Industry Leader Establishes Seven Regional Sales and Support Facilities Throughout the United States

WESTFORD, Mass., November 15, 1999 - To keep pace with the rapidly increasing demand for its award-winning packet telephony solutions, Sonus Networks today announced that it is expanding its domestic sales and support infrastructure. Sonus, the emerging leader in carrier-class packet telephony solutions, has opened sales offices in Atlanta, Dallas, Denver, New York, San Francisco, Tulsa and Washington, D.C. With the addition of these seven regional offices to complement its Massachusetts-based sales headquarters, Sonus has significantly intensified its presence in the key centers of the U.S. telecommunications market.

"Service providers throughout the United States have begun to aggressively evaluate and adopt packet technology as the foundation for their next-generation voice networks," said Gary Rogers, Sonus' vice president of sales and marketing. "By establishing these new sales and support offices, Sonus is well-positioned to meet the growing demand for innovative packet voice solutions that enable carriers to expand their network coverage and rapidly deploy new, revenue-generating services."

Sonus offers a complete Packet Telephony suite, featuring the GSX9000™ Open Services Switch, PSX6000™ SoftSwitch and the SGX2000TM SS7 Signaling Gateway, that satisfies the stringent requirements of public carrier networks for interconnectivity, capacity, reliability, scalability and voice quality. Moreover, Sonus' Open Services ArchitectureTM (OSA) provides a unique, open approach through which new services can be created easily and implemented quickly.

Sonus' solutions have quickly gained the attention of leading next-generation carriers, incumbent inter-exchange carriers, local exchange carriers and competitive local exchange carriers (CLECs). In July 1999, Global Crossing (formerly Frontier Communications) became the first major voice carrier to announce its intention to migrate its voice and telephony services to an all-packet environment. Global Crossing selected Sonus' GSX9000 as the infrastructure switch to build out the carrier's next-generation VoIP network, which is expected to be completed by year-end 2002.

About Sonus Networks

Sonus Networks, Inc. is delivering a new class of carrier solutions that enable the movement of telephony to converged packet networks and the development of a new generation of innovative voice and data services. The award-winning Sonus Packet Telephony suite and Open Services Architecture (OSA) cut the time-to-market for competitive new service products, allowing carriers and third-party developers to sustain and expand marketshare, and build important new revenue streams. Its highly scalable products fully interoperate with and extend the life and utility of today's public network. Sonus, founded in 1997, is headquartered in Westford, Massachusetts and is privately held. Additional information is available at: http://www.sonusnet.com.

GSX9000, PSX6000, SGX2000 and Open Services Switch are trademarks of Sonus Networks. All other company and product names may be trademarks of the respective companies with which they are associated.