAGE>

     3.   Change in Control. For purposes of the Plan, a "Change in Control"
          -----------------
shall be deemed to have occurred upon the occurrence of any of the events
described in subsections (a), (b), (c) or (d) below:

          (a)  Any Person acquires beneficial ownership (within the meaning of
     Rule 13d-3 promulgated under the Exchange Act) of 30% or more of either (i)
     then the outstanding shares of common stock of the Company (the
     "Outstanding Company Common Stock") or (ii) the combined voting power of
     the then outstanding voting securities of the Company entitled to vote
     generally in the election of directors (the "Outstanding Company Voting
     Securities"); provided, that for purposes of this subsection (a) the
     following acquisitions shall not constitute a Change in Control: (i) any
     acquisition directly from the Company, (ii) any acquisition by the Company,
     (iii) any acquisition by an employee benefit plan (or related trust)
     sponsored or maintained by the Employer, or (iv) any Business Combination
     (but except as provided in subsection (c) of this Section 3 a Business
     Combination may nevertheless constitute a Change in Control under that
     subsection); and provided further, that an acquisition by a Person of 30%
     or more but less than 50% of the Outstanding Company Common Stock or of the
     combined voting power of the Outstanding Company Voting Securities shall
     not constitute a Change in Control under this subsection (a) if within 15
     day of being advised that such ownership level has been reached, a majority
     of the "Incumbent Directors" (as hereinafter defined) then in office adopt
     a resolution approving the acquisition of that level of securities
     ownership by such Person; or

          (b)  Individuals who, as of July 13, 1999, constituted the Board (the
     "Incumbent Directors") cease for any reason to constitute at least a
     majority of the Board; provided, that any individual who becomes a member
     of the Board subsequent to July 13, 1999 and whose election or nomination
     for election was approved by a vote of at least two-thirds of the Incumbent
     Directors shall be treated as an Incumbent Director unless he or she
     assumed office as a result of an actual or threatened election contest with
     respect to the election or removal of directors; or

          (c)  There is consummated a reorganization, merger or consolidation
     involving the Company, of a sale or other disposition of all or
     substantially all of the assets of the Company (a "Business Combination"),
     in each case unless, following such Business Combination, (i) the Persons
     who where the beneficial owners, respectively, of the Outstanding Company
     Common Stock and of the combined voting power of the Outstanding Company
     Voting Securities immediately prior to the Business Combination
     beneficially own, directly or indirectly, more than 50% of, respectively,
     the then outstanding shares of common stock and the combined voting power
     of the then outstanding voting securities entitled to vote generally in the
     election of directors, as the case may be, of the entity resulting from
     such Business Combination in substantially the same proportions as their
     ownership immediately prior to such Business Combination of the Outstanding
     Company Common Stock and of the combined voting power of the Outstanding
     Company Voting Securities, as the case may be, (ii) no Person (excluding
     any entity resulting from such Business Combination or any employee benefit
     plan (or related trust) of the Employer or of such corporation resulting
     from such Business Combination) beneficially owns, directly or indirectly,
     30% or more of, respectively, the

                                      -2-
<PAGE>

     then outstanding shares of common stock of the corporation resulting from
     such Business Combination or the combined voting power of the then
     outstanding voting securities of such corporation entitled to vote
     generally in the election of directors, except to the extent that such
     ownership existed prior to the Business Combination and (iii) at least a
     majority of the members of the Board resulting from such Business
     Combination were Incumbent Directors at the time of the execution of the
     initial agreement, or of the action of the Board, providing for such
     Business Combination; or

          (d)  The shareholders of the Company approve a complete liquidation or
     dissolution of the Company.

     4.   Severance Benefit. If during the period of eighteen (18) months
          -----------------
following a Change in Control, either (i) the employment of a Participant is
terminated by the Employer for any reason other than for "Cause" (as defined in
Section 5 below), or (ii) the Participant terminates his or her employment with
the Employer for "Good Reason" (as defined in Section 6 below):

          (a)  The Company shall pay to the Participant in cash, within five (5)
     days of the date of termination, the sum of (i) all salary earned by the
     Participant as of the date of termination but not yet paid, (ii) the
     Participant's accrued vacation earned through the date of termination, and
     (iii) an amount equal to the Participant's target incentive bonus, if any,
     for the fiscal year in which termination occurs, multiplied times a
     fraction, the numerator of which is the number of days elapsed between the
     beginning of such year and the date of termination reduced by any periods
     (expressed in days) for which amounts under such incentive bonus
     arrangement have already been paid in such year and the denominator of
     which is 365;

