BRCD Brocade Communications Systems, Inc.

SUPPLEMENT TO PROXY STATEMENT

This Supplement to the Definitive Proxy Statement on Schedule 14A filed on December 20, 2016, which we refer to as the “ Definitive Proxy Statement ,” by Brocade Communications Systems, Inc., which we refer to as the “ Company ” or “ Brocade ,” is being filed to supplement the Definitive Proxy Statement as described in the Explanatory Note below.

EXPLANATORY NOTE

In connection with the Merger, five purported class action complaints have been filed on behalf of Company stockholders against the Company and its directors in the United States District Court for the Northern District of California. Two of the five complaints also named Ultimate Parent, Broadcom Corporation and Merger Sub as defendants. The five complaints are captioned as follows: Steinberg v. Brocade Communications Systems, Inc., et al. (filed December 12, 2016); Gross v. Brocade Communications Systems, Inc., et al. (filed December 15, 2016); Bragan v. Brocade Communications Systems, Inc., et al. (filed December 21, 2016); Jha v. Brocade Communications Systems, Inc., et al. (filed December 21, 2016); and Chuakay v. Brocade Communications Systems, Inc., et al. (filed January 5, 2017). We refer to these five actions collectively as the “ Stockholder Actions .”

The Company believes that no supplemental disclosures are required under applicable laws; however, to avoid the risk of the Stockholder Actions delaying or adversely affecting the Merger and to minimize the expense of defending the Stockholder Actions, and without admitting any liability or wrongdoing, the Company is making certain disclosures below that supplement and revise those contained in the Definitive Proxy Statement, which we refer to as the “ litigation-related supplemental disclosures .” The litigation-related supplemental disclosures contained below should be read in conjunction with the Definitive Proxy Statement, which is available on the Internet site maintained by the Securities and Exchange Commission at http://www.sec.gov, along with periodic reports and other information the Company files with the Securities and Exchange Commission. The Company and the other named defendants have denied, and continue to deny, that they have committed or assisted others in committing any violations of law or breaches of duty to Company stockholders, and expressly maintain that, to the extent applicable, they have complied with their fiduciary and other legal duties and are providing the litigation-related supplemental disclosures below solely to try to eliminate the burden and expense of further litigation, to put the claims that were or could have been asserted to rest, and to avoid any possible delay to the closing of the Merger that might arise from further litigation. Nothing in the litigation-related supplemental disclosures shall be deemed an admission of the legal necessity or materiality under applicable laws of any of the litigation-related supplemental disclosures. To the extent that the information set forth herein differs from or updates information contained in the Definitive Proxy Statement, the information set forth herein shall supersede or supplement the information in the Definitive Proxy Statement. References to sections and subsections herein are references to the corresponding sections or subsections in the Definitive Proxy Statement, all page references are to pages in the Definitive Proxy Statement, and terms used herein, unless otherwise defined, have the meanings set forth in the Definitive Proxy Statement.

Forward-Looking Statements

This Supplement to the Definitive Proxy Statement and the documents to which we refer you in this Supplement to the Definitive Proxy Statement, as well as information included in oral statements or other written statements made or to be made by us, contain statements that, in our opinion, may constitute “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Forward-looking statements may be typically identified by such words as “may,” “will,” “should,” “would,” “expect,” “anticipate,” “plan,” “likely,” “believe,” “estimate,” “project,” “intend,” “potential,” “predict,” “aim,” and other similar expressions, among others, which appear in a number of places in this Supplement to the Definitive Proxy Statement (and the documents to which we refer you in this Supplement to the Definitive Proxy Statement) and include, but are not limited to, all statements relating directly or indirectly to the timing or likelihood of consummating the Merger, plans for future growth and other business development activities as well as capital expenditures, financing sources and the effects of regulation and competition and all other statements regarding our intent, plans, beliefs or expectations or those of our directors or officers. These forward-looking statements reflect the current analysis of existing information and are subject to various risks and uncertainties. As a result, caution must be exercised in relying on forward-looking statements. Due to known and unknown risks, our actual results may differ materially from our expectations or projections.

The following factors, among others, could cause our actual results to differ materially from those described or implied in these forward-looking statements:

The foregoing review of important factors that could cause actual events to differ from expectations should not be construed as exhaustive and should be read in conjunction with statements that are included herein and elsewhere, including the risk factors included in the Company’s and Ultimate Parent’s respective most recent Annual Reports on Form 10-K and more recent other reports filed with the SEC. The Company and Ultimate Parent can give no assurance that the conditions to the Merger will be satisfied. Except as required by applicable law, neither the Company nor Ultimate Parent undertakes any obligation to revise or update any forward-looking statement, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise.

