Sonus Networks to Host Yankee Group Presentation on Migration to Packet Voice Networks

WESTFORD, Mass., May 13, 2002 - Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, will host a webcast presentation on Tuesday, May 14, 2002 at 10:30 am EST. In the presentation, Christin Flynn, director, Communications Network Infrastructure, the Yankee Group, will discuss the market for packet voice technologies, such as media gateways and softswitches, and how the market is evolving. Ms. Flynn will highlight market drivers and opportunities for packet voice products and the vendors supplying these solutions. Additionally, Ms. Flynn will outline critical strategies for vendors, and will offer valuable insights on the future of the market.

Date: Tuesday, May 14, 2002

Time: 10:30 am EDT

Webcast: The presentation will be delivered via webcast. To access the webcast, go to the Sonus Networks Investor Relations site at www.sonusnet.com. A replay of the webcast will be also available on Sonus' Investor Relations site through Tuesday, June 4, 2002.

About The Yankee Group

The Yankee Group is a global leader in technology research and consulting. Its customers, which include technology vendors and users, benefit from the Yankee Group's accurate, reliable, and trusted research, consulting, and personalized one-to-one client interaction covering communications and IT products and services. Now in its fourth decade, the company is headquartered in Boston and maintains offices throughout North America, Europe, Latin America, and the Pacific Rim. (www.yankeegroup.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 (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.

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.