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                                                                    EXHIBIT 10.3



                            TURNSTONE SYSTEMS, INC.

                                 2000 STOCK PLAN



      1. Purposes of the Plan. The purposes of this 2000 Stock Plan are:

            -     to attract and retain the best available personnel for
                  positions of substantial responsibility,

            -     to provide additional incentive to Employees, Directors and
                  Consultants, and

            -     to promote the success of the Company's business.

            Options granted under the Plan may be Incentive Stock Options or
Nonstatutory Stock Options, as determined by the Administrator at the time of
grant. Stock Purchase Rights may also be granted under the Plan.

      2. Definitions. As used herein, the following definitions shall apply:

            (a) "Administrator" means the Board or any of its Committees as
shall be administering the Plan, in accordance with Section 4 of the Plan.

            (b) "Applicable Laws" means the requirements relating to the
administration of stock option plans under U. S. state corporate laws, U.S.
federal and state securities laws, the Code, any stock exchange or quotation
system on which the Common Stock is listed or quoted and the applicable laws of
any foreign country or jurisdiction where Options or Stock Purchase Rights are,
or will be, granted under the Plan.

            (c) "Board" means the Board of Directors of the Company.

            (d) "Cause" means (i) any act of personal dishonesty taken by the
Optionee in connection with his responsibilities as an Employee which is
intended to result in personal enrichment of the Optionee, (ii) the Optionee's
conviction of a felony, (iii) any act by the Optionee that constitutes
misconduct, and (iv) continued violations by the Optionee of the Optionee's
obligations to the Company.

            (e) "Code" means the Internal Revenue Code of 1986, as amended.

            (f) "Committee" means a committee of Directors appointed by the
Board in accordance with Section 4 of the Plan.

            (g) "Common Stock" means the common stock of the Company.

            (h) "Company" means Turnstone Systems, Inc., a Delaware corporation.

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            (i) "Consultant" means any person, including an advisor, engaged by
the Company or a Parent or Subsidiary to render services to such entity.

            (j) "Director" means a member of the Board.

            (k) "Disability" means total and permanent disability as defined in
Section 22(e)(3) of the Code.

            (l) "Employee" means any person, including Officers and Directors,
employed by the Company or any Parent or Subsidiary of the Company. A Service
Provider shall not cease to be an Employee in the case of (i) any leave of
absence approved by the Company or (ii) transfers between locations of the
Company or between the Company, its Parent, any Subsidiary, or any successor.
For purposes of Incentive Stock Options, no such leave may exceed ninety days,
unless reemployment upon expiration of such leave is guaranteed by statute or
contract. If reemployment upon expiration of a leave of absence approved by the
Company is not so guaranteed, on the 181st day of such leave any Incentive Stock
Option held by the Optionee shall cease to be treated as an Incentive Stock
Option and shall be treated for tax purposes as a Nonstatutory Stock Option.
Neither service as a Director nor payment of a director's fee by the Company
shall be sufficient to constitute "employment" by the Company.

            (m) "Exchange Act" means the Securities Exchange Act of 1934, as
amended.

            (n) "Fair Market Value" means, as of any date, the value of Common
Stock determined as follows:

                     (i) If the Common Stock is listed on any established stock
exchange or a national market system, including without limitation the Nasdaq
National Market or The Nasdaq SmallCap Market of The Nasdaq Stock Market, its
Fair Market Value shall be the closing sales price for such stock (or the
closing bid, if no sales were reported) as quoted on such exchange or system for
the last market trading day prior to the time of determination, as reported in
The Wall Street Journal or such other source as the Administrator deems
reliable;

                     (ii) If the Common Stock is regularly quoted by a
recognized securities dealer but selling prices are not reported, the Fair
Market Value of a Share of Common Stock shall be the mean between the high bid
and low asked prices for the Common Stock on the last market trading day prior
to the day of determination, as reported in The Wall Street Journal or such
other source as the Administrator deems reliable; or

                     (iii) In the absence of an established market for the
Common Stock, the Fair Market Value shall be determined in good faith by the
Administrator.

            (o) "Incentive Stock Option" means an Option intended to qualify as
an incentive stock option within the meaning of Section 422 of the Code and the
regulations promulgated thereunder.

            (p) "Inside Director" means a Director who is an Employee.



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            (q) "IPO Effective Date" means the date upon which the Securities
and Exchange Commission declares the initial public offering of the Company's
Common Stock as effective.

            (r) "Nonstatutory Stock Option" means an Option not intended to
qualify as an Incentive Stock Option.

            (s) "Notice of Grant" means a written or electronic notice
evidencing certain times and conditions of an individual Option or Stock
Purchase Right grant. The Notice of Grant is part of the Option Agreement.

            (t) "Officer" means a person who is an officer of the Company within
the meaning of Section 16 of the Exchange Act and the rules and regulations
promulgated thereunder.

            (u) "Option" means a stock option granted pursuant to the Plan.

            (v) "Option Agreement" means an agreement between the Company and an
Optionee evidencing the terms and conditions of an individual Option grant. The
Option Agreement is subject to the terms and conditions of the Plan.

            (w) "Option Exchange Program" means a program whereby outstanding
Options are surrendered in exchange for Options with a lower exercise price.

            (x) "Optioned Stock" means the Common Stock subject to an Option or
Stock Purchase Right.

            (y) "Optionee" means the holder of an outstanding Option or Stock
Purchase Right granted under the Plan.

            (z) "Outside Director" means a Director who is not an Employee and
who is not the "beneficial owner" (as defined in Rule 13d-3 of the Securities
Exchange Act of 1934, as amended), directly or indirectly, of securities of the
Company representing 1% or more of the total voting power represented by the
Company's outstanding voting securities on the date of any grant hereunder.

            (aa) "Plan" means this 2000 Stock Option Plan, as amended and
restated.

            (bb) "Restricted Stock" means shares of Common Stock acquired
pursuant to a grant of Stock Purchase Rights under Section 11 of the Plan.

            (cc) "Restricted Stock Purchase Agreement" means a written agreement
between the Company and the Optionee evidencing the terms and restrictions
applying to stock purchased under a Stock Purchase Right. The Restricted Stock
Purchase Agreement is subject to the terms and conditions of the Plan and the
Notice of Grant.

