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As filed with the Securities and Exchange Commission on August 26, 2008

Registration No. 333-

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

BROCADE COMMUNICATIONS SYSTEMS, INC.

(Exact name of Registrant as specified in its charter)



Delaware		77-0409517
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification No.)

1745 Technology Drive

San Jose, California 95110

(408) 333-8000

(Address, including zip code, and telephone number, including area code, of Registrant’s principal executive offices)

Tyler Wall, Esq.

Vice President, General Counsel and Corporate Secretary

Brocade Communications Systems, Inc.

1745 Technology Drive

San Jose, California 95110

(408) 333-8000

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copy to:

Nancy H. Wojtas, Esq.

Cooley Godward Kronish LLP

Five Palo Alto Square

3000 El Camino Real

Palo Alto, California 94306-2155

Telephone: (650) 843-5000

Approximate date of commencement of proposed sale to the public: From time to time after the effective date of this Registration Statement, as determined by Registrant.

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. o

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box. þ

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):


Large accelerated filer þ	Accelerated filer o	Non-accelerated filer o	Smaller reporting company o
		(Do not check if a smaller reporting company)

CALCULATION OF REGISTRATION FEE


		Proposed Maximum		Amount of
Title of Each Class of	Amount	Offering	Proposed Maximum Aggregate	Registration
Securities to be Registered	to be Registered	Price per Unit	Offering Price	Fee(1)
Common Stock, $0.001 par value per share	(2)	(3)	(3)	—
Preferred Stock, $0.001 par value per share	(2)	(3)	(3)	—
Debt Securities	(2)	(3)	(3)	—
Warrants	(2)	(3)	(3)	—
Units	(2)	(3)	(3)	—
Total	(2)		$750,000,000	$29,475.00


(1)		Calculated pursuant to Rule 457(o) under the Securities Act.

(2)		There are being registered hereunder such indeterminate number of shares of common stock and preferred stock, such indeterminate principal amount of debt securities, such indeterminate principal amount of units, and such indeterminate number of warrants to purchase common stock, preferred stock, debt securities or units, as shall have an aggregate initial offering price not to exceed $750,000,000. If any debt securities are issued at an original issued discount, then the offering price of such debt securities shall be in such greater principal amount as shall result in an aggregate initial offering price not to exceed $750,000,000, less the aggregate dollar amount of all securities previously issued hereunder. Any securities registered hereunder may be sold separately or as units with other securities registered hereunder. The securities registered also include such indeterminate amounts and numbers of shares of common stock and debt securities as may be issued upon conversion of or exchange for debt securities that provide for conversion or exchange, or pursuant to the antidilution provisions of any such securities.

(3)		The proposed maximum aggregate offering price per class of security will be determined from time to time by the Registrant in connection with the issuance by the Registrant of the securities registered hereunder and is not specified as to each class of security pursuant to General Instruction II.D. of Form S-3 under the Securities Act.

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

SUBJECT TO COMPLETION, DATED AUGUST 26, 2008

PROSPECTUS

$750,000,000

BROCADE COMMUNICATIONS SYSTEMS, INC.

Common Stock

Preferred Stock

Debt Securities

Warrants

Units

From time to time, we may sell up to an aggregate of $750,000,000 of any combination of the securities described in this prospectus, either individually or in units. We may also offer common stock or preferred stock upon conversion of debt securities, common stock upon conversion of preferred stock, or common stock, preferred stock or debt securities upon the exercise of warrants.

We will provide the specific terms of these offerings and securities in one or more supplements to this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference, before buying any of the securities being offered.

Our common stock is traded on the NASDAQ Global Select Market under the symbol “BRCD.” The applicable prospectus supplement will contain information as to other listings, if any, on the NASDAQ Global Select Market or other securities exchange of the securities covered by the prospectus supplement.

You should read this prospectus, any prospectus supplement and any related free writing prospectus carefully before you invest.

INVESTING IN OUR SECURITIES INVOLVES A HIGH DEGREE OF RISK. YOU SHOULD REVIEW CAREFULLY THE RISKS AND UNCERTAINTIES DESCRIBED UNDER THE HEADING “RISK FACTORS” CONTAINED IN THE APPLICABLE PROSPECTUS SUPPLEMENT AND ANY RELATED FREE WRITING PROSPECTUS, AND UNDER SIMILAR HEADINGS IN OUR MOST RECENT ANNUAL REPORT ON FORM 10-K OR QUARTERLY REPORT ON FORM 10-Q FILED WITH THE SECURITIES AND EXCHANGE COMMISSION, AS UPDATED BY ANY SUBSEQUENT FILING WITH THE COMMISSION THAT IS INCORPORATED BY REFERENCE HEREIN.

THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE ANY SECURITIES UNLESS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.

The securities may be sold directly by us to investors, through agents designated from time to time or to or through underwriters or dealers, on a continuous or delayed basis. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution” in this prospectus. If any agents or underwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such agents or underwriters and any applicable fees, discounts or commissions and over allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds that we expect to receive from such sale will also be set forth in a prospectus supplement.

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

The date of this prospectus is , 2008

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or SEC, using a “shelf” registration process. Under this shelf registration process, we may sell common stock, preferred stock, various series of debt securities and/or warrants to purchase such securities, either individually or in units, in one or more offerings up to a total dollar amount of $750,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will contain more specific information about the terms of those securities. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. We may also add, update or change in the prospectus supplement (and in any related free writing prospectus that we may authorize to be provided to you) any of the information contained in this prospectus or in the documents that we have incorporated by reference into this prospectus. We urge you to carefully read this prospectus, any applicable prospectus supplement and any related free writing prospectus, together with the information incorporated herein by reference as described under the heading “Where You Can Find More Information,” beginning on page 24, before buying any of the securities being offered.

THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.

You should rely only on the information that we have provided or incorporated by reference in this prospectus, any applicable prospectus supplement and any related free writing prospectus that we may authorize to be provided to you. We have not authorized anyone to provide you with different information. No dealer, salesperson or other person is authorized to give any information or to represent anything not contained in this prospectus, any applicable prospectus supplement or any related free writing prospectus that we may authorize to be provided to you. You must not rely on any unauthorized information or representation. This prospectus is an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so. You should assume that the information in this prospectus, any applicable prospectus supplement or any related free writing prospectus is accurate only as of the date on the front of the document and that any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus, any applicable prospectus supplement or any related free writing prospectus, or any sale of a security.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading “Where You Can Find More Information.”

OVERVIEW

We are the leading supplier of storage area network equipment and a leading provider of data center networking solutions that help enterprises connect and manage their information. We offer a comprehensive line of data center networking products, software and services that enable businesses to make their data centers more efficient, reliable and adaptable. Our products and services are designed to help information technology organizations manage their data assets in an efficient, cost-effective manner. In the first fiscal quarter of 2008, we reorganized the Company into four operating units. The objective of this new organization is to allow us to more effectively focus on growth opportunities, while being well-positioned to more rapidly scale and accommodate new business opportunities, including potential future acquisitions. The four operating units are as follows:


	•	The Data Center Infrastructure operating unit encompasses our family of Storage Area Network, or SAN, business which includes infrastructure products and solutions including directors, switches, routers, fabric-based software applications, distance/extension products, as well as management applications and utilities to centralize data management.


	•	The Server Edge and Storage operating unit includes our new HBAs and Intelligent Server Adapter initiatives, as well as our SAN switch modules for bladed servers and embedded switches for blade servers.

	•	The Services, Support and Solutions operating unit includes services that assist customers with consulting and support in designing, implementing, deploying and managing data center enterprise solutions as well as post-contract customer support.

	•	The Files operating unit includes our family of File Area Network solutions which includes both software and hardware offerings for more effectively managing file data and storage resources.

Together, our products and services simplify information technology infrastructure, increase resource utilization, ensure availability of mission critical applications and serve as a platform for corporate data back up and disaster recovery. Our products and services are marketed, sold and supported worldwide to end-user customers through distribution partners, including OEMs, distributors, systems integrators, value-added resellers and by us directly.

We have entered into a merger agreement with Foundry Networks, Inc. for us to acquire Foundry. In the proposed transaction, a wholly-owned subsidiary of us will merge with and into Foundry, with Foundry continuing after the merger as the surviving corporation and our wholly-owned subsidiary.

