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                                                                    EXHIBIT 99.6



                               CISCO SYSTEMS, INC.

                        STOCK OPTION ASSUMPTION AGREEMENT
                           MAXCOMM TECHNOLOGIES, INC.
                      1998 STOCK OPTION/STOCK ISSUANCE PLAN


OPTIONEE:  [Employee],

        STOCK OPTION ASSUMPTION AGREEMENT effective as of the 13th day of
September, 1999 by Cisco Systems, Inc., a California corporation ("Cisco").

        WHEREAS, the undersigned individual ("Optionee") holds one or more
outstanding options to purchase shares of the common stock of MaxComm
Technologies, Inc., a Delaware corporation ("MaxComm"), which were granted to
Optionee under the MaxComm 1998 Stock Option/Stock Issuance Plan (the "Plan")
and are each evidenced by a Stock Option Agreement (the "Option Agreement").

        WHEREAS, MaxComm has been acquired by Cisco through the merger of
MaxComm with and into Cisco (the "Merger") pursuant to the Agreement and Plan of
Reorganization, by and between Cisco and MaxComm (the "Merger Agreement").

        WHEREAS, the provisions of the Merger Agreement require Cisco to assume
all obligations of MaxComm under all outstanding options under the Plan at the
consummation of the Merger and to issue to the holder of each outstanding option
an agreement evidencing the assumption of such option.

        WHEREAS, pursuant to the provisions of the Merger Agreement, the
exchange ratio (the "Exchange Ratio") in effect for the Merger is 0.09032 shares
of Cisco common stock ("Cisco Stock") for each outstanding share of MaxComm
common stock ("MaxComm Stock").

        WHEREAS, this Agreement became effective immediately upon the
consummation of the Merger (the "Effective Time") in order to reflect certain
adjustments to Optionee's outstanding options which have become necessary by
reason of the assumption of those options by Cisco in connection with the
Merger.

        NOW, THEREFORE, it is hereby agreed as follows:

        1.     The number of shares of MaxComm Stock subject to the options
held by Optionee immediately prior to the Effective Time (the "MaxComm Options")
and the exercise price payable per share are set forth below. Cisco hereby
assumes, as of the Effective Time, all the duties and obligations of MaxComm
under each of the MaxComm Options. In connection with such assumption, the
number of shares of Cisco Stock purchasable under each MaxComm Option hereby
assumed and the exercise price payable thereunder have been adjusted to reflect
the Exchange Ratio. Accordingly, the number of shares of Cisco Stock subject to
each MaxComm Option hereby assumed shall be as specified for that option below,
and the adjusted






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exercise price payable per share of Cisco Stock under the assumed MaxComm Option
shall also be as indicated for that option below.

<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------------------
             MAXCOMM STOCK OPTIONS                            CISCO ASSUMED OPTIONS
-------------------------------------------------------------------------------------------------
 # of Shares of MaxComm     Exercise Price per      # of Shares of      Adjusted Exercise Price
      Common Stock                 Share          Cisco Common Stock           per Share
-------------------------------------------------------------------------------------------------
<S>                         <C>                   <C>                   <C>

-------------------------------------------------------------------------------------------------
                                     $                                             $
-------------------------------------------------------------------------------------------------
</TABLE>

        2.     The intent of the foregoing adjustments to each assumed MaxComm
Option is to assure that the spread between the aggregate fair market value of
the shares of Cisco Stock purchasable under each such option and the aggregate
exercise price as adjusted pursuant to this Agreement will, immediately after
the consummation of the Merger, be not less than the spread which existed,
immediately prior to the Merger, between the then aggregate fair market value of
the MaxComm Stock subject to the MaxComm Option and the aggregate exercise price
in effect at such time under the Option Agreement. Such adjustments are also
intended to preserve, immediately after the Merger, on a per share basis, the
same ratio of exercise price per option share to fair market value per share
which existed under the MaxComm Option immediately prior to the Merger.

