Document:

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                                                                 EXHIBIT - 10.68

                             FOURTH AMENDMENT TO THE
                 SKYPORT PLAZA DECLARATION OF COMMON EASEMENTS,
                     COVENANTS, CONDITIONS AND RESTRICTIONS

         THIS FOURTH AMENDMENT TO THE SKYPORT PLAZA DECLARATION OF COMMON
EASEMENTS, COVENANTS, CONDITIONS AND RESTRICTIONS (this "Fourth Amendment") is
made effective as of this _18th_ day of October, 2003, by the undersigned
Owners, the President and the Secretary of the Center Association for the
purpose of amending the following described instrument (the "Declaration"):

         Skyport Plaza Declaration of Common Easements, Covenants, Conditions
         and Restrictions dated as of February 14, 2001, and recorded on
         February 14, 2001 as Instrument No. 15560409 of the Official Records of
         Santa Clara County, California (the "Official Records"), as amended by
         First Amendment to the Skyport Plaza Declaration of Common Easements,
         Covenants, Conditions and Restrictions dated as of October 26, 2001,
         and recorded on October 26, 2001 as Instrument No. 15929606 of the
         Official Records, as further amended by Second Amendment to Skyport
         Plaza Declaration of Common Easements, Covenants, Conditions and
         Restrictions dated as of October 14, 2002, and recorded on October 22,
         2002, as Instrument No. 16552265 of the Official Records, and as
         further amended by Third Amendment to Skyport Plaza Declaration of
         Common Easements, Covenants, Conditions and Restrictions dated as of
         June 17, 2003, and recorded on September 12, 2003, as Instrument No.
         17343456 of the Official Records.

                                    RECITALS

         WHEREAS, concurrently with this Fourth Amendment, EOP-Skyport I, L.L.C.
("EOP-I"), as the Owner of Adjusted Parcel II, will convey fee simple title in
and to a portion of Adjusted Parcel II (the "Brocade Parcel") to Brocade
Communications Systems Skyport LLC, a Delaware limited liability company
("Brocade");

         WHEREAS, concurrently with this Fourth Amendment, EOP-I will subdivide
Adjusted Parcel II and record a final parcel map in compliance with the City
requirements;

         WHEREAS, after the recordation of the final parcel map, the Brocade
Parcel and the remainder of Adjusted Parcel II (the "EOP-I Parcel") shall each
be deemed to be a separate Building Parcel within Adjusted Parcel II under the
Declaration and shall continue to be governed by and subject to the Declaration;

         WHEREAS, after the conveyance, Brocade shall be deemed to be an Owner
and a Member under the Declaration;

         WHEREAS, after the conveyance, EOP-I will continue to own the EOP-I
Parcel;

         WHEREAS, EOP-I desires to amend the Declaration to reflect (1) the
subdivision of Adjusted Parcel II, (2) the continued governance of the Brocade
Parcel and the EOP-I Parcel by the Declaration, (3) the allocation of all
obligations and rights under the Declaration with respect

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to the Brocade Parcel to Brocade, (4) that Brocade will have all of the rights
and obligations of an Owner and a Member with respect to the Brocade Parcel
under the Declaration as a result of its acquisition of the Brocade Parcel,
subject to the terms of this Fourth Amendment, and (5) the allocation of voting
rights and Assessment Percentage for Adjusted Parcel II between the Brocade
Parcel and the EOP-I Parcel;

         WHEREAS, pursuant to Section 11.4 of the Declaration, amendments to the
Declaration occurring after the first conveyance of a Parcel to an Owner other
than Declarant requires the affirmative vote (in person, by ballot or by proxy)
of sixty percent of the total Voting Power of the Owners, subject to the consent
of any First Mortgagees as may be required pursuant to Section 11.6 of the
Declaration;

         WHEREAS, the undersigned Owners constitute sixty percent of the total
Voting Power of the Owners, and, since the amendments to the Declaration set
forth in this Fourth Amendment do not constitute any amendments described in
said Section 11.6, no consent of any First Mortgagee is required; and

         WHEREAS, pursuant to Exhibit "C" to the Declaration, the allocations
for Assessment Percentage may be changed by the filing of an amendment by the
President and the Secretary of the Center Association due to the subdivision of
a portion of a Building Parcel.

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
set forth in this Fourth Amendment, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
undersigned Owners and the President and the Secretary of the Center Association
do hereby agree as follows:

         1.       All capitalized terms used but not otherwise defined herein
shall have the meanings ascribed to them in the Declaration.

         2.       Exhibit "A" to the Declaration is hereby modified as follows:
The legal description for "Adjusted Parcel II" shall be modified to read as set
forth on Exhibit A attached hereto.

