Design And Implemention Of SIP Communication System Based On P2P Technology

With the development of Internet technology and IP technology, VoIP related research becomes a popular research field nowadays, and SIP protocol in VoIP gradually becomes a hot topic in VoIP related research because of its low cost and great extensibility.Current VoIP system based on SIP is working in a centralized way for user localization which belongs to C/S mode or mixed mode. If the number of users increases, cost to maintain and configure server increases too which may cause the system bottleneck problem. However, the distributed characteristics and concept of equality of P2P mode provide a good base of solution to SIP applications.This paper selects one routing algorithm in P2P network technology to deal with search and localization of network node and information maintainance, to implement SIP communication system over P2P network. Because of P2P network's characteristics, in this network nodes are categoried to normal node and super node based on node ability, thus the functions of proxy server and registraion server in SIP application over P2P network are implemented by super node to provide registration and search service of node information. A normal node can use the search algorithm to select proper super node be its registration server and proxy server.This paper describes detailedly how to implement functional entities in SIP, such as registration server, proxy server and redirection server. This paper also provides a detailed design of a SIP on-time message system based on P2P networkafter analyzing the most stable open source Vocal stack protocol of current related protocols, and this paper also makes some tests of this system. Experiments results show that, SIP application based on P2P network can distrbute the data originally processed by server to the super nodes, which can reduce a node's operation load and effectively reduce the number of average jumps and average delay to set up a call.