Today, Microsoft Corp. (Nasdaq: MSFT) and RADVISION (Nasdaq:), a leading provider of multimedia conferencing, communications platforms and software developer toolkits, announced a licensing agreement that will enable third-party developers to integrate the communications capabilities of Microsoft® Office Live Communications Server 2005 with additional Session Initiation Protocol (SIP) communications platforms.

As part of the agreement, Microsoft is licensing to RADVISION the SIP extensions for Live Communications Server. RADVISION will implement and integrate the extensions into its toolkit products and offer the extensions to third-party developers. The SIP extensions for Live Communications Server will be available as optional add-ons to the award-winning RADVISION SIP, SIP Server and Videophone SIP toolkits. Existing RADVISION SIP customers also may license the SIP extensions as an add-on to SIP toolkits previously licensed from RADVISION.

“We are pleased that RADVISION is embracing the SIP standard to extend interoperability for our third-party developers with Live Communications Server on non-Windows® operating systems in addition to Windows-based operating systems,” said Gurdeep Singh Pall, corporate vice president of Microsoft’s Unified Communications Group. “The SIP extensions enable developers to unlock innovation to help businesses make better decisions more quickly by connecting people, information and business processes.”