         3.       Brocade is deemed to be an Owner and a Member under the
Declaration, and shall have all rights and obligations of an Owner and a Member
under the Declaration.

         4.       Upon the recordation of the final parcel map, the Brocade
Parcel and the EOP-I Parcel shall each be deemed a separate Building Parcel
under the Declaration.

         5.       Pursuant to Section 7.17.4 of the Declaration, the votes
previously allocated to Adjusted Parcel II are hereby re-allocated between
Brocade, with respect to the Brocade Parcel, and EOP-I, with respect to the
EOP-I Parcel, as set forth on Exhibit "C" attached hereto. Notwithstanding
anything to the contrary contained in Section 3.3 and the definition of "Voting
Power" under the Declaration, EOP-I and Brocade have agreed that each of
Brocade's and EOP-I's Voting Power and Assessment Percentage shall be as set
forth on Exhibit "C" attached hereto.

         6.       Exhibit "C" to the Declaration is hereby deleted in its
entirety and replaced with the revised Exhibit C attached hereto and made a part
hereof.

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         7.       In accordance with Section 11.4 of the Declaration, upon the
execution hereof the undersigned Owners shall instruct the Center Association to
cause this Fourth Amendment to be certified by an authorized officer of the
Center Association and recorded in the Official Records of the County of Santa
Clara, California.

         8.       In the event of any conflict between the terms of, or exhibits
attached to, the Declaration and the provisions of this Fourth Amendment, the
terms of, and exhibit attached to, this Fourth Amendment shall control.

         9.       Except as specifically modified herein, there are no other
modifications to the Declaration, and all of the terms and provisions contained
in the Declaration shall remain in full force and effect.

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         IN WITNESS WHEREOF, the Owners hereto and the President and the
Secretary of the Center Association have executed this Fourth Amendment as of
the date first set forth above.

OWNER OF ADJUSTED                   EOP-SKYPORT LAND, L.L.C.,
                                    a Delaware limited liability company
PARCELS I AND IV:

                                    By:  EOP Operating Limited Partnership, a
                                         Delaware limited partnership, its sole
                                         member

                                         By: Equity Office Properties Trust, a
                                             Maryland real estate investment
                                             trust, its general partner

                                         By:   /s/ Jeffrey S. Arnold
                                               -----------------------------
                                         Name:  Jeffrey S. Arnold
                                         Title: Vice President - Legal

OWNER OF ADJUSTED PARCEL II:        EOP-SKYPORT I, L.L.C., a Delaware limited
                                    liability company

                                    By: EOP Operating Limited Partnership,
                                        a Delaware limited partnership, its sole
                                        member

                                        By: Equity Office Properties Trust,
                                            a Maryland real estate
                                            investment trust, its general
                                            partner

                                        By:    /s/ Jeffrey S. Arnold
                                               -----------------------------
                                        Name:  Jeffrey S. Arnold
                                        Title: Vice President - Legal

                       [SIGNATURES CONTINUED ON NEXT PAGE]

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OWNER OF ADJUSTED PARCEL III:       EOP-SKYPORT II, L.L.C., a Delaware limited
                                    liability company

                                    By: EOP Operating Limited Partnership, a
                                        Delaware limited partnership, its sole
                                        member

                                        By:  Equity Office Properties Trust, a
                                             Maryland real estate, investment
                                             trust, its general partner

                                        By:    /s/ Jeffrey S. Arnold
                                               -----------------------------
                                        Name:  Jeffrey S. Arnold
                                        Title: Vice President - Legal

CENTER ASSOCIATION:

                                    By: /s/ John W. Petersen
                                        ----------------------------------------
                                        Name: John W. Petersen
                                        President of the SKYPORT PLAZA
                                        OWNERS ASSOCIATION, a
                                        California non-profit corporation

                                    By: /s/ Stanley M. Stevens
                                        ----------------------------------------
                                        Name: Stanley M. Stevens
                                        Secretary of the SKYPORT PLAZA
                                        OWNERS ASSOCIATION, a
                                        California non-profit corporation

                            [END OF SIGNATURES PAGES]

<PAGE>

                              CONSENT OF DECLARANT

         The undersigned, as successor-by-merger to Spieker Properties, L.P.
(the Declarant named under the Skyport Plaza Declaration of Common Easements,
Covenants, Conditions and Restrictions dated and recorded February 14, 2001, as
amended by First Amendment dated as of October 26, 2001 and recorded on October
26, 2001 as Instrument No. 15929606, as further amended by Second Amendment to
Skyport Plaza Declaration of Common Easements, Covenants, Conditions and
Restrictions dated as of October 14, 2002, and recorded on October 22, 2002, as
Instrument No. 16552265, and as further amended by Third Amendment to Skyport
Plaza Declaration of Common Easements, Covenants, Conditions and Restrictions
dated as of June 17, 2003, and recorded on September 12, 2003, as Instrument No.
17343456 of the Official Records of Santa Clara County, California), does hereby
consent to the action of the Owners signatory to the Fourth Amendment attached
hereto.

