Research And Implementation Of P2p Streaming Media On Demand System Cache Strategy

Along with rapid development of large scale storage, high performance work station, broadband networks and data compression technique, streaming VOD service comes into reality technically and economically, enriching contents in Internet. In a VOD system, video server divides files users request into data segments and sends to the network, while client side decodes and plays. However, traditional C/S architecture doesn't demonstrate as good QoS in streaming service as text/picture based web service, especially in scalability and error tolerance.In recently years, P2P network research has called attention on file sharing and application layer multicasting. The core concept of P2P mode is that there is no specific server in the network. Every client is a small server providing data for other clients while receiving data. The basic problems in C/S structure, server overload and resource bottleneck, are resolved by sharing resources and services with direct interaction among nodes. P2P VOD system combines P2P network and VOD system, increases simultaneously supported user scale in the system and improves client side video quality.Buffer management of a P2P VOD system plays an important role in determining the system performance. It includes two parts: super nodes acquire data segments of programs from hard disk, store them in buffer then transmits them to network; common nodes receive data segments, put them into buffer then play them. We research mainly on the buffer management of super nodes.We retrospect existing streaming, P2P network and buffer technique, analyze advantages and disadvantages of current streaming VOD buffer strategy and propose a buffer managing strategy with dynamic and static buffers which fits for super nodes in a P2P VOD system.Based on a complete P2P VOD prototype, we explicate its holistic design and module design, as well as algorithm and API design of buffer strategy. We propose basic concept, implementation and replacement algorithm for prefix buffering in static buffer according to visit orientation for streaming. We also design the buffer queues and major operations in dynamic buffers for suffix buffering on the ground of analysis of super nodes in P2P VOD system. We conduct a performance test whose result justifies the effectiveness of the buffer strategy in this thesis.At last, we summarize the future research issues and direction in this field.