We were incorporated in California on August 24, 1995 and re-incorporated in Delaware on May 14, 1999. Our mailing address and executive offices are located at 1745 Technology Drive, San Jose, California 95110. Our telephone number is (408) 333-8000. Our corporate website is www.brocade.com. Our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and amendments to reports filed pursuant to Sections 13(a) and 15(d) of the Securities Exchange Act of 1934, as amended, are available free of charge on our website when such reports are available on the SEC website. The public may read and copy any materials filed by us with the SEC at the SEC’s Public Reference Room at 100 F Street, NE, Washington, DC 20549. The public may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. The SEC maintains an Internet site that contains reports, proxy and information statements and other information regarding issuers that file electronically with the SEC at http://www.sec.gov. The contents of these websites are not incorporated into this filing. Further, our references to the URLs for these websites are intended to be inactive textual references only.

Brocade, Fabric OS, File Lifecycle Manager, MyView, and StorageX are registered trademarks and the Brocade B-wing symbol, DCX, and SAN Health are trademarks of Brocade Communications Systems, Inc., in the United States and/or in other countries. All other brand names, logos and trademarks appearing elsewhere in this prospectus are the property of their respective owners.

Whenever we refer to “Brocade,” “we,” “our” or “us” in this prospectus or in any prospectus supplement, we mean Brocade Communications Systems, Inc., unless the context indicates otherwise.

RISK FACTORS

Investing in our securities involves a high degree of risk. You should carefully review the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus. Additional risks and uncertainties that are not yet identified or that we think are immaterial may also materially harm our business, operating results and financial condition and could result in a complete loss of your investment.

NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference into this prospectus contain certain “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995 with respect to our financial condition, results of operations and business. All statements other than statements of historical fact are statements that could be deemed forward-looking statements, including, but not

limited to, projections of revenue, margins, expenses, tax provisions, earnings, cash flows, benefit obligations, share repurchases or other financial items; any statements of the plans, strategies and objectives of management for future operations; any statements concerning expected development, performance or market share relating to products or services; any statements regarding future economic conditions or performance; any statements regarding pending litigation, including the federal securities class action preliminary settlement, investigations, claims or disputes; any statements of expectation or belief; and any statements of assumptions underlying any of the foregoing. Words such as “anticipates,” “expects,” “intends,” “plans,” “predicts,” “believes,” “seeks,” “estimates,” “targets,” “goals,” “could,” “would,” “will,” “may,” “can,” “continue,” “potential,” “should,” and the negative of these terms or other comparable terminology often identify forward-looking statements. These statements are based on current expectations, estimates, forecasts, and projections about the industries in which we operate and the beliefs and assumptions of our management. Statements in this prospectus and the other documents incorporated by reference that are not historical facts are hereby identified as “forward-looking statements” for the purpose of the safe harbor provided by Section 21E of the Securities Exchange Act of 1934, as amended, and Section 27A of the Securities Act. These forward looking statements are subject to a number of risks and uncertainties, including those risks discussed under “Risks Factors” contained in the applicable prospectus supplement and any related free writing prospectus, in our Annual Report on Form 10-K for the fiscal year ended October 27, 2007 in Item 1A under “Risk Factors” as well as in Item 7A “Qualitative and Quantitative Disclosures About Market Risk,” our Quarterly Report on Form 10-Q for the period ended July 26, 2008 in Part II, Item 1A under “Risk Factors” and the risks detailed from time to time in our future SEC reports. Any such forward looking statements are not guarantees of future performance and actual results, developments and business decisions may differ from those contemplated by such forward looking statements. Further, we undertake no obligation to revise or update any forward-looking statements for any reason.

THE SECURITIES WE MAY OFFER

We may offer shares of our common stock and preferred stock, various series of debt securities, or warrants to purchase any of such securities, either individually or in units, with a total value of up to $750,000,000 from time to time under this prospectus, together with any applicable prospectus supplement and related free writing prospectus, at prices and on terms to be determined by market conditions at the time of any offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:


	•	designation or classification;

	•	aggregate principal amount or aggregate offering price;

	•	maturity, if applicable;

	•	rates and times of payment of interest, dividends or other payments, if any;

	•	redemption, conversion, exercise, exchange or sinking fund terms, if any;

	•	conversion prices, if any;

	•	restrictive covenants;

	•	voting or other rights, if any;

	•	exercise prices, if any; and

	•	certain United States federal income tax considerations.

A prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in documents we have incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.

THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.

We may sell the securities directly to investors or through agents, underwriters or dealers. We, and our agents, or underwriters, reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities through agents or underwriters, we will include in the applicable prospectus supplement:


	•	the name of those agents or underwriters;

	•	applicable fees, discounts and commissions to be paid to them;

	•	details regarding over-allotment options, if any; and

	•	the net proceeds to us.

Common Stock. We may issue shares of our common stock from time to time. The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of stockholders and do not have cumulative voting rights. Subject to any preferences of any of our preferred stock that may be outstanding, holders of our common stock are entitled to dividends when, as and if declared by our board of directors. Upon our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preferences of any then outstanding shares of preferred stock.

Debt Securities. We may offer debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. The senior debt securities will rank equally with any other unsecured and unsubordinated debt. The subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner described in the instrument governing the debt, to all of our senior indebtedness. Convertible debt securities will be convertible into or exchangeable for our common stock, preferred stock or our other securities. Conversion may be mandatory or at the option of the holders of our debt securities and would be at prescribed conversion rates.

The debt securities will be issued under one or more documents called indentures, which are contracts between us and a national banking association, as trustee. In this prospectus, we have summarized certain general features of the debt securities. We urge you, however, to read the prospectus supplement related to the series of debt securities being offered, as well as the complete indentures that contain the terms of the debt securities. Forms of a senior indenture and subordinated indenture have been filed as exhibits to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports we file with the SEC.

Preferred Stock. We may issue shares of our preferred stock from time to time, in one or more series. Under our amended and restated certificate of incorporation, our board of directors has the authority, without further action by stockholders, to designate up to 5,000,000 shares of preferred stock in one or more series and to fix the rights, preferences, privileges, qualifications and restrictions granted to or imposed upon the preferred stock, including dividend rights, conversion rights, voting rights, rights and terms of redemption, liquidation preference and sinking fund terms, any or all of which may be greater than the rights of the common stock.

If we sell any series of preferred stock under this prospectus, we will fix the rights, preferences, privileges, qualifications and restrictions of the preferred stock of each series that we sell under this prospectus and applicable prospectus supplements in the certificate of designation relating to that series. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of the related series of preferred stock. We urge you, however, to read the prospectus supplements (and any related free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

Warrants. We may issue warrants for the purchase of common stock, preferred stock and/pr debt securities in one or more series. We may issue warrants independently or together with common stock, preferred stock and/or debt securities, and the warrants may be attached to or separate from these securities.

In this prospectus, we have summarized certain general features of the warrants. We urge you, however, to read the applicable prospectus supplement and any free writing prospectus that we may authorize to be provided to you related to the particular series of warrants being offered, as well as the complete warrant agreements and warrant certificates that contain the terms of the warrants. Forms of warrant agreements and forms of warrants containing the terms of the warrants being offered have been filed as exhibits to the registration statement of which this prospectus is a part, and supplemental agreements and forms of warrants containing the terms of the warrants being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports we file with the SEC.

The warrants will be evidenced by warrant certificates issued under one or more warrant agreements, which are contracts between us and an agent for the holders of the warrants. We will indicate the name and address of the warrant agent, if applicable, in the prospectus supplement relating to the particular series of warrants being offered.

Units. We may issue, in one or more series, units consisting of common stock, preferred stock, debt securities and/or warrants for the purchase of common stock, preferred stock and/or debt securities in any combination from time to time. In this prospectus, we have summarized certain general features of the units. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of units being offered, as well as the complete unit agreement that contains the terms of the units. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of unit agreement and any supplemental agreements that describe the terms of the series of units we are offering before the issuance of the related series of units.

We will evidence each series of units by unit certificates that we will issue. Units may be issued under a unit agreement that we enter into with a unit agent. We will indicate the name and address of the unit agent, if applicable, in the applicable prospectus supplement relating to the particular series of units being offered.

RATIO OF EARNINGS TO FIXED CHARGES

The following table sets forth our ratio of earnings to fixed charges and ratio of combined fixed charges and preference dividends to earnings for the periods indicated:

Nine Months

Ended

Year Ended

July 26,

October 27,

October 28,

October 29,

October 30,

October 25,

2008

2007

2006

2005

2004

2003

Ratio of earnings to fixed charges(1)

—

(2)

13.5

10.2

5.9

—

(2)

—

(2)


(1)		The ratio of earnings to fixed charges was computed by dividing earnings (loss) from continuing operations before taxes by fixed charges from continuing operations for the periods indicated. Fixed charges from continuing operations include (i) interest expense and amortization of debt discount and issuance costs on all indebtedness, and (ii) one-third of all rental expense, which we consider to be a reasonable approximation of the interest factor included in rental expense.

(2)		Earnings were inadequate to cover fixed charges for the years ended October 30, 2004 and October 25, 2003 and for the nine months ended July 26, 2008. We needed additional earnings of $19.6 million, $134.7 million and $5.2 million, respectively, to achieve a ratio of earnings to fixed charges of 1.0x.

USE OF PROCEEDS

We currently intend to use the net proceeds from the sale of securities offered hereby to finance the proposed acquisition of Foundry Networks, Inc., or Foundry, as set forth in the Agreement and Plan of Merger, dated as of July 21, 2008, among Foundry Systems, Inc., Brocade Communications Systems, Inc. and Falcon Acquisition Sub,

Inc., a wholly-owned subsidiary of Brocade Communications Systems, Inc., and/or other general corporate purposes including capital expenditures. A description of our proposed acquisition of Foundry can be found in our Current Report on Form 8-K filed with the SEC on July 24, 2008, which is incorporated by reference herein.

DESCRIPTION OF CAPITAL STOCK

As of the date of this prospectus, our authorized capital stock consists of 800,000,000 shares of common stock, par value $0.001 per share and 5,000,000 shares of preferred stock, par value $0.001 per share. As of August 21, 2008, there were approximately 371,873,270 shares of common stock outstanding and no shares of preferred stock outstanding.

The following summary description of our capital stock is based on the provisions of our certificate of incorporation and bylaws and the applicable provisions of the Delaware General Corporation Law. This information is qualified entirely by reference to the applicable provisions of our amended and restated certificate of incorporation, bylaws and the Delaware General Corporation Law. For information on how to obtain copies of our certificate of incorporation and bylaws, which are exhibits to the registration statement of which this prospectus is a part, see “Where You Can Find More Information.”

Common Stock

The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of stockholders. The holders of our common stock do not have cumulative voting rights in the election of directors. Subject to preferences that may be applicable to any outstanding shares of preferred stock, the holders of common stock are entitled to receive ratably such dividends as may be declared by our board of directors out of legally available funds. Upon our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preferences of any outstanding shares of preferred stock. Holders of common stock have no preemptive rights and no right to convert their common stock into any other securities. There are no redemption or sinking fund provisions applicable to our common stock.

The rights of the holders of our common stock are subject to, and may be adversely affected by, the rights of holders of shares of any preferred stock that we may designate and issue in the future.

Preferred Stock

We may issue shares of our preferred stock from time to time, in one or more series. Under our amended and restated certificate of incorporation, our board of directors has the authority, without further action by stockholders, to designate up to 5,000,000 shares of preferred stock in one or more series and to fix the rights, preferences, privileges, qualifications and restrictions granted to or imposed upon the preferred stock, including dividend rights, conversion rights, voting rights, rights and terms of redemption, liquidation preference and sinking fund terms, any or all of which may be greater than the rights of the common stock.

We will fix the rights, preferences, privileges, qualifications and restrictions of the preferred stock of each series that we sell under this prospectus and applicable prospectus supplements in the certificate of designation relating to that series. We will file as an exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of that related series of preferred stock. This description will include:


	•	the title and stated value;

	•	the number of shares we are offering;

	•	the liquidation preference per share;

	•	the purchase price;

	•	the dividend rate, period and payment date and method of calculation for dividends;


	•	whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;

	•	the procedures for any auction and remarketing, if any;

	•	the provisions for a sinking fund, if any;

	•	the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;

	•	any listing of the preferred stock on any securities exchange or market;

	•	whether the preferred stock will be convertible into our common stock, and, if applicable, the conversion price, or how it will be calculated, and the conversion period;

	•	whether the preferred stock will be exchangeable into debt securities, and, if applicable, the exchange price, or how it will be calculated, and the exchange period;

	•	voting rights, if any, of the preferred stock;

	•	preemptive rights, if any;

	•	restrictions on transfer, sale or other assignment, if any;

	•	whether interests in the preferred stock will be represented by depositary shares;

	•	a discussion of any material United States federal income tax considerations applicable to the preferred stock;

	•	the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;

	•	any limitations on the issuance of any class or series of preferred stock ranking senior to or on a parity with the series of preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and

	•	any other specific terms, preferences, rights or limitations of, or restrictions on, the preferred stock.

We urge you, however, to read the applicable prospectus supplement and any related free writing prospectus that we may authorize to be provided to you related to that series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

Anti-Takeover Effects of Provisions of Delaware Law and Our Charter Documents

Certain provisions of Delaware law and our amended and restated certificate of incorporation and amended and restated bylaws could make more difficult the acquisition of Brocade by means of a tender offer, a proxy contest, or otherwise, and the removal of incumbent officers and directors. These provisions are expected to discourage certain types of coercive takeover practices and inadequate takeover bids and to encourage persons seeking to acquire control of Brocade to first negotiate with us. We believe that the benefits of increased protection of Brocade’s potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure Brocade outweighs the disadvantages of discouraging such proposals, including proposals that are priced above the then current market value of our common stock, because, among other things, negotiation of such proposals could result in an improvement of their terms.

Delaware Takeover Statute. We are subject to section 203 of the Delaware General Corporation Law. This provision generally prohibits a Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years following the date such stockholder became an interested stockholder, unless:


	•	prior to such date the board of directors of the corporation approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder;


	•	upon consummation of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding for purposes of determining the number of shares outstanding those shares owned by persons who are directors and also officers and by employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or

	•	on or subsequent to such date, the business combination is approved by the board of directors and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least 662/3% of the outstanding voting stock that is not owned by the interested stockholder.

Section 203 defines business combination to include:


	•	any merger or consolidation involving the corporation and the interested stockholder;

	•	any sale, transfer, pledge or other disposition of 10% or more of the assets of the corporation involving the interested stockholder;

	•	subject to certain exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder;

	•	any transaction involving the corporation that has the effect of increasing the proportionate share of the stock of any class or series of the corporation beneficially owned by the interested stockholder; or the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided by or through the corporation.

In general, section 203 defines an interested stockholder as any entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person affiliated with or controlling or controlled by such entity or person.

Charter Documents. Our amended and restated certificate of incorporation and amended and restated bylaws provide for, among other things, the following:


	•	that our board of directors may issue up to 5,000,000 shares of preferred stock, with any rights, preferences and privileges as they may designate;

	•	that any action required or permitted to be taken by our stockholders must be effected at a duly called annual or special meeting of the stockholders and may not be effected by a consent in writing;

	•	a special meeting of our stockholders may be called only by the board of directors, certain of our officers or stockholders holding a majority of our outstanding voting securities;

	•	that our board of directors is divided into three classes, with each class serving staggered three-year terms; and

	•	that certain amendments of the amended and restated certificate of incorporation and of the amended and restated bylaws require the approval of holders of at least 662/3% of the voting power of all outstanding stock.

These and other provisions contained in our amended and restated certificate of incorporation and amended and restated bylaws could delay or discourage some types of transactions involving an actual or potential change in our control or change in our management, including transactions in which stockholders might otherwise receive a premium for their shares over then current prices, and may limit the ability of stockholders to remove current management or approve transactions that stockholders may deem to be in their best interests and, therefore, could adversely affect the price of our common stock.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Wells Fargo Bank Minnesota, N.A. Its address is Shareholder Services, 161 North Concord Exchange, South St. Paul, Minnesota 55075 and its telephone number is (800) - 468-9716.

DESCRIPTION OF DEBT SECURITIES

We may issue debt securities, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any future debt securities we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities we offer under a prospectus supplement may differ from the terms we describe below. Unless the context requires otherwise, whenever we refer to the “indentures,” we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

We will issue any senior debt securities under the senior indenture that we will enter into with the trustee named in the senior indenture. We will issue any subordinated debt securities under the subordinated indenture that we will enter into with the trustee named in the subordinated indenture. We have filed forms of these documents as exhibits to the registration statement, of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

The indentures will be qualified under the Trust Indenture Act of 1939, as amended, or the Trust Indenture Act. We use the term “trustee” to refer to either the trustee under the senior indenture or the trustee under the subordinated indenture, as applicable.

