Sonus Networks Leads 2007 IP Voice Market

Synergy Research Reports Sonus Increased its Market Share Leadership in Key Segments of IP Voice Market for Q4 and Full Year 2007

WESTFORD, Mass., March 04, 2008 – 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, reported that Sonus grew more than twice as fast as the industry average in key segments of the next generation voice solutions industry during Q4 2007 versus Q3, and increased its market share leadership position for 2007 as a whole.

In Q4 2007, Sonus ranked #1 in the global high density gateway market segment with 34.3% and 20.1% for the total global VoIP gateway segment. For the full year 2007, Sonus outpaced the market securing #1 market share in the global high density gateway segment with 32%. In the total global VoIP gateway market, Sonus' annual performance of 19% moved the company from #3 in 2006, to #1 in 2007.

"Sonus continued to build on its market share leadership position in Q4 and in 2007 as a whole," said Jeremy Duke, president and CEO, Synergy Research Group. "The Company broadened its deep roots with existing customers and continued to win new deals that spurred growth faster than the overall market."

"Over the past ten years, we have built some of the largest and most sophisticated IP voice networks in the world. Our field-proven technology continues to yield new returns for our existing customers, spurring continued investment in Sonus' IP infrastructure, and our reputation as the premier provider of IP voice services continues to help us expand geographically and into new areas of the network," said Hassan Ahmed, chairman and CEO, Sonus Networks. "The Company’s performance over the past year is indicative of Sonus' coveted position as a leader in this highly competitive market."

Sonus Networks has the world's most broadly deployed IMS-based solutions in the market. 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 September 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.