SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 ------------- FORM 8-A FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES PURSUANT TO SECTION 12(b) OR 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934 SONUS NETWORKS, INC. -------------------- (Exact Name of Registrant as Specified in its Charter) DELAWARE 04-3387074 - -------------------------------------------------------------------------------- (State of Incorporation or Organization) (I.R.S. Employer Identification no.) 5 Carlisle Road, Westford, Massachusetts 01886 - -------------------------------------------------------------------------------- (Address of principal executive offices) (zip code) If this form relates to the If this form relates to the registration of a class of securities registration of a class of securities pursuant to Section 12(b) of the pursuant to Section 12(g) of the Exchange Act and is effective Exchange Act and is effective pursuant to General Instruction pursuant to General Instruction A.(c), please check the following A.(d), please check the following box. / / box. /X/ Securities Act registration statement file number to which this form relates: 333-32206 Securities to be registered pursuant to Section 12(b) of the Act: Title of Each Class Name of Each Exchange on Which to be so Registered Each Class is to be Registered - ------------------- ------------------------------ None. Securities to be registered pursuant to Section 12(g) of the Act: Common Stock, $0.001 Par Value ------------------------------ (Title of Class)

-2- INFORMATION REQUIRED IN REGISTRATION STATEMENT ITEM 1. DESCRIPTION OF REGISTRANT'S SECURITIES TO BE REGISTERED The information required by Item 202 of Regulation S-K is included under the heading "Description of Capital Stock" in the Registrant's Registration Statement on Form S-1 (File No. 333-32206), filed with the Securities and Exchange Commission on March 10, 2000 (the "Registration Statement"), including any form of the prospectus contained therein filed by the Registrant pursuant to Rule 424(b) under the Securities Act of 1933, as amended, which is incorporated herein by reference. ITEM 2. EXHIBITS 1. The Fourth Amended and Restated Certificate of Incorporation of the Registrant is incorporated herein by reference to Exhibit 3.1 to the Registration Statement. 2. The Amended and Restated By-Laws of the Registrant are incorporated herein by reference to Exhibit 3.2 to the Registration Statement. 3. A specimen copy of the certificate representing shares of the Registrant's Common Stock is incorporated herein by reference to Exhibit 4.1 to the Registration Statement.

-3- SIGNATURE Pursuant to the requirements of Section 12 of the Securities Exchange Act of 1934, the registrant has duly caused this registration statement, as amended, to be signed on its behalf by the undersigned, thereto duly authorized. SONUS NETWORKS, INC. By: /s/ Hassan M. Ahmed ------------------------------------- Hassan M. Ahmed President and Chief Executive Officer Date: April 4, 2000