The following summaries of material provisions of the senior debt securities, the subordinated debt securities and the indentures are subject to, and qualified in their entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus, as well as the complete indentures that contains the terms of the debt securities. Except as we may otherwise indicate, the terms of the senior indenture and the subordinated indenture are identical.

General

We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:


	•	the title;

	•	the principal amount being offered, and if a series, the total amount authorized and the total amount outstanding;

	•	any limit on the amount that may be issued;

	•	whether or not we will issue the series of debt securities in global form, and, if so, the terms and who the depositary will be;

	•	the maturity date;

	•	whether and under what circumstances, if any, we will pay additional amounts on any debt securities held by a person who is not a United States person for tax purposes, and whether we can redeem the debt securities if we have to pay such additional amounts;

	•	the annual interest rate, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

	•	whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

	•	the terms of the subordination of any series of subordinated debt;

	•	the place where payments will be payable;

	•	restrictions on transfer, sale or other assignment, if any;


	•	our right, if any, to defer payment of interest and the maximum length of any such deferral period;

	•	the date, if any, after which, and the price at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;

	•	the date, if any, on which, and the price at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder’s option, to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

	•	whether the indenture will restrict our ability or the ability of our subsidiaries to:


	•	incur additional indebtedness;

	•	issue additional securities;

	•	create liens;

	•	pay dividends or make distributions in respect of our capital stock or the capital stock of our subsidiaries;

	•	redeem capital stock;

	•	place restrictions on our subsidiaries’ ability to pay dividends, make distributions or transfer assets;

	•	make investments or other restricted payments;

	•	sell or otherwise dispose of assets;

	•	enter into sale-leaseback transactions;

	•	engage in transactions with stockholders or affiliates;

	•	issue or sell stock of our subsidiaries; or

	•	effect a consolidation or merger;


	•	whether the indenture will require us to maintain any interest coverage, fixed charge, cash flow-based, asset-based or other financial ratios;

	•	a discussion of certain material or special United States federal income tax considerations applicable to the debt securities;

	•	information describing any book-entry features;

	•	provisions for a sinking fund purchase or other analogous fund, if any;

	•	the applicability of the provisions in the indenture on discharge;

	•	whether the debt securities are to be offered at a price such that they will be deemed to be offered at an “original issue discount” as defined in paragraph (a) of Section 1273 of the Internal Revenue Code of 1986, as amended;

	•	the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;

	•	he currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars; and

	•	any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, including any additional events of default or covenants provided with respect to the debt securities, and any terms that may be required by us or advisable under applicable laws or regulations.

Conversion or Exchange Rights

We will set forth in the applicable prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock, our preferred stock or other securities (including securities

of a third-party). We will include provisions as to whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock, our preferred stock or other securities (including securities of a third-party) that the holders of the series of debt securities receive would be subject to adjustment.

Consolidation, Merger or Sale

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indentures will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of all or substantially all of our assets. However, any successor to or acquirer of such assets must assume all of our obligations under the indentures or the debt securities, as appropriate. If the debt securities are convertible into or exchangeable for our other securities or securities of other entities, the person with whom we consolidate or merge or to whom we sell all of our property must make provisions for the conversion of the debt securities into securities that the holders of the debt securities would have received if they had converted the debt securities before the consolidation, merger or sale.

Events of Default under the Indenture

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indentures with respect to any series of debt securities that we may issue:


	•	if we fail to pay interest when due and payable and our failure continues for 30 days and the time for payment has not been extended;

	•	if we fail to pay the principal, premium or sinking fund payment, if any, when due and payable at maturity, upon redemption or repurchase or otherwise, and the time for payment has not been extended;

	•	if we fail to observe or perform any other covenant contained in the debt securities or the indentures, other than a covenant specifically relating to another series of debt securities, and our failure continues for 60 days after we receive notice from the trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series; and

	•	if specified events of bankruptcy, insolvency or reorganization occur.

We will describe in each applicable prospectus supplement any additional events of default relating to the relevant series of debt securities.

If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series, by notice to us in writing, and to the trustee if notice is given by such holders, may declare the unpaid principal, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the unpaid principal, premium, if any, and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the trustee or any holder.

The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.

Subject to the terms of the indentures, if an event of default under an indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the trustee reasonable indemnity or security satisfactory to it against any loss, liability or expense. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and

place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to the debt securities of that series, provided that:


	•	the direction so given by the holder is not in conflict with any law or the applicable indenture; and

	•	subject to its duties under the Trust Indenture Act, the trustee need not take any action that might involve it in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.

The indentures provide that if an event of default has occurred and is continuing, the trustee will be required in the exercise of its powers to use the degree of care that a prudent person would use in the conduct of its own affairs. The trustee, however, may refuse to follow any direction that conflicts with law or the indenture, or that the trustee determines is unduly prejudicial to the rights of any other holder of the relevant series of debt securities, or that would involve the trustee in personal liability. Prior to taking any action under the indentures, the trustee will be entitled to indemnification satisfactory to it against all costs, expenses and liabilities that would be incurred by taking or not taking such action.

A holder of the debt securities of any series will have the right to institute a proceeding under the indentures or to appoint a receiver or trustee, or to seek other remedies only if:


	•	the holder has given written notice to the trustee of a continuing event of default with respect to that series;

	•	the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made written request, and such holders have offered reasonable indemnity to the trustee or security satisfactory to it against any loss, liability or expense or to be incurred in compliance with instituting the proceeding as trustee; and

	•	the trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series other conflicting directions within 60 days after the notice, request and offer.

These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities, or other defaults that may be specified in the applicable prospectus supplement.

We will periodically file statements with the trustee regarding our compliance with specified covenants in the indentures.

The indentures provide that if a default occurs and is continuing and is actually known to a responsible officer of the trustee, the trustee must mail to each holder notice of the default within 90 days after it occurs, unless such default has been cured or waived. Except in the case of a default in the payment of principal or premium of or interest on any debt security or certain other defaults specified in an indenture, the trustee shall be protected in withholding such notice if and so long as the board of directors, the executive committee or a trust committee of directors, or responsible officers of the trustee, in good faith determine that withholding notice is in the best interests of holders of the relevant series of debt securities.

Modification of Indenture; Waiver

Subject to the terms of the indenture for any series of debt securities that we may issue, we and the trustee may change an indenture without the consent of any holders with respect to the following specific matters:


	•	to fix any ambiguity, defect or inconsistency in the indenture;

	•	to comply with the provisions described above under “Description of Debt Securities — Consolidation, Merger or Sale”;

	•	to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust Indenture Act;

	•	to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms, or purposes of issue, authentication and delivery of debt securities, as set forth in the indenture;


	•	to provide for the issuance of and establish the form and terms and conditions of the debt securities of any series as provided under “Description of Debt Securities — General,” to establish the form of any certifications required to be furnished pursuant to the terms of the indenture or any series of debt securities, or to add to the rights of the holders of any series of debt securities;

	•	to evidence and provide for the acceptance of appointment hereunder by a successor trustee;

	•	to provide for uncertificated debt securities and to make all appropriate changes for such purpose;

	•	to add to our covenants such new covenants, restrictions, conditions or provisions for the benefit of the holders, to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default or to surrender any right or power conferred to us in the indenture; or

	•	to change anything that does not adversely affect the interests of any holder of debt securities of any series in any material respect.

In addition, under the indentures, the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, subject to the terms of the indenture for any series of debt securities that we may issue or otherwise provided in the prospectus supplement applicable to a particular series of debt securities, we and the trustee may only make the following changes with the consent of each holder of any outstanding debt securities affected:


	•	extending the stated maturity of the series of debt securities;

	•	reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any premium payable upon the redemption or repurchase of any debt securities; or

	•	reducing the percentage of debt securities, the holders of which are required to consent to any amendment, supplement, modification or waiver.

