Based P2p Video-on-demand System Design And Simulation

As the popularization of Internet and the increase of the number of Internet users, Video On Demnad has become the hot point of Internet application. But the traditional Internet model of C/S communication makes the VOD service quality unsatisfactory because of the limitation of server's performance and bandwidth. IP multicast remains just a research commodity with limited penetration into commercially deployed Internet because of the problems of technology and market. The researchers have begun to consider the use of resources which belong to Internet edge users, and achieve the rapid distribution of video data by P2P technology in the video streaming media network.The most important character of P2P is that it cancels the client/server mode. Within a P2P newtork,a node is a client and a server at the same time. The service is provided by different nodes,not by one. This improves the use ratio of resources, bandwidth of network, etc. Nodes within this network can communicate with each other directly and share resources. Through adding an overly upon the physical network, P2P network can work efficiently.After the analyses of the application of P2P in the field of video streaming network, this paper presents PPVOD, a segment cache streaming network module based on P2P and builds a three-tiered VOD architecture composed of video server, tracker, super peers and common peers. In thePPVOD, every peer exchanges data availability with others, retrieves unavailable data or supplies available data to others. PPVOD makes a good tradeoff between server load and user experience. Its main characteristics include the following parts: (1) low server load, as it uses super peers to manage a certain number of common peers, reducing the tracker's load; (2) easy to implement, as it distributes video streaming data according to different content, and does not have to maintain a complex global structure; (3) good expansibility, as it has better performance with the increase of users; (4) high utilizing of bandwidth, as it can control the peers according to the change of bandwidth of them and make good use of their bandwidth; (5) low delay of peer to peer, as it joins the group which matches the physical network and has the lowest delay to minimize the delay between peers; (6) good user experience, as a peer maintains the source of all segment real-time, and the user can get the date which he or she needs at any time; (7) high user affinity, as a peer only caches a segment of video file, a small mount of hard disk space will be occupied.