Exhibit 4.1

SUPPLEMENTAL INDENTURE

TO BE DELIVERED BY SUBSEQUENT GUARANTORS

This Supplemental Indenture (this “Supplemental Indenture”), dated as of May 27, 2016, among Foundry Networks, LLC, a Delaware limited liability company, Ruckus Wireless, Inc., a Delaware corporation, and Ruckus Wireless International, Inc., a Delaware corporation (each, a “Guaranteeing Subsidiary” and collectively, the “Guaranteeing Subsidiaries”), each a Subsidiary of Brocade Communications Systems, Inc., a Delaware corporation (the “Company”), and Wells Fargo Bank, National Association, as trustee (the “Trustee”).

W I T N E S S E T H

WHEREAS, each of the Company and the Guarantors (as defined in the Indenture referred to below) has heretofore executed and delivered to the Trustee an indenture (the “Indenture”), dated as of January 22, 2013, providing for the issuance of an unlimited aggregate principal amount of 4.625% Senior Notes due 2023 (the “Notes”);

WHEREAS, the Indenture provides that under certain circumstances the Guaranteeing Subsidiaries shall execute and deliver to the Trustee a supplemental indenture pursuant to which each Guaranteeing Subsidiary shall unconditionally guarantee all of the Company’s Obligations under the Notes and the Indenture on the terms and conditions set forth herein and under the Indenture;

WHEREAS, this Supplemental Indenture shall not result in a material modification of the Notes for purposes of compliance with the Foreign Accounts Tax Compliance Act; and

WHEREAS, pursuant to Section 9.01 of the Indenture, the Trustee is authorized to execute and deliver this Supplemental Indenture.

NOW THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the parties mutually covenant and agree for the equal and ratable benefit of the Holders as follows:

1. Capitalized Terms. Capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture.

2. Guarantor. Each Guaranteeing Subsidiary hereby agrees to be a Guarantor under the Indenture and to be bound by the terms of the Indenture applicable to Guarantors, including, but not limited to, Article 10 thereof.

3. Governing Law. THIS SUPPLEMENTAL INDENTURE WILL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

4. Counterparts. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of them together represent the same agreement.

5. Headings. The headings of the Sections of this Supplemental Indenture have been inserted for convenience of reference only, are not to be considered a part of this Supplemental Indenture and shall in no way modify or restrict any of the terms or provisions hereof.

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IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed, all as of the date first above written.