Discharge

Each indenture provides that, subject to the terms of the indenture and any limitation otherwise provided in the prospectus supplement applicable to a particular series of debt securities, we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:


	•	register the transfer or exchange of debt securities of the series;

	•	replace stolen, lost or mutilated debt securities of the series;

	•	maintain paying agencies;

	•	hold monies for payment in trust;

	•	recover excess money held by the trustee;

	•	compensate and indemnify the trustee; and

	•	appoint any successor trustee.

In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, any premium and interest on, the debt securities of the series on the dates payments are due.

Form, Exchange and Transfer

We will issue the debt securities of each series only in fully registered form without coupons and, unless we otherwise specify in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indentures provide that we may issue debt securities of a series in temporary or permanent global form

and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company or another depositary named by us and identified in a prospectus supplement with respect to that series. See “Legal Ownership of Securities” below for a further description of the terms relating to any book-entry securities.

At the option of the holder, subject to the terms of the indentures and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subject to the terms of the indentures and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will make no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

If we elect to redeem the debt securities of any series, we will not be required to:


	•	issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or

	•	register the transfer of or exchange any debt securities so selected for redemption, in whole or in part, except the unredeemed portion of any debt securities we are redeeming in part.

Information Concerning the Trustee

The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs.

Subject to this provision, the trustee is under no obligation to exercise any of the powers given it by the indentures at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

Payment and Paying Agents

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

Governing Law

The indentures and the debt securities will be governed by and construed in accordance with the laws of the State of New York, except to the extent that the Trust Indenture Act is applicable.

Ranking Debt Securities

The subordinated debt securities will be unsecured and will be subordinate and junior in priority of payment to certain of our other indebtedness to the extent described in a prospectus supplement. The subordinated indenture does not limit the amount of subordinated debt securities that we may issue. It also does not limit us from issuing any other secured or unsecured debt.

The senior debt securities will be unsecured and will rank equally in right of payment to all our other senior unsecured debt. The senior indenture does not limit the amount of senior debt securities that we may issue. It also does not limit us from issuing any other secured or unsecured debt.

Existing Subordinated Debt

On January 29, 2007, effective upon the consummation of our merger with McDATA Corporation, Inc., or McDATA, we fully and unconditionally guaranteed and became a co-obligor on its outstanding 2.25% convertible subordinated debt. The convertible subordinated notes were convertible into Class A common stock at a conversion rate of 93.3986 shares per $1,000 principal amount of notes (aggregate of approximately 16.1 million shares) at any time prior to February 15, 2010, subject to adjustments. Pursuant to the merger agreement, at the effective time of the merger each outstanding share of McDATA’s Class A common stock, $0.01 par value per share, was converted into the right to receive 0.75 shares of Brocade’s common stock, $0.001 par value per share, together with cash in lieu of fractional shares. As a result, an approximate aggregate of 12.1 million shares are subject to conversion at any time prior to February 15, 2010, subject to adjustments.

As of July 26, 2008, the approximate aggregate fair value of the outstanding convertible notes was $163.9 million.

DESCRIPTION OF WARRANTS

We may issue warrants for the purchase of common stock, preferred stock and/or debt securities in one or more series. We may issue warrants independently or together with common stock, preferred stock and/or debt securities, and the warrants may be attached to or separate from these securities. While the terms summarized below will apply generally to any warrants that we may offer, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. The terms of any warrants offered under a prospectus supplement may differ from the terms described below.

We have filed forms of the warrant agreements and forms of the warrant certificates containing the terms of the warrants being offered as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant agreement, including a form of warrant certificate, that describes the terms of the particular warrants we are offering before the issuance of the related warrants. The following summaries of material provisions of the warrants and the warrant agreements are subject to, and qualified in their entirety by reference to, all the provisions of the warrant agreement and warrant certificate applicable to the warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplements related to the warrants that we may offer under this prospectus, and the complete warrant agreements and warrant certificates that contain the terms of the warrants.

General

We will describe in the applicable prospectus supplement the terms of the series of the warrants being offered, including:


	•	the offering price and aggregate number of warrants offered;

	•	the currency for which the warrants may be purchased;

	•	if applicable, the number of warrants issued with each share of common stock;

	•	if applicable, the date on and after which the warrants and the related common stock will be separately transferable;

	•	in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at, and currency in which, this principal amount of debt securities may be purchased upon such exercise;

	•	in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or preferred stock, as the case may be, purchasable upon the exercise of one warrant and the price at which these shares may be purchased upon such exercise;

	•	the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreements and the warrants;

	•	the terms of any rights to redeem or call the warrants;

	•	any provisions for changes to or adjustments in the exercise price or number of shares of common stock issuable upon exercise of the warrants;

	•	the dates on which the right to exercise the warrants will commence and expire;

	•	the manner in which the warrant agreements and warrants may be modified;

	•	a discussion of any material or special United States federal income tax consequences of holding or exercising the warrants; and

	•	any other specific terms, preferences, rights or limitations of, or restrictions on, the warrants.

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:


	•	in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium, if any, or interest on, the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture; or

	•	in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any.

Exercise of Warrants

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. Holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

Holders of the warrants may exercise the warrants by delivering the warrant certificate representing the warrants to be exercised together with specified information, and paying the required amount to the warrant agent in immediately available funds, as provided in the applicable prospectus supplement. We will set forth on the reverse side of the warrant certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver to the warrant agent.

Upon receipt of the required payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, we will issue and deliver the securities purchasable upon such exercise. If fewer than all of the warrants represented by the warrant certificate are exercised, then we will issue a new warrant certificate for the remaining amount of warrants. If we so indicate in the applicable prospectus supplement, holders of the warrants may surrender securities as all or part of the exercise price for warrants.

Governing Law

Unless we provide otherwise in the applicable prospectus supplement, the warrants and warrant agreements will be governed by and construed in accordance with the laws of the State of New York.

Enforceability of Rights by Holders of Warrants

Each warrant agent will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

DESCRIPTION OF UNITS

We may issue, in one more series, units consisting of common stock, preferred stock, debt securities and/or warrants for the purchase of common stock, preferred stock and/or debt securities in any combination. While the terms we have summarized below will apply generally to any units that we may offer under this prospectus, we will describe the particular terms of any series of units in more detail in the applicable prospectus supplement. The terms of any units offered under a prospectus supplement may differ from the terms described below.

We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of unit agreement that describes the terms of the series of units we are offering, and any supplemental agreements, before the issuance of the related series of units. The following summaries of material terms and provisions of the units are subject to, and qualified in their entirety by reference to, all the provisions of the unit agreement and any supplemental agreements applicable to a particular series of units. We urge you to read the applicable prospectus supplements related to the particular series of units that we may offer under this prospectus, as well as any related free writing prospectuses and the complete unit agreement and any supplemental agreements that contain the terms of the units.

General

Each unit will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date.

We will describe in the applicable prospectus supplement the terms of the series of units, including:


	•	the designation and terms of the units, including whether and under what circumstances the securities comprising the units may be held or transferred separately;

	•	any provisions of the governing unit agreement that differ from those described below; and

	•	any provisions for the issuance, payment, settlement, transfer or exchange of the units or of the securities comprising the units.

The provisions described in this section, as well as those described under “Description of Capital Stock,” “Description of Debt Securities” and “Description of Warrants,” will apply to each unit and to any common stock, preferred stock, debt securities or warrant included in each unit, respectively.

Issuance in Series

We may issue units in such amounts and in such numerous distinct series as we determine.

Enforceability of Rights by Holders of Units

Each unit agent will act solely as our agent under the applicable unit agreement and will not assume any obligation or relationship of agency or trust with any holder of any unit. A single bank or trust company may act as unit agent for more than one series of units. A unit agent will have no duty or responsibility in case of any default by us under the applicable unit agreement or unit, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a unit may, without the consent of the related unit agent or the holder of any other unit, enforce by appropriate legal action its rights as holder under any security included in the unit.

Title

We, and any unit agent and any of their agents may treat the registered holder of any unit certificate as an absolute owner of the units evidenced by that certificate for any purpose and as the person entitled to exercise the rights attaching to the units so requested, despite any notice to the contrary. See “Legal Ownership of Securities” below.

LEGAL OWNERSHIP OF SECURITIES

We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee or warrant agent maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities.

As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

Book-Entry Holders

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Securities issued in global form will be registered in the name of the depositary or its participants. Consequently, for securities issued in global form, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a book-entry security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s

book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not legal holders, of the securities.

Street Name Holders

We may terminate a global security or issue securities in non-global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not legal holders, of those securities.