            (dd) "Rule 16b-3" means Rule 16b-3 of the Exchange Act or any
successor to Rule 16b-3, as in effect when discretion is being exercised with
respect to the Plan.



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            (ee) "Section 16(b) " means Section 16(b) of the Exchange Act.

            (ff)  "Service Provider" means an Employee, Director or Consultant.

            (gg) "Share" means a share of the Common Stock, as adjusted in
accordance with Section 14 of the Plan.

            (hh) "Stock Purchase Right" means the right to purchase Common Stock
pursuant to Section 11 of the Plan, as evidenced by a Notice of Grant.

            (ii) "Subsidiary" means a "subsidiary corporation", whether now or
hereafter existing, as defined in Section 424(f) of the Code.

      3. Stock Subject to the Plan. Subject to the provisions of Section 14 of
the Plan, the maximum aggregate number of Shares which may be optioned and sold
under the Plan is 5,000,000 Shares, plus the Shares available for future
issuance under the Turnstone Systems, Inc. 1998 Stock Plan (the "1998 Stock
Plan") as of the effective date of this Plan and any Shares returned to the 1998
Stock Plan. The number of Shares reserved for issuance under the Plan shall
increase annually on the first day of the Company's fiscal year beginning in
2000 by an amount of Shares equal to the lesser of (i) 5,000,000 Shares, (ii) 6%
of the outstanding Shares on such date or (iii) an amount determined by the
Board. The Shares may be authorized, but unissued, or reacquired Common Stock.

            If an Option or Stock Purchase Right expires or becomes
unexercisable without having been exercised in full, or is surrendered pursuant
to an Option Exchange Program, the unpurchased Shares which were subject thereto
shall become available for future grant or sale under the Plan (unless the Plan
has terminated); provided, however, that Shares that have actually been issued
under the Plan, whether upon exercise of an Option or Right, shall not be
returned to the Plan and shall not become available for future distribution
under the Plan, except that if Shares of Restricted Stock are repurchased by the
Company at their original purchase price, such Shares shall become available for
future grant under the Plan.

      4. Administration of the Plan.

            (a) Procedure.

                     (i) Multiple Administrative Bodies. The Plan may be
administered by different Committees with respect to different groups of Service
Providers.

                     (ii) Section 162(m). To the extent that the Administrator
determines it to be desirable to qualify Options granted hereunder as
"performance-based compensation" within the meaning of Section 162(m) of the
Code, the Plan shall be administered by a Committee of two or more "outside
directors" within the meaning of Section 162(m) of the Code.

                     (iii) Rule 16b-3. To the extent desirable to qualify
transactions hereunder as exempt under Rule 16b-3, the transactions contemplated
hereunder shall be structured to satisfy the requirements for exemption under
Rule 16b-3.



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                     (iv) Other Administration. Other than as provided above,
the Plan shall be administered by (A) the Board or (B) a Committee, which
committee shall be constituted to satisfy Applicable Laws.

            (b) Powers of the Administrator. Subject to the provisions of the
Plan, and in the case of a Committee, subject to the specific duties delegated
by the Board to such Committee, the Administrator shall have the authority, in
its discretion:

                     (i) to determine the Fair Market Value;

                     (ii) to select the Service Providers to whom Options and
Stock Purchase Rights may be granted hereunder;

                     (iii) to determine the number of shares of Common Stock
to be covered by each Option and Stock Purchase Right granted hereunder;

                     (iv) to approve forms of agreement for use under the Plan;

                     (v) to determine the terms and conditions, not inconsistent
with the terms of the Plan, of any Option or Stock Purchase Right granted
hereunder. Such terms and conditions include, but are not limited to, the
exercise price, the time or times when Options or Stock Purchase Rights may be
exercised (which may be based on performance criteria), any vesting acceleration
or waiver of forfeiture restrictions, and any restriction or limitation
regarding any Option or Stock Purchase Right or the shares of Common Stock
relating thereto, based in each case on such factors as the Administrator, in
its sole discretion, shall determine;

                     (vi) to reduce the exercise price of any Option or Stock
Purchase Right to the then current Fair Market Value if the Fair Market Value of
the Common Stock covered by such Option or Stock Purchase Right shall have
declined since the date the Option or Stock Purchase Right was granted;

                     (vii) to institute an Option Exchange Program;

                     (viii) to construe and interpret the terms of the Plan and
awards granted pursuant to the Plan;

                     (ix) to prescribe, amend and rescind rules and regulations
relating to the Plan, including rules and regulations relating to sub-plans
established for the purpose of qualifying for preferred tax treatment under
foreign tax laws;

                     (x) to modify or amend each Option or Stock Purchase Right
(subject to Section 16(c) of the Plan), including the discretionary authority to
extend the post-termination exercisability period of Options longer than is
otherwise provided for in the Plan;

                     (xi) to allow Optionees to satisfy withholding tax
obligations by electing to have the Company withhold from the Shares to be
issued upon exercise of an Option or Stock Purchase Right that number of Shares
having a Fair Market Value equal to the amount required to be



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withheld. The Fair Market Value of the Shares to be withheld shall be determined
on the date that the amount of tax to be withheld is to be determined. All
elections by an Optionee to have Shares withheld for this purpose shall be made
in such form and under such conditions as the Administrator may deem necessary
or advisable;

                     (xii) to authorize any person to execute on behalf of the
Company any instrument required to effect the grant of an Option or Stock
Purchase Right previously granted by the Administrator;

                     (xiii) to make all other determinations deemed necessary
or advisable for administering the Plan.

            (c) Effect of Administrator's Decision. The Administrator's
decisions, determinations and interpretations shall be final and binding on all
Optionees and any other holders of Options or Stock Purchase Rights.

      5. Eligibility. Nonstatutory Stock Options and Stock Purchase Rights may
be granted to Service Providers. Incentive Stock Options may be granted only to
Employees.

      6. Limitations.

            (a) Each Option shall be designated in the Option Agreement as
either an Incentive Stock Option or a Nonstatutory Stock Option. However,
notwithstanding such designation, to the extent that the aggregate Fair Market
Value of the Shares with respect to which Incentive Stock Options are
exercisable for the first time by the Optionee during any calendar year (under
all plans of the Company and any Parent or Subsidiary) exceeds $100,000, such
Options shall be treated as Nonstatutory Stock Options. For purposes of this
Section 6(a), Incentive Stock Options shall be taken into account in the order
in which they were granted. The Fair Market Value of the Shares shall be
determined as of the time the Option with respect to such Shares is granted.

