Sonus Networks Leads Worldwide, North American And Asia Pacific Markets For Key Segments of IP Voice Market For 2006

Infonetics Research Names Sonus Market Share Leader in High Density and Total Gateway Markets

CHELMSFORD, Mass., December 6, 2006 - Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, announced today that Infonetics Research, a leading independent industry research firm, has named Sonus Networks the market share leader in several segments of the IP-based voice market for year-to-date 2006 in its “Service Provider Next Generation Voice and IMS Equipment Market Forecast." Sonus leads the high density gateway market worldwide with approximately 23% market share, as well as in North America with 37% and Asia Pacific with approximately 29% market share for the first nine months of 2006, according to the industry research firm.

"Market adoption for next generation voice solutions is on the rise worldwide, but the pace of adoption varies considerably from region to region," said Stéphane Téral, Principal Analyst, Service Provider Next Gen Voice VoIP, IMS, and FMC, with Infonetics Research. “Sonus' success in the market underscores the Company's ability to identify and address the unique market conditions that are driving decisions by network operators and its ability to deliver the products and services that help network operators around the world capitalize on the benefits of IP-based voice solutions."

In addition to leadership in the high density gateway market, Sonus Networks leads the total gateway market for 2006 in several regions. In North America, Sonus holds approximately 32% market share, and in Asia Pacific, the Company leads with approximately 21%, driven largely by the Company's success in Japan where Sonus is the dominant provider of next generation voice solutions.

“2006 has been a fantastic growth year for Sonus, extending our position in strategic geographic markets and partnering with some of the largest network operators around the world," said Hassan Ahmed, chairman and CEO, Sonus Networks. “We currently have major deployments underway in North America, Europe, and Asia Pacific, and are actively extending our reach into other major network operators, providing a strong foundation for continued growth in 2007."

For a copy of the Infonetics Research report, please contact Larry Howard at 408.583.3335 or larry@infonetics.com.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of voice over IP (VoIP) infrastructure solutions for wireline and wireless service providers. With its comprehensive IP Multimedia Subsystem (IMS) solution, Sonus addresses the full range of carrier applications, including residential and business voice services, wireless voice and multimedia, trunking and tandem switching, carrier interconnection and enhanced services. Sonus' voice infrastructure solutions are deployed in service provider networks worldwide. Founded in 1997, Sonus is headquartered in Chelmsford, Massachusetts. Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain forward-looking statements regarding future events that involve risks and uncertainties. Readers are cautioned that these forward-looking statements are only predictions and may differ materially from actual future events or results. Readers are referred to Item 1A “Risk Factors" of Sonus' Quarterly Report on Form 10-Q dated May 8, 2006, filed with the SEC, which identifies important risk factors that could cause actual results to differ from those contained in the forward-looking statements. Risk factors include among others: the impact of material weaknesses in our disclosure controls and procedures and our internal control over financial reporting on our ability to report our financial results timely and accurately; the unpredictability of our quarterly financial results; risks and uncertainties associated with the Company's announced review of its historical stock option grants and accounting, including any potential impact on the Company's financial statements or results, any tax liabilities or penalties, the Company's inability to timely report with the Securities and Exchange Commission, the Company's potential inability to meet NASDAQ requirements for continued listing, potential investigations, regulatory actions or litigation arising out of the review or any restatement; risks associated with our international expansion and growth; consolidation in the telecommunications industry; and potential costs resulting from pending securities litigation against the company. Any forward-looking statements represent Sonus' views only as of today and should not be relied upon as representing Sonus' views as of any subsequent date. While Sonus may elect to update forward-looking statements at some point, Sonus specifically disclaims any obligation to do so.

Sonus is a registered trademark of Sonus Networks, Inc. All other company and product names may be trademarks of the respective companies with which they are associated.