Sonus Networks Achieves Historic IP-Voice Milestone With Over One Trillion Minutes

Sonus IP-Based Networks Set New Standard for NGN Communications; Independent Analyst Ranks Sonus as the IP-Voice Leader

WESTFORD, Mass., January 15, 2008 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider IP-voice infrastructure solutions, today announced it entered 2008 achieving a historic voice network milestone. Leveraging Sonus’ industry leading, breakthrough technology for voice networks, operators now report that they have carried over one trillion minutes in aggregate on their Sonus-based networks. With Sonus-based networks deployed in more than 50 countries, operators around the world are setting new standards for next-generation communications by delivering unparalleled quality of service, reliability and unique service creation opportunities.

According to a report entitled, "VoIP Minutes and Subscribers: 3Q07 Update," issued by iLocus, approximately 40% of all long distance IP-based voice traffic is carried over Sonus Networks' IP Multimedia Subsystem (IMS)-ready networks, more than three times its nearest competitor. At the end of 2007, Sonus-based networks carried 36 billion IP-voice minutes per month.

"The trillion-minute mark is an important milestone for our company and our customers. It demonstrates just how widely embraced IP as a transformative technology has become in the communications space," said Hassan Ahmed, president, chairman and CEO, Sonus Networks. "With the volume of traffic in the core of the network continuing to scale in such a dramatic fashion, the business imperative to adopt IP at the edge of the networks continues to grow as well, and Sonus is well poised to capitalize on its leadership position."

The iLocus report stated that there were 232 billion national long distance minutes, with Sonus-based networks comprising 42.2 percent. International long distance minutes totaled 24.4 billion minutes, with Sonus capturing 21.6 percent. Both market share numbers represent an increase over Q2 2007.

"Many factors in today's telecommunications market are driving the evolution to a converged network infrastructure," said Jahangir Raina, Director, iLocus. "Operators trying to maximize the benefits of their IP network require a robust IP-voice platform designed to withstand the current demands of voice communications and scale for future growth. Sonus has demonstrated its ability to meet these requirements and is continuing to evolve its solution to manage increasing IP-services."

Sonus marked its 10 year anniversary in 2007 by unveiling advanced solutions for today's next-generations networks, including femtocell technologies for in-building wireless networks; advanced features for its Network Border Switch product family, allowing disparate IP networks to connect seamlessly; a new platform for residential networks, Access 7.0; and the industry’s most advanced services technology, IMX 2.0. These unique capabilities expand operators' next-generation voice networks beyond traditional boundaries enabling businesses and consumers greater service quality and advanced features.

Today, Sonus is the leader in next-generation communications with a comprehensive architecture designed to address all elements of the voice network including long-distance, residential, enterprise, packet peering, IP-applications and professional services.

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 September 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.