Sonus Networks Continues to Lead Market with Most IP-Voice Traffic in the Industry

Company Carries 35 Billion Minutes of IP-Voice Traffic Per Month

WESTFORD, Mass., September 25, 2007 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider IP-voice infrastructure solutions, announced today that according to a report entitled, "VoIP Minutes and Subscribers: 2Q07 Update," issued by iLocus, approximately 39% of all long distance IP-based voice traffic is carried over Sonus Networks' IP Multimedia Subsystem (IMS)-ready networks, nearly 3.5 times its nearest competitor, and up approximately 60% from the same period in 2006. Sonus-based networks currently carry 35 billion of IP-voice minutes per month.

"Traffic volume is an important metric because it's a measure of the growing traction of Sonus solutions on a global scale," said Hassan Ahmed, president, chairman and CEO, Sonus Networks. "It's a testament to the continued momentum of Sonus and its customers that we continue to set the bar in terms of scalable, real-world deployments of IP-voice networks."

The iLocus report recognized that Sonus leads both the national and international long distance market with 41.4% and 21.5% of voice traffic respectively. Carrying 39.4% of total long distance voice traffic, Sonus carries 4 out of 10 IP-based voice minutes. In the first six months of 2007, the Company carried 200 billion minutes of traffic in aggregate.

"In Q2 2007, we witnessed a growth in Sonus-based traffic due in large part to contributions from international network operators, as well as increased traffic from incumbent network operators," said Jahangir Raina, Director, iLocus. "Sonus has been a consistent traffic leader, and as its already-robust customer base continues to expand, we expect that trend to continue throughout the year."

About Sonus Networks

Sonus Networks, Inc. is a leading provider of IP-voice 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 June 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.