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                                                                   EXHIBIT 10.89

                             OEM PURCHASE AGREEMENT

                                 THIRD AMENDMENT

This Third Amendment effective as of the 1st day of February, 2003, (the
"Effective Date") amends the OEM Purchase Agreement (the "Agreement") dated
December 16, 2002, by and between HEWLETT-PACKARD COMPANY, a Delaware
corporation having its principal place of business at 3000 Hanover Street, Palo
Alto, California 94304 ("HP") and BROCADE COMMUNICATIONS SYSTEMS, INC. a
Delaware corporation having its principal place of business at 1745 Technology
Drive, San Jose, California 95110, and BROCADE COMMUNICATIONS SYSTEMS
SWITZERLAND SARL., a corporation organized under the laws of Geneva, and having
its principal place of business at 29 Route de l'Aeroport Case Postale 105,
CH-1215 Geneva 15, Switzerland (collectively "Supplier").

                                    RECITALS

WHEREAS, HP and Supplier have entered into the Agreement pursuant to which HP
agreed to purchase, and Supplier agreed to sell OEM Products in accordance with
the terms and conditions set forth therein; and

WHEREAS, HP and Supplier desire to enter into this Third Amendment to amend
certain provisions of the Agreement.

                                   AGREEMENTS

NOW, THEREFORE, in consideration of the mutual covenants contained herein, and
for other good and valuable consideration the receipt and sufficiency of which
are hereby acknowledged, HP and Supplier agree as follows:

1.    DEFINITIONS. Terms used in this Third Amendment that are not defined
      herein shall have the meaning given thereto in the Agreement.

2.    CONFIRMATION AND RATIFICATION. Except as expressly amended herein all
      unmodified and remaining terms and conditions of the Agreement shall
      remain in full force and effect. All capitalized terms not defined in this
      Third Amendment shall have the meaning set forth in the Agreement. In the
      event a conflict between the Agreement and this Third Amendment, the terms
      of this Third Amendment shall govern.

3.    AMENDMENTS. HP and Supplier hereby agree that the Agreement is hereby
      amended as follows:

      3.1. Delete the following language from section 9.1:

            Product Warranties. Supplier represents and warrants to HP that, for
            a period of [**] from the date of [**] for each [**] OEM Product
            unit (excluding [**]) and [**] from each [**] and [**] OEM Product,
            that all OEM Products under this Agreement will:

      3.2. Insert the following language at section 9.1:

            9.1. Product Warranties.

**    Certain information on this page has been omitted and filed separately
      with the Securities and Exchange Commission. Confidential treatment has
      been requested with respect to the omitted portions.

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                  9.1.1. For [**] purchased by HP prior to [**], Supplier
                         represents and warrants to HP that, for a period of
                         [**] from the date of [**] for each [**] OEM Product
                         unit (excluding [**]) and [**] for each [**] and [**]
                         OEM Product, that all OEM Products under this Agreement
                         will meet the requirements stated at subsection [**]
                         below.

                  9.1.2. For [**] purchased by HP on or after [**], Supplier
                         represents and warrants to HP that, for a period of
                         [**] from the date of [**]for each [**] OEM Product
                         unit (excluding [**]) and [**] for each [**] and [**]
                         OEM Product, that all OEM Products under this Agreement
                         will meet the requirements stated at subsections [**]
                         below.

4.    COUNTERPARTS. This SecondThird Amendment may be executed in counterparts,
      each of which will be deemed an original, but both of which together will
      constitute one and the same instrument. The parties agree that facsimile
      signatures of the parties will be binding.

IN WITNESS WHEREOF, HP and Supplier have entered into this Third Amendment as of
the Effective Date as provided above.

AGREED:

BROCADE COMMUNICATIONS                        HEWLETT-PACKARD COMPANY
SYSTEMS INC. ("SUPPLIER")                     ("HP")

By: /s/  Michael Klayko                        By: [**]
    ------------------                            ------------------------------

Name: Michael Klayko                          Name: [**]

Title:  VP                                    Title: Director, SWD Procurement

BROCADE COMMUNICATIONS
SWITZERLAND, SARL. ("SUPPLIER")

By:   /s/ Ian Whiting
     ------------------
Name: Ian Whiting
      Vice President EMEA

Title: 22  November 2004

**    Certain information on this page has been omitted and filed separately
      with the Securities and Exchange Commission. Confidential treatment has
      been requested with respect to the omitted portions.

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