RADVISION Continues to Break New Ground with Version 3.0 of SIP Developer Toolkit.

Business Editors/High-Tech Writers

Fall VON

BOSTON & GLEN ROCK, N.J.--(BUSINESS WIRE)--Sept. 22, 2003

RADVISION (Nasdaq: RVSN) today announced the general availability of version 3.0 of its industry-leading SIP Developer Toolkit, designed to provide tools that enable

Significant new features in version 3.0 include:

-- Advanced SIP call security (TLS)

-- Connection management (persistent connection) functionality

for reduced network overhead

-- Signaling parsing flexibility, allowing SIP User Agents to

receive and fix corrupted messages

-- Flexible URL scheme support

"As SIP communications solutions continue to evolve from basic functionality to now address some of the higher level features of packet-based communications, equipment developers have been turning to third party vendors such as RADVISION for solutions that enable the quick and cost effective development of these advanced features," said Yoni Malachi, Chief Technology Officer for RADVISION's Technology Business Unit. "With the newest version of our SIP Developer Toolkit equipment developers can now easily develop the solutions that will set the standard in features, functionality, security, and reliability."

Cutting Edge in SIP Call Security

TLS (Transport Layer Security) is a security protocol that is typically layered on top of connection-oriented transports, such as TCP. TLS allows client/server applications to communicate over TCP in a way that is designed to prevent eavesdropping, tampering, or message forgery. RADVISION's SIP Toolkit v3.0 enables the development of TLS support in a SIP User Agent, thereby providing a solution for many of the security issues that SIP applications face.

Network Optimization Through Advanced Connection Management

The opening and closing of TCP connections for each message, transaction, or dialog is often not desirable because of the extra messaging overhead of the TCP handshake (even more so in TLS connections). RFC 3261, which defines the SIP standard, permits connection persistency, which reuses an open connection instead of creating a new one. As such, in many cases, a single connection (TCP or TLS) can be reused for different messages, transactions or dialogs.

The persistent connection feature delivered in version 3.0 of RADVISION's SIP Developer Toolkit enables developers to develop applications that seamlessly identify that a message can be sent over an existing open connection and reuse it - thereby minimizing network overhead.

Enhanced Parser Functionality

Version 3.0 of the SIP toolkit enables developers to create applications (e.g., User Agents) which can accept and fix bad message syntax, rather then simply rejecting the anomalous message. This feature is important for both dealing with corrupted message parts and also enables products developed with this toolkit to interwork with other vendors' and/or products' proprietary implementations.

With Enhanced Parser Functionality the SIP product parses messages with syntax errors into regular message and header objects. The SIP stack, delivered as part of the SIP toolkit, then consults with the application, via callback, on how to handle incoming messages with syntax errors. The application can then fix the message syntax and instruct the SIP Stack on how to continue with the message processing (discard the message, reject the message or continue message processing).

General URL Scheme Support

SIP defines and uses different URL schemes, such as SIP, IM and TEL to map SIP IP addresses to other addresses such as telephone number or e-mail. This is a key factor in the ease of use that many experience with SIP-based communications products and architectures. A general framework in the SIP Stack delivered in the Sip Developer Toolkit v3.0 provides support for sending and receiving any type of URL scheme in a SIP device.

Symmetric-response support

When SIP is used over UDP, responses to requests are always targeted to the source address from which the request came, and to the port written into the top most "Via" header field value of the request. However, this functionality is not desirable in many cases, most notably when the client is behind a Network Address Translator (NAT) and so such a message will never reach the target recipient. The new version of the RADVISION toolkit supports the "draft-ietf-sip-symmetric-response" extension, which defines a new parameter for the Via header field, called "rport," which allows a client to request that the server send the response back to the source IP address and port from where the request came.

Availability

RADVISION's SIP Developer Toolkit v3.0 is currently available worldwide.

About RADVISION

RADVISION Ltd. (Nasdaq: RVSN) is the industry's leading provider of high quality, scalable and easy-to-use products and technologies for videoconferencing, video telephony, and the development of converged voice, video and data over IP and 3G networks. For more information please visit our website at www.radvision.com.