RiverDelta Networks and Clarent Demonstrate End-to-End IP Telephony for Broadband Networks.

Business/Technology Editors

CHICAGO--(BUSINESS WIRE)--June 11, 2001

-- Per-Flow Queuing and Statistics Collection Enables Integrated

Voice and Data Management --

RiverDelta Networks, Inc., a leading provider of carrier-class broadband routing, switching, and service management solutions, and Clarent(R) Corporation (Nasdaq: CLRN), a leading provider of softswitch and Internet Protocol (IP) communications solutions, today announced a demonstration of a PacketCable(TM)-based end-to-end IP Telephony solution. Comprising the Clarent OpenAccess(TM) solution and RiverDelta Networks integrated CMTS/edge router, the system is being demonstrated at Cable 2001, the National Cable Television Association's 50th Annual Convention & International Exposition, June 11 - 13, in Chicago, IL at RiverDelta's booth #3728 and Clarent's booth #4755.

The RiverDelta Networks and Clarent solution is designed to provide broadband operators:

-- A fully redundant Cable Modem Termination Switch (CMTS)/router,

-- A highly scalable, standards-based softswitch incorporating the

essential elements of a traditional Class 5 telecommunications switch,

-- High-capacity VoIP gateways for connecting telephone voice, fax and modem data calls over the Internet or a TCP/IP Intranet, and

-- Customer premise gateways that connect business and residential users to the converged network.

"The successful delivery of voice services over IP infrastructure requires strict Quality of Service (QoS) control and intelligent, carrier-class routing at the edge of the broadband access network. By building a highly reliable network infrastructure and isolating each traffic stream using hierarchical per-flow queuing, broadband service providers can create new revenue streams by offering Voice over IP (VoIP) services," said Dave Callan, President and CEO of RiverDelta Networks.

"The type of PacketCable-based solution being offered by RiverDelta Networks and Clarent will enable cable operators to introduce high-quality telephone services and add potential new revenue streams," said Steve Craddock, Vice President, New Media Development, Comcast Corporation. "The availability of integrated voice and data management systems will be a major step in the mass deployment of IP voice and data systems."

The integrated voice and data management solution is designed to enable broadband operators to create and manage diverse, highly differentiated services by integrating voice and data from a single platform, rather than multiple management systems that are typically required. Broadband operators will be able to deliver the end-to-end QoS requirements needed for low-latency applications such as voice, as well as collect usage statistics, automate service creation, subscriber management, and provisioning to support new users and services, as well as additional providers of both content and services.

"The combination of Clarent's fully-featured VoIP last mile OpenAccess solution and RiverDelta Networks' integrated CMTS/edge router is an essential step on the cable operators' path to deploying VoIP services. Uniting the two solutions creates the ultimate IP Telephony solution for cable networks," said Michael Pritz, vice president of marketing, Local Access Business Unit, Clarent Corporation. "To date, VoIP trials have been based on subscribers willing to live with a `best attempt' at service. The advent of a CMTS solution with five-nines reliability provides cable operators with the high quality and availability necessary to meet the needs of the telephony services market."

PacketCable-based end-to-end IP Telephony

Providers can deliver VoIP over Hybrid Fiber Coax (HFC) access networks, with the Broadband Services Router(TM) (BSR) 64000 and Clarent's OpenAccess solution. Clarent OpenAccess comprises three principal elements:

-- Clarent softswitch: The Clarent Call Manager(TM) and the Clarent Command Center(TM), provide a highly scalable, standards-based service and application platform that offers the essential elements of a traditional Class 5 telecommunications switch. It also includes a comprehensive set of tools to enable the development of next generation service applications by third parties.

-- Clarent Customer Premise Gateway (CPG): The Clarent OpenAccess solution provides a wide variety of customer premise gateways that connect business and residential users to the converged network.

