Top Notch Experienced Management Team Receives $23 Million in Funding, Taps Top Design Team to Deliver Next Generation IP-Based Central Office Switches.

WESTFORD, Mass., November 23, 1998 – Sonus Networks, developers of the next generation of carrier grade IP Telephony, today announced its formation and entry into the high-end IP Telephony Switch market. Sonus Networks has received $23 million in preliminary capital to fund the development and delivery of products that interconnect the Public Switched Telephone Network (PSTN) and carrier IP networks and that meet the stringent requirements of new and traditional carriers.

The company also disclosed that it has named former Ascend Senior Executive Hassan Ahmed as President and CEO. Ahmed is well-known among service provider organizations for his understanding of carrier technology issues and his ability to drive organizations toward products that meet their particular needs.

"The telecommunications industry has come to a consensus that the future belongs to the converged network - a single managed IP network that supports both voice and data," said Ahmed. "Previously announced IP Telephony products, while perhaps suitable for small scale deployments, have neither the capabilities nor the performance to meet the much broader requirements of major carriers and ISPs. These organizations must more rapidly define and deliver competitive new user services, substantially scale the size of their networks to improve their support for escalating IP call volumes and new applications such as multi-media, manage the flow of traffic among their existing circuit switched and new IP based traffic paths, and significantly improve the economics of service delivery. Sonus Networks' mission is to enable carriers to substantially improve their central office infrastructure and remain viable in this aggressive new market."

"Sonus has a clear early leadership position in the carrier-grade IP telephony market," said Rubin Gruber, Chairman and co-founder. "The opportunity in this market is reflected in the emergence of several major new IP-based carriers and announced plans by established carriers to migrate voice traffic to IP networks. Sonus is in a unique position to capitalize on the opportunity to provide true carrier-grade IP telephony equipment that meets this important new telecommunications market requirement."

Sonus Networks has received preliminary funding of $23 million from some of the telecommunications industry's most successful and well-respected venture capital firms, including: Bedrock, Charles River Ventures, Matrix Partners, North Bridge Venture Partners, and Bessemer Venture Partners.

Top Industry Talent Positions Sonus for IP Telephony Success

The Sonus executive team is comprised of exceptionally experienced professionals, including

• Rubin Gruber, Chairman and co-founder, previously founder of VideoServer (Nasdaq - VSVR), Davox (Nasdaq - DAVX), and Cambridge Telecommunications, acquired by GTE (NYSE - GTE);
• Hassan Ahmed, Ph.D., President and CEO, most recently Executive Vice President and General Manager of Ascend Communications' (ASND) Core Systems Division. Previously, he served as Cascade Communications' Chief Technology Officer was President and founder of WaveAccess, a pioneer in high speed wireless network products
• Dr. Michael Hluchyj, Vice President, founder and CTO, previously VP and CTO at Summa Four, recently acquired by Cisco (Nasdaq - CSCO), Director of Networking Research at Motorola Codex (NYSE - MOT), and Member of the Technical Staff at AT&T Bell Laboratories (NYSE - LU);
• Kwok Wong, VP of Engineering, formerly Director of Software Development and Architecture at VideoServer, Director of Software Development at BBN Communications, and a founding member of the software development team at Davox;
• Jeffrey Mayersohn, VP for Carrier Relations, formerly Senior Vice President at GTE (NYSE - GTE) Internetworking, who during his 20-year tenure at BBN/GTE Internetworking managed relationships with such organizations as AT&T Worldnet and America Online, and was principal designer of networks such as the U.S. Defense Data Network
• Frank Winiarski, Vice President, Manufacturing, formerly Vice President of Manufacturing at Net2Net, recently acquired by Visual Networks (Nasdaq- VNWK), Vice President of Manufacturing at VideoServer and Synernetics, acquired by 3COM (Nasdaq - COMS), Vice President for Operations at Ashton-Tate, and Director of Manufacturing at MASSCOMP
• Bob Dye, Director, Product Marketing, was previously Director of Product Marketing at Polycom, Inc. (Nasdaq - PLCM) and Compression Labs (Nasdaq - VTEL), and has also served as Senior Director, Product Management for BBN Communications

About Sonus Networks

Sonus Networks, Inc. is developing and marketing the next generation of carrier-grade IP Telephony. Its equipment facilitates the movement of telephony from traditional circuit networks to packet networks, enabling a host of new carrier and end user services. The Sonus management and engineering teams have unsurpassed success in the development and delivery of carrier-class equipment to support data, voice and multimedia information.