Company Leads Worldwide and North American Markets; Grows EMEA Position by 50%

WESTFORD, Mass., August 29, 2007 – 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 its "Service Provider Next Generation Voice and IMS Equipment Market Forecast" in Q2 2007. In Q2 2007, Sonus outpaced the overall market growth, extended its reach into its target geographies, continued to grow existing customer deployments, and was selected by new operators as their preferred partner for next generation voice solutions.

In Q2 2007, Sonus Networks led the worldwide high density gateway market with 24% market share. In North America, Sonus continued its market-leading position with approximately 38% market share, as well as 30% of the total gateway market. In addition, Sonus continued to grow its early position in EMEA, increasing its market share by 50% and ranking among the top three vendors for the region in the total gateway market.

"Network operators worldwide are shifting a greater portion of their spending towards next generation solutions, and Sonus continues to capitalize on this industry-wide migration," said Stéphane Téral, Principal Analyst, Service Provider Next Gen Voice VoIP, IMS, and FMC, with Infonetics Research. "Network operators have long trusted Sonus solutions as a way to help them capitalize on the benefits of IP technology to transform their voice networks, as demonstrated by the Company's consistent presence as the number one market share leader in key segments of the IP voice industry."

"In the last 10 years, Sonus has broadened its customer base to more than 150 network operators with deployments in more than 50 countries. Sonus solutions form the foundation of today's largest IP long-distance voice networks, innovative IP wireless networks, and residential and enterprise IP access networks," said Hassan Ahmed, president, chairman and CEO, Sonus Networks. "A major growth driver for Sonus this quarter was the continued migration of traffic from our existing customers, increased penetration into the world's largest networks, and ability to anticipate emerging market dynamics."

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 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 March 31, 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; whether the Company will remain listed on the NASDAQ Global Select Market; 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.