Technology Research Of P2P Based Multimedia Streaming Data Transmission And Scheduling

In the VOD system established with conventional C/S mode, the Servers must transmit each client the same data through the network.For the multimedia data generally bulks large, along with the increasement of the clients, Servers frequently become the bottleneck of the whole system's capacity. In order to lighten the server's load,the P2P-based multimedia streaming technology occurred. In recent years, the peer-to-peer live multimedia streaming business achieves a great success. However, by virtue of the requirment of highly interactive operation (VCR operations) of the vod (video-on-demand) system, implementing such a system involes a lot of complex work, thus p2p-based system hasn't been spread widely.The video-on-demand system is an asynchronous system,when clients play back the same program, each user's starting time may be different. And users would run vcr operations such as: pause, speed, skip backwards and drag, so in the VOD services, larger local buffer and more flexible data scheduling strategy are required; in the traditional vod system, for the sake of relieving the burden of the servers and improve the expansibility of the system,scholars proposed many kinds of data scheduling strategies,all of these scheduling strategies alleviated the load of source server in different aspects and improved the system expansibility as well as the Qos.but as the extension of the system, the expansibility problem still exists; thanks to combination of the multimedia streaming technology with the P2P technology, the reliability and expansibility of the multimedia streaming service system have been greately improved.Still there are some new problems need to be settled.such as: how can the peer find the sources needed,how to select peers to serve the demander with high Qos.how to reduce the user's average delay time and so on.the solutions of these issues are very important to the P2P VOD system.On lucubrating the existing data scheduling strategies, this paper proposed a two-stage indexical resource location technology QuicTrack and top-selection based best sender selecting strategy,which have been implemented in our P2P VOD system─PPVOD.The simulation and analysis indicate that this new kind of scheduling strategy greatly lightens the load of the Tracker server and reduces query messages in the network; the Qos of the system has been improved a lot.