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                                                                    EXHIBIT 99.8


                                                        PERFORMANCE ACCELERATION


                              CISCO SYSTEMS, INC.

                        STOCK OPTION ASSUMPTION AGREEMENT
                        GEOTEL COMMUNICATIONS CORPORATION
                             1995 STOCK OPTION PLAN
                  1998 NON-EXECUTIVE EMPLOYEE STOCK OPTION PLAN


OPTIONEE:  <<Employee>>

                STOCK OPTION ASSUMPTION AGREEMENT effective as of the 24th day
of June, 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 GeoTel
Communications Corporation, a Delaware corporation ("GeoTel"), which were
granted to Optionee under the GeoTel 1995 Stock Option Plan or the 1998
Non-Executive Employee Stock Option Plan (the "Plans") and are each evidenced by
a Stock Option Agreement (the "Option Agreement").

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

                WHEREAS, the provisions of the Merger Agreement require Cisco to
assume all obligations of GeoTel under all outstanding options under the Plans
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 1.0276 shares
of Cisco common stock ("Cisco Stock") for each outstanding share of GeoTel
common stock ("GeoTel 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 GeoTel Stock subject to the
options held by Optionee immediately prior to the Effective Time (the "GeoTel
Options") and the exercise price payable per share are set forth in Exhibit(s) A
hereto. Cisco hereby assumes, as of the Effective Time, all the duties and
obligations of GeoTel under each of the GeoTel Options. In connection with such
assumption, the number of shares of Cisco Stock purchasable under each GeoTel
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 GeoTel Option hereby assumed shall be as specified
for that option in attached Exhibit(s) A, and the


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adjusted exercise price payable per share of Cisco Stock under the assumed
GeoTel Option shall also be as indicated for that option in attached Exhibit(s)
A.

                2.      The intent of the foregoing adjustments to each assumed
GeoTel 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 GeoTel Stock subject to the GeoTel 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 GeoTel Option immediately prior
to the Merger.

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

                                (a)     Unless the context otherwise requires,
                all references in each Option Agreement and, if applicable, in
                the Plans (as incorporated into such Option Agreement) (i) to
                the "Company" shall mean Cisco, (ii) to "Shares" shall mean
                shares 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 GeoTel Option and all other provisions which
                govern either the exercise or the termination of the assumed
                GeoTel 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)     Each GeoTel Option shall be assumed by
                Cisco as of the Effective Time. Pursuant to the terms of the
                Option Agreement, each of your GeoTel options assumed by Cisco
                in connection with the transaction will become fully vested and
                exercisable twelve (12) months earlier than the outside vesting
                date established in your Option Agreement. For example, if your
                option would have vested in full on January 15, 2003 if you
                remained in service  until that date, your option will now vest
                in full on January 15, 2002. In addition, in accordance with the
                terms of your Option Agreement, your option will become fully
                vested and exercisable on the date established in your Option
                Agreement if the performance goals established at the time of
                grant have been met prior to the date established in your Option
                Agreement.

                                (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 GeoTel,
                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 GeoTel
                Options upon Optionee's cessation of service as an employee or a
                consultant of GeoTel shall hereafter be applied on the basis of
                Optionee's


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                cessation of employee or consultant status with Cisco and its
                subsidiaries, and each assumed GeoTel Option shall accordingly
                terminate, within the designated time period in effect under the
                Option Agreement for that option, generally a thirty (30) day
                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 GeoTel 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 GeoTel Stock prior to the Merger shall
                be taken into account.

                                (f)     In order to exercise each assumed GeoTel
                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.
                                255 West Tasman Drive, Building J
                                San Jose, CA 95134
                                Attention: Option Plan Administrator

                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 16th day of July, 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 GeoTel 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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