The Design And Realization Of IM System Based On P2P-SIP

Nowadays, SIMPLE is the chief protocol used in IM and it's based on SIP protocol. SIP is a simple, flexible, easy to extended protocol. It is based on clients/server architecture so with the high speed increase of users SIP has got two problems:single point of failure and performance bottleneck. P2P is another information exchange technique, in P2P environment all the points are equal. Meanwhile, the P2P system can't be fail because of one point. SIP and P2P have complementarities in some ways. So researches on how to combine SIP with P2P are very significant. In consideration of application integrity, this system will support off-line message in order to improve service quality.This article first introduces research status of IM, P2P and P2P-SIP. And Then analyzes SIP protocol from functional entity, message type and presence message. Then study on P2P technique deeply, after doing comparison with four classical structured P2P technology we choose Kademlia algorithm to be used in our system and introduces elementary operation, routing search mechanism of it. This article does system design and detailed design on two main modules:P2P and SIP. After realized this system on Windows operating system, we also tested it.The characteristics and innovations in this article are as follows:In consideration of off-line environment, this system has a module to solve this problem.Using module programming method to reduce the coupling and support reusability.