CHELMSFORD, Mass., January 24, 2006 - Sonus Networks (Nasdaq: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, today announced the appointment of industry veteran, Howard Janzen, to the Company's Board of Directors. Mr. Janzen will also serve on the Company's Audit Committee.

With more than 30 years of experience in the telecommunications and energy industries, Mr. Janzen brings a wealth of experience in deploying some of the most advanced communications networks in the United States. Mr. Janzen most recently served as the president of Sprint Business Solutions, where he successfully integrated Sprint's wireless, wireline and local voice and data services to meet the full communication needs of each customer segment. Prior to joining Sprint, Mr. Janzen was the chairman, president and chief executive officer of Williams Communications Group, building the largest next-generation fiber optic network in the United States.

“We are very pleased to welcome Howard to the Sonus Networks board,” said Hassan Ahmed, chairman and CEO, Sonus Networks. “Howard brings intimate knowledge of our markets and customers to the Sonus board. He has built and managed some of the most advanced telecommunications networks in the world. His insights and guidance will be tremendous assets to Sonus as we continue to drive the migration of the world's communications networks to IP.”

“I am honored to be joining the board of Sonus Networks,” said Howard Janzen. “Sonus' vision for the future of communications combined with its proven track record and ability to execute on the business fundamentals make this an exciting opportunity.”

Mr. Janzen received his Bachelor and Master of Science degrees in Metallurgical Engineering from the Colorado School of Mines. He also completed the Harvard Business School Program for Management Development.

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' Annual Report on Form 10-K, dated March 15, 2005, and the “Cautionary Statements” section of Sonus' Quarterly Report on Form 10-Q, dated November 8, 2005, both filed with the SEC, which identify 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 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.