Design And Implementation Of P2P-VoD System Based On BitTorrent

With the rapid development of the Internet, the information demanded by people is getting more and more enriched and diversified. VoD System, which could provide customers with high-quality images, sound and other recreation services, is under rapid development in the broadband network, as a result of its advantage of choosing the content and controlling the progress freely.The traditional vod system is based on the C/S model. In this model, the bottlenecks existed in band resources and server processing ability restrict the development of industry seriously, and leads to the situation that mass media are unable to pay the high release costs, though they have high quality resources. Therefore, researchers propose the P2P strategy, which can fully utilize the computing power and bandwidth of nodes. This strategy plans that while accepting services from others, nodes also provide services to them, in which way load pressure of streaming media server could be reduced maximumly. Meanwhile, P2P network runs with the way of node self-organizing, which is helpful to realize the operation of join and exit for nodes, and has a big advantage in the fault tolerance and expansibility of system.BitTorrent is a kind of content distribution protocols, which plays a decisive role in the field of P2P resources sharing. However, it was designed originally to provide high-capacity document distribution, but could not meet the real-time requirements for streaming media. Therefore, on the base of BitTorrent protocol, how to construct the VoD system with high fluency is one of the hottest issues in the P2P field.This paper first analyzes the progress of P2P technology and its application fields at home and abroad, especially in the part of the present situation and future tendency of VoD business, and then makes a study of the protocol of BitTorrent file system. On that basis, this paper, combining with priority strategy, improves the BitTorrent algorithm, and puts forward node-choice algorithm and data transmission and scheduling algorithm, which both make the BitTorrent algorithm be applied in the VoD system. According to this algorithm, this paper also designs and implements a P2P-VoD system including four parts:data capture, super peer, tracker server and clients. The experiment result shows that the system equalizes data distribution effectively, improving the utilization of bandwidth resources of node, and can satisfy users’ demands for the business application requirements on VoD.