Research And Realization Of VOD System And Its Key Technology Based On P2P Network

Along with the rapid development of the network and the multimedia technology, stream media technology comes out. The live system and VOD system based on the P2P have become the research hot spot.The disadvantages of the traditional VOD system are appearing day by day. On one hand it is because the stream media itself has a high request for real-time controlling and large quantity of data and so on. On the other hand it is because both data source and control center concentrate on the server, but server's I/O and network bandwidth are limited, therefore it provides limited users. P2P technology can fully take use of peer resources, and then effectively reduces the server load. Therefore, VOD system based on P2P network can improve data distribution efficiency and enlarge user scale. The existing models are mainly based on tree or net topology, but there are still some problems.On the base of research on relative technology of the stream media and the existing models, this paper provides PPVOD---a VOD model based on hybrid P2P. It divides three kinds of peer in the model, and discus the functions of each kind peer. Also this paper does research on the essential technology of this model, including the buffer and the schedule mechanism, the participation and withdrawal of peer, the neighbor management as well as the load control and so on And then it give a analysis to PPVOD, contrasts the advantages and disadvantages with other models. At last, it verifies the technology discussed above through the system design and experiment.The key point of VOD system based on P2P network is how to enhance the service of qulity of stream media data and support VCR operation. PPVOD carries on the grouping to the peers, discusses the function of group administration peer, and explains the support to the VCR. GFcache designed in this paper extends Tracker server's functions and enhances data redundancy; The neighbor management module optimizes peer's discovery. Based on all above, it discusses key technology such as buffer and schedule mechanism and unifies the advantages of the tree and the net topology so as to improve Qos.