Legal Holders

Our obligations, as well as the obligations of any applicable trustee and of any third parties employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice even if that holder is required, under agreements with depositary participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of the indenture or for other purposes. In such an event, we would seek approval only from the legal holders, and not the indirect holders, of the securities. Whether and how the holders contact the indirect holders is up to the legal holders.

Special Considerations for Indirect Holders

If you hold securities through a bank, broker or other financial institution, either in book-entry form or in street name, you should check with your own institution to find out:


	•	how it handles securities payments and notices;

	•	whether it imposes fees or charges;

	•	how it would handle a request for the holders’ consent, if ever required;

	•	whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if that is permitted in the future;

	•	how it would exercise rights under the securities if there were a default or other event triggering the need for holders to act to protect their interests; and

	•	if the securities are in book-entry form, how the depositary’s rules and procedures will affect these matters.

Global Securities

A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for

this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, The Depository Trust Company, or DTC, will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below under “Special Situations When a Global Security Will Be Terminated.” As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and legal holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a legal holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued in global form only, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

Special Considerations for Global Securities

The rights of an indirect holder relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a legal holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only in the form of a global security, an investor should be aware of the following:


	•	an investor cannot cause the securities to be registered in his or her name and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;

	•	an investor will be an indirect holder and must look to his or her own bank or broker for payments on the securities and protection of his or her legal rights relating to the securities, as we describe above;

	•	an investor may not be able to sell interests in the securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;

	•	an investor may not be able to pledge his or her interest in a global security in circumstances where certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

	•	the depositary’s policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to an investor’s interest in a global security;

	•	we and any applicable trustee have no responsibility for any aspect of the depositary’s actions or for its records of ownership interests in a global security;

	•	we and the trustee also do not supervise the depositary in any way;

	•	the depositary may, and we understand that DTC will, require that those who purchase and sell interests in a global security within its book-entry system use immediately available funds, and your broker or bank may require you to do so as well; and

	•	financial institutions that participate in the depositary’s book-entry system, and through which an investor holds its interest in a global security, may also have their own policies affecting payments, notices and other matters relating to the securities.

There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

Special Situations when a Global Security Will Be Terminated

In a few special situations described below, the global security will terminate, and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own name, so that they will be direct holders. We have described the rights of holders and street name investors above.

The global security will terminate when the following special situations occur:


	•	if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for that global security and we do not appoint another institution to act as depositary within 90 days; or

	•	if an event of default has occurred with regard to securities represented by that global security and has not been cured or waived.

The prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the applicable prospectus supplement. When a global security terminates, the depositary, and not we or any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

PLAN OF DISTRIBUTION

We may sell the securities from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through underwriters or dealers, through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:


	•	at a fixed price or prices, which may be changed;

	•	at market prices prevailing at the time of sale;

	•	at prices related to such prevailing market prices; or

	•	at negotiated prices.

A prospectus supplement or supplements will describe the terms of the offering of the securities, including, to the extent applicable:


	•	the name or names of any underwriters;

	•	the purchase price of the securities and the proceeds we will receive from the sale;

	•	any over-allotment options under which underwriters may purchase additional securities from us;

	•	any agency fees or underwriting discounts and other items constituting agents’ or underwriters’ compensation;

	•	any public offering price;

	•	any discounts or concessions allowed or reallowed or paid to dealers; and

	•	any securities exchange or market on which the securities may be listed.

Only underwriters named in the prospectus supplement will be underwriters of the securities offered by the prospectus supplement.

If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to

certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement, other than securities covered by any over-allotment option. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, the nature of any such relationship.

We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will describe any commissions we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for the period of its appointment.

We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

We may provide agents and underwriters with indemnification against civil liabilities, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may make with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.

All securities we offer, other than common stock, will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.

Any underwriter may engage in over-allotment, stabilizing transactions, short covering transactions and penalty bids in accordance with Regulation M under the Exchange Act. Over-allotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time.

Any underwriters that are qualified market makers on the NASDAQ Global Select Market may engage in passive market making transactions in the common stock on the NASDAQ Global Select Market in accordance with Rule 103 of Regulation M under the Exchange Act, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the common stock. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

In compliance with guidelines of the Financial Industry Regulatory Authority, or FINRA, the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate amount of the securities offered pursuant to this prospectus and any applicable prospectus supplement.

LEGAL MATTERS

The validity of the securities being offered by this prospectus will be passed upon by Cooley Godward Kronish LLP, Palo Alto, California.

EXPERTS

The consolidated financial statements of Brocade Communications Systems, Inc. and subsidiaries as of October 27, 2007 and October 28, 2006 and for each of the years in the three-year period ended October 27, 2007, and related financial statement schedule, are incorporated by reference herein in reliance on the report of KPMG LLP, independent registered public accounting firm, also incorporated by reference herein, and upon the authority of said firm as experts in auditing and accounting.

The consolidated financial statements of Foundry Networks, Inc. appearing in Foundry Networks, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2007 have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their reports thereon, included therein, and incorporated herein by reference. Such consolidated financial statements are incorporated herein by reference in reliance upon such reports given on the authority of such firm as experts in accounting and auditing.

MATERIAL CHANGES

As disclosed in our Current Report on Form 8-K filed July 24, 2008, incorporated by reference herein, on July 21, 2008 we entered into an agreement and plan of merger with Foundry Networks, Inc., a Delaware corporation, and Falcon Acquisition Sub, Inc., a Delaware corporation and our wholly-owned subsidiary, pursuant to which, on the terms and subject to the conditions set forth in the merger agreement, Falcon Acquisition Sub will be merged with and into Foundry Networks, Inc., with Foundry Networks, Inc. surviving the merger as our wholly-owned subsidiary. As required by Rule 3-05 and Article 11 of Regulation S-X, the financial information for Foundry Networks, Inc. for the years ended December 31, 2007, 2006 and 2005, for the three months ended March 31, 2008 and 2007, for the six months ended June 30, 2008 and 2007, and the pro forma financial information related to the proposed merger, which have been filed as Exhibits 99.1, 99.2, 99.3 and 99.4, respectively, to the registration statement of which this prospectus is a part, are incorporated by reference herein. See the section of this prospectus titled “Incorporation by Reference” for further information.

WHERE YOU CAN FIND MORE INFORMATION

This prospectus is part of a registration statement we filed with the SEC. You should rely only on the information contained in this prospectus or incorporated by reference. We have not authorized anyone else to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus is accurate as of any date other than the date on the front page of this prospectus, regardless of the time of delivery of this prospectus or any sale of common stock.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy any document filed by us with the Securities and Exchange Commission at the Securities and Exchange Commission’s Public Reference Room at 100 F Street NE, Washington, D.C. 20549. You may obtain information on the operation of the Public Reference Room by calling the Securities and Exchange Commission at 1-800-SEC-0330. The Securities and Exchange Commission maintains a website that contains reports, proxy statements and other information regarding issuers that file electronically with the Securities and Exchange Commission, including Brocade Communications Systems, Inc. We maintain a website at www.brocade.com. Information contained in or accessible through our website does not constitute a part of this prospectus.

INCORPORATION BY REFERENCE

The SEC allows us to “incorporate by reference” information into this prospectus, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is an important part of this prospectus. Information in this prospectus supersedes information incorporated by reference that we filed with the SEC prior to the date of this prospectus,

while information that we file later with the SEC will automatically update and supersede the information in this prospectus.

