Major Network Operators around the World Rely on Sonus for Their IP Voice Networks

WESTFORD, Mass., January 9, 2007 - Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, announced today that according to a report entitled, “VoIP Minutes and Subscribers: 3Q06 Update,” issued by iLocus, 38% of all long distance IP-based voice traffic is carried over Sonus Networks' IP Multimedia Subsystem (IMS)-ready networks. The percentage of traffic being carried over Sonus' IMS-based networks has increased steadily in 2006, up from 37% in Q2 and 32% in Q1. Sonus Networks currently carries more than 29 billion minutes of IP-based voice traffic every month, up approximately 70% from the same period in 2005.

“IP voice traffic for both national and international long distance is on the rise, and throughout 2006, Sonus has successfully extended its lead in this exciting market,” said Jahangir Raina, Director, iLocus. “Sonus Networks is present in 4 out of the 5 largest network operators in the world, has a strong global footprint, continues to win new customers, and has helped their existing customers migrate more and more of their traffic to an IP-based network.”

“We're excited that the recent report from iLocus validates our market leading position,” said Hassan Ahmed, chairman and CEO, Sonus Networks. “Sonus Networks has been an integral player in driving the adoption of IP-based voice solutions, and the biggest opportunities still lies ahead. In 2006, major tier one network operators around the world have turned to Sonus to leverage the Company's rich experience and unparalleled success building today's most sophisticated IP voice networks.”

The iLocus report recognized that Sonus leads both the national and international long distance market with 40% and approximately 26% of voice traffic respectively. Carrying 38% of total long distance voice traffic, Sonus carries approximately 4 out of 10 IP-based voice minutes. In addition to the continued ramping of traffic by early adopters of Sonus' technology, the adoption of Sonus solutions by major tier one network operators has been a strong growth driver for the Company throughout 2006.

“Minutes are an important metric, as they reflect what network operators are doing today. As is evidenced by the amount of IP voice traffic being carried every month on Sonus solutions, this market has entered the mainstream and still has a lot of room to grow. With more IP-voice minutes carried on Sonus-based networks than any other vendor, it's clear that Sonus is delivering the right solutions and top-of-the-line service for our customers,” continued Ahmed.

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.