            (b) Neither the Plan nor any Option or Stock Purchase Right shall
confer upon an Optionee any right with respect to continuing the Optionee's
relationship as a Service Provider with the Company, nor shall they interfere in
any way with the Optionee's right or the Company's right to terminate such
relationship at any time, with or without Cause.

            (c) The following limitations shall apply to grants of Options:

                     (i) No Service Provider shall be granted, in any fiscal
year of the Company, Options to purchase more than 1,000,000 Shares.

                     (ii) In connection with his or her initial service, a
Service Provider may be granted Options to purchase up to an additional
2,000,000 Shares, which shall not count against the limit, set forth in
subsection (i) above.

                     (iii) The foregoing limitations shall be adjusted
proportionately in connection with any change in the Company's capitalization as
described in Section 14.



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                     (iv) If an Option is cancelled in the same fiscal year of
the Company in which it was granted (other than in connection with a transaction
described in Section 14), the cancelled Option will be counted against the
limits set forth in subsections (i) and (ii) above. For this purpose, if the
exercise price of an Option is reduced, the transaction will be treated as a
cancellation of the Option and the grant of a new Option.

      7. Term of Plan. Subject to Section 20 of the Plan, the Plan shall become
effective upon its adoption by the Board. It shall continue in effect for a term
of ten (10) years unless terminated earlier under Section 16 of the Plan.

      8. Term of Option. The term of each Option shall be stated in the Option
Agreement. In the case of an Incentive Stock Option, the term shall be ten (10)
years from the date of grant or such shorter term as may be provided in the
Option Agreement. Moreover, in the case of an Incentive Stock Option granted to
an Optionee who, at the time the Incentive Stock Option is granted, owns stock
representing more than ten percent (10%) of the total combined voting power of
all classes of stock of the Company or any Parent or Subsidiary, the term of the
Incentive Stock Option shall be five (5) years from the date of grant or such
shorter term as may be provided in the Option Agreement.

      9. Option Exercise Price and Consideration.

            (a) Exercise Price. The per share exercise price for the Shares to
be issued pursuant to exercise of an Option shall be determined by the
Administrator, subject to the following:

                     (i) In the case of an Incentive Stock Option

                        (A) granted to an Employee who, at the time the
Incentive Stock Option is granted, owns stock representing more than ten percent
(10%) of the voting power of all classes of stock of the Company or any Parent
or Subsidiary, the per Share exercise price shall be no less than 110% of the
Fair Market Value per Share on the date of grant.

                        (B) granted to any Employee other than an Employee
described in paragraph (A) immediately above, the per Share exercise price shall
be no less than 100% of the Fair Market Value per Share on the date of grant.

                     (ii) In the case of a Nonstatutory Stock Option, the per
Share exercise price shall be determined by the Administrator. In the case of a
Nonstatutory Stock Option intended to qualify as "performance-based
compensation" within the meaning of Section 162(m) of the Code, the per Share
exercise price shall be no less than 100% of the Fair Market Value per Share on
the date of grant.

                     (iii) Notwithstanding the foregoing, Options may be granted
with a per Share exercise price of less than 100% of the Fair Market Value per
Share on the date of grant pursuant to a merger or other corporate transaction.



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            (b) Waiting Period and Exercise Dates. At the time an Option is
granted, the Administrator shall fix the period within which the Option may be
exercised and shall determine any conditions that must be satisfied before the
Option may be exercised.

            (c) Form of Consideration. The Administrator shall determine the
acceptable form of consideration for exercising an Option, including the method
of payment. In the case of an Incentive Stock Option, the Administrator shall
determine the acceptable form of consideration at the time of grant. Such
consideration may consist entirely of:

                     (i) cash;

                     (ii) check;

                     (iii) promissory note;

                     (iv) other Shares which (A) in the case of Shares acquired
upon exercise of an option, have been owned by the Optionee for more than six
months on the date of surrender, and (B) have a Fair Market Value on the date of
surrender equal to the aggregate exercise price of the Shares as to which said
Option shall be exercised;

                     (v) consideration received by the Company under a cashless
exercise program implemented by the Company in connection with the Plan;

                     (vi) a reduction in the amount of any Company liability to
the Optionee, including any liability attributable to the Optionee's
participation in any Company-sponsored deferred compensation program or
arrangement;

                     (vii) any combination of the foregoing methods of payment;
or

                     (viii) such other consideration and method of payment for
the issuance of Shares to the extent permitted by Applicable Laws.

      10. Exercise of Option.

            (a) Procedure for Exercise; Rights as a Shareholder. Any Option
granted hereunder shall be exercisable according to the terms of the Plan and at
such times and under such conditions as determined by the Administrator and set
forth in the Option Agreement. Unless the Administrator provides otherwise,
vesting of Options granted hereunder shall be tolled during any unpaid leave of
absence. An Option may not be exercised for a fraction of a Share.

                An Option shall be deemed exercised when the Company receives:
(i) written or electronic notice of exercise (in accordance with the Option
Agreement) from the person entitled to exercise the Option, and (ii) full
payment for the Shares with respect to which the Option is exercised. Full
payment may consist of any consideration and method of payment authorized by the
Administrator and permitted by the Option Agreement and the Plan. Shares issued
upon exercise of an Option shall be issued in the name of the Optionee or, if
requested by the Optionee, in the name of the Optionee and his or her spouse.
Until the Shares are issued (as evidenced by the appropriate



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entry on the books of the Company or of a duly authorized transfer agent of the
Company), no right to vote or receive dividends or any other rights as a
shareholder shall exist with respect to the Optioned Stock, notwithstanding the
exercise of the Option. The Company shall issue (or cause to be issued) such
Shares promptly after the Option is exercised. No adjustment will be made for a
dividend or other right for which the record date is prior to the date the
Shares are issued, except as provided in Section 14 of the Plan.

                  Exercising an Option in any manner shall decrease the number
of Shares thereafter available, both for purposes of the Plan and for sale under
the Option, by the number of Shares as to which the Option is exercised.