The following documents are incorporated by reference into this document:


	•	our Annual Report on Form 10-K for the fiscal year ended October 27, 2007 and filed with the SEC on December 21, 2007;

	•	the information specifically incorporated by reference into our Annual Report on Form 10-K for the fiscal year ended October 27, 2007 from our definitive proxy statement on Schedule 14A for our 2008 Annual Meeting of Stockholders filed with the SEC on March 27, 2008;

	•	our Quarterly Report on Form 10-Q for the quarter ended January 26, 2008 filed with the SEC on February 29, 2008;

	•	our Quarterly Report on Form 10-Q for the quarter ended April 26, 2008 filed with the SEC on June 4, 2008;

	•	our Quarterly Report on Form 10-Q for the quarter ended July 26, 2008 filed with the SEC on August 22, 2008;

	•	our Current Reports on Form 8-K filed on February 22, 2008, April 15, 2008, May 23, 2008, May 27, 2008, June 2, 2008, July 24, 2008 and August 14, 2008;

	•	the description of Brocade’s common stock contained in its Registration Statement on Form 8-A as filed on March 19, 1999 pursuant to Section 12(g) of the Exchange Act, including any amendment or report filed for the purpose of updating such descriptions;

	•	the audited consolidated balance sheets of Foundry Networks, Inc. as of December 31, 2007 and 2006, the related consolidated statements of income, stockholders’ equity, and cash flows for each of the three years in the period ended December 31, 2007 including the notes thereto, which have been filed as Exhibit 99.1 to the registration statement of which this prospectus is a part;

	•	the unaudited condensed consolidated financial statements of Foundry Networks, Inc. and its subsidiaries as of March 31, 2008 and for the three months ended March 31, 2008 and 2007 including the notes thereto, which have been filed as Exhibit 99.2 to the registration statement of which this prospectus is a part;

	•	the unaudited condensed consolidated financial statements of Foundry Networks, Inc. and its subsidiaries as of June 30, 2008 and for the three and six months ended June 30, 2008 and 2007 including the notes thereto, which have been filed as Exhibit 99.3 to the registration statement of which this prospectus is a part; and

	•	the unaudited pro forma condensed combined financial statements of Brocade Communications Systems, Inc. and Foundry Networks, Inc., which have been filed as Exhibit 99.4 to the registration statement of which this prospectus is a part.

We also incorporate by reference into this prospectus all documents (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items) that are filed by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (i) after the date of the initial registration statement and prior to effectiveness of the registration statement, or (ii) from the date of this prospectus but prior to the termination of the offering . These documents include periodic reports, such as Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as proxy statements.

We will provide to each person, including any beneficial owner, to whom a prospectus is delivered, without charge upon written or oral request, a copy of any or all of the documents that are incorporated by reference into this prospectus but not delivered with the prospectus, including exhibits which are specifically incorporated by reference into such documents. You should direct any requests for any of the foregoing documents to:

Investor Relations

Brocade Communications Systems, Inc.

1745 Technology Drive

San Jose, California 95110

(408) 333-6758

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS


Item 14.	*Other Expenses of Issuance and Distribution.*

The following table sets forth the best estimate of the Registrant as to its anticipated fees and expenses (other than underwriting discounts and commissions) expected to be incurred in connection with a distribution of securities registered hereby. All amounts shown are estimates except for the SEC registration fee.


SEC registration fee	$	29,475
NASDAQ Global Select Market fee		42,500
FINRA filing fee		75,500
Legal fees and expenses		100,000
Accounting fees and expenses		245,000
Trustee fees and expenses		20,000
Transfer Agent fees and expenses		5,000
Printing and miscellaneous		25,000

Total	$	542,475


Item 15.	*Indemnification of Officers and Directors.*

Section 145(a) of the Delaware General Corporation Law (the “DGCL”) provides in relevant part that “[a] corporation shall have power to indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of the corporation) by reason of the fact that the person is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by the person in connection with such action, suit or proceeding if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had no reasonable cause to believe the person’s conduct was unlawful.” With respect to derivative actions, Section 145(b) of the DGCL provides in relevant part that “[a] corporation shall have power to indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action or suit by or in the right of the corporation to procure a judgment in its favor...[by reason of the person’s service in one of the capacities specified in the preceding sentence] against expenses (including attorneys’ fees) actually and reasonably incurred by the person in connection with the defense or settlement of such action or suit if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation and except that no indemnification shall be made in respect of any claim, issue or matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the Court of Chancery or the court in which such action or suit was brought shall determine upon application that, despite the adjudication of liability but in view of all the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses which the Court of Chancery or such other court shall deem proper.”

The Registrant’s amended and restated certificate of incorporation provides that to the fullest extent permitted by the DGCL, no director of the Registrant shall be personally liable to the Registrant or its stockholders for monetary damages for breach of fiduciary duty as a director. The amended and restated certificate of incorporation also provides that no amendment or repeal of such provision shall apply to or have any effect on the right to indemnification permitted thereunder with respect to claims arising from acts or omissions occurring in whole or in part before the effective date of such amendment or repeal whether asserted before or after such amendment or repeal.

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The Registrant’s amended and restated bylaws provide for the indemnification of officers, directors and third parties acting on behalf of the Registrant if such person acted in good faith and in a manner reasonably believed to be in and not opposed to the best interest of the Registrant, and, with respect to any criminal action or proceeding, the indemnified party had no reason to believe his or her conduct was unlawful. The Registrant has entered into indemnification agreements with its directors and executive officers and intends to enter into indemnification agreements with any new directors and executive officers in the future.

The Registrant carries officer and director liability insurance with respect to certain matters, including matters arising under the Securities Act.


Item 16.	*Exhibits and Financial Statement Schedules.*


Exhibit
Number			Description of Document

	1	.1	Form of Underwriting Agreement(1)
	2	.1	Agreement and Plan of Merger, dated as of July 21, 2008, among the Registrant, Foundry Systems, Inc., and Falcon Acquisition Sub, Inc., a wholly-owned subsidiary of the Registrant(2)
	3	.1	Amended and Restated Certificate of Incorporation of Registrant(3)
	3	.2	Amended and Restated Bylaws of Registrant(4)
	4	.1	Reference is made to Exhibits 3.1 and 3.2
	4	.2	Form of Registrant’s Common Stock Certificate(5)
	4	.3	Specimen Preferred Stock Certificate and Form of Certificate of Designation of Preferred Stock(1)
	4	.4	First Supplemental Indenture dated as of January 29, 2007 by and among McDATA Corporation, the Registrant, and Wells Fargo Bank, National Association, as successor in interest to Wells Fargo Bank Minnesota, National Association(6)
	4	.5	Second Supplemental Indenture dated as of January 29, 2007 by and among McDATA Corporation, McDATA Services Corporation, a Minnesota corporation f/k/a Computer Network Technology Corporation, the Registrant, and U.S. Bank National Association(7)
	4	.6	Indenture dated February 7, 2003 by and among McDATA Corporation and Wells Fargo Bank Minnesota National Association(8)
	4	.7	Form of Senior Indenture, between Registrant and one or more trustees to be named.
	4	.8	Form of Subordinated Indenture, between Registrant and one or more trustees to be named.
	4	.9	Form of Senior Note(1)
	4	.10	Form of Subordinated Note(1)
	4	.11	Form of Common Stock Warrant Agreement and Warrant Certificate
	4	.12	Form of Preferred Stock Warrant Agreement and Warrant Certificate
	4	.13	Form of Debt Securities Warrant Agreement and Warrant Certificate
	4	.14	Form of Unit Agreement(1)
	5	.1	Legal Opinion of Cooley Godward Kronish LLP
	12	.1	Statement of Computation of Ratio of Earnings to Fixed Charges
	23	.1	Consent of Independent Registered Public Accounting Firm (KPMG LLP)
	23	.2	Consent of Independent Registered Public Accounting Firm (Ernst & Young LLP)
	23	.3	Consent of Cooley Godward Kronish LLP (included in Exhibit 5.1 hereto)
	24	.1	Power of Attorney (included on the signature page and incorporated by reference)
	25	.1	Statement of Eligibility of Trustee under the Senior Indenture(1)
	25	.2	Statement of Eligibility of Trustee under the Subordinated Indenture(1)
	99	.1	Audited Consolidated Financial Statements of Foundry Networks, Inc. for the year ended December 31, 2007.
	99	.2	Unaudited Condensed Consolidated Financial Statements of Foundry Networks, Inc. for the three months ended March 31, 2008.

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Exhibit
Number			Description of Document

	99	.3	Unaudited Condensed Consolidated Financial Statements of Foundry Networks, Inc. for the six months ended June 30, 2008.
	99	.4	Unaudited Pro Forma Condensed Combined Financial Statements of Brocade Communications Systems, Inc. and Foundry Networks, Inc.


(1)		To be filed by amendment or as an exhibit to a Current Report of the Registrant on Form 8-K and incorporated herein by reference.

(2)		Incorporated by reference to Exhibit 2.1 from the Registrant’s Current Report on Form 8-K as filed on July 24, 2008.

(3)		Incorporated by reference to Exhibit 3.1 from the Registrant’s Quarterly Report on Form 10-Q for the fiscal quarter ended July 28, 2007.

