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

CHELMSFORD, Mass., September 7, 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 Q2 2006 in its “Service Provider Next Generation Voice and IMS Equipment Market Forecast.”

“In Q2, Sonus successfully extended its leadership position in several categories of the next generation voice market. In addition, the Company continues to shape the dynamics of the industry by challenging the existing Session Border Controller (SBC) market with its Network Border Switch, a security and peering solution that is integrated into their market leading gateway,” said Stéphane Téral, Principal Analyst, Service Provider Next Gen Voice VoIP, IMS, and FMC, with Infonetics Research. "Sonus' continued leadership in the gateway market, coupled with the innovation they've demonstrated in terms of product development, have made Sonus a leader in the industry.”

The Infonetics report named Sonus the market leader in several categories of the carrier packet voice market including the worldwide high density gateway segment with 23% of the total market. In North America, the largest geographic market for next generation voice solutions, Sonus led the combined total gateway and softswitch market with 25%, the total gateway market with 33%, and the high density gateway market with 44%.

“Sonus' market share results in Q2 were driven by a number of factors, including our continued success with major tier one wireline and wireless network operators,” said Hassan Ahmed, chairman and CEO, Sonus Networks. “Sonus continues to build its leadership in North America, where it has traditionally had a dominant market presence, while at the same time, building our worldwide leadership position by expanding our footprint in emerging markets, such as Europe.”

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 the “Risk Factors” section of Sonus' Quarterly Report on Form 10-Q, dated May 8, 2006, filed with the Securities and Exchange Commission, 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 of the Company's financial statements or results, 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 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. All other company and product names may be trademarks of the respective companies with which they are associated.