Sonus Networks Leads 2006 Market Share For Key Segment Of IP Voice Industry

Year-To-Date Market Share Report Shows Sonus Networks Growing Faster Than Overall Industry

CHELMSFORD, Mass., November 21, 2006 - Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, announced today that according to Synergy Research Group, a leading independent industry analysis firm, Sonus Networks leads the high density gateway market for 2006. Year-to-date results in the Q3 market share report entitled, “3Q06 Service Provider Worldwide VoIP Market Share Report," show Sonus Networks with approximately 29% market share. In addition, according to the latest market growth estimates from Synergy Research Group. Sonus continues to outpace overall market growth.

"This is a great time for Sonus and our industry. Network operators throughout the world are launching next-generation communications networks. Sonus is present in 4 out of 5 of the world's largest network operators, carries more than 25 billion minutes of voice traffic every month, and is relied upon by carriers across the globe to provide robust solutions that meet key business imperatives and rigorous end user demands," said Hassan Ahmed, chairman and CEO. “Our dedication and continual execution has resulted in Sonus growing well ahead of market forecasts."

“2006 has been an exciting year for voice over IP deployments, with major projects underway globally," said Jeremy Duke, president and CEO, Synergy Research Group. “This year alone, Sonus Networks has announced significant deployments in North America, Europe and Asia-Pacific and has been a driving force for the overall market growth. The Company's success has earned it a position as a well established leader in the IP-based voice industry."

Sonus has deployed its award-winning IP Multimedia Subsystem (IMS)-ready architecture in 34 countries worldwide, and has announced partnerships with 58 of the leading network operators, including 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 Item 1A “Risk Factors" of Sonus' Quarterly Report on Form 10-Q dated May 8, 2006, 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 announced review of its historical stock option grants and accounting, including any potential impact on the Company's financial statements or results, any tax liabilities or penalties, 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, regulatory actions 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, Inc. All other company and product names may be trademarks of the respective companies with which they are associated.