Sonus Networks and Atreus Systems Launch Self-Service Solution for VoIP and IMS-based Offerings

User Self-Provisioning Portals Empower Service Providers to Rapidly Deliver Advanced IP Offerings to Business, Residential and Wholesale Markets

GLOBALCOMM, Chicago, IL, June 6, 2006 – Sonus Networks, Inc. (Booth #33077; Nasdaq: SONS), a leading supplier of service provider voice over IP (VoIP) infrastructure solutions, and Atreus Systems™ (Booth #50085), the leading supplier of provisioning software for VoIP, IMS and advanced IP service bundles, today announced that they have extended their partnership to deliver a Self-care Access Portal as part of the Sonus Certified Voice over Broadband (VoBB) solution. The Self-care Access Portal is designed to help service providers offload operating costs and dramatically improve the user experience for VoIP subscribers.

As a member of Sonus' Open Service Partner Alliance (OSPA), Atreus will partner with Sonus to deliver a fully integrated, best-in-class Self-care Access Portal that empowers service providers to automate the configuration and management of VoIP features, giving end users more flexibility, simplicity, and increased service personalization that are the hallmark of next generation voice offerings. The Self-care Access Portal delivers a wide range of compelling service management capabilities directly to the end user, including:

• an intuitive web-based self-care portal for Consumer VoIP;
• simplified user-driven voice feature configuration;
• detailed logs of incoming, outgoing and missed calls;
• simplified voicemail download and playback, and
• entry-level solution that easily migrates to the full self-provisioning solution for Business VoIP, Wholesale VoIP and IMS-based offerings.

Powered by Sonus' award-winning IP Multimedia Subsystem (IMS)-ready architecture, the Sonus VoBB solution enables the rapid deployment of full featured voice service, including next generation enhanced services such as the Atreus Self-care Access Portal. Atreus' carrier-grade provisioning solution empowers service providers to lower costs, simplify market trials, and rapidly introduce compelling communications bundles via direct, reseller and partner channels.

“By leveraging the interoperability and IMS testing capabilities of the OSPA, Sonus is able to deliver a VoBB solution that streamlines the complex business and operational challenges associated with launching new voice offerings,” said Steve Edwards, chief marketing officer, Sonus Networks. “This partnership with Atreus enables us to specifically address the increased end-user demand for greater customization without sacrificing ease of use.”

“Together, Atreus and Sonus are helping service providers of all sizes unlock VoIP's potential with entry level self-care portals and facilitating their migration to fully-featured user self-provisioning solutions,” said Len Castelli, vice president of business development, Atreus Systems. “This partnership will help service providers to differentiate themselves by automating the processes to quickly turn up VoIP and rich IMS-based multimedia offerings for business, residential and wholesale markets.”

Visit Atreus at booth 50085 and Sonus at booth 33077 of the GLOBALCOMM Conference in Chicago, IL, from June 5-7, 2006. Learn how Atreus and Sonus are helping communications providers win new business and lower costs with automated provisioning and customer self-management solutions for Hosted PBX, IP Centrex, Business Trunking and rich IMS-based multimedia services.

About Atreus Systems

Atreus Systems™ is the leading supplier of provisioning software for VoIP, IMS and advanced IP service bundles. Atreus is the vendor of choice for the delivery of advanced IP services by leading providers, including Qwest, Telus, Aliant, Voila IP and Xspedius. Atreus has formed strategic partnerships with BroadSoft, Ericsson, Level 3, Sonus and Sylantro, delivering carrier-class reliability and scalability for VoIP, IMS and advanced IP bundles. For more information, visit www.atreus-systems.com.

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. Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain forward-looking statements regarding future events 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 the “Risk Factors” section of Sonus' Annual Report on Form 10-K, dated March 13, 2006, filed with the SEC, which identify important risk factors that could cause actual results to differ from those contained in the forward-looking statements. Risk factors include among others: the impact of material weaknesses in our disclosure controls and procedures and our internal control over financial reporting on our ability to report our financial results timely and accurately; the unpredictability of our quarterly financial results; risks associated with our international expansion and growth; consolidation in the telecommunications industry; and potential costs resulting from pending securities litigation against the company. Any forward-looking statements represent Sonus' views only as of today and should not be relied upon as representing Sonus' views as of any subsequent date. While Sonus may elect to update forward-looking statements at some point, Sonus specifically disclaims any obligation to do so.

Sonus is a registered trademark of Sonus Networks, Inc. Sonus GSX9000 Open Services Switch, PSX Call Routing Server, SGX Signaling Gateway, and the Sonus Insight Management System are trademarks of Sonus Networks, Inc. All other company and product names may be trademarks of the respective companies with which they are associated.