Company Helps Transform World's Communications Networks to IP

WESTFORD, Mass., January 17, 2007 - Sonus Networks (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, continues to lead the industry with the most minutes of voice traffic, strategic new product introductions to its award winning IP Multimedia Subsystem (IMS)-ready portfolio, and expanded presence in some of the world's most sophisticated networks.

Over the course of 2006, Sonus announced new or expanded projects with 18 of the world's most innovative network operators, including eight in North America, seven in Europe, Middle East, and Africa (EMEA), and three in Asia Pacific region, underscoring the Company's unique ability to deliver and support sophisticated next generation voice solutions on a global scale. Sonus customers have embraced Sonus solutions to deliver a wide variety of services, including the transport of long distance voice traffic, end-to-end voice over broadband services, and the delivery of enhanced, next generation consumer applications.

“We strategically selected Sonus Networks as the foundation for our voice over broadband network because the Company has proven it has the technology, service and support to build networks that can rapidly scale to meet increased consumer demand,” said Neil McArther, managing director, Opal Telecom networks division, which was announced as a Sonus customer in June 2006. “In the past year, we've had an extremely positive experience with our Sonus team, and our network has seen excellent reliability.”

Sonus has maintained its profitable market share leadership position, and established new records for the support of IP-based voice traffic. Sonus-based networks around the world now carry more than 29 billion minutes of voice traffic per month. In addition, throughout the year, Sonus made new strides on the technology front, bringing to market new solutions such as the GSX4000™ Open Services Switch to help network operators to expand the reach of their core IP-voice networks into new applications, new geographic regions or to deploy IP-based multimedia services; the latest version of the Network Border Switch (NBS), which combines session control, PSTN gateway services and security into a single, high performance, carrier-class system; and the latest version of Sonus' carrier class billing platform, enabling network operators to further streamline the integration of next generation applications with existing Operational Support Systems (OSS).

“Sonus has had a solid year on a number of fronts, expanding its global footprint, bringing new technology to market, and demonstrating that it can compete effectively with the industry's biggest players,” said Brian Partridge, senior analyst with Yankee Group. “The Company continued to build a leadership position in the core IP trunking market, and has seen some early success with its transition into the class 5 market as well as with wireless operators.”

“In the evolution of the voice industry, 2006 was a critical year - demonstrating that IP-voice technology has now entered the mainstream. Virtually every major carrier has IP-voice projects underway or in the planning stages, and we're pleased that so many diverse network operators have selected Sonus as their partner of choice,” said Hassan Ahmed, chairman and CEO, Sonus Networks. “We are all anxiously looking forward to 2007 as another year where Sonus will lead the industry into the new frontier of integrated voice communications.”

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 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 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.