SONUS NETWORKS' GATEWAY SWITCH, IP TELEPHONY SUITE ARE FIRST WITH THE CAPACITY, FEATURES AND SERVICES TO DRIVE GLOBAL-SCALE IP TELEPHONY 
Global Carriers Project Major Operational Savings, Competitive Services and New Revenue Streams Through 1999 Deployment of the Sonus Gateway Switch and IP Telephony Suite. 

WESTFORD, Mass., December 15, 1998 - Sonus Networks, innovators in carrier-class IP telephony products and services, today introduced the industry's first comprehensive suite of IP-based central office solutions that enable global carriers to implement and fully realize the promise of global-scale IP telephony. The Suite includes the Sonus Gateway Switch (GSW), the first IP telephony switch with the capacity, sophistication and absolute reliability to support tens of thousands of simultaneous calls, and the Sonus Open Services Architecture??, the only open platform for IP telephony innovation that lets carriers and independent developers quickly create and deliver competitive new services. 

In response to today's announcement, IP carriers and industry analysts uniformly praised the Sonus IP Telephony Suite for its unprecedented ability and readiness to support world-class, massive-scale telephony services via managed IP networks. "The Sonus GSW Switch and IP Telephony Suite promise to substantially evolve the intelligence, economics and market dynamics of the IP telephony industry," noted Probe Research Executive Vice President Hilary Mine. "At last we are seeing truly carrier-class equipment that cost-effectively integrates voice and data over IP networks while offering meaningful integration with the existing public switched network." 

The Sonus IP Telephony Suite is 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 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 by employing the Sonus Suite as part of a converged IP network for voice, fax, data, video, and other applications. 

"Sonus is quickly becoming a major new factor in the redefinition of the telecommunications industry," said Yankee Group President Howard Anderson. "By providing the first IP Telephony solution with true voice quality, scalability, and an open architecture for services innovation, Sonus is enabling both new IP and incumbent carriers to aggressively up the ante in terms of service products and pricing. Undoubtedly, this rapid creation and delivery of new services, through which carriers must differentiate themselves, will significantly evolve the market." 

The Move To IP Telephony
According to industry analyst estimates, demand on today's networks is growing at exponential rates, driven by the rapid growth of internet traffic and accelerating demand for voice services. 

Carriers and industry analysts alike agree that the best solution for servicing this demand is a single engineered data network handling all types of traffic and accommodating new services and traffic volumes. Sonus' new generation of equipment meets the strict public utility criteria demanded by this network, including: 

• absolute reliability, 
• full interoperability with the existing Public Switched Telephone Network (PSTN) and Private Branch Exchanges (PBXs), 
• the scalability to support massive call volumes, 
• the openness to support all existing service platforms and future caller services, 
• toll-quality voice transmission and QoS to support next generation voice, data and multi-media applications, and 
• a dense, compact form factor that permits installation in central office locations with severe floor space constraints, frequently referred to as "the world's most expensive real estate." 

The Sonus Gateway Switch: The First True Carrier-Grade Central Office IP Switch
IP holds the clear promise to serve as the foundation of a converged network that powerfully and economically supports all traffic types: voice, fax, data, and video. Its promise for telephony, however, is still unrealized because current products are derived from existing equipment that cannot meet the capacity needs and stringent reliability standards of the public network. The market entry of the GSW brings new viability to IP-based telephony. The GSW paves the way for significant operational savings, new multi-media applications, and the potential for carriers to realize significant incremental revenues through a new generation of targeted customer services. 

Chris Rothlis, Vice President of New Product Development for IXC, noted: "A carrier class solution is needed by carriers to develop the infrastructure of their new IP telephony networks. Sonus is well positioned to provide cost-effective IP solutions for the public network." 

The Sonus Gateway Switch was conceived and built exclusively as a carrier-class solution. It leverages state-of-the-art telecommunications and multimedia hardware, software, and standards to support the carrier requirements of the new converged IP network. The Sonus GSW is the first product that delivers the interconnectivity, capacity and quality to meet the most stringent demands of public carrier networks, including: 

• Reliability - the public network's "five 9's" requirement, ie., 99.999% availability. Designed for full redundancy and hot-swap capability, it is capable of maintaining the integrity and stability of calls during failover. 
• Scalability - the Sonus GSW can scale to thousands of simultaneous calls, equaling and exceeding the capacity of current circuit switches. A single GSW shelf can support more than 8,000 calls; a fully configured GSW can support more than 64,000 calls. 
• SS7 Signaling - the Sonus GSW fully supports SS7. 
• One-stage dialing - "1+" dialing, unlike existing IP telephony solutions which require users to complete complex multi-stage dialing sequences to complete a call. 
• True Toll-Quality Voice - the GSW's high voice quality, extremely low delay, and support for standard IP QoS techniques allow it to provide true toll quality voice. 

Sonus President and CEO Hassan Ahmed, Ph.D., observed: "The Sonus Gateway Switch and full IP Telephony Suite are the foundation through which global IP carriers and incumbents will soon re-define their public telephony network into an intelligent, mass-capacity transport for new applications that will re-shape our ability to work, learn and communicate." 

The Sonus Open Services Architecture
This industry-first open architecture is a unique platform for the rapid development and delivery of new applications, allowing carriers to quickly bring to market competitive new caller services. It offers a clear advantage over legacy closed architectures, with their lengthy service development/delivery cycles. The Open Services Architecture is the result of close collaboration between Sonus and a number of carriers carriers on an open platform for ongoing innovation. The Open Services Architecture leverages standards such as LDAP and the proposed MGCP, and will be delivered on the Sonus GSW and future Sonus products (see accompanying press release.). 

Sonus Chairman and Founder Rubin Gruber concluded: "Sonus was founded with substantial input from new and incumbent carriers, and we're dedicated to providing the absolute reliability, call processing and advanced capabilities that they need to reach their next market stage. Carriers no longer have to attempt to deliver massive-scale telephony on platforms built for other, far less demanding conditions, and they'll never again be locked in by proprietary architectures that prevent innovation and immediate responsiveness to their dynamic market." 

Availability
The Sonus IP Telephony solution will begin field trials in the first quarter of 1999. 

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