Based On P2p Technology, Video On Demand System

Because of limited server capacity and network bandwidth,the traditional C/S service model, for video streaming media application, limits the system capacity and scalability. P2P technology can make full use of idle network bandwidth resources and client service capabilities. Through data exchange among clients, it can greatly reduce the pressure on server. At present, the video-based business can be divided into downloading, live-streaming and video-on-demand (VoD). At present, P2P-based downloading system and live-streaming system are mature, and have been widely used. However, because of the features of asynchronous progress and interactive playback, the implementation of P2P-based VoD system has much difficult. Now, it is still relatively hot research topic.After studying the existing P2P technology and VoD technology, this paper proposes a Hierarchical P2P video-on-demand system (HPVoD).First, this paper introduces the HPVoD system from an overall perspective. It divided network into several hierarchical domains in accordance with the topology of ISP. That makes clients connect to the peers in the same smaller domain, thereby reduces the traffic cross domains.Moreover, this thesis describes the design of P2P VoD client system, focusing on the design and implementation of P2P-related modules. After analyzing the existing network service model, it selects the asynchronous event-driven framework. Since scheduling all events in the framework, it reduces the difficulty of programming. HPVoD classifies peer connections according to the proportion of obtained data. Then eliminates poor connections and joins high-quality connections. That improves the system distributing efficiency and user experience. Against P2P VoD application, By combining the passive piece selection and active piece scheduling, this system ensures the video playback, and takes full advantage of nodes'service capabilities. In addition, through using pre-allocation cache management strategies and formating the caching block with the size of piece, it can avoid the fragmentation and improve memory utilization. With caching multivideos in discs, clients can increase the amount of served videos. Moreover, it can reduce server load and bandwidth.Finally, through testing the HPVoD system and the analysing the results, we verifies the availability and performance of HPVoD.