Leader in Carrier-Class Voice-Over-Packet Telephony Solutions Recognized for Technology Achievement in IP Technology Category

WESTFORD, Mass., June 9, 1999 – Sonus Networks Inc., an emerging leader in carrier-class packet telephony solutions that fully integrate with the existing public voice network, today announced it was honored at the SUPERQuest awards at SUPERCOMM '99 for most promising new solution in IP Telephony. Sonus was selected from a field of more than 130 entrants for the prestigious industry awards, and was the only carrier switch vendor recognized in the IP technology category. Bridgewater Systems, a leader in policy and provisioning solutions, and a Sonus Open Services Alliance Partner, received the SUPERQuest award in the IP technology category.

Sonus' award was based on its successful introduction of the GSX9000 Open Services Switch, the industry's only "any-to-any" voice-over-packet central office switch that extends the life, scalability, and services potential of today's public voice network.

The SUPERQuest Awards showcase implementations of public and private network solutions, and the key product/technology involved in those solutions that have advanced business for the customer. The program also recognizes the most promising new technologies represented on the SUPERCOMM show floor.

"We are honored to receive recognition of the GSX9000 and its ability to facilitate the movement of telephony from circuit to packet networks, while also enabling carriers to provide new, differentiated services," said Hassan Ahmed, Sonus Networks President and CEO.

About the GSX9000 Open Services Switch

The GSX9000 Open Services Switch is the first carrier-class switch with the capacity, reliability, and sophistication to enable the new converged PSTN/IP-based infrastructure. It is the central component of the Sonus Networks Open Services Architecture^TM (OSA), a unique, open approach through which new services can be created easily and implemented quickly. Using the GSX9000 in the network infrastructure, the Sonus OSA enables carriers to expand their network coverage and deploy new services more rapidly than with any other approach. The GSX9000 is being publicly demonstrated for the first time at SUPERCOMM '99 in Atlanta.

About Sonus Networks

Sonus Networks, Inc. is delivering a new class of carrier solutions that enable the movement of telephony to converged circuit-packet networks, and the development of a new generation of innovative voice and data services. The Sonus Packet Telephony suite and Open Services Architecture (OSA) cut the time-to-market for competitive new service products from years to weeks, 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. Its management team has developed and introduced many of the industry's most widely used carrier solutions, and has led organizations such as: Ascend Communications (Nasdaq: ASND), recently acquired by Lucent Technologies (Nasdaq: LU); Summa Four, recently acquired by Cisco Systems (Nasdaq: CSCO); Bay Networks, recently acquired by Northern Telecom (NYSE:NT); and VideoServer (Nasdaq: VSVR).

Sonus was named one of Red Herring's "Top Ten to Watch" companies, awarded Data Communications magazine's prestigious Hot Startup of the Year and Hot Product of the Year awards, and received Technologic Partners' Investor's Choice award. Additional information is available at: http://www.sonusnet.com