CEO Hassan Ahmed to Deliver Keynote on the Importance of IMS

CHELMSFORD, Mass., September 12, 2005 - At the Voice On the Net (VON) Fall 2005 Conference, Sonus Networks, Inc. (Nasdaq: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, will be highlighting how the rapidly emerging IP Multi-media Subsystem (IMS) standard is redefining convergence for next-generation multimedia networks in both fixed and mobile environments in its exhibit and through participation in several conference presentations. The Sonus booth will feature demonstrations of the Sonus IMS solution which includes: the GSX™ family, PSX™, SGX™, ASX™, Insight Management System™, as well as the Company's recently introduced IMX™ Application Platform. Sonus will also demonstrate a variety of IMS-ready services, including applications that leverage both fixed and wireless broadband services, in the Sonus Network booth, #708.

In addition to Sonus' presence in the exhibit hall, executives from the company will deliver a variety of educational presentations highlighting key trends affecting the packet voice infrastructure market.

Wednesday, September 21, 9:00 am - 10:15 am ET

Session: Breakout Session: VC Investment in VoIP
Speaker: Rubin Gruber, Founder

Wednesday, September 21, 1:00pm - 1:30 pm ET

Keynote: The Importance of the Industry Standard IMS Architecture
Speaker: Hassan Ahmed, Chairman and CEO

Thursday, September 22, 11:15 - 11:45 am ET

Session: VoIP Evolution: Core to Edge, Wireline to Wireless
Speaker: Mike Hluchyj, Founder and CTO

Thursday, September 22, 4:30 - 5:30 pm ET

Session: Update on Gateway Technology
Speaker: Rob MacLeod, Product Manager

Pulver.com's VON Fall 2005 conference begins on Monday, September 19, 2005 and will conclude on Thursday, September 22, 2005. All events will be held at the Boston Convention Center. Fall VON 2005 is the leading conference and exhibition for the IP communications industry and is attended by carriers, service providers, mobile operators and vendors. For more information on VON Fall 2005, please visit www.pulver.com/von.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of voice over IP (VoIP) infrastructure solutions for wireline and wireless service providers. With its comprehensive IP Multimedia Subsystem (IMS) solution, Sonus addresses the full range of carrier applications, including residential and business voice services, wireless voice and multimedia, trunking and tandem switching, carrier interconnection and enhanced services. Sonus' voice infrastructure solutions are deployed in service provider networks worldwide. Founded in 1997, Sonus is headquartered in Chelmsford, Massachusetts of U.S. Additional information on Sonus is available at http://www.sonusnet.com.

Sonus is a registered trademark of Sonus Networks. Open Services Architecture is a trademark of Sonus Networks. All other company and product names may be trademarks of the respective companies with which they are associated