          DECLARANT:       EOP OPERATING LIMITED
                           PARTNERSHIP, a Delaware limited
                           partnership, successor-by-merger to Spieker
                           Properties, L.P., California limited partnership

                           By: Equity Office Properties Trust, a
                               Maryland real estate investment trust, its
                               general partner

                               By:    /s/ Jeffrey S. Arnold
                                      ------------------------------------------
                               Name:  Jeffrey S. Arnold
                               Title: Vice President - Legal

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                                    EXHIBIT A
                              (ADJUSTED PARCEL II)

                                 BROCADE PARCEL

All that certain real property situate in the City of San Jose, County of Santa
Clara, State of California, described as follows:

Parcel A, as shown on the Parcel Map filed for record in the office of the
Recorder of the County of Santa Clara, State of California on Nov 18, in Book
766 of Maps, page(s) 14-18.

                                  EOP-I PARCEL

All that certain real property situate in the City of San Jose, County of Santa
Clara, State of California, described as follows:

Parcel B, as shown on the Parcel Map filed for record in the office of the
Recorder of the County of Santa Clara, State of California on Nov 18, 2003, in
Book 766 of Maps, page(s) 14-18.<PAGE>

                                                                 EXHIBIT - 10.69

                GUARANTY OF BROCADE COMMUNICATIONS SYSTEMS, INC.

         The undersigned, Brocade Communications Systems, Inc., a Delaware
corporation ("Guarantor"), hereby absolutely and unconditionally guarantees (x)
to EOP Skyport I, L.L.C., a Delaware limited liability company and its
successors and assigns (collectively, the "EOP Owner"), payment by Brocade
Communications Systems Skyport LLC, a Delaware limited liability corporation
(together with its successors and assigns which are its Affiliates (as defined
in the Declaration), the "Brocade Owner") of the Brocade Owner's obligations
(the "Declaration Obligations") under that certain Skyport Plaza (Adjusted
Parcel II) Declaration of Common Easements, Covenants, Conditions and
Restrictions dated as of November 18, 2003 (as amended from time to time, the
"Declaration"), and (y) to EOP Skyport II, L.L.C., a Delaware limited liability
company and its successors and assigns ( "EOP II"), payment by the Brocade Owner
of the Brocade Owner's obligations (the "License Obligations", and together with
the Declaration Obligations, the "Obligations") under that certain License
Agreement for Space dated as of November 18, 2003 (as amended from time to time,
the "License"), all subject to the limitations below .

         In the event of any default on the part of the Brocade Owner with
respect to the Obligations, the EOP Owner or EOP II, as applicable, may give a
written notice of such default to Guarantor and a demand (a "Demand for
Performance by Guarantor") that Guarantor perform, prior to the expiration of
any applicable cure period in the Declaration or the License, as applicable, and
to the extent such obligation is not performed by the Brocade Owner, that
portion of the Obligations with respect to which the Brocade Owner is in
default. Such Demand for Performance by Guarantor shall state in reasonable
detail the nature of the default, together with the applicable cure period for
the cure of such default and the payment amount that the EOP Owner or EOP II (as
applicable) demands from the Brocade Owner or from Guarantor pursuant to this
Guaranty in order to cure such default. The other provisions of this Guaranty to
the contrary notwithstanding, Guarantor shall not be required to perform the
Obligations with respect to any default until the EOP Owner or EOP II (as
applicable) has given to Guarantor a Demand for Performance by Guarantor, and
the Guarantor shall have the benefit of all cure periods provided to the Brocade
Owner in the Declaration or the License (as applicable). Any performance by
Guarantor of the Obligations prior to expiration of any applicable cure period
under the Declaration or the License (as applicable) shall be deemed a cure of
the applicable default by Brocade Owner under the Declaration or the License (as
applicable), to the extent of such performance by Guarantor.

         To the extent that the performance by the Brocade Owner of any of the
Obligations is expressly waived in a writing executed and delivered by the EOP
Owner or EOP II (as applicable) to the Brocade Owner pursuant to the Declaration
or the License, Guarantor shall have the benefit of such waiver. Without
limiting the foregoing, no Obligation shall be deemed to have been waived, or
the performance of such Obligation excused, by any failure or delay in the
enforcement of such Obligation by the EOP Owner or EOP II (as applicable).