          (b)  The Company shall also pay to the Participant in cash, within ten
     (10) days of the date of termination, the sum of the Participant's Base
     Salary and Bonus. "Base Salary" for this purpose means the Participant's
     annual rate of base salary as determined immediately prior to the date of
     termination (or, if higher, his or her annual rate of base salary as
     determined immediately prior to the Change in Control), and "Bonus" means
     the highest aggregate amount of bonus or incentive compensation paid in
     cash to the Participant (or that would have been so paid absent deferral)
     for any one of the three most recent fiscal years ended prior to such
     termination (or, if higher, the Participant's target incentive bonus for
     the fiscal year in which the Change in Control occurs).

          (c)  Unless provided otherwise in the applicable Plan Agreement, the
     portion of each stock option and each other stock-based right held by the
     Participant on the date of termination that is not yet vested or
     exercisable but that would have become vested or exercisable, as calculated
     pursuant to this Section 4(c), through the date 18 months following the
     date of such Participant's termination of employment, shall be treated as
     having vested (and, to the extent relevant, as having become exercisable)
     immediately prior to the Participant's termination of employment. The
     formula for determining what portion of an option or right would have
     become vested or exercisable through the date 18 months following the date
     of such Participant's termination of employment is as follows: Daily
     Vesting Rate multiplied by the number of days in the Acceleration Period

                                      -3-
<PAGE>

     (rounded down to the nearest whole number). The "Acceleration Period" shall
     mean the period beginning with the date following the last date a portion
     of such option became exercisable (the "Start Date") and ending on and
     including the date 18 months following the date of such Participant's
     termination of employment. The "Daily Vesting Rate" shall equal the number
     of shares for which the option remains unvested or unexercisable on the
     date of such Participant's termination of employment (not taking into
     account the accelerated vesting provided by this Section 4(c)) divided by
     the total number of days in the period beginning with the Start Date and
     ending on and including the last day upon which such option could become
     exercisable or vested for any portion of such option. Except as provided in
     this Section 4(c), all stock options and stock-based rights held by the
     Participant on the date of termination shall be administered in accordance
     with their terms and the terms of the applicable plan. The following
     illustrates the effect of this paragraph: Assume a Participant (i) was
     granted an option to purchase 1,000 shares of the Company's common stock on
     January 1, 1999 that became exercisable with respect to 25% of the
     underlying shares on January 1 of each of the following four years and (ii)
     was terminated after a change in control on April 30, 2000 without cause
     (as defined herein). Start Date = January 2, 2000. Acceleration Period:
     January 2, 2000 through October 31, 2001 = 669 days. Daily Vesting Rate:
     750 shares / 1,096 days = .684. Total exercisable shares: 250 [vested on
     January 1, 2000] + 457 shares [669 days x .684] for a total of 707.

          (d)  The Participant, together with his or her dependents, will
     continue for the duration of the "coverage continuation period" (as
     hereinafter defined) to be eligible to participate at the Employer's
     expense (subject to any applicable waiting periods or similar requirements
     to the extent such requirements had not been satisfied prior to the date of
     termination, and subject to the payment by the Participant or his or her
     dependents of premiums, co-pays or similar amounts at rates not greater
     than those applicable immediately prior to the Change in Control to active
     employees and their dependents) in all medical, dental and life insurance
     plans or programs maintained or sponsored by the Employer immediately prior
     to the Change in Control; provided, that if such continued participation is
     impracticable because such plans or programs are no longer generally
     available, the Participant and his or her dependents will be entitled to
     substantially equivalent coverage on substantially equivalent terms or to
     the full value thereof paid promptly in cash. For purposes of this
     subsection, the "coverage continuation period" means the one (1) year
     period following the Participant's termination of employment; provided,
     that if the plan or program in question, or applicable law, provides for a
     longer period of coverage following termination of employment, such longer
     period shall constitute the "coverage continuation period" with respect to
     that plan or program. If the coverage continuation period with respect to a
     plan or program exceeds one (1) year following the Participant's
     termination of employment, the terms and conditions of coverage following
     the first-year anniversary of the date of the Participant's termination of
     employment shall be as set forth in the plan or program or as prescribed by
     applicable law. Notwithstanding the foregoing provisions of this
     subsection, if the Participant becomes reemployed by another employer and
     is eligible (together with his or her dependents) for medical, dental or
     life-insurance coverage that is substantially equivalent to the coverage of
     the same type that he or she (and his or her dependents) were entitled

                                      -4-
<PAGE>

     to receive under this subsection, the Employer's obligation to the
     Participant and his or her dependents under this subsection shall cease
     with respect to that type of coverage.