            (b) Termination of Relationship as a Service Provider. Subject to
Section 14, if an Optionee ceases to be a Service Provider (but not in the event
of an Optionee's change of status from Employee to Consultant (in which case an
Employee's Incentive Stock Option shall automatically convert to a Nonstatutory
Stock Option on the ninety-first (91st) day following such change of status) or
from Consultant to Employee), such Optionee may, but only within such period of
time as is specified in the Option Agreement (but in no event later than the
expiration date of the term of such Option as set forth in the Option
Agreement), exercise his or her Option to the extent that Optionee was entitled
to exercise it at the date of such termination. In the absence of a specified
time in the Option Agreement, the Option shall remain exercisable for three (3)
months following the Optionee's termination. If, on the date of termination, the
Optionee is not vested as to his or her entire Option, the Shares covered by the
unvested portion of the Option shall revert to the Plan. If, after termination,
the Optionee does not exercise his or her Option within the time specified by
the Administrator, the Option shall terminate, and the Shares covered by such
Option shall revert to the Plan.

            (c) Disability of Optionee. If an Optionee ceases to be a Service
Provider as a result of the Optionee's Disability, the Optionee may, but only
within twelve (12) months from the date of such termination (and in no event
later than the expiration date of the term of such Option as set forth in the
Option Agreement), exercise his or her Option to the extent that the Option is
vested on the date of termination. If, on the date of termination, the Optionee
is not vested as to his or her entire Option, the Shares covered by the unvested
portion of the Option shall revert to the Plan. If, after termination, the
Optionee does not exercise his or her Option within the time specified herein,
the Option shall terminate, and the Shares covered by such Option shall revert
to the Plan.

            (d) Death of Optionee. If an Optionee dies while a Service Provider,
the Option may be exercised at any time within twelve (12) months following the
date of death (but in no event later than the expiration of the term of such
Option as set forth in the Notice of Grant), by the Optionee's estate or by a
person who acquires the right to exercise the Option by bequest or inheritance,
but only to the extent that the Option is vested on the date of death. If, at
the time of death, the Optionee is not vested as to his or her entire Option,
the Shares covered by the unvested portion of the Option shall immediately
revert to the Plan. The Option may be exercised by the executor or administrator
of the Optionee's estate or, if none, by the person(s) entitled to exercise the
Option under the Optionee's will or the laws of descent or distribution. If the
Option is not so



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exercised within the time specified herein, the Option shall terminate, and the
Shares covered by such Option shall revert to the Plan.

            (e) Buyout Provisions. The Administrator may at any time offer to
buy out for a payment in cash or Shares an Option previously granted based on
such terms and conditions as the Administrator shall establish and communicate
to the Optionee at the time that such offer is made.

      11. Stock Purchase Rights.

            (a) Rights to Purchase. Stock Purchase Rights may be issued either
alone, in addition to, or in tandem with other awards granted under the Plan
and/or cash awards made outside of the Plan. After the Administrator determines
that it will offer Stock Purchase Rights under the Plan, it shall advise the
offeree in writing or electronically, by means of a Notice of Grant, of the
terms, conditions and restrictions related to the offer, including the number of
Shares that the offeree shall be entitled to purchase, the price to be paid, and
the time within which the offeree must accept such offer. The offer shall be
accepted by execution of a Restricted Stock Purchase Agreement in the form
determined by the Administrator.

            (b) Repurchase Option. Unless the Administrator determines
otherwise, the Restricted Stock Purchase Agreement shall grant the Company a
repurchase option exercisable upon the voluntary or involuntary termination of
the purchaser's service with the Company for any reason (including death or
Disability). The purchase price for Shares repurchased pursuant to the
Restricted Stock Purchase Agreement shall be the original price paid by the
purchaser and may be paid by cancellation of any indebtedness of the purchaser
to the Company. The repurchase option shall lapse at a rate determined by the
Administrator.

            (c) Other Provisions. The Restricted Stock Purchase Agreement shall
contain such other terms, provisions and conditions not inconsistent with the
Plan as may be determined by the Administrator in its sole discretion.

            (d) Rights as a Shareholder. Once the Stock Purchase Right is
exercised, the purchaser shall have the rights equivalent to those of a
shareholder, and shall be a shareholder when his or her purchase is entered upon
the records of the duly authorized transfer agent of the Company. No adjustment
will be made for a dividend or other right for which the record date is prior to
the date the Stock Purchase Right is exercised, except as provided in Section 14
of the Plan.

      12. Non-Transferability of Options and Stock Purchase Rights. Unless
determined otherwise by the Administrator, an Option or Stock Purchase Right may
not be sold, pledged, assigned, hypothecated, transferred, or disposed of in any
manner other than by will or by the laws of descent or distribution and may be
exercised, during the lifetime of the Optionee, only by the Optionee. If the
Administrator makes an Option or Stock Purchase Right transferable, such Option
or Stock Purchase Right shall contain such additional terms and conditions as
the Administrator deems appropriate.

      13. Formula Option Grants to Outside Directors. Outside Directors shall be
granted Options each year in accordance with the following provisions:



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            (a) All Options granted pursuant to this Section shall be
Nonstatutory Stock Options and, except as otherwise provided herein, shall be
subject to the other terms and conditions of the Plan.

            (b) Except as provided in subsection (d) below, each person who
first becomes an Outside Director on or after the IPO Effective Date, whether
through election by the stockholders of the Company or appointment by the Board
to fill a vacancy shall be automatically granted an Option to purchase up to
30,000 Shares (the "First Option"), as determined by the Board in its sole and
absolute discretion, on the date he or she first becomes an Outside Director;
provided, however, that an Inside Director who ceases to be an Inside Director
but who remains a Director shall not receive a First Option.

            (c) Except as provided in subsection (d) below, each Outside
Director shall be automatically granted an Option to purchase up to 10,000
Shares (a "Subsequent Option") following each annual meeting of the stockholders
of the Company occurring after the end of the Company's fiscal year 2000, if
immediately after such meeting, he or she shall continue to serve on the Board
and shall have served on the Board for at least the preceding six (6) months.

