Sonus Networks Enables IDT Corporation to Expand International Presence

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Sonus Infrastructure allows Carrier to Cost Effectively Deliver SIP-Based Voice Services

ATLANTA, Ga., June 2, 2003 – Sonus Networks (Nasdaq: SONS) today announced that IDT Corporation has deployed Sonus' industry-leading voice infrastructure solutions as the foundation of IDT Corp.'s next-generation packet voice network. With the Sonus-based network, IDT Corp. is able to offer a range of domestic and international Session Initiation Protocol (SIP)-based network services.

"We are committed to expanding our core telecommunications business through investments in our worldwide network infrastructure," said Jim Courter, CEO and vice chairman, IDT Corporation. "In Sonus, we've found a partner that can truly deliver the next-generation carrier-class packet voice solutions that allow us to build a network to support our current offerings and enable us to deliver a range of new services in the future."

Sonus has supplied IDT Corp. with a complete set of voice infrastructure solutions, including the GSX9000 Open Services Switch, the Insignus Softswitch and the Sonus Insight Management System. Sonus' highly flexible and scalable packet voice solutions enable carriers to cost-effectively enhance the capacity of their networks. More importantly, Sonus' solutions allow service providers such as IDT Corp. to support a variety of traditional voice services such as business and residential long distance, wholesale long distance and calling card services, as well as SIP-based enhanced services.

"IDT Corp. has leveraged its two strengths – voice and data transmission – to become an early leader in the packet voice market," said Hassan Ahmed, president and CEO, Sonus Networks. "Now, IDT Corp. is moving to the next level of convergence, and we are extremely pleased to be working with them to create a scalable, high-performance next-generation packet voice network to support their global business initiatives."

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.

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 the "Risk Factors" section of Sonus' Annual Report on Form 10-K, dated March 19, 2003 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. In addition, 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. GSX9000, Insignus, Sonus Insight and Open Services Architecture are trademarks of Sonus Networks. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.