Sonus Networks Bridges Gap Between 2g and 3g Networks with IMS-Ready Wireless Network Infrastructure

Sonus Adds New Application Functionality to SMARRT Wireless Solution

CHELMSFORD, Mass. and BARCELONA, Spain, February 13, 2006 - Today at the 3GSM World Congress 2006, Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, announced that it has enhanced its IMS-ready SMARRT Wireless solution to include support for legacy wireless service protocols. The Sonus solution empowers wireless carriers with the ability to offer a bundle of services that include their existing services in combination with cutting edge next generation SIP (Session Initiation Protocol)-based services.

By providing support for key application protocols, such as Customized Applications for Mobile Network Enhanced Logic (CAMEL), into its Gateway Mobile Switching Center (GMSC) solution, Sonus enables wireless network operators to differentiate their service with new SIP-based applications while leveraging their existing CAMEL infrastructure for services such as prepaid calling plans. Sonus' solution provides an architecture capable of delivering legacy applications over a more cost-efficient IP-based network, while at the same time, providing a foundation for full scale migration to the IP Multimedia Subsystem (IMS). This IMS capability is called the IP Multimedia - Services Switching Function (IM-SSF) and provides the inter-working of the SIP message to the corresponding CAMEL, ANSI-41, Intelligent Network Application Protocol (INAP) or Transaction Capabilities Application Part (TCAP) messages. The result is that carriers can intermix next-generation and existing service platforms to provide a seamless user experience to their customers.

“Wireless operators are eager to embrace next generation solutions, but are understandably reticent to abandon the investments they have already made,” said Mike Hluchyj, Founder and Chief Technology Officer, Sonus Networks. “Sonus' SMARRT Wireless solution helps network operators maximize their existing investment in legacy applications and authentication protocols, while building out a state of the art network infrastructure that will leverage the full power and flexibility of IMS and set the stage for a whole new generation of enhanced applications and services.”

“VoIP and IMS are top of mind for nearly every wireless operator in the market,” noted Peter Jarich, Principal Analyst for Wireless Infrastructure with Current Analysis. “Yet, the full migration to a new service delivery architecture will take time. In interim, operators must continue supporting their legacy applications; Sonus' wireless solutions facilitate a streamlined migration to IMS without jeopardizing current revenue streams.”

Built on Sonus' award winning IMS-ready architecture, Sonus' SMARRT Wireless solution is a family of packet-based wireless switching solutions that allows carriers to cost-effectively deploy and operate wireless networks, increase network capacity to accommodate growing subscriber traffic, and build new revenue streams and customer loyalty through the delivery of packet-based enhanced services. In addition, Sonus' IMS-ready SMARRT Wireless solution provides a streamlined migration path towards Fixed-Mobile Convergence (FMC), the integration of wireline and wireless technologies and services to create a single telecommunications network foundation (See related announcement, “Sonus Unveils Strategy for FMC At 3gsm World Congress 2006”).

“Sonus solutions have always focused on delivering compelling value today with a keen eye on the future. We want to ensure that an investment in our technology is not just about addressing today's business challenges, but also focuses on laying the appropriate groundwork for the next generation of telecommunications,” said Hassan Ahmed, chairman and CEO, Sonus Networks. “Wireless is clearly the next big area for growth in the VoIP industry, and Sonus is committed to establishing a strong leadership position in this exciting market.”

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, 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.