Implement Of Session Service Based On P2PSIP Technique

As Internet develops rapidly,the multimedia session based on IP network becomes one of the important applications of the next generation network.Being a protocol of creating multimedia dialog,SIP is simple, flexible and has good expansibility.Now,SIP is selected to be the controlling protocol for the IP Multimedia Subsystem and becoming the research hotspot of multimedia communication.The services based SIP like multimedia communication,Presence and IM are gradually coming to maturity and put into reality.At present,because most systems based on SIP use the C/S mode,the performance of system is restricted by the performance of server and the application can't be deployed rapidly and flexibly too.P2P network is good at expansibility,self-organization and reliability, and it can avoid the problem of single failure brought by server under traditional C/S mode.The idea of P2P has been applied in different kinds of service in Internet.But there isn't any standard between nodes in P2P network and P2P technology is rarely used in multimedia communication.The combination of P2P and SIP can optimize the performance of SIP and make up the defect of SIP though the idea and technology of P2P. The P2PSIP system can break away from the server and has more reliability,more expansibility and more flexible in deployment.The P2PSIP system is especially fit for the environment of requiring communication to be built quickly and the environment of building communication in low cost.After the study on P2P network based on Chord,SIP and SIMPLE based SIP,this paper designs a P2PSIP communication system,referring the drafts of IETF P2PSIP working group.The entity in this system is both client and server.The function of server in traditional architecture is replaced by the whole network.The P2PSIP system makes use of the network to store resource,route message and implements the distributed Presence and call service.This paper describes the design by showing the network architecture of system,the message flow and the structure of the module.