Clarent and Siemens Atea Announce First Fully Featured IP Telephony PBX Integration for IP Networks; First Product Launch Following Siemens/Clarent OEM Announcement.

REDWOOD CITY, Calif.--(BUSINESS WIRE)--Nov. 16, 1999--

Clarent(R) Corporation (Nasdaq:CLRN), a worldwide leader in carrier-grade, phone-to-phone IP telephony solutions, and Siemens Atea, a leader in the provisioning of global private, public and mobile telephony networks have announced the development of a VPN-IP (Virtual Private Network over IP) solution that is intended to allow fully featured and transparent PBX networks over IP telephony-based networks.

This solution is the first combined product announcement following last month's announcement of an OEM relationship between Clarent and Siemens.

Today, ITSPs (Internet Telephony Service Providers) and data telcos approach major corporate clients with a challenging offer to converge their telephony and data network into one single Virtual Private Network based on IP.

However, until now, ITSPs did not manage to create a major breakthrough into the corporate VPN market, in part because they could only offer a limited number of telephony features. Traditionally, PBXs in these medium and large companies are linked via point to point digital leased lines using signaling protocols such as DPNSS (Digital Private Network Signaling System) or QSIG (Q-reference point signaling). These protocols provide inter-PBX signaling for the enhanced features commonly used within a corporate environment. Since this functionality was lacking in the offer of the ITSP's, most corporate network owners were reluctant to sacrifice the enhanced functionality common to today's PBX networking.

To address this drawback, Clarent and Siemens Atea have developed a VPN-IP solution which is designed to allow a single communications network based on IP to transmit both the inter-PBX signaling information needed for the enhanced PBX features and the voice conversations over the same network. Consequently, all typical PBX features such as "call back when free," "calling name display," "network-wide call pickup" and "central attendant" may be made available network-wide over IP.

By offering a VPN-IP solution, ITSPs and data telcos should be able to allow enterprises to take full advantage of low cost long distance and international calling without compromising the efficiency and user-friendliness of their corporate networks. Furthermore, having one single network introduces a whole range of possible network management and maintenance cost savings to the enterprise.

Another anticipated benefit of the Clarent Siemens Atea VPN-IP solution is the flexibility to replace the private line point-to-point signaling connections in the enterprise network with an IP-based point-to-multipoint solution.

Matthew Chiang, director, Enterprise Products, Clarent Corporation said of the announcement: "We are delighted to work with Siemens Atea in this solution. VPN-IP is designed to increase functionality and reduce costs for the corporate user and therefore speed up the implementation of IP telephony in the enterprise."

Trials for the VPN-IP solution are currently underway. One of the beta trials is with Mitel, Inc., a manufacturer and major provider of PBX's and PBX networks. "The rapid deployment of network IP telephony in our markets is contingent upon our ability to provide fully featured, highly transparent PBX networks in both national and international applications," said Bill Tommaney, chief engineer of Mitel, Inc. Systems Engineering group, located in Dallas, Texas.

"Mitel's Systems Engineering group has been testing the Clarent/Siemens VPN/IP solutions in conjunction with Mitel PBXs equipped with Mitel Superswitch Digital Network (MSDN)/Digital Private Network Signaling System (DPNSS) capabilities. The MSDN/DPNSS networking capability has been successfully demonstrated over IP. With this capability, we can recommend a feature rich, transparent IP telephony solution for existing or future Mitel MSDN/DPNSS network users. This solution can accommodate simple or complex, and national or international networks."

Commercial availability is targeted for this quarter (4th quarter 1999).

Forward Looking Statements

This release may contain forward-looking statements regarding Clarent's products, business, customers or other factors that may affect future earnings or financial results. Such statements involve risks and uncertainties, including but not limited to potential issues relating to interoperability, inability to introduce new products, ability to retain key customers, changes in market conditions, government regulations, the international communications industry, technological changes 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 quarterly report filed with the Securities and Exchange Commission on Oct. 25, 1999.

About Clarent Corporation

Clarent Corporation is a premier provider of scalable, IP telephony products to carriers and Internet service providers around the world. Clarent's intelligent architecture and the Clarent Command Center enable Clarent products to route, manage, inter-connect and terminate high volumes of calls for service provider customers including the world's largest long distance telecommunication companies. According to a Cape Saffron report published in 1999, more minutes travel across Clarent-enabled networks worldwide than those of any other equipment supplier.(1)

Founded in July 1996, Clarent is headquartered in Redwood City and has offices in major cities in Asia, Europe, Latin America and North America. Additional information about Clarent is available at http://www.clarent.com.

About Siemens and Siemens Atea

The Siemens Information and Communication Networks Group was established on Oct. 1, 1998 as part of the restructuring of the Siemens Information and communication activities. Information and Communication Networks has around 60,000 employees and sales of about DM 24 billion, making it one of the world's leading suppliers of end-to-end solutions for voice, data and mobile networks.

Information and Communication Networks provides products, systems, solutions, servicing and support for setting up, operating and maintaining complete corporate and carrier networks. It also offers ancillary services ranging from network planning and financial consulting through startup support to user training. Further information on this Siemens Group can be found on the Internet at http://www.siemens.com/ic/networks/.

Siemens Atea is part of the new Siemens organization "Information and Communication Networks" (ICN). The company, whose registered offices are located in Belgium, focuses on the development, the production, the marketing and the maintenance of integrated network solutions. Siemens Atea is active in over 60 countries around the world. Siemens Atea employs approximately 1,500 people, of which 1/3 are active in research and development. The total yearly turnover is 10.6 billion BEF, of which 50% is generated by export. Additional information on Siemens Atea is available at www.atea.be.

Note to Editors: Clarent is a registered trademark of Clarent Corporation in the United States and other jurisdictions. All other company or product names mentioned may be trademarks or registered trademarks of the respective companies with which they are associated.

(1) Cape Saffron "Global IP Voice/ Fax Market 1999." Cape Saffron is a UK-based research group focused on the international voice market. http://www.capesaffron.com