Sip And Realization

SIP (Session Initiation Protocol) is one of the IP technology signaling protocols. It's proposed by IETF (Internet Engineering Task Force). Based on SIP, combined with traditional voice and its adding value, and by providing the newest real time service and video service over IP network, other more value adding application service provider could be offer a normal expandable plat form. SIP system adopts the distributing structure of Internet absolutely. It has high flexibility and expandability. Just because the series of advantage, SIP is widely used in the next generation network.This paper firstly introduces the definition, operation type, instruction and voice communication protocol including H.323 of ITU-T and Session Initiation Protocol (SIP) of IETF. This paper talks about SIP mostly, analysis the origin of SIP, the Internet instruction and grammar based on client/Server and entities of SIP such as proxy, redirect server and registrar. Also, Vovida Networks Corporation's VOCAL, which is a SIP based VoIP system, is studied. There are analysis of its system requirement and structure in this paper. The last part is the idea and method of SIP system, which is realized by VOCAL after analyzing and modifying its instruction and code.