Sonus Solutions Selected to Power Leading European IP-Based Voice Service

Telio Deploys Full Suite of Sonus IMS-Ready Infrastructure to Support Increasing Subscriber Traffic

CHELMSFORD, Mass., May 16, 2006 – Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider Voice over IP (VoIP) infrastructure solutions, announced today that Telio, the largest and fastest growing access independent VoIP provider in Europe, has selected Sonus’ industry-leading IP Multimedia Subsystem (IMS)-ready solutions as the foundation for its next generation IP-based voice network. Telio, which offers primary line residential services throughout Europe, selected Sonus because of its ability to meet European-specific signaling requirements and to support carrier-grade reliability and scalability for Telio’s plug-and-play IP-based voice service, which currently carries more than 100 million minutes of voice traffic per month.

“To encourage the adoption of IP-based voice services, it is imperative that consumers experience the same quality, reliability, and ease of use that they’re accustomed to with legacy voice offerings,” said Alan Duric, co-founder and CTO, Telio. “Telio’s service is a straightforward plug-and-play solution. By selecting Sonus as the foundation for the network, we’re able to deliver the level of service that our customers expect, introduce interesting new features and applications, and scale as the demand for our service continues to grow across Europe.”

Telio offers IP-based voice service in Norway under the Telio brand, as well as offering its Telio Voice Production System (TVPS) service on a white label basis for European ISPs. Telio has deployed a suite of Sonus solutions including the GSX9000™ and GSX4000™ Open Service Switches, PSX™ Call Routing Server, SGX™ Signaling Gateway, and the Sonus Network Border Switch for enhanced security and direct IP-to-IP peering. With a full suite of IMS-ready solutions in place, Telio’s network can scale seamlessly, introducing new applications and features quickly and efficiently.

“Sonus is one of the only solutions available today that delivers proven quality and reliability with a robust suite of residential voice features required for primary line service in Europe,” said Hassan Ahmed, chairman and CEO. “Sonus is dedicated to helping European operators unlock the potential of next-generation communications, increasing their average revenue per user, and supporting enhanced applications that will redefine the expectations for communications services.”

“The European market for both next generation networks and IMS represents one of the most dynamic and rapidly evolving opportunities for vendors in these market segments. Whereas regulatory restraints hampered deployment of solutions throughout the 1990s and early 2000s, the new regulatory paradigm has opened the doors for innovative companies to gain mind- and market share,” said Tom Valovic, Program Director for VoIP Infrastructure at IDC. “Sonus, which has been addressing the European market and aligning and customizing resources to meet its unique demands, is well positioned to capitalize on these trends.”

Sonus’ IMS-ready architecture provides one of the industry’s most complete end-to-end network solutions that meet the unique demands of the European market. Sonus’ solutions support the delivery of services that match, and in many cases surpass, those services offered through traditional voice networks.

“By providing the sophisticated network foundation needed to support a feature-rich primary line voice service, Sonus is helping to reshape the competitive landscape throughout the European market,” said Joop Van Aard, vice president of sales, EMEA, Sonus Networks. “Service providers like Telio are taking advantage of next generation solutions to not only emulate the services available through traditional voice networks, but also to offer new and exciting services that capture consumers’ attention, promote customer loyalty, and improve long term customer retention.”

About Telio

Telio is the largest and fastest growing access independent VoIP provider in Europe. The company is privately held and headquartered in Oslo, Norway. In addition to offering services to end customers, Telio is also offering Telio Voice Production System (TVPS) on a white label basis for European ISPs. Among Telio’s founders and advisory board are found some of the most respected VoIP and SIP experts in the world, and Telio aims to at all times offer the most advanced multimodal broadband communications platform in Europe. For additional details on Telio, please visit http://www.Telio.no.

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. All other company and product names may be trademarks of the respective companies with which they are associated.