Industry Leader Triples Density of GSX9000 Open Services Switch; New Release 4.0 Software Expands International Capabilities

WESTFORD, Mass., February 25, 2002 - Sonus Networks (Nasdaq: SONS), a leading provider of voice infrastructure solutions for the new public network, today announced significant enhancements to its award-winning hardware and software platforms with the latest versions of the company's GSX9000 Open Services Switch and Insignus Softswitch. These new product releases, which are geared to the requirements of large telecommunications providers as well as international service providers, extend the Sonus solutions that currently transport more than 2.0 billion minutes of traffic per month in live carrier networks worldwide.

"From the very beginning, we architected our solution set with the requirements of the world's largest service providers in mind," said Mike Hluchyj, founder and chief technology officer, Sonus Networks. "The new capabilities announced today build upon the technologies that have been deployed in global production environments for nearly three years, to deliver even higher levels of performance, scalability, reliability and interoperability."

Sonus is enhancing the GSX9000 Open Services Switch through the addition of new circuit modules, which significantly increase port capacity of a single chassis. By tripling the density of the GSX9000, Sonus' industry-leading platform represents the highest density packet voice solution on the market today. The GSX9000 features new higher density T3 interfaces, as well as optical interfaces designed for Asian and European markets, including STM-0 and STM-1. The GSX9000's high-density circuit modules feature the most advanced DSP technology available. The combination of the latest in DSP technology and the GSX9000's mature, fully featured software make it particularly well-suited for deployment with major service providers worldwide.

"BellSouth has successfully deployed, and is currently running, an Internet Call Diversion solution using Sonus technology," said Herb Cash, network vice president, BellSouth. "BellSouth is pleased with Sonus' focus on customer service and its ability to provide robust and innovative switching technology."

"The advances announced by Sonus today underscore the importance of delivering deployment features that enable carriers to drive minutes across their networks," said Teresa Mastrangelo, senior analyst, Packet Networks & Services, RHK, Inc. "Moreover, the combination of Sonus' highly scalable architecture, mature and resilient software, and broad international capabilities strengthens their position as one of the leading vendors in the emerging packet voice market."

Sonus' Insignus Softswitch also delivers robust functionality for global carrier deployments. In the Insignus Release 4.0 software, Sonus provides support for additional international signaling variants, ensuring that voice traffic can be terminated in the applicable countries. With the national signaling types announced today, Sonus supports nearly 30 different SS7 variants in addition to international versions of ISDN PRI and CAS. New signaling variants include ETSI v3, Belgium ISUP, Denmark ISUP, France ISUP, Italy ISUP, Mexico ISUP, Netherlands ISUP and Singapore ISUP. Sonus' robust signaling interworking capabilities enable service providers, such as multinational or wholesale carriers, to seamlessly and cost-effectively terminate traffic in multiple countries while using a single platform.

"Our early commitment to the international market has resulted in unmatched worldwide packet voice deployments," continued Hluchyj. "For instance, Sonus solutions have been homologated, or certified, in nearly 30 countries around the globe, and as of today, service providers have implemented our systems in at least 16 countries. And of course we're not stopping there - we will continue to expand our industry-leading international capabilities going forward."

In addition to new international signaling variants, the latest release of the Insignus Softswitch provides carriers a simple and flexible method to build the dialing plans of countries across the globe, allowing customers to quickly and easily enter new countries. For additional ease, Sonus has pre-loaded into the Insignus Softswitch a range of dialing plans, including plans for China, Germany, India, Italy, Mexico, North America and the United Kingdom.

The Insignus Softswitch also delivers new features to aid large carriers in the evolution to a packet voice network. Sonus offers support for AIN 0.2, which provides carriers additional customization capabilities needed to support complex AIN (Advanced Intelligent Network) services, enabling them to migrate these legacy services to the Sonus packet voice infrastructure more quickly. The Insignus Softswitch also provides new configurable call processing options that are compatible with the unique, and often proprietary, features of circuit switches, supporting carriers through the transition to next-generation voice architectures.

"As packet voice solutions continue to migrate to mainstream markets and applications, carriers are placing greater emphasis on the day-to-day operational capabilities of new switching systems," said Tom Valovic, program director, IP Telephony at IDC. "As a leader in the carrier gateway switch market, Sonus understands these requirements and is delivering a new set of features which not only enhances the ability to bridge the circuit and packet worlds but also extends packet voice solutions into emerging international markets."

Availability

The GSX9000 Open Services Switch and Release 4.0 software are commercially available today. Pricing for both products is configuration dependent.

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 Sonus' Quarterly Report on Form 10-Q, dated November 14, 2001, 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 and manufacturing and sourcing risks.

GSX9000, Insignus and Open Services Architecture are trademarks of Sonus Networks. Open Services Partner Alliance is a service mark of Sonus Networks. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners.