Carrier-Class IP Telephony Startup Named Recipient of Prestigious Industry Award From Data Communications Magazine

WESTFORD, Mass., December 10, 1998 – Sonus Networks, innovators in carrier-class IP telephony products and services, today announced its selection by Data Communications as one of the year's Top 25 Hot Startups. Sonus Networks develops IP-based central office solutions that enable global carriers to implement and fully realize the promise of global-scale IP telephony.

Its management team has a distinctly successful track record in delivering carrier grade solutions, and the telecommunications, multimedia and data communications experience pivotal to the delivery of IP telephony solutions with the capacity, scalability, sophistication and reliability to support the public network, and enable the rapid development and delivery of innovative new services. The Sonus management team is led by 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' (Nasdaq - ASND) Core Systems Division, and previously, Cascade Communications' Chief Technology Officer; and 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 a leading member of the Technical Staff at AT&T Bell Laboratories (NYSE - LU).

Data Communications is a worldwide technology magazine written for corporate networking professionals. Consideration for "Hot Startup" was limited to private companies under five years old. Data Communications selected the 25 hot startups based on innovative technology, VC investment and the level of industry experience of the staff.

"We are honored to be named as recipients of Data Communications' prestigious Hot Startups Award, and view it as both an important validation of our strategy, and recognition of the urgent need for central office solutions that will redefine the intelligence and economics of the public network," said Rubin Gruber, Founder and Chairman of Sonus Networks

Sonus President Dr. Hassan Ahmed concluded, noting: "The true promise of the public network - and the basis on which carriers must increasingly compete - is the rapidly delivery of new service products to expand the use of the public network and drive customer retention. Sonus was formed to meet this mission, and is working closely with carriers to enable them to realize this promise."

Sonus Networks is funded by 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

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 proven success records in the development and delivery of carrier-class equipment to support data, voice and multimedia information.