            (d) Notwithstanding the provisions of subsections (b) and (c)
hereof, any exercise of an Option granted before the Company has obtained
stockholder approval of the Plan in accordance with Section 20 hereof shall be
conditioned upon obtaining such stockholder approval of the Plan in accordance
with Section 20 hereof.

            (e) The terms of each First Option granted pursuant to this Section
shall be as follows:

                     (i) the term of the Option shall be ten (10) years.

                     (ii) the exercise price per Share shall be 100% of the Fair
Market Value per Share on the date of grant of the Option.

                     (iii) the Option shall vest and become exercisable in three
(3) equal annual installments on each of the first three anniversaries of its
date of grant; provided that the Outside Director shall continue to serve on the
Board on such dates.

            (f) The terms of each Subsequent Option granted pursuant to this
Section shall be as follows:

                     (i) the term of the Option shall be ten (10) years.

                     (ii) the exercise price per Share shall be 100% of the Fair
Market Value per Share on the date of grant of the Option.

                     (iii) the Option shall vest and become exercisable on the
first anniversary of the date that all stock options have vested that were
granted to the Outside Director by the Company before the Option; provided,
however, that the Option shall in all events vest and become



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exercisable on the last day of its ten-year term; provided, further, that in
each case the Outside Director shall continue to serve on the Board on such
date.

      14. Adjustments Upon Changes in Capitalization, Merger or Asset Sale.

            (a) Changes in Capitalization. Subject to any required action by the
stockholders of the Company, the number of shares of Common Stock covered by
each outstanding Option or Stock Purchase Right, and the number of shares of
Common Stock which have been authorized for issuance under the Plan but as to
which no Options or Stock Purchase Rights have yet been granted or which have
been returned to the Plan upon cancellation or expiration of an Option or Stock
Purchase Right, as well as the price per share of Common Stock covered by each
such outstanding Option or Stock Purchase Right, shall be proportionately
adjusted for any increase or decrease in the number of issued shares of Common
Stock resulting from a stock split, reverse stock split, stock dividend,
combination or reclassification of the Common Stock, or any other increase or
decrease in the number of issued shares of Common Stock effected without receipt
of consideration by the Company. The conversion of any convertible securities of
the Company shall not be deemed to have been "effected without receipt of
consideration." Such adjustment shall be made by the Board, whose determination
in that respect shall be final, binding and conclusive. Except as expressly
provided herein, no issuance by the Company of shares of stock of any class, or
securities convertible into shares of stock of any class, shall affect, and no
adjustment by reason thereof shall be made with respect to, the number or price
of shares of Common Stock subject to an Option or Stock Purchase Right.

            (b) Dissolution or Liquidation. In the event of the proposed
dissolution or liquidation of the Company, the Administrator shall notify each
Optionee as soon as practicable prior to the effective date of such proposed
transaction. The Administrator in its discretion may provide for an Optionee to
have the right to exercise his or her Option or Stock Purchase Right until
fifteen (15) days prior to such transaction as to all of the Optioned Stock
covered thereby, including Shares as to which the Option or Stock Purchase Right
would not otherwise be exercisable. In addition, the Administrator may provide
that any Company repurchase option applicable to any Shares purchased upon
exercise of an Option or Stock Purchase Right shall lapse as to all such Shares,
provided the proposed dissolution or liquidation takes place at the time and in
the manner contemplated. To the extent it has not been previously exercised, an
Option or Stock Purchase Right will terminate immediately prior to the
consummation of such proposed action.

            (c) Merger or Asset Sale.

                     (i) General. Subject to subsections (ii) and (iii) below,
in the event of a merger of the Company with or into another corporation, or the
sale of substantially all of the assets of the Company (a "Merger"), each
outstanding Option and Stock Purchase Right shall be assumed or an equivalent
option or right substituted by the successor corporation or a Parent or
Subsidiary of the successor corporation (the "Successor Corporation"). In the
event that the Successor Corporation refuses to assume or substitute for the
Option or Stock Purchase Right, the Optionee shall fully vest in and have the
right to exercise the Option or Stock Purchase Right as to all of the Optioned
Stock, including Shares as to which it would not otherwise be vested or
exercisable. If an Option or Stock



                                      -12-
<PAGE>   13
Purchase Right becomes fully vested and exercisable in lieu of assumption or
substitution in the event of a Merger, the Administrator shall notify the
Optionee in writing or electronically that the Option or Stock Purchase Right
shall be fully vested and exercisable for a period of fifteen (15) days from the
date of such notice, and the Option or Stock Purchase Right shall terminate upon
the expiration of such period. For the purposes of this Section 14(c), the
Option or Stock Purchase Right shall be considered assumed if, following the
Merger, the option or right confers the right to purchase or receive, for each
Share of Optioned Stock subject to the Option or Stock Purchase Right
immediately prior to the Merger, the consideration (whether stock, cash, or
other securities or property) received in the Merger by holders of Common Stock
for each Share held on the effective date of the transaction (and if holders
were offered a choice of consideration, the type of consideration chosen by the
holders of a majority of the outstanding Shares); provided, however, that if
such consideration received in the Merger is not solely common stock of the
Successor Corporation or its Parent, the Administrator may, with the consent of
the Successor Corporation, provide for the consideration to be received upon the
exercise of the Option or Stock Purchase Right, for each Share of Optioned Stock
subject to the Option or Stock Purchase Right, to be solely common stock of the
Successor Corporation or its Parent equal in fair market value to the per share
consideration received by holders of Common Stock in the Merger.

                     (ii) Employee and Consultant Options.

                        (A) General. In the event of a Merger in which the
stockholders immediately prior to the Merger hold less than 50% of the
outstanding voting equity securities of the Successor Corporation immediately
after such Merger (a "Change of Control Merger"), then (i) the vesting of each
outstanding Option and Stock Purchase Right shall be deemed vested to the extent
each such outstanding Option and Stock Purchase Right would have been vested on
the date twelve (12) months following the effectiveness of the Change of Control
Merger and (ii) each outstanding Option and Stock Purchase Right held by an
Employee or Consultant (and granted to such person in such capacity) shall be
assumed or an equivalent option or right substituted by the Successor
Corporation. In the event that the Successor Corporation refuses to assume or
substitute for the Option or Stock Purchase Right, the Employee or Consultant
shall, as set forth in subsection (i) above, fully vest in and have the right to
exercise such Option or Stock Purchase Right as to all of the Optioned Stock,
including Shares as to which the Employee or Consultant would not otherwise be
vested or exercisable.

