Synergy Research Reports Sonus Increased its Market Share Leadership Worldwide and in United States and Japan; Sonus Recognized as the Leader in IMS

WESTFORD, Mass., October 10, 2007 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider IP-voice infrastructure solutions, announced today that Synergy Research Group, a leading independent industry research firm, has named Sonus Networks the market share leader in key segments of the next generation voice solutions industry for the second quarter of 2007.

Sonus delivers a broad portfolio of IP-voice solutions with technologies that span from core networking and access solutions, to the Network Border Switch and advanced applications. Sonus' renowned solutions have been critical to the success of many innovative operators globally, which is reflected again in the second quarter results from Synergy Research. 

Worldwide, Sonus grew its market share leading position to 29.2% of the high density gateway market. This achievement was during a time when several operators delayed capital spending decisions. Sonus extended its leadership by capturing a higher percentage of the overall market and growing revenue over 18% in the first half of 2007 compared to the first half of 2006.  

In the United States, Sonus held number one positions in the total gateway and high density gateway markets with 28.1% and 36.7%, respectively. Sonus also continued to increase its position in Europe, Middle East and Africa (EMEA), a region that has been a growing focus for the Company. In Japan, Sonus led in three categories: Total IMS Infrastructure (27.9%), Total Media Gateway (41.2%) and High Density Media Gateway (53.6%).

"I'm proud to see that our recent focus on expanding our presence in Europe has had such a dramatic effect on our market share position. Q2 results are up nearly 50%, which is a dramatic step forward in a short period of time," said Hassan Ahmed, president, chairman and CEO, Sonus Networks.

"We have aligned our resources to transform the communications landscape on a global scale, and our success is demonstrated by our continued leadership across North America, EMEA, and Japan. As the industry now looks for practical migration paths to IMS, more network operators are relying on Sonus as a trusted partner with the technology expertise that will be critical for this transition."

"Sonus' growth in 2007 and the impact the Company has had on the world's voice market are reflected in the results of our Q2 report," said Jeremy Duke, president and CEO, Synergy Research Group. "Sonus is the consistent leader in the United States and Japan, and with its growing presence in EMEA, has proven its ability to execute on a global stage."

Sonus Networks has the world's most broadly deployed IMS-based solutions in the market, carrying nearly 3.5x the amount of IP voice traffic as any other vendor. The Company's award-winning IMS-based portfolio, renowned for the scalability and reliability network operators demand, has been deployed in more than 150 networks in more than 50 countries around the world. 

About Sonus Networks

Sonus Networks, Inc. is a leading provider of IP-voice 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 Westford, 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 for the period ended June 30, 2007, 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 restatement of its historical stock option granting practices and accounting including regulatory actions or litigation; 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.