Rapid Development and Deployment of New Carrier Services Re-Defines Competitive Time-to-Market, Creates Major New Service Revenue Potential.

WESTFORD, Mass., December 15, 1998 – Sonus Networks, innovators in carrier-class IP telephony products and services, today introduced the Sonus Open Services Architecture™ (OSA), the industry's first open architecture that supports the immediate development and delivery of new telephony services. The Open Services Architecture lets both carriers and a new breed of independent applications developers rapidly deliver competitive new telephony services. Carriers and industry analysts confirm the OSA's potential to re-shape the competitive dynamics of the carrier market.

Chris Rothlis, Vice President of New Product Development at IXC, noted, "The ability to innovate and immediately deliver new products and services will be a key differentiator for new and incumbent carriers. Sonus is positioned to deliver a true carrier-class IP telephony platform."

The Sonus IP Telephony Suite and its Open Services Architecture are targeted at new converged-network carriers and incumbent carriers, both of whom need to rapidly introduce competitive new services, add massive incremental call capacity, and ensure full interoperability with and graceful migration from existing circuit networks. The Sonus IP Telephony Suite and its flagship Gateway Switch let these organizations redefine the state-of-the-art for toll quality voice and create important new customer services to fuel and expand demand. Moreover, carriers achieve substantial operational savings from employing the Sonus Suite as part of a converged IP network for voice, fax, data, video, and other applications.

The Sonus Open Services Architecture Slashes Time-to-Market of New Services

Sonus closely collaborated with carriers to develop the Open Services Architecture. The result is an open and unique platform that fosters innovation, slashes time-to-market for new services, and redefines the dynamics of the competitive carrier market.

Enabling New Third Party Developers and Enterprise Services

The Open Services Architecture conforms to existing standards, with published APIs that open the carrier services market to a new segment of developers who can - for the first time - build new caller services on IP servers. The Open Services Architecture also allows carriers to offer services that their customers can configure and manage themselves via open interfaces such as Web browsers. Sonus Chairman Rubin Gruber observed: "The Open Services Architecture is the first true open blueprint for innovation and expanded IP Telephony services. It clearly sets Sonus apart from both traditional circuit switch vendors and IP telephony vendors who use closed development platforms."

Key Open Service Architecture elements include:

• Interworking with SS7-based services, allowing continued support for existing applications on carriers' SCPs or supplied by service providers
• Policy-based service management, allowing centralized management of services and provisioning while distributing processing to maximize scalability and minimize cost;
• Rapid service development, allowing new services such as conferencing, language translation, enterprise VPNs, and merged multi-media to be implemented on standard hardware and software platforms;
• Open APIs, allowing equipment from multiple vendors to interact to provide the desired services. Carriers can flexibly combine services developed internally, by network equipment providers, and by third parties;
• Full Interoperabilitythrough compliance with key standards such as LDAP and the emerging MGCP;
• Script-based service definition, allowing carriers to rapidly define and deliver new services by simply using scripts that invoke processing facilities within the gateways; and

"Sonus' attention to real service provider requirements, from network management details to price/performance and the ability to develop new services independently and rapidly, distinguishes them from both legacy switch developers and IP telephony market entrants with proprietary platforms, and holds the potential to re-shape the pricing and competitive nature of the carrier market," noted Probe Research Executive Vice President Hilary Mine. "The Sonus Internet Telephony Suite's true carrier-class capacity, scalability, form factor and ability to interoperate with and enhance the existing telephony infrastructure positions Sonus as the leading vendor prepared to leverage the multi-billion market for IP Telephony," observed Paul Johnson, leading industry analyst and a co-author with Geoffrey A. Moore of The Guerilla Game: An Investor's Guide to Picking Winners in High Technology.

Sonus President and CEO Hassan Ahmed summarized: "While IP telephony will undoubtedly yield early and substantial operational savings, its most powerful impact will be in the redefinition of the market forces that define carrier competitiveness. The Open Services Architecture drives this shift, opening the door to a new market era of advanced, targeted customer services and service revenues."

Availability

The Sonus Open Services Architecture will be delivered on the Sonus Gateway Switch (see related press release) and future Sonus IP Telephony solutions.

About Sonus Networks

Sonus Networks, Inc. is developing and marketing the next generation of carrier-grade IP telephony. Its equipment facilitates the movement of telephony from traditional circuit networks to packet networks, enabling a host of new carrier and end user services. The Sonus management and engineering teams have proven success records, having led organizations such as Ascend Communications (Nasdaq:ASND) and Summa Four, recently acquired by Cisco (Nasdaq:CSCO), where they directed the development and delivery of carrier-class equipment to support data, voice and multimedia information. Sonus Networks was recently awarded the prestigious Hot Startup of the Year Award by Data Communications Magazine. Additional information is available at www.sonusnet.com