Research On System Model Of Video Conference, Protocol Stack And Concerning Extension Based On SIP

Multimedia Session has become a research focus with the development of Internet technology. One important application of multimedia session is Video Conference.Undoubtedly signaling technology is the core one among the Video Conference technologies. Nowadays software and hardware used in Video Conference are based on the protocol suite H.323. Based on signaling architecture of traditional telecommunication network, H.323 is very complicated as well as complete. People have wanted easier controlling technology for Internet that could describe communication ways between different types of multimedia and accord with the features of network connectionless and termination intelligence. So in 1999,IETF issued a signaling protocol—SIP (Session Initiation Protocol). It is used to control signal based on IP-Network and create, modify and terminate a multimedia session as a controlling protocol based on application layer .Comparatively the documents don't abound with multimedia conference systems based on SIP. Without conference controlling service, SIP doesn't have controlling signaling of multimedia channel or communication message of conference that are provided by H.245 in H.323 protocol stack. So it brings a lot of difficulties to the implementation of conference system based the above. On the other hand, application design is of more agility because of it.System model of Video Conference, protocol stack and concerning extension are the key technologies tp the development of Video Conference based on SIP. A good-designed system model of Video Conference based on SIP could quicken the process, and decrease difficulty or risk for the system development. Design and implementation of a good SIP plays an important role in the developing difficulty and lifecycle. SIP extension is also necessary.The following is about the research work including the creative points in this paper:1 .Designing a system model of Video Conference based on SIPVideo Conferences with different scale should adopt different system models, and controlling topology uses concentrating methods. Media topologies differ according to the different conference scale.2. Establishing SIP protocol stack based on oSIPThe oSIP is chosen from five open source SIP protocol stacks. Some new functions are added and some existing functions are modified to establish a SIP...