CHELMSFORD, Mass., July 17, 2006 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, announced today that Steve Edwards, Chief Marketing Officer, Sonus Networks, has been elected to serve on the Board of Directors for the IMS Forum, a global, non-profit industry association dedicated to service creation and applications delivery on IP Multimedia Subsystem (IMS) Architecture Frameworks, in addition to interoperability and certifications of IMS services and solutions. Sonus Networks is a founding member of the IMS Forum, formerly the International Packet Communications Consortium (IPCC), and is one of the industry's leading providers of IMS-ready solutions.

In his role as a member of the Board of Directors, Edwards will work with industry-leading service providers, application developers, system integrators and government agencies to help drive the adoption of emerging IMS frameworks, and streamline the delivery of bundled services, applications, and multimedia content.

“This is a very exciting time in the evolution of IP-based communications networks, and the work the IMS Forum is doing to help the industry as a whole address the implementation process for IMS-based solutions is extremely valuable,” said Edwards. “Sonus is one of the industry's foremost authorities on the development and deployment of IMS-ready solutions, and I'm eager to leverage our experience to further the success of the IMS Forum.”

Sonus Networks has been honored with a number of industry accolades as a result of its leadership in IMS, including Frost & Sullivan's 2006 IP Communication Carrier Infrastructure Technology Innovation & Leadership of the Year Award, which recognized Sonus' role and experience in the development and deployment of some of the largest VoIP networks in the world that adhere to the principles that govern today's IMS protocols. Since its inception, Sonus adopted a SIP-based distributed architecture, which is closely aligned to IMS with session control, border management, applications and management layers. The Company also founded the Open Services Partner Alliance (OSPA), the industry's largest interoperability program to develop a broad portfolio of Session Initiation Protocol (SIP)-based applications including messaging, conferencing, IP Centrex, etc.

“Sonus is an industry pioneer and one of the earliest companies to embrace the principles of IMS,” said Michael Khalilian, chairman and president, IMS Forum. “Mr. Edwards brings to the IMS Forum Board of Directors rich experience in field-proven deployment of IMS-ready solutions, and I look forward to leveraging his extensive expertise to help the IMS Forum introduce best practices and approaches for IMS rollouts.”

The Sonus IMS-ready solution builds on the proven benefits of Sonus' architecture, which supports more than 20 billion minutes of traffic per month. To learn more about Sonus' award-winning IMS architecture, please visit the Sonus website at www.sonusnet.com or download the Sonus whitepaper entitled, “Architectural Choices in a Changing Market: The IMS Industry Standard” at http://www.sonusnet.com/contents/brochures/Sonus_IMS_022006_wp.pdf.

For additional information on the IMS Forum, please visit the IMS Forum Web site at www.IMSForum.org.

About the IMS FORUM

The IMS FORUM is a global, non-profit industry association devoted to interoperable IMS services and solutions. The mission of the Forum is to accelerate the adoption of IP Multimedia Subsystems (IMS) by providing an environment for discussion and resolution of real-world implementation issues relating to interoperability, best practices, and standards-based architectures in the application layer. In addition, the Forum will provide consultancy to the industry, service providers, and vendors on best practices and approaches for IMS rollouts and interconnectivity. For additional information or to join the IMS Forum, please visit www.IMSForum.org.

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 14, 2006 and Quarterly Report on Form 10-Q, dated May 8, 2006, 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, Inc. Sonus GSX9000 Open Services Switch, PSX Call Routing Server, SGX Signaling Gateway, and the Sonus Insight Management System are trademarks of Sonus Networks, Inc. All other company and product names may be trademarks of the respective companies with which they are associated.