Sonus Networks Expands Membership in Open Services Partner Alliance; OpenCon Systems and RADVision Join OSPA; Alliance Participation Grows to Nearly 20 Industry-Leading Vendors.

WESTFORD, Mass.--(BUSINESS WIRE)--Aug. 31, 1999--

Sonus Networks, an emerging leader in carrier-class packet telephony solutions, today welcomed OpenCon Systems and RADVision into its Open Services Partner Alliance(TM) (OSPA). The newest members of the OSPA bring to the Alliance considerable experience in the key areas of Operations Support System (OSS) integration and enhanced IP-based services.

With nearly 20 participating vendors, the OSPA allows carriers, application services providers, third-party independent service developers (ISDs) and telephony system software providers to rapidly develop and deliver competitive customer services and applications based on the Sonus Networks Open Services Architecture(TM) (OSA).

"In the new public voice network, services are the name of the game, and Sonus is fully committed to helping carrier customers bring new revenue-generating services to market quickly," said Gary Rogers, vice president of sales and marketing at Sonus. "We're excited to work with our newest partners, OpenCon Systems and RADVision, to offer carriers the ability to not only deliver new IP services, but also to ensure integration of critical legacy Operations Support Systems services."

Sonus' work with OpenCon Systems will help ensure interoperability with carriers' OSS. OpenCon's standards-compliant Billing Mediation Platform and TMN Gateway protocol mediator will interwork with the Sonus Element Management System (EMS) to help carriers seamlessly manage their new IP networks as well as their legacy systems. This will allow for immediate deployment and billing of new services.

RADVision's industry-leading H.323 protocol stack is incorporated into Sonus' GSX9000(TM) Open Services Switch, providing interoperability with H.323 terminals and smaller VoIP gateways, and enabling communication between traditional PSTN-based telephones and new IP-based audio devices. Sonus will also be participating in the RADVision Voice and Video Over IP Convergence Pavilion (Booth #5168) at NetWorld+Interop Atlanta, which is being held at the Georgia World Congress Center, September 14-16.

Launched in June 1999, the OSPA has gained significant industry momentum, with membership of nearly 20 leading independent vendors offering subscriber-specified and user-provisioned services for the New Public Network. The OSPA gives carriers the flexibility to both develop and integrate "best of breed" applications, creating important new revenue streams. For participating partners, the OSPA provides open, published APIs, comprehensive developer tools, testing and support services, technology exchanges and co-marketing and sales activities. Equally important, the alliance provides a unified customer/vendor forum for creating interoperable standards and technologies. Additional information on the OSPA is available at: http://www.sonusnet.com/partners.

About OpenCon Systems

OpenCon Systems (OCS) Inc., founded in 1991, is a turnkey provider specializing in Transmission and Access, Network Management and Communication Software solutions to the communications marketplace. OCS' solutions reside on products such as SONET ADMs, Digital Cross Connects, Next Generation Digital Loop Carriers and Advanced Individual Electronic Systems. The company's equipment vendor clients include Fujitsu and ADC, as well as service providers, such as GTE. Inc. magazine selected OCS as the 90th fastest growing company. OCS, located in Piscataway, New Jersey, is a privately held company. For more information about OCS' products and services, visit the company's web site at http://www.opencon.com.

About RADVision

RADVision is the recognized global technology leader for industry standard "building blocks" needed for enabling voice and video calls on packet networks like the Internet. Virtually all of the builders of voice or video over IP solutions for Internet Protocol (IP) networks rely on RADVision technology and products. The company offers a comprehension suite of multi-protocol developer toolkits for IP telephony and multimedia conferencing, and a family of enterprise networking products that can be used to build a total enterprise IP based multimedia PBX (Private Branch Exchange). As a pioneer and market leader in the area of IP communications, the company participated in defining the H.323 standard and continues to work closely with the ITU and other industry consortia on the evolution and specification of a broad spectrum of IP telephony protocols for voice and video communication. RADVision, together with its industry leading partners, is driving the IP communications revolution by delivering compelling new enhanced applications, services and functionality for converged networks. For more information, please visit RADVision's website at: www.radvision.com

About Sonus Networks

Sonus Networks, Inc. is delivering a new class of carrier solutions that enable the movement of telephony to converged packet networks and the development of a new generation of innovative voice and data services. The award-winning Sonus Packet Telephony suite and Open Services Architecture (OSA) cut the time-to-market for competitive new service products from years to weeks, allowing carriers and third-party developers to sustain and expand marketshare, 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, founded in 1997, is headquartered in Westford, Massachusetts and is privately held. Additional information is available at: http://www.sonusnet.com.

Open Services Partner Alliance, Open Services Architecture and GSX9000 are trademarks of Sonus Networks. All other company and product names may be trademarks of the respective companies with which they are associated.