NTT Com Implements Sonus Systems for Internet Offload, Carrying Live Traffic Today; Japanese Carrier Plans to Deliver Packet Services on Sonus-based Network

WESTFORD, Mass., November 18, 2002 – Sonus Networks (Nasdaq: SONS), a leading provider of packet voice infrastructure solutions for the new public network, today announced that NTT Communications (NTT Com) is using Sonus' Open Services Architecture (OSA) and packet voice infrastructure solutions to offload modem-generated Internet traffic from its circuit-switched network, providing significant cost benefits to the Japanese carrier. NTT Com has also begun a field trial of enterprise VoIP services using the Sonus platform. NTT Com's service offers business users low cost, reliable voice service, providing key enterprise capabilities such as voice VPN and private numbering plans.

"As one of the world's leading carriers, NTT Com is keenly focused on its mission of becoming a global IP company," said Hassan Ahmed, president and CEO, Sonus Networks. "To fulfill this vision, NTT Com is implementing innovative new technologies to deliver new IP-based services offering greater value to their customers. We are very proud to be working with NTT Com in this endeavor, and look forward to continuing a successful partnership."

NTT Com has implemented Sonus' solutions, which support critical Japanese SS7 variants such as NTT ISUP and TTC ISUP, in addition to INS 1500, the Japanese version of ISDN PRI. The Sonus-based network augments NTT Com's existing circuit switches, diverting Internet traffic from its local voice network to relieve network pressure points and free up expensive network resources. With the new packet infrastructure in place, NTT Com can make an easy transition from the initial Internet offload application and enterprise VoIP services to offer enhanced services on the same packet platform.

"By deploying the Sonus systems for Internet offload, NTT Com is able to reduce costs in the short term, which is a priority in these economic times," continued Ahmed. "And with NTT Com's enterprise VoIP service, NTT offers business customers a cost-effective, high-value alternative to traditional PBX-based services."

About NTT Communications Corporation (NTT Com)

NTT Com, a Tokyo-based subsidiary of Nippon Telegraph and Telephone Corporation, provides long-distance and international services for voice, video and data communication reaching more than 200 countries. NTT Com also provides world-class IP services under the NTT/VERIO brand, as well as managed data, multimedia and additional services under the Arcstar brand. For details, please visit www.ntt.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^TM (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' Quarterly Report on Form 10-Q, dated November 13, 2002 and 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 adverse effect of recent developments in the telecommunications industry, the weakened financial position of many service providers, Sonus' 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.

Sonus is a registered trademark of Sonus Networks. Open Services Architecture is a trademark of Sonus Networks. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.