Research Of P2P Streaming Media Technology Based On Network Coding

With the popularity of computers and the rapid development of Internet, Network video become people’s main entertainment. Traditional of C/S mode has cannot meet user, P2P technology came into being, a node (peer) does not need to rely on a central server, each node is equal and can communicate directly with each other and exchange data, serves as client and server identity, it can request service and can provide service too, has high extendedand deployment cost low features elimination and eliminates the streaming media system bottlenecks,it has a good of extended capacity. Network coding combines route and coding of information exchange, it point a new development direction to improve the network transmission capacity. The use of network coding can be on the network intermediate nodes for combinations of data coding and then forward,it can improve the network throughput, reduce the startup delay and improve the network load balancing.The network coding combined with P2P technology, which can reduce the time delay of data transmission system, strengthen the robustness of system.This thesis first introduces P2P technology, streaming media technology, P2P streaming media technology and network coding, focuses on application of network coding in P2P streaming media, discusses the application of network coding in P2P streaming media, detailed analyses the existing network coding based P2P streaming media system, and points out the existing problems, easy to produce redundant data and system delay. Aiming at this problem, this paper from the reduced data redundancy and the transmission delay of two aspects to be improved, designs based on network coding with comprehensive factors scheduling P2P live streaming media system NCCFS (Network Coding with Comprehensive Factors Scheduling), scheduling algorithm considers the urgency and the scarcity of data to determine the number according to the period of priority, and estimates the neighbor nodes network bandwidth, according to the data segment priority and each neighbor node bandwidth determines the data transmission order and direction, data scheduling uses push-pull strategy, when the node just joined the system, take the initiative to the neighbor customization of a small amount of data, active accurately obtain the playback data segment need, at the same time the neighbor node down sending data segment number, once these successful decoding, a node into the stable play stage, nodes no longer actively send data request packet, node through the push strategy to obtain data. If the data segment when the nodes near the playback deadline is not decoded using pull strategy, node to active to neighbor nodes request data to avoid data streaming have stalled phenomenon, pull as a remedial measures to meet the continuous playback. Simulation results show that NCCFS effectively reduces playback delay and control overhead of the system, improves the quality of playback of streaming media.