         Except as otherwise provided hereunder and to the extent provided
herein, the obligations of Guarantor hereunder are unconditional and absolute
and not subject to termination for any reason other than the satisfaction of the
Obligations or expiration of this Guaranty. In addition,

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the Obligations of Guarantor hereunder are not subject to counterclaim, set-off,
abatement, deferment or defense based upon any claim that Guarantor may have
against the EOP Owner or EOP II:

                  (a)      unrelated to the transaction giving rise to the
Obligations herein; or

                  (b)      regarding (i) the release or discharge of the Brocade
Owner in any creditor's receivership, bankruptcy or other proceedings or (ii)
the impairment, limitation, modification or termination of the liabilities of
the Brocade Owner or the estate of the Brocade Owner in bankruptcy, or any
remedy for the enforcement of the Brocade Owner's liability under the
Declaration or the License, resulting from the operation of any present or
future provision of Title 11 of the United States Code or other statute or from
the decision in any court.

         Except as expressly provided herein and to the extent provided herein,
Guarantor irrevocably waives acceptance hereof, presentment, demand, protest, to
the fullest extent permitted by law, any notice not provided for herein, as well
as any requirement that at any time any action be taken by any person against
the Brocade Owner or Guarantor. Until payment of the Obligations by the Brocade
Owner under the Declaration and the License, any right of subrogation on the
part of Guarantor shall be in all respects subordinate to all rights and claims
of the EOP Owner and EOP II for all other payments or damages which shall be or
become due and payable by the Brocade Owner under the provisions of the
Declaration or the License. The EOP Owner may compromise or adjust any part of
the Declaration Obligations, EOP II may compromise or adjust any part of the
License Obligations, and the EOP Owner or EOP II make any other accommodation
with the Brocade Owner or exercise any other right or remedy available to it
against the Brocade Owner without affecting or impairing in any way the
liability of the Guarantor under this Guaranty except to the extent the
Obligations have been performed; provided that neither the EOP Owner or EOP II
shall have no right to increase the liability of the Guarantor hereunder without
the express written consent of Guarantor.

         In the event of any litigation between the EOP Owner and/or EOP II, on
the one hand and the Guarantor, on the other hand, seeking a declaration of
rights hereunder, damages for breach or any other remedy pertaining to this
Guaranty, the prevailing party shall recover its reasonable attorneys' fees and
court costs. For purposes hereof, the EOP Owner and/or EOP II shall be deemed
the prevailing party in the event that the result of any proceeding requires
Guarantor to pay any amount to the EOP Owner or EOP II or perform any obligation
for the benefit of the EOP Owner and/or EOP II.

         Notwithstanding anything to the contrary herein, the total obligations
of Guarantor hereunder shall be limited to the sum of One Million Fifteen
Thousand Dollars ($1,015,000) (the "Limit"); provided, however, that any
Obligations that arise out of the Brocade Owner's obligations under Section
17.13 of the Declaration, the penultimate sentence of Section 24 of the License
or the obligations of the Guarantor under the immediately preceding paragraph
for reasonable attorneys' fees and court costs (the "Non-Capped Obligations")
shall not be subject to the Limit. . All payments by Guarantor hereunder, other
than those related to the Non-Capped Obligations shall be credited against the
Limit. Upon termination of the License and satisfaction

<PAGE>

of all obligations under the License by Brocade Owner, the Limit, as it may have
already been reduced as of such time in accordance with the previous sentence,
shall be further reduced by the difference between (a) $15,000 and (b) the
amount of previous reduction in the Limit in respect of Guarantor's payment of
License Obligations.

         This Guaranty shall remain in full force and effect as to any
Obligation for so long as the Brocade Owner named herein or an Affiliate thereof
owns the Brocade Building. After any sale or conveyance of the entire Brocade
Building by the Brocade Owner named herein to a party other than an Affiliate of
the Brocade Owner, this Guaranty shall terminate and be of no further force or
effect (except as to claims against Guarantor hereunder then existing, which
claims shall survive such termination) and the EOP Owner and EOP II shall
execute an agreement acknowledging the termination of this Guaranty, and the EOP
Owner and EOP II shall not be entitled to seek or obtain a replacement guaranty
for this Guaranty from any successor in interest to the Brocade Owner named
herein.

         IN WITNESS WHEREOF, Guarantor has executed this Guaranty as of the 18th
day of November, 2003.

                                    GUARANTOR:

                                    BROCADE COMMUNICATIONS SYSTEMS, INC.,
                                    a Delaware corporation

                                    By:   /s/ Antonio Canova
                                          --------------------------------------
                                    Name: Antonio Canova
                                    Its:  Chief Financial Officer

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