        3.     The following provisions shall govern each MaxComm Option hereby
assumed by Cisco:

                    (a) Unless the context otherwise requires, all references in
        each Option Agreement and, if applicable, in the Plan (as incorporated
        into such Option Agreement) (i) to the "Corporation" shall mean Cisco,
        (ii) to "Share" shall mean share of Cisco Stock, (iii) to the "Board"
        shall mean the Board of Directors of Cisco and (iv) to the "Committee"
        shall mean the Compensation Committee of the Cisco Board of Directors.

                    (b) The grant date and the expiration date of each assumed
        MaxComm Option and all other provisions which govern either the exercise
        or the termination of the assumed MaxComm Option shall remain the same
        as set forth in the Option Agreement applicable to that option, and the
        provisions of the Option Agreement shall accordingly govern and control
        Optionee's rights under this Agreement to purchase Cisco Stock.

                    (c) Pursuant to the terms of the Option Agreement, your
        options assumed by Cisco in connection with the transaction will vest
        and become exercisable on an accelerated basis upon the consummation of
        the Merger. Each MaxComm Option shall be assumed by Cisco as of the
        Effective Time.






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                    (d) For purposes of applying any and all provisions of the
        Option Agreement and/or the Plan relating to Optionee's status as an
        employee or a consultant of MaxComm, Optionee shall be deemed to
        continue in such status as an employee or a consultant for so long as
        Optionee renders services as an employee or a consultant to Cisco or any
        present or future Cisco subsidiary. Accordingly, the provisions of the
        Option Agreement governing the termination of the assumed MaxComm
        Options upon Optionee's cessation of service as an employee or a
        consultant of MaxComm shall hereafter be applied on the basis of
        Optionee's cessation of employee or consultant status with Cisco and its
        subsidiaries, and each assumed MaxComm Option shall accordingly
        terminate, within the designated time period in effect under the Option
        Agreement for that option, generally a three (3) month period, following
        such cessation of service as an employee or a consultant of Cisco and
        its subsidiaries.

                    (e) The adjusted exercise price payable for the Cisco Stock
        subject to each assumed MaxComm Option shall be payable in any of the
        forms authorized under the Option Agreement applicable to that option.
        For purposes of determining the holding period of any shares of Cisco
        Stock delivered in payment of such adjusted exercise price, the period
        for which such shares were held as MaxComm Stock prior to the Merger
        shall be taken into account.

                    (f) In order to exercise each assumed MaxComm Option,
        Optionee must deliver to Cisco a written notice of exercise in which the
        number of shares of Cisco Stock to be purchased thereunder must be
        indicated. The exercise notice must be accompanied by payment of the
        adjusted exercise price payable for the purchased shares of Cisco Stock
        and should be delivered to Cisco at the following address:

                             Cisco Systems, Inc.
                             170 West Tasman Drive
                             MS 11-3
                             San Jose, CA 95134-1706
                             Attention:  Stock Administration

        4.     Except to the extent specifically modified by this Option
Assumption Agreement, all of the terms and conditions of each Option Agreement
as in effect immediately prior to the Merger shall continue in full force and
effect and shall not in any way be amended, revised or otherwise affected by
this Stock Option Assumption Agreement.








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        IN WITNESS WHEREOF, Cisco Systems, Inc. has caused this Stock Option
Assumption Agreement to be executed on its behalf by its duly-authorized officer
as of the 13th day of September, 1999.




                                        CISCO SYSTEMS, INC.



                                        By:  /s/ LARRY R. CARTER
                                            ------------------------------------
                                             Larry R. Carter
                                             Corporate Secretary




                                 ACKNOWLEDGMENT


        The undersigned acknowledges receipt of the foregoing Stock Option
Assumption Agreement and understands that all rights and liabilities with
respect to each of his or her MaxComm Options hereby assumed by Cisco are as set
forth in the Option Agreement, the Plan, as applicable, and such Stock Option
Assumption Agreement.



                                        ----------------------------------------
                                        [Employee],  OPTIONEE



DATED: __________________, 1999






















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