Steenkiste, “A conference gateway supporting interoperability between SIP and H.323

Increased network bandwidth is making desktop video conferencing an attractive application for an increasing number of computer users. Unfortunately, two competing standards for video conferencing signaling are in use, H.323 and SIP. In this paper we look at the interoperability between these two standards by developing a conferencing gateway that supports conferences involving both SIP and H.323 clients. By appropriately translating between H.323 and SIP operations, our prototype gateway supports basic multi-party video conferencing between NetMeeting (an H.323 client) and VIC (a SIP client) without modifications to the clients. However, our experiments also show that seamless interoperation would require changes to the client implementations and the standards. Categories and Subject Descriptors D.3.3 [Information systems applications]: Communications Applications – Computer conferencing, teleconferencing, and videoconferencing