(4)		Incorporated by reference to Exhibit 3.1 from the Registrant’s Current Report on Form 8-K as filed on February 22, 2008.

(5)		Incorporated by reference to Exhibit 4.1 from the Registrant’s Registration Statement on Form S-1 (No. 333-74711), as amended.

(6)		Incorporated by reference to Exhibit 4.2 from the Registrant’s Quarterly Report on Form 10-Q filed on June 7, 2007.

(7)		Incorporated by reference to Exhibit 4.3 from the Registrant’s Quarterly Report on Form 10-Q filed on June 7, 2007.

(8)		Incorporated by reference to Exhibit 4.4 from Registrant’s Quarterly Report on Form 10-Q filed on June 7, 2007.


Item 17.	*Undertakings.*

The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided, however, that paragraphs (a)(1)(i), (a)(1)(ii) and (a)(1)(iii) above do not apply if the registration statement is on Form S-3 or Form F-3 and the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

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(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(4) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

(i) If the Registrant is relying on Rule 430B:

(a) Each prospectus filed by the Registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(b) Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii), or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.

(5) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

(iv) Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

(6) That, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be

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deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(7) The undersigned registrant hereby undertakes to deliver or cause to be delivered with the prospectus, to each person to whom the prospectus is sent or given, the latest annual report to security holders that is incorporated by reference in the prospectus and furnished pursuant to and meeting the requirements of Rule 14a-3 or Rule 14c-3 under the Securities Exchange Act of 1934; and, where interim financial information required to be presented by Article 3 of Regulation S-X are not set forth in the prospectus, to deliver, or cause to be delivered to each person to whom the prospectus is sent or given, the latest quarterly report that is specifically incorporated by reference in the prospectus to provide such interim financial information.

(8) That, for purposes of determining any liability under the Securities Act of 1933, the information omitted from the form of prospectus filed as part of this registration statement in reliance upon Rule 430A and contained in a form of prospectus filed by the registrant pursuant to Rule 424(b) (1) or (4) or 497(h) under the Securities Act shall be deemed to be part of this registration statement as of the time it was declared effective.

(9) That, for the purpose of determining any liability under the Securities Act of 1933, each post-effective amendment that contains a form of prospectus shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof

(10) To file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act in accordance with the rules and regulations prescribed by the Commission under Section 305(b)(2) of the Act.

Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue.

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SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of San Jose, State of California, on August 26, 2008.

BROCADE COMMUNICATIONS SYSTEMS, INC.


	By:	/s/ Michael Klayko

Michael Klayko

Chief Executive Officer

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Michael Klayko, Richard Deranleau and Tyler Wall, and each of them acting individually, as his true and lawful attorneys-in-fact and agents, each with the full power of substitution and resubstitution, for him and his name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this Registration Statement, and to sign any registration statement for the same offering covered by this Registration Statement that are to be effective upon filing pursuant to Rule 462(b) promulgated under the Securities Act, and all post-effective amendments thereto, and to file the same, with all exhibits thereto and all documents in connection therewith, with the SEC, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that such attorneys-in-fact and agents or any of them, or his or their substitute or substitutes, may lawfully do or cause to be done by virtue hereof. This power of attorney may be executed in counterparts.

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons on behalf of the registrant and in the capacities and on the dates indicated.


Signature	Title	Date


/s/ Michael Klayko Michael Klayko	Chief Executive Officer (Principal Executive Officer and Director)	August 26, 2008

/s/ Richard Deranleau Richard Deranleau	Chief Financial Officer and Vice President, Finance (Principal Financial and Accounting Officer)	August 26, 2008

/s/ David L. House David L. House	Chairman of the Board of Directors	August 26, 2008

/s/ L. William Krause L. William Krause	Director	August 26, 2008

/s/ Glenn Jones Glenn Jones	Director	August 26, 2008

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INDEX TO EXHIBITS


Exhibit
Number			Description of Document

	1	.1	Form of Underwriting Agreement(1)
	2	.1	Agreement and Plan of Merger, dated as of July 21, 2008, among the Registrant, Foundry Systems, Inc., and Falcon Acquisition Sub, Inc., a wholly-owned subsidiary of the Registrant(2)
	3	.1	Amended and Restated Certificate of Incorporation of Registrant(3)
	3	.2	Amended and Restated Bylaws of Registrant(4)
	4	.1	Reference is made to Exhibits 3.1 and 3.2
	4	.2	Form of Registrant’s Common Stock Certificate(5)
	4	.3	Specimen Preferred Stock Certificate and Form of Certificate of Designation of Preferred Stock(1)
	4	.4	First Supplemental Indenture dated as of January 29, 2007 by and among McDATA Corporation, the Registrant, and Wells Fargo Bank, National Association, as successor in interest to Wells Fargo Bank Minnesota, National Association(6)
	4	.5	Second Supplemental Indenture dated as of January 29, 2007 by and among McDATA Corporation, McDATA Services Corporation, a Minnesota corporation f/k/a Computer Network Technology Corporation, the Registrant, and U.S. Bank National Association(7)
	4	.6	Indenture dated February 7, 2003 by and among McDATA Corporation and Wells Fargo Bank Minnesota National Association(8)
	4	.7	Form of Senior Indenture, between Registrant and one or more trustees to be named.
	4	.8	Form of Subordinated Indenture, between Registrant and one or more trustees to be named.
	4	.9	Form of Senior Note(1)
	4	.10	Form of Subordinated Note(1)
	4	.11	Form of Common Stock Warrant Agreement and Warrant Certificate
	4	.12	Form of Preferred Stock Warrant Agreement and Warrant Certificate
	4	.13	Form of Debt Securities Warrant Agreement and Warrant Certificate
	4	.14	Form of Unit Agreement(1)
	5	.1	Legal Opinion of Cooley Godward Kronish LLP
	12	.1	Statement of Computation of Ratio of Earnings to Fixed Charges
	23	.1	Consent of Independent Registered Public Accounting Firm (KPMG LLP)
	23	.2	Consent of Independent Registered Public Accounting Firm (Ernst & Young LLP)
	23	.3	Consent of Cooley Godward Kronish LLP (included in Exhibit 5.1 hereto)
	24	.1	Power of Attorney (included on the signature page and incorporated by reference)
	25	.1	Statement of Eligibility of Trustee under the Senior Indenture(1)
	25	.2	Statement of Eligibility of Trustee under the Subordinated Indenture(1)
	99	.1	Audited Consolidated Financial Statements of Foundry Networks, Inc. for the year ended December 31, 2007.
	99	.2	Unaudited Condensed Consolidated Financial Statements of Foundry Networks, Inc. for the three months ended March 31, 2008.
	99	.3	Unaudited Condensed Consolidated Financial Statements of Foundry Networks, Inc. for the six months ended June 30, 2008.
	99	.4	Unaudited Pro Forma Condensed Combined Financial Statements of Brocade Communications Systems, Inc. and Foundry Networks, Inc.


(1)		To be filed by amendment or as an exhibit to a Current Report of the Registrant on Form 8-K and incorporated herein by reference.

(2)		Incorporated by reference to Exhibit 2.1 from the Registrant’s Current Report on Form 8-K as filed on July 24, 2008.

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	Page

ABOUT THIS PROSPECTUS		2
OVERVIEW		2
RISK FACTORS		3
NOTE REGARDING FORWARD-LOOKING STATEMENTS		3
THE SECURITIES WE MAY OFFER		4
RATIO OF EARNINGS TO FIXED CHARGES		6
USE OF PROCEEDS		6
DESCRIPTION OF CAPITAL STOCK		7
DESCRIPTION OF DEBT SECURITIES		10
DESCRIPTION OF WARRANTS		16
DESCRIPTION OF UNITS		18
LEGAL OWNERSHIP OF SECURITIES		19
PLAN OF DISTRIBUTION		22
LEGAL MATTERS		24
EXPERTS		24
MATERIAL CHANGES		24
WHERE YOU CAN FIND MORE INFORMATION		24
INCORPORATION BY REFERENCE		24
EXHIBIT 4.7
EXHIBIT 4.8
EXHIBIT 4.11
EXHIBIT 4.12
EXHIBIT 4.13
EXHIBIT 5.1
EXHIBIT 12.1
EXHIBIT 23.1
EXHIBIT 23.2
EXHIBIT 99.1
EXHIBIT 99.2
EXHIBIT 99.3
EXHIBIT 99.4