                        (B) Employee and Consultant Options Following Assumption
or Substitution. Following an assumption or substitution in connection with a
Merger or Change of Control Merger, if an Employee or Consultant's status as an
Employee (or employee) or Consultant (or consultant) of the Successor
Corporation, as applicable, is terminated by the Successor Corporation as a
result of an involuntary termination (other than for Cause) within twelve months
following the Merger, the Optionee shall fully vest in and have the right to
exercise Optionee's Option or Stock Purchase Right as to all of the Optioned
Stock, including Shares as to which Optionee would not otherwise be vested or
exercisable. Thereafter, the Option or Stock Purchase Right shall remain
exercisable in accordance with Section 10.



                                      -13-
<PAGE>   14

                     (iii) Outside Director Options. In the event of a Change of
Control Merger, each outstanding Option and Stock Purchase Right held by an
Outside Director (and granted to such person in such capacity) shall fully vest
as to all of the Optioned Stock, including Shares as to which the Outside
Director would not otherwise be vested or exercisable. If an Option or Stock
Purchase Right becomes fully vested and exercisable as provided in this
paragraph, the Administrator shall notify the Optionee in writing or
electronically that the Option or Stock Purchase Right shall be fully vested and
exercisable for a period of fifteen (15) days from the date of such notice, and
the Option or Stock Purchase Right shall terminate upon the expiration of such
period.

      15. Date of Grant. The date of grant of an Option or Stock Purchase Right
shall be, for all purposes, the date on which the Administrator makes the
determination granting such Option or Stock Purchase Right, or such other later
date as is determined by the Administrator. Notice of the determination shall be
provided to each Optionee within a reasonable time after the date of such grant.

      16. Amendment and Termination of the Plan.

            (a) Amendment and Termination. The Board may at any time amend,
alter, suspend or terminate the Plan.

            (b) Shareholder Approval. The Company shall obtain shareholder
approval of any Plan amendment to the extent necessary and desirable to comply
with Applicable Laws.

            (c) Effect of Amendment or Termination. No amendment, alteration,
suspension or termination of the Plan shall impair the rights of any Optionee,
unless mutually agreed otherwise between the Optionee and the Administrator,
which agreement must be in writing and signed by the Optionee and the Company.
Termination of the Plan shall not affect the Administrator's ability to exercise
the powers granted to it hereunder with respect to Options granted under the
Plan prior to the date of such termination.

      17. Conditions Upon Issuance of Shares.

            (a) Legal Compliance. Shares shall not be issued pursuant to the
exercise of an Option or Stock Purchase Right unless the exercise of such Option
or Stock Purchase Right and the issuance and delivery of such Shares shall
comply with Applicable Laws and shall be further subject to the approval of
counsel for the Company with respect to such compliance.

            (b) Investment Representations. As a condition to the exercise of an
Option or Stock Purchase Right, the Company may require the person exercising
such Option or Stock Purchase Right to represent and warrant at the time of any
such exercise that the Shares are being purchased only for investment and
without any present intention to sell or distribute such Shares if, in the
opinion of counsel for the Company, such a representation is required.

      18. Inability to Obtain Authority. The inability of the Company to obtain
authority from any regulatory body having jurisdiction, which authority is
deemed by the Company's counsel to be necessary to the lawful issuance and sale
of any Shares hereunder, shall relieve the Company of any



                                      -14-
<PAGE>   15

liability in respect of the failure to issue or sell such Shares as to which
such requisite authority shall not have been obtained.

      19. Reservation of Shares. The Company, during the term of this Plan, will
at all times reserve and keep available such number of Shares as shall be
sufficient to satisfy the requirements of the Plan.

      20. Shareholder Approval. The Plan shall be subject to approval by the
shareholders of the Company within twelve (12) months after the date the Plan is
adopted. Such shareholder approval shall be obtained in the manner and to the
degree required under Applicable Laws.



                                      -15-
<PAGE>   16
                            TURNSTONE SYSTEMS, INC.

                                 2000 STOCK PLAN

                             STOCK OPTION AGREEMENT

      Unless otherwise defined herein, the terms defined in the Plan shall have
the same defined meanings in this Option Agreement.

I.    NOTICE OF STOCK OPTION GRANT

      [Optionee's Name and Address]

      You have been granted an option to purchase Common Stock of the Company,
subject to the terms and conditions of the Plan and this Option Agreement, as
follows:

      Grant Number                  ______________________________

      Date of Grant                 ______________________________

      Vesting Commencement Date     ______________________________

      Exercise Price per Share      $_____________________________

      Total Number of Shares Granted______________________________

      Total Exercise Price          $_____________________________

      Type of Option:               ___  Incentive Stock Option

                                    ___  Nonstatutory Stock Option

      Term/Expiration Date:         10 years from the Date of Grant


      Vesting Schedule:

      Subject to accelerated vesting as set forth in the Plan, this Option may
be exercised, in whole or in part, in accordance with the following schedule:

      25% of the Shares subject to the Option shall vest twelve months after the
Vesting Commencement Date, and 1/48 of the Shares subject to the Option shall
vest each month thereafter, provided that on such dates the Optionee remains in
Continuous status as a Service Provider on such dates.

      Termination Period:

      This Option may be exercised for three months after Optionee ceases to be
a Service Provider. Upon the death or Disability of the Optionee, this Option
may be exercised for twelve months after Optionee ceases to be a Service
Provider. In no event shall this Option be exercised later than the
Term/Expiration Date as provided above.
<PAGE>   17
II.   AGREEMENT

      A.    Grant of Option.

            The Plan Administrator of the Company hereby grants to the Optionee
named in the Notice of Grant attached as Part I of this Agreement (the
"Optionee") an option (the "Option") to purchase the number of Shares, as set
forth in the Notice of Grant, at the exercise price per share set forth in the
Notice of Grant (the "Exercise Price"), subject to the terms and conditions of
the Plan, which is incorporated herein by reference. Subject to Section 15(c) of
the Plan, in the event of a conflict between the terms and conditions of the
Plan and the terms and conditions of this Option Agreement, the terms and
conditions of the Plan shall prevail.