SUPPLEMENTAL DISCLOSURES TO DEFINITIVE PROXY STATEMENT RELATED TO STOCKHOLDER ACTIONS

The section of the Definitive Proxy Statement under the heading “The Merger — Opinion of Evercore Group L.L.C.” is hereby amended by:

Amending the second full paragraph on page 55 in the section titled “Sum of the Parts Analysis” as follows (with new text in underline):

For the Storage Networking component, Evercore performed a discounted cash flow analysis to estimate the implied enterprise value as of October 31, 2016, using (1) the unlevered, after-tax free cash flows that were projected to be generated by the Company from the Storage Networking component from the period from November 1, 2016 through October 31, 2021, plus (2) the portion of the estimated terminal value of the Company attributable to the Storage Networking component as of October 31, 2021 based on a perpetuity growth rate of -6.0% to -4.0%, reflecting the Company’s perspective on the prospects for the Storage Networking component. The total cash flows attributable to the Storage Networking component were then discounted to present value using an estimate range of discount rates from 8.5% to 11.0%. Evercore estimated the Storage Networking component’s weighted average cost of capital based on application of the capital asset pricing model and its professional judgment given the nature of the Storage Networking component. The resulting range of implied enterprise values for the Storage Networking component was approximately $2.8 billion to $3.6 billion.

Amending the third full paragraph on page 55 in the section titled “Sum of the Parts Analysis” as follows (with new text in underline):

For the SRA and Software Networking component, Evercore performed a discounted cash flow analysis to estimate the implied enterprise value as of October 31, 2016, using (1) the unlevered, after-tax free cash flows that were projected to be generated by the Company from the SRA and Software Networking component from the period from November 1, 2016 through October 31, 2026, plus (2) the portion of the estimated terminal value of the Company attributable to the SRA and Software Networking component as of October 31, 2026 based on an Adjusted EBITDA multiple of 10.0x to 12.0x. Evercore estimated the terminal value multiple based on the financial projections provided by the Company’s management, the trading multiples for the companies included in the selected publicly traded companies analysis, and its professional judgment given the nature of the SRA and Software Networking component. The total cash flows attributable to the SRA and Software Networking component were then discounted to present value using an estimate range of discount rates from 8.5% to 11.0%. Evercore estimated the SRA and Software Networking component’s weighted

average cost of capital based on application of the capital asset pricing model and its professional judgment given the nature of the SRA and Software Networking component. The resulting range of implied enterprise values for the SRA and Software Networking component was approximately $1.1 billion to $1.6 billion.

Amending the fourth full paragraph on page 55 in the section titled “Sum of the Parts Analysis” as follows (with new text in underline):

For the Campus component, Evercore assumed a multiple range of 1.0x to 1.5x management’s projection of the Company’s estimated fiscal year 2017 revenue from the Campus component . The multiple range was derived by analyzing the results from an analysis of the revenue multiples for the companies included in the selected publicly traded companies analysis and took into account qualitative judgments for the nature of the business. The resulting range of implied enterprise values for the Campus component was approximately $0.3 billion to $0.5 billion.

Amending the second sentence in the first full paragraph on page 57 in the section titled “Miscellaneous” as follows (with new text in underline):

Pursuant to the terms of its engagement letter, Evercore is entitled to receive (1) an opinion fee of $2 million, regardless of the conclusion reached therein, which was earned upon delivery of its fairness opinion and which is fully creditable, to the extent previously paid, against any transaction fee payable and (2) a transaction fee, comprised of a success fee currently estimated to equal $29.7  million and a discretionary component currently estimated to equal $5.9  million (the payment of which was approved by the Company Board at a meeting on November 1, 2016), currently estimated to total approximately $35.6 million, the entirety of which Evercore will earn subject to and upon the consummation of the Merger.

Inserting the following paragraph below the first full paragraph on page 57 in the section titled “Miscellaneous”:

For services rendered by it as the Company’s financial advisor in the acquisition by the Company of Ruckus, Evercore received, in total, $6.5 million as compensation. Other than compensation paid or payable to Evercore in connection with the acquisition of Ruckus and the proposed acquisition of the Company, for the period from October 2013 through October 2016, Evercore has received $1.4 million as compensation in connection with other engagements by the Company. Other than ongoing services in connection with the acquisitions of the Company and Ruckus, no future engagement is currently mutually understood to be contemplated between the Company and Evercore.

The section of the Definitive Proxy Statement under the heading “The Merger — Certain Company Forecasts” is hereby amended by:

Amending and restating footnote 9 on page 61 in the section titled “The September Management Case” as follows:

Inserting the following paragraph and table below the table and related footnotes that appear under the heading “The September Management Case” on page 60.

