CHELMSFORD, Mass., January 04, 2006 ? Sonus Networks (Nasdaq: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, and Vonage Network, a subsidiary of Vonage Holdings Corp. and the leading provider of broadband telephone services to residential customers in the U.S., announced today that Vonage Network has selected the Sonus Network architecture to support the increasing growth in its subscriber base. Vonage has deployed Sonus solutions including the GSX9000™, PSX™ Call Routing Server, SGX™ Signaling Gateway, and the Sonus Insight™ Management System in New York and Los Angeles and is expanding deployment into additional major markets throughout the United States. In future phases of the network expansion, Vonage plans to broaden the network to international locations.

?Voice over broadband is a technology that's redefining how service providers and consumers alike think about communications,? said Hassan Ahmed, chairman and CEO, Sonus Networks. ?From day one, Vonage has been one of the most successful service providers in the industry. By selecting Sonus Networks, Vonage will have the ability to build out a premium network infrastructure to support the rapidly increasing demand for its services.?

?Vonage has been a VoIP pioneer in North America,? said Michael Tribolet, executive vice president of operations for Vonage Network. ?Throughout Vonage's history we have remained committed to providing high-quality telephony service. By selecting Sonus, another pioneer in the VoBB market, we are in a position to continue to do this, while rapidly and successfully scaling the size of our network.?

Vonage Network has deployed over 1 million lines throughout its network. The Sonus Network solution provides Vonage with the flexibility, scalability and reliability required to support growth and the addition of new services. Sonus Network IMS-based Voice over Broadband (VoBB) solution, including central components GSX9000™, PSX™ Call Routing Server, SGX™ Signaling Gateway, and the Sonus Insight™ Management System, is proven architecture deployed in some of the world's largest broadband VoIP networks. By enabling network operators to rapidly scale their deployments, the Sonus solution improves the operators? ability to add new revenue-generating subscribers to their network. Additionally, Sonus was a pioneer in the deployment of Session Initiation Protocol (SIP) based voice services, which allows network operators to rapidly integrate applications and solutions from third-party vendors with Sonus products. The ability to seamlessly interoperate offers a key advantage for providers like Vonage that are focused on maintaining and expanding a network that facilitates the delivery of high quality telephony service.