            If designated in the Notice of Grant as an Incentive Stock Option
("ISO"), this Option is intended to qualify as an Incentive Stock Option under
Section 422 of the Code. However, if this Option is intended to be an Incentive
Stock Option, to the extent that it exceeds the $100,000 rule of Code Section
422(d) it shall be treated as a Nonstatutory Stock Option ("NSO").

      B.    Exercise of Option.

            (a) Right to Exercise. This Option is exercisable during its term
in accordance with the Vesting Schedule set out in the Notice of Grant and the
applicable provisions of the Plan and this Option Agreement.

            (b) Method of Exercise. This Option is exercisable by delivery of
an exercise notice, in the form attached as Exhibit A (the "Exercise Notice"),
which shall state the election to exercise the Option, the number of Shares in
respect of which the Option is being exercised (the "Exercised Shares"), and
such other representations and agreements as may be required by the Company
pursuant to the provisions of the Plan. The Exercise Notice shall be completed
by the Optionee and delivered to the Stock Plan Administrator of the Company.
The Exercise Notice shall be accompanied by payment of the aggregate Exercise
Price as to all Exercised Shares. This Option shall be deemed to be exercised
upon receipt by the Company of such fully executed Exercise Notice accompanied
by such aggregate Exercise Price.

                  No Shares shall be issued pursuant to the exercise of this
Option unless such issuance and exercise complies with Applicable Laws. Assuming
such compliance, for income tax purposes the Exercised Shares shall be
considered transferred to the Optionee on the date the Option is exercised with
respect to such Exercised Shares.

      C.    Method of Payment.

            Payment of the aggregate Exercise Price shall be by any of the
following, or a combination thereof, at the election of the Optionee:

             1. cash; or

             2. check; or

             3. consideration received by the Company under a cashless
exercise program implemented by the Company in connection with the Plan; or



                                      -2-
<PAGE>   18
             4. surrender of other Shares which (i) in the case of Shares
acquired upon exercise of an option, have been owned by the Optionee for more
than six (6) months on the date of surrender, and (ii) have a Fair Market Value
on the date of surrender equal to the aggregate Exercise Price of the Exercised
Shares; or

             5. a reduction in the amount of any Company liability to the
Optionee, including any liability attributable to the Optionee's participation
in any Company-sponsored deferred compensation program or arrangement; or

            6. such other consideration and method of payment for the
issuance of Shares to the extent permitted by Applicable Laws.


      D.    Non-Transferability of Option.

            This Option may not be transferred in any manner otherwise than by
will or by the laws of descent or distribution and may be exercised during the
lifetime of Optionee only by the Optionee. The terms of the Plan and this Option
Agreement shall be binding upon the executors, administrators, heirs, successors
and assigns of the Optionee.

      E.    Term of Option.

            This Option may be exercised only within the term set out in the
Notice of Grant, and may be exercised during such term only in accordance with
the Plan and the terms of this Option Agreement.

      F.    Tax Consequences.

            Some of the federal tax consequences relating to this Option, as of
the date of this Option, are set forth below. THIS SUMMARY IS NECESSARILY
INCOMPLETE, AND THE TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE. THE OPTIONEE
SHOULD CONSULT A TAX ADVISER BEFORE EXERCISING THIS OPTION OR DISPOSING OF THE
SHARES.

      G.    Exercising the Option.

             1. Nonstatutory Stock Option. The Optionee may incur regular
federal income tax liability upon exercise of a NSO. The Optionee will be
treated as having received compensation income (taxable at ordinary income tax
rates) equal to the excess, if any, of the Fair Market Value of the Exercised
Shares on the date of exercise over their aggregate Exercise Price. If the
Optionee is an Employee or a former Employee, the Company will be required to
withhold from his or her compensation or collect from Optionee and pay to the
applicable taxing authorities an amount in cash equal to a percentage of this
compensation income at the time of exercise, and may refuse to honor the
exercise and refuse to deliver Shares if such withholding amounts are not
delivered at the time of exercise.

             2. Incentive Stock Option. If this Option qualifies as an ISO, the
Optionee will have no regular federal income tax liability upon its exercise,
although the excess, if any, of the Fair Market Value of the Exercised Shares on
the date of exercise over their aggregate Exercise Price will be treated as an
adjustment to alternative minimum taxable income for federal tax purposes and
may



                                      -3-
<PAGE>   19
subject the Optionee to alternative minimum tax in the year of exercise. In the
event that the Optionee ceases to be an Employee but remains a Service Provider,
any Incentive Stock Option of the Optionee that remains unexercised shall cease
to qualify as an Incentive Stock Option and will be treated for tax purposes as
a Nonstatutory Stock Option on the date three (3) months and one (1) day
following such change of status.

             3. Disposition of Shares.

                  (a) NSO. If the Optionee holds NSO Shares for at least one
year, any gain realized on disposition of the Shares will be treated as
long-term capital gain for federal income tax purposes.

                  (b) ISO. If the Optionee holds ISO Shares for at least one
year after exercise and two years after the grant date, any gain realized on
disposition of the Shares will be treated as long-term capital gain for federal
income tax purposes. If the Optionee disposes of ISO Shares within one year
after exercise or two years after the grant date, any gain realized on such
disposition will be treated as compensation income (taxable at ordinary income
rates) to the extent of the excess, if any, of the lesser of (A) the difference
between the Fair Market Value of the Shares acquired on the date of exercise and
the aggregate Exercise Price, or (B) the difference between the sale price of
such Shares and the aggregate Exercise Price. Any additional gain will be taxed
as capital gain, short-term or long-term depending on the period that the ISO
Shares were held.

                  (c) Notice of Disqualifying Disposition of ISO Shares. If the
Optionee sells or otherwise disposes of any of the Shares acquired pursuant to
an ISO on or before the later of (i) two years after the grant date, or (ii) one
year after the exercise date, the Optionee shall immediately notify the Company
in writing of such disposition. The Optionee agrees that he or she may be
subject to income tax withholding by the Company on the compensation income
recognized from such early disposition of ISO Shares by payment in cash or out
of the current earnings paid to the Optionee.

