Customers Driving Half Trillion Minutes of IP-Based Voice Minutes on Sonus Solutions; IP Voice Market Approaching Inflection Point

CHELMSFORD, Mass., August 17, 2006 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, announced today that the industry is approaching a critical inflection point. Based on traffic reports from its customers, Sonus-based networks have carried more than half trillion minutes of IP-based voice traffic. This half trillion minute milestone demonstrates the rapid growth in IP traffic and the increasing migration by network operators globally to IP-based voice solutions. The latest industry research recognizes Sonus as the market leader based on this industry benchmark, with nearly 40% market share according to market researcher iLocus.

“The pace of deployments and migration of traffic onto IP-based voice solutions is continuing to accelerate. It took 5 years to reach the first 100 billion minutes of IP-voice traffic, but in just the last 1.5 years, we've been able to increase that amount 5x to more than a half trillion minutes on Sonus-based networks alone,” said Hassan Ahmed, chairman and CEO, Sonus Networks. “The growth in IP-voice traffic on Sonus-based networks is a testament to the quality, reliability and scalability of our solutions. We are committed to helping our customers achieve the greatest possible performance from their IP-voice networks with cost-effective, innovative solutions that maximize value for consumers.”

“XO Communications was one of the first carriers to embrace the power of IP-voice. We partnered with Sonus because they had a clear understanding of how to deliver new efficiencies into the network immediately and a vision for the future of IP-based networks,” said Randy Nicklas, vice president of network engineering, XO Communications. “Our Sonus-based network currently carries nearly 4 billion minutes of voice traffic per quarter. We continue to grow the amount of traffic, and the solution has proved it has the ability to scale while delivering 99.999% performance.”

“Sonus continues to build on its reputation as an industry leader by breaking through new IP-based voice milestones,” said Brian Partridge, Yankee Group. “Sonus has demonstrated success across both wireless and wireline operators who leverage Sonus solutions for their next-generation VoIP architectures. The pace at which they have grown the amount of traffic they support is a testament to solid technology and the ability to service large IP-based voice networks.”

“One of the hardest challenges in telecommunications is delivering IP-voice with carrier-class reliability and seamless scalability,” said Vikram Saksena, chief architect, Sonus Networks. “Sonus' early decision to design an architecture that centers around IP and Session Initial Protocol in a distributed model is critical to the success network operators are having today accelerating their traffic volumes on their Sonus-based networks. With unparalleled performance at very high traffic levels, it is easy to see why operators are so enthusiastic. We are proud that the world's largest network operators are increasingly relying on Sonus solutions for their next-generation voice network.”

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.