Synergy Research Group Reports Sonus Owns 32% High Density Gateway Market, Nearly Double Closest Competitor

CHELMSFORD, Mass., August 29, 2006 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, announced today that Synergy Research Group, a leading independent industry analysis firm, has named Sonus Networks the market share leader in high density media gateways, a key component in Sonus' award winning IP Multimedia Subsystem (IMS)-ready architecture. Sonus grew its market share in Q2 to approximately 32%, nearly double the next closest competitor.

“Sonus performed extremely well in Q2 2006, adding to its already substantial leadership position in the market,” said Jeremy Duke, president and CEO, Synergy Research Group. “Carriers on a global basis continue to select Sonus' IMS-ready architecture as the foundation for their next generation networks, and the Company has proven to be a driving force in the world's migration toward IP-based networks.”

“Sonus has achieved a number of successes already in 2006. We've announced 13 new customers this year, and our existing customers continue to migrate traffic off of legacy networks and onto their Sonus-based platform,” said Hassan Ahmed, chairman and CEO, Sonus Networks. “This momentum is reflected in Synergy's market share results for Q2 and underscores Sonus' coveted position as a trusted provider to the world's most aggressive and innovative network operators.”

Sonus has deployed its award-winning IMS-ready architecture in 34 countries worldwide, and has announced partnerships with 56 of the leading network operators, including leading tier 1 wireline and wireless carriers. The Company also maintains partnerships with leading brands in the communications industry, increasing Sonus' ability to address key segments of the market and increase exposure in strategic geographic regions.

For a copy of the Synergy Research Group Report, entitled “2Q06 Service Provider Worldwide VoIP Market Share Report,” please contact Heather M. Wilson, Synergy Research Group, Inc., hwilson@srgresearch.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.