     5.   Cause. "Cause" means only: (a) the Participant's conviction of, or a
          -----
plea of nolo contendere with respect to, a crime involving moral turpitude or a
felony; (b) the Participant's refusal to perform, or gross negligence in the
performance of, his or her duties to the Company; or (c) an act of willful
misfeasance by the Participant that is intended to result in substantial
personal enrichment of the Participant at the expense of the Employer.

     6.   Voluntary Termination for Good Reason. A Participant shall be deemed
          -------------------------------------
to have voluntarily terminated his or her employment for Good Reason if he or
she leaves the employ of the Employer for any of the following reasons:

          (a)  Any action by the Company which results in a material diminution
     in Participant's position, authority, duties or responsibilities
     immediately prior to the Change in Control, excluding for this purpose an
     isolated, insubstantial and inadvertent action not taken in bad faith and
     which is remedied by the Company promptly after receipt of notice thereof
     given by the Participant; provided, however, that a sale or transfer of
     some or all of the business of the Company or any of its subsidiaries or
     other reduction in its business or that of its subsidiaries, or the fact
     that the Company shall become a subsidiary of another company or the
     securities of the Company shall no longer be publicly traded, shall not
     constitute "Good Reason" hereunder; or

          (b)  Any reduction in the Participant's rate of annual base salary for
     any fiscal year to less than the greater of 100% of the rate of annual base
     salary paid to him or her in the completed fiscal year immediately
     preceding the Change in Control or 100% of the rate at which annual base
     salary was being paid to the Participant immediately prior to such
     reduction; or

          (c)  Any failure of the Company to continue or cause to be continued
     in effect any retirement, life, medical, dental, disability, accidental
     death or travel insurance plan in which the Participant was participating
     immediately prior to the Change in Control unless the Company provides the
     Participant with a plan or plans that provide substantially equivalent
     benefits, or the taking of any action by the Employer that would adversely
     effect the Participant's participation in or materially reduce the
     Participant's benefits under any of such plans or deprive the Participant
     of any material fringe benefit enjoyed by the Participant immediately prior
     to the Change in Control, other than an isolated, insubstantial and
     inadvertent failure not occurring in bad faith and which is remedied by the
     Employer promptly after receipt of notice thereof given by the Participant;
     or

          (d)  The Company requires the Participant to be based at any office or
     location that is more than 50 miles distant from the Participant's base
     office or work location immediately prior to the Change in Control; or

          (e)  Any failure by the Company to comply with and satisfy Section 8
     of the Plan.

                                      -5-
<PAGE>

     7.   Certain Tax-Related Payments.
          ----------------------------

          (a)  If any "payment in the nature of compensation" (hereinafter
     "Payment") as that term is used in Section 2806 of the Internal Revenue
     Code of 1986, as amended (the "Code"), including but not limited to
     payments and benefits under the Plan (other than payments pursuant to this
     Section 7), made with respect to a Participant is determined to be subject
     to the excise tax imposed by Section 4999 of the Code (the "Section 4999
     tax"), the Company will pay to the Participant an additional amount in cash
     (the "Gross-Up Payment") which, after reduction for all taxes (including,
     but not limited to, the Section 4999 tax with respect to such Additional
     Amount), is sufficient to pay the Section 4999 tax and all related interest
     and penalties, if any, with respect to the Payment. All determinations
     under this Section shall be made at the Company's expense by a nationally
     recognized accounting firm selected by the Company.

          (b)  If there is a determination by the Internal Revenue Service (the
     "IRS") with respect to Participant that is inconsistent with a
     determination pursuant to Section 7(a) and that if sustained would result
     in a Section 4999 tax (or a greater Section 4999 tax) or in interest or
     penalties (or increased interest or penalties) with respect to any such tax
     (an "initial IRS determination"), the determination under Section 7(a)
     shall be deemed automatically modified to conform to the initial IRS
     determination and the Company, upon receipt from the IRS of the initial IRS
     determination or of written notice from the Participant setting forth the
     initial IRS determination, shall promptly pay to the Participant the
     additional Gross-Up Payment required by such modification (the "Additional
     Gross-Up Payment"). The Company may elect to contest at its expense any
     initial IRS determination in respect of which the Company has made an
     Additional Gross-Up Payment, in which case such Additional Gross-Up Payment
     shall be considered an interest-free loan (the "Loan") to Participant until
     such time as the IRS' determination is withdrawn or modified or otherwise
     becomes final (a "final IRS determination"). Upon a final IRS determination
     that is no longer subject to modification or judicial review and that
     results in a Section 4999 tax and related interest and penalties lower than
     those in respect of which the Additional Gross-Up Payment was made, the
     Participant shall repay to the Company so much of the Loan, if any, as
     shall leave the Participant on an after-tax basis in the same position he
     or she would have been in had the initial IRS determination never been
     made. The Participant shall cooperate reasonably with the Company in any
     effort by the Company to contest an IRS determination under this paragraph,
     including by the making of such filings and appeals as the Company may
     reasonably require, but nothing herein shall be construed as requiring
     Participant to bear any cost or expense of such a contest or in connection
     therewith to compromise any tax item (including without limitation any
     deduction or credit) other than the Section 4999 tax and related interest
     and penalties, if any, that are the subject of the contested IRS
     determination.