      H.    Entire Agreement; Governing Law.

            The Plan is incorporated herein by reference. The Plan and this
Option Agreement constitute the entire agreement of the parties with respect to
the subject matter hereof and supersede in their entirety all prior undertakings
and agreements of the Company and Optionee with respect to the subject matter
hereof, and may not be modified adversely to the Optionee's interest except by
means of a writing signed by the Company and Optionee. This agreement is
governed by the internal substantive laws, but not the choice of law rules, of
California.

      I.    NO GUARANTEE OF CONTINUED SERVICE.

      OPTIONEE ACKNOWLEDGES AND AGREES THAT THE VESTING OF SHARES PURSUANT TO
THE VESTING SCHEDULE HEREOF IS EARNED ONLY BY CONTINUING AS A SERVICE PROVIDER
AT THE WILL OF THE COMPANY (AND NOT THROUGH THE ACT OF BEING HIRED, BEING
GRANTED AN OPTION OR PURCHASING SHARES HEREUNDER). OPTIONEE FURTHER ACKNOWLEDGES
AND AGREES THAT THIS AGREEMENT, THE TRANSACTIONS CONTEMPLATED HEREUNDER AND THE
VESTING SCHEDULE SET FORTH HEREIN DO NOT CONSTITUTE AN EXPRESS OR IMPLIED
PROMISE OF CONTINUED ENGAGEMENT AS A SERVICE PROVIDER FOR THE VESTING PERIOD,
FOR ANY PERIOD, OR AT ALL, AND SHALL NOT INTERFERE WITH



                                      -4-
<PAGE>   20
OPTIONEE'S RIGHT OR THE COMPANY'S RIGHT TO TERMINATE OPTIONEE'S RELATIONSHIP AS
A SERVICE PROVIDER AT ANY TIME, WITH OR WITHOUT CAUSE.

      By your signature and the signature of the Company's representative below,
you and the Company agree that this Option is granted under and governed by the
terms and conditions of the Plan and this Option Agreement. Optionee has
reviewed the Plan and this Option Agreement in their entirety, has had an
opportunity to obtain the advice of counsel prior to executing this Option
Agreement and fully understands all provisions of the Plan and Option Agreement.
Optionee hereby agrees to accept as binding, conclusive and final all decisions
or interpretations of the Administrator upon any questions relating to the Plan
and Option Agreement. Optionee further agrees to notify the Company upon any
change in the residence address indicated below.


OPTIONEE:                                 TURNSTONE SYSTEMS, INC.


------------------------------------      --------------------------------------
Signature                                 By


------------------------------------      --------------------------------------
Print Name                                Title


------------------------------------
Residence Address


------------------------------------



                                      -5-
<PAGE>   21
                                CONSENT OF SPOUSE



      The undersigned spouse of Optionee has read and hereby approves the terms
and conditions of the Plan and this Option Agreement. In consideration of the
Company's granting his or her spouse the right to purchase Shares as set forth
in the Plan and this Option Agreement, the undersigned hereby agrees to be
irrevocably bound by the terms and conditions of the Plan and this Option
Agreement and further agrees that any community property interest shall be
similarly bound. The undersigned hereby appoints the undersigned's spouse as
attorney-in-fact for the undersigned with respect to any amendment or exercise
of rights under the Plan or this Option Agreement.




                                          --------------------------------------
                                          Spouse of Optionee

<PAGE>   22
                                    EXHIBIT A

                             TURNSTONE SYSTEMS, INC.

                             2000 STOCK OPTION PLAN

                                 EXERCISE NOTICE

Turnstone Systems, Inc.
274 Ferguson Drive
Mountain View, CA  94043

Attention:  Corporate Secretary

      1. Exercise of Option. Effective as of today, ________________, 2000,
the undersigned ("Purchaser") hereby elects to purchase ______________ shares
(the "Shares") of the Common Stock of Turnstone Systems, Inc. (the "Company")
under and pursuant to the Turnstone Systems, Inc. 2000 Stock Plan (the "Plan")
and the Stock Option Agreement dated, _____ (the "Option Agreement"). The
purchase price for the Shares shall be $_____, as required by the Option
Agreement.

      2. Delivery of Payment.  Purchaser herewith delivers to the Company the
full purchase price for the Shares.

      3. Representations of Purchaser. Purchaser acknowledges that Purchaser
has received, read and understood the Plan and the Option Agreement and agrees
to abide by and be bound by their terms and conditions.

      4. Rights as Shareholder. Until the issuance (as evidenced by the
appropriate entry on the books of the Company or of a duly authorized transfer
agent of the Company) of the Shares, no right to vote or receive dividends or
any other rights as a shareholder shall exist with respect to the Optioned
Stock, notwithstanding the exercise of the Option. The Shares so acquired shall
be issued to the Optionee as soon as practicable after exercise of the Option.
No adjustment will be made for a dividend or other right for which the record
date is prior to the date of issuance, except as provided in Section 13 of the
Plan.

      5. Tax Consultation. Purchaser understands that Purchaser may suffer
adverse tax consequences as a result of Purchaser's purchase or disposition of
the Shares. Purchaser represents that Purchaser has consulted with any tax
consultants Purchaser deems advisable in connection with the purchase or
disposition of the Shares and that Purchaser is not relying on the Company for
any tax advice.

<PAGE>   23
      6. Entire Agreement; Governing Law. The Plan and Option Agreement are
incorporated herein by reference. This Agreement, the Plan and the Option
Agreement constitute the entire agreement of the parties with respect to the
subject matter hereof and supersede in their entirety all prior undertakings and
agreements of the Company and Purchaser with respect to the subject matter
hereof, and may not be modified adversely to the Purchaser's interest except by
means of a writing signed by the Company and Purchaser. This agreement is
governed by the internal substantive laws, but not the choice of law rules, of
California.



Submitted by:                             Accepted by:

PURCHASER:                                TURNSTONE SYSTEMS, INC.


------------------------------------      --------------------------------------
Signature                                 By


------------------------------------      --------------------------------------
Print Name                                Its


Address:                                  Address:

------------------------------------      Turnstone Systems, Inc.
                                          274 Ferguson Drive
------------------------------------      Mountain View, CA  94043



                                          --------------------------------------
                                          Date Received



                                      -2-