Within the September Management Case, projections and extrapolations derived therefrom were prepared for the four components of the Company’s business (its Storage Networking component; its SRA and Software Networking component; its Campus component; and its Ruckus component) on a stand-alone basis, and portions of such projections and extrapolations derived therefrom were used in the sum of the parts analysis (described in “The Merger — Opinion of Evercore Group L.L.C.” beginning on page 48). Such forecasts and extrapolations derived therefrom are set forth below. Unlevered free cash flow was not derived for the Company’s Campus and Ruckus components or for fiscal year 2016 for the Storage Networking and SRA and Software Networking components in the September Management Case.

Campus (1)

Ruckus (1)

Amending and restating footnote 8 on page 62 in the section titled “The October Management Case” as follows:

Inserting the following paragraph and table below the table and related footnotes that appear under the heading “The October Management Case” beginning on page 61.

Within the October Management Case, projections and extrapolations derived therefrom were prepared for the four components of the Company’s business (its Storage Networking component; its SRA and Software Networking component; its Campus component; and its Ruckus component) on a stand-alone basis, and portions of such projections and extrapolations derived therefrom were used in the sum of the parts analysis (described in “The Merger — Opinion of Evercore Group L.L.C.” beginning on page 48). Such forecasts and extrapolations derived therefrom are set forth below. Unlevered free cash flow was not derived for the Company’s Campus component or for fiscal year 2016 for the Storage Networking, SRA and Software Networking, and Campus components in the October Management Case.

Campus (1)

Amending and restating the section under the heading “The Management Case Forecasts” beginning on page 62 as follows:

The Company management believes non-GAAP financial measures provide useful information to investors by offering (1) the ability to make more meaningful period-to-period comparisons of the Company’s ongoing operating results, (2) the ability to make more meaningful comparisons of the Company’s operating performance relative to its competitors, (3) the ability to better identify trends in the Company’s underlying business and to perform related trend analyses and (4) a better understanding of how management plans and measures the Company’s underlying business. The Company has presented below a reconciliation of each non-GAAP financial measure utilized in the September Management Case and the October Management Case to the most comparable GAAP financial measure. These reconciliations constitute “forward-looking statements” as described above. The Company believes that such reconciliations are inherently unreliable. The inclusion of these reconciliations and the GAAP financial measures presented therein therefore should not be regarded as an indication that the Company management, the Company Board, its advisors or any other person considers such reconciliations or such GAAP financial measures to be a reliable prediction of actual future results, and should not be relied upon as such. The Company does not regularly forecast most of the reconciling items presented below, and the Company views providing such reconciliations as a purely speculative exercise as the actual amounts of most of the reconciling items presented are highly uncertain due to the combination of the variability and volatility of the amounts of such items incurred or recorded historically over time. Without limitation of the foregoing: (a) the actual acquisition and integration expense and the actual amortization expense associated with acquired intangibles to be incurred in future periods will be directly related to the nature and timing of future acquisitions by the Company, which is impossible to predict; (b) the actual restructuring charges to be recorded in future periods will be directly related to the nature and timing of future restructuring actions taken by the Company, which are similarly impossible to predict; (c) the actual impairment charges to be recorded in future periods will be directly related to the future fair values of assets subject to impairment testing, which cannot be forecasted accurately; and (d) the actual gains or losses relating to sales of assets will be directly related to the nature and timing of future sales of assets by the Company, which also cannot be forecasted accurately. For purposes of presenting the reconciliations below, the Company has assumed that no such acquisition and integration expenses, amortization expenses associated with acquired intangibles, restructuring charges, asset impairment charges or gains or losses relating to sales of assets will be incurred or recorded in any of the future periods presented. As a result, and particularly given the historical variability, volatility and magnitude of those items, actual results likely will differ, and may differ materially, from those implied by the reconciliations below. For purposes of the below reconciliations, amounts provided for fiscal year 2016 are based on the actual fiscal year 2016 results available to Company management at the time of the preparation of these reconciliations and therefore differ from the estimated amounts for fiscal year 2016 used at the time of the preparation of the forecasts.

A reconciliation of unlevered free cash flow to Non-GAAP EBITDA (for which the reconciliation to net income has been presented in the tables above) is set forth below.

Non-GAAP EBITDA to unlevered free cash flow reconciliation

A reconciliation of unlevered free cash flow to Non-GAAP EBITDA (for which the reconciliation to net income has been presented in the tables above) is set forth below.

Non-GAAP EBITDA to unlevered free cash flow reconciliation

SUBMISSION OF PROXIES

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If you have not yet voted your shares, EVEN IF YOU PLAN TO ATTEND THE SPECIAL MEETING, YOU ARE URGED TO EITHER SUBMIT A PROXY FOR YOUR SHARES ELECTRONICALLY ON THE INTERNET, BY TELEPHONE OR BY COMPLETING, SIGNING AND RETURNING THE PROXY CARD AS SOON AS POSSIBLE.