     8.   Pooling-of-Interests Accounting. If the Company proposes to engage in
          -------------------------------
an acquisition intended to be accounted for as a pooling-of-interests, and in
the event that Section 4(c) of this Plan is determined by the Company's
independent public accountants to cause such acquisition to fail to be accounted
for as a pooling-of-interests, then (a) Section 4(c) shall be deleted from this
Plan and the vesting or exercise of options held by the Participant shall not be
accelerated hereunder and (b) under Section 4(b), the Company shall pay to the
Participant in

                                      -6-
<PAGE>

cash, within ten (10) days of the date of termination, two (2) times the sum of
the Participant's Base Salary and Bonus (instead of one times).

     9.   Binding Effect on Successor Entity. If the Company is merged or
          ----------------------------------
consolidated into or with any other entity (whether or not the Company is the
surviving entity), or if substantially all of the assets thereof are transferred
to another entity, the provisions of the Plan will be binding upon and inure to
the benefit of the entity resulting from such merger or consolidation or the
acquiror of such assets (the "Successor Entity"). The Company will require any
such Successor Entity to assume expressly and agree to perform the provisions of
the Plan (including any Plan Agreements) in the same manner and to the same
extent that the Company would have been required to perform if no such
transaction had taken place.

     10.  Payment-Obligations Absolute. Upon termination of employment
          ----------------------------
described in Section 4, the Company's obligations to pay the Severance Benefits
described in Section 4 shall be absolute and unconditional and shall not be
affected by any circumstances, including, without limitation, any set-off,
counterclaim, recoupment, defense or other right which the Employer may have
against any Participant. In no event shall a Participant be obligated to seek
other employment or take any other action by way of mitigation of the amounts
payable to a Participant under any of the provisions of the Plan and, except as
otherwise provided in Section 4(d), in no event shall the amount of any payment
hereunder be reduced by any compensation earned by a Participant as a result of
employment by another employer.

     11.  Limited Effect. Nothing herein or in any Plan Agreement shall be
          --------------
construed as giving any Participant a right of continued employment or as
limiting the Employer's right to terminate a Participant's employment, subject,
in the case of any such termination described in Section 4, to the payment of
the benefits described in Section 4.

     12.  Amendment and Termination. The Board may amend the Plan at any time
          -------------------------
and from time to time, and may terminate the Plan at any time; provided, that no
action purporting to amend or terminate the Plan that is approved by the Board
within the one hundred eighty (180) day period immediately preceding a Change in
Control and that, if effective, would adversely affect the rights of any
Participant hereunder, shall affect the rights of such Participant without his
or her express written consent.

     13.  Withholding. All payments and benefits hereunder shall be subject to
          -----------
reduction for applicable tax withholdings.

     14.  Indemnification. Employer agrees to pay all costs and expenses
          ---------------
incurred by any Participant in connection with efforts to enforce his or her
rights under this Plan and will indemnify and hold harmless Participant from and
against any damages, liabilities and expenses (including without limitation
reasonable fees and expenses of counsel) incurred by any Participant in
connection with any litigation or threatened litigation, including any
regulatory proceedings, arising out of the making, performance or enforcement of
this Plan.

     15.  Source of Payment. Nothing herein shall be construed as establishing a
          -----------------
trust or as requiring the Company to set aside funds to meet its obligations
hereunder. Notwithstanding the

                                      -7-
<PAGE>

foregoing, if the Board in its discretion so determines the Company may
establish a so-called "rabbi trust" or similar arrangement to assist it in
meeting any such obligations that it may have.

     16.  Governing Law. The Plan and agreements made with Participants
          -------------
hereunder shall be governed by the laws of the State of New Hampshire.

                                      -8-