Infonetics Research Names Sonus Networks Market Share Leader in Key Segments of IP Voice Industry

WESTFORD, Mass., November 28, 2007 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider IP-voice infrastructure solutions, announced today that, based on an evaluation of equipment revenue, 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 Q3 2007. In Q3 2007, Sonus extended its leadership position and grew faster than the overall IP-voice market.

In the high density gateway market, Sonus captured 26% of the worldwide market, with regional leadership in North America at 42%. Sonus also increased its market share position in EMEA, capturing 19% of the high density gateway market, demonstrating the Company's continued momentum in the region. Sonus also grew its position in the total gateway market worldwide with 19% and the North American total gateway market with 33%, both figures representing increases over Q2 2007.

"In Q3, the Company outpaced the overall market growth and secured its leadership position on several fronts," said Stéphane Téral, Principal Analyst, Service Provider Next Gen Voice VoIP, IMS, and FMC, with Infonetics Research. "Sonus is the only pure play IP-voice provider in the market with 10 years of experience building and deploying large-scale IP-voice networks, and their expertise is reflected in their continued market share leadership position."

"Sonus has announced partnerships with 6 of the top 10 network operators in the world and has been deployed in more than 150 network operators worldwide. Our customer-centric vision, field-proven technology, and team of experienced customer services and support professionals make Sonus the premier provider of IP-voice solutions," said Hassan Ahmed, chairman, president and CEO, Sonus Networks. "We continue to expand our presence with new operators, in new portions of the network and in new geographies."

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 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.