Radvision this week demonstrated support for SIP in its viaIP MCU (Multipoint Conference Unit). During the Voice on the Net show, Radvision connected two Microsoft SIP-based Windows Messenger clients together using the viaIP. Adding SIP support expands the number of devices and endpoints that can connect into a single conference call using the MCU. The SIP functionality will begin shipping in Q2'03. For current viaIP users, a free software upgrade will add SIP support.