N20 Supports Scalable Deployment of Real-Time Voice and Converged Applications; First Carrier-Class Media Server to Interoperate with Sonus' ASX Access Server

WESTFORD, Mass., April 9, 2002 – Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, today announced that SnowShore Networks, a member of its Open Services Partner Alliance^SM (OSPA), has recently attained the "Powered" partner designation for proven interoperability with Sonus products. A beta version of SnowShore Networks' N20 Media Server, the first such product to feature carrier-class media processing and real-time integration of distributed voice/Web/data content to support enhanced services, has successfully completed rigorous interoperability tests with Sonus' Insignus Softswitch, including the ASX Access Server, at the company's OSPA Interoperability Lab.

The SnowShore Media Server fills an integral role in a complete end-to-end solution for packet-based access services, as well as enhanced services, in the carrier network. It provides a single carrier-class platform to support all of the necessary announcements and conferencing resources needed for Class 5 services, voice mail, and additional enhanced services, therefore enabling carriers to deploy truly converged and profitable next-generation applications.

"In achieving OSPA "Powered" status, SnowShore Networks has clearly demonstrated their ability to support next-generation converged network solutions fully compatible with Sonus' products," said Terri Griffin, vice president, marketing, Sonus Networks. "Working with Powered Partners such as SnowShore, we deliver products that let carriers cost-effectively deliver innovative, high margin services while minimizing the roll-out cycles and operational cost burdens associated with interoperability and scalability measurement and validation."

The OSPA's mission is to help empower standards-based interoperability between applications, third-party vendors and Sonus products. Sonus' OSPA Interoperability Lab is uniquely positioned to test packet voice solutions through the use of state-of-the-art testing equipment within environmentally controlled facilities. Once an OSPA member demonstrates interoperability with a Sonus product, the partner becomes "Powered." Sonus and its "Powered" partners offer service providers with end-to-end packet-based network solutions using best-of-breed technologies and applications.

"We are pleased that our N20 media server has achieved "Powered" status and has become the first carrier-class media server to attain this distinction," said Joel Hughes, SnowShore CEO. "The N20's WirespeedMedia architecture and carrier-class media processing power make it an ideal complement to Sonus' products, and enables Sonus to offer a full suite of both access and services infrastructure to their carrier customers."

About Sonus' OSPA

Sonus Networks' Open Services Partner Alliance Program provides a framework that offers service providers end-to-end packet-based network solutions using best-of-breed technologies and applications. The goal of the OSPA is to empower standards-based interoperability between applications, hardware vendors, and the Sonus product family. An integral part of the Sonus OSPA, the OSPA Interoperability Laboratory is the first in the industry where product interoperability is verified, trial testing is performed and complete solutions are ultimately produced. To find additional information on the OSPA, including a list of all OSPA partners, log on to http://ospa.sonusnet.com.

About Sonus Networks

Sonus Networks, Inc., is a leading provider of packet voice infrastructure products for the new public network. With its Open Services Architecture (OSA), Sonus delivers end-to-end solutions addressing a full range of carrier applications, including trunking, residential access and Centrex, tandem switching, and IP voice termination, as well as enhanced services. Sonus' award-winning voice infrastructure solutions, including media gateways, softswitches and network management systems, are deployed in service provider networks worldwide. Sonus, founded in 1997, is headquartered in Westford, Massachusetts. Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain projections or other forward-looking statements regarding future events or the future financial performance of Sonus 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 Sonus' Annual Report on Form 10-K, dated March 27, 2002, filed with the SEC, which identifies important risk factors that could cause actual results to differ from those contained in the forward-looking statements. These risk factors include, among others, the Company's ability to grow its customer base, dependence on new product offerings, market acceptance of its products, rapid technological and market change and manufacturing and sourcing risks.

Open Services Partner Alliance is a service mark of Sonus Networks and Open Services Architecture is a trademark of Sonus Networks. All other company and product names may be trademarks of the respective companies with which they are associated.