-- Clarent Trunking Gateway: The Clarent OpenAccess solution also utilizes Clarent's high capacity VoIP gateway, Clarent BHG, for connecting telephone voice, fax and modem data calls over the Internet or a TCP/IP Intranet.

The SmartFlow(TM) QoS features of the BSR 64000 perform content-aware packet classification through Layer 4 to provide improved QoS flexibility. Since all the processing-intense filtering, forwarding, accounting, and QoS functions are performed in hardware at wire speed, the BSR 64000 reduces latency to a fraction of that commonly found in mainstream, software-based routers.

The RiverDelta Networks BSR 64000 is designed to provide hierarchical per-flow queuing so that every voice call can be guaranteed Public Switched Telephone Network (PSTN) levels of voice quality. VoIP application flows can be isolated at the edge of the broadband network and the proper QoS treatments can be applied to ensure toll-quality voice services. Broadband operators can support multiple revenue-sharing partners by isolating CLEC traffic and allowing subscribers to self-select voice providers.

"The advent of carrier-class redundancy and intelligent, per-flow QoS make IP Telephony over the cable network a service offering that delivers the high quality that consumers have come to demand from their phone service," continued Dave Callan, President and CEO of RiverDelta Networks. "Broadband providers can now capture subscribers from both Incumbent Local Exchange Carriers and Competitive Local Exchange Carriers and gain a competitive edge by building close, long-term subscriber relationships by bundling voice, broadcast television, Internet access and other enhanced services as part of a complete broadband product offering. This is a solution that is ready for deployment today."

AVAILABILITY

The PacketCable-based end-to-end IP Telephony system is currently available from RiverDelta Networks and Clarent.

About RiverDelta Networks

RiverDelta Networks, based in Tewksbury, MA, designs, develops, and markets solutions for broadband service providers building carrier-class networks for delivering voice, data, and video services for consumers and businesses. RiverDelta Networks received CableLabs(R) DOCSIS 1.0 qualification in record time and has built upon and extended the DOCSIS 1.1 Quality of Service specifications with its SmartFlow per-flow processing. RiverDelta Networks has received $46 million in funding from Pequot Capital Management, Battery Ventures, and Charles River Ventures. Additional company information can be found at www.riverdelta.com.

About Clarent

Clarent Corporation (Nasdaq:CLRN) is a world leader in providing intelligent, software-driven products for new generation, IP-based communications networks. Clarent solutions enable interconnection among communications service providers' disparate networks and foster the creation of global footprints for more than 300 telecom service providers worldwide, including AT&T, NTT and China Telecom. Clarent's software platform and softswitch encourage innovation by allowing carriers to develop multiple new features for consumers and enterprises. Founded in 1996, Clarent is headquartered in Redwood City, Calif. and has offices in Asia, Europe, Latin America and North America. To learn more about Clarent, visit its Web site at www.clarent.com.

Note: RiverDelta, Broadband Services Router, and SmartFlow are trademarks of RiverDelta Networks. DOCSIS and PacketCable are registered trademarks of Cable Television Laboratories, Inc. Clarent, the Clarent logo, Clarent Call Manager, OpenAccess, Clarent Command Center, Clarent ThroughPacket, Clarent CPG, and Clarent OpenAccess, are trademarks or registered trademarks, and "The Clearer. The Better" is a service mark of Clarent Corporation in the United States and other jurisdictions. All other trademarks are properties of their respective owners.

Forward Looking Statements

This release contains forward-looking statements, including statements about the functional capabilities of integrated Clarent/RiverDelta solutions and the benefits that the integration of Clarent's and RiverDelta products presents to broadband providers. These statements involve risks and uncertainties, including potential issues relating to successful deployment and market acceptance of the integrated Clarent/RiverDelta solutions, the technical and functional performance of the integrated solutions, successful interoperability, technological performance and other factors, which could cause actual results to vary materially from those expressed in or indicated by the forward-looking statements. These risks and uncertainties are described further in the risk factors discussed in Clarent's periodic filings with the SEC.