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Integrates Best Components of Previous Sonus and telecom technologies Partner Programs; Multi-Tiered Program Structure and Interoperability Lab Are Cornerstones of New Program

WESTFORD, Mass., March 19, 2001 – Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, today launched a new and improved program structure for its Open Services Partner Alliance (OSPA), designed to deliver even greater value to both service providers and partners alike. In related news, Sonus also introduced several new members joining the OSPA program, as well as a number of companies who have achieved "Powered" status through successful interoperability testing with Sonus (See today's press releases "Sonus Networks Expands Open Services Partner Alliance with Addition of Eleven Telecom Vendors" and "Sonus Networks Designates "Powered" Status to Four Alliance Partners").

The new OSPA now combines Sonus' original partner program with the INIP PoweredSM Partner Program, which was gained through Sonus' recent acquisition of telecom technologies, inc. The goal of the OSPA program is to empower standards-based interoperability between applications, infrastructure vendors and the Sonus product suite. The program creates end-to-end, integrated solutions for carriers and service providers and accelerates the time to market for these solutions.

"We believe that both our carrier customers and partners will be excited about the enhancements we've made to the Open Services Partner Alliance," said Terri Griffin, vice president of marketing, INtelligentIP(R) division, Sonus Networks. "Now, more than ever, service providers have the ability to gain the competitive advantage with the explosion of next-generation, packet-based enhanced services provided by Sonus' OSPA partners."

A major distinction between the revamped OSPA and Sonus' previous partner programs is the combination of a multi-tiered participation structure and Sonus' state-of-the-art OSPA Interoperability Lab. Companies joining the OSPA enter the program as Sonus Partners, which signifies that these vendors provide products and applications that are complementary to Sonus Networks' product family. Sonus Partners may then elect to become Sonus Powered Partners by successfully completing interoperability testing with one of the Sonus Networks products in the OSPA Interoperability Lab in Richardson, Texas. Sonus Powered Partners then have the ability to become Sonus Platinum Partners when they have proven, commercially deployed products interoperating with Sonus solutions in live service provider environments.

The OSPA is the only program of its kind backed by an interoperability lab where standards-based product interoperability can be verified, trial testing can be performed, and complete best-of-breed solutions are produced. Here, telecom vendors can demonstrate next-generation voice and data communications services in a real-world setting and show the ways in which end users benefit from integrated solutions

"The new OSPA tier structure and interoperability lab address the real issues of carriers and separate the "truth" from the "hype" in the marketplace," continued Griffin.

The new OSPA program now has more than 100 partners offering a wide variety of products that range from network infrastructure and operations support systems (OSS) to next-generation, revenue-generating enhanced services. Through these partnerships, Sonus is committed to offering end-to-end solutions with technologies such as:

• OSPA Enhanced Services - provides carriers applications such as access feature servers, call center/ACD, conferencing, Internet call waiting, IP PBX, one number/personal assistant, prepaid and calling card applications, video conferencing, voice/unified messaging, voice portals and many others.
• OSPA Network Infrastructure - offers a range of products such as application servers, DSLAMs/DSL modems, gateways, softswitches, IADs, media servers, remote access servers, routers, phones, SIP infrastructure products and more.
• OSPA Operations Support Systems (OSS) - includes solutions such as billing mediation platforms, usage-based billing services, service level management, policy engines and provisioning systems.

The Sonus OSPA provides a framework that enables service providers to deploy end-to-end packet voice networks using best-of-breed technologies and applications. By deploying Sonus' market-leading packet-based network solutions, service providers are well positioned to capture market share with the plethora of next-generation packet-based infrastructure and services provided by OSPA members. For more information on Sonus' OSPA, visit http://ospa.sonusnet.com.

About Sonus Networks

Sonus Networks, Inc. is a leading provider of voice infrastructure products for the new public network. Sonus' solutions enable service providers to deploy an integrated network capable of carrying both voice and data traffic, and to deliver a range of innovative, new services. The Sonus Open Services ArchitectureTM (OSA) and award-winning Packet Telephony suite cut the time-to-market for competitive new service products, allowing carriers and third-party developers to expand market share and build important new revenue streams. Its highly scalable products fully interoperate with and extend the life and utility of today's public network. Sonus embodies in its management and staff decades of experience in developing carrier-class voice, data and multimedia solutions for implementation in the world's largest networks. 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' Prospectus, dated January 12, 2001, and associated Registration Statement on Form S-4, 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 Company's ability to grow its customer base, dependence on new product offerings, market acceptance of its products, rapid technological and market change, integration risks relating to the acquisition of telecom technologies and manufacturing and sourcing risks.

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