Research On Optimization Of Real-time P2P Streaming Media Transfer Protocol

In recent years, the popularity of the Internet and the rapid development of network technology have laid a good foundation for the development of P2P technology. Now, P2P technology has become the key technology of streaming media, and it has been widely used in many fields. However, it still exists some problems. For example, transmission quality can not be guaranteed, network topology and physical topology does not match, and server is overloaded. So how to take full advantage of the multitudinous user nodes'bandwidth resources and processing power in the P2P network to ensure the transmission quality of streaming AV(audio/video) and video playback quality has become the key issues.This paper studied the P2P streaming protocol, analyzed and discussed the advantages and disadvantages of the existing P2P streaming technology in-depth, and put forward a new buffer management model BBVM(Buffer Bitmap Virtual Matrix), which is used to describe the available chunk state in the buffer of a peer and its neighbors, for the lack of current P2P streaming buffer management.Based on the buffer management model, this paper proposed a new dynamic buffer management strategies, TMAP(The Most Appropriate Position). TMAP strategy is mainly used to determine the init buffer window offset, when a new peer just added to the system and the dynamically adjust the window offset during data playback. Besides, this paper also propesed a dynamic buffer synchronization algorithm based on TMAP strategy, which is effective use of the network bandwidth and ordinary users' upload ability to improve the performance of the entire P2P streaming system.In addition, in allusion to the inadequate of current P2P streaming media technology transport mechanisms, this paper proposed a new hybrid Push-Pull transport mechanisms, which decided to use the Push or Pull to forward data based on chunk's Rarity-ratio and the Request-ratio relationship between peers. And it put forward a new hybrid Push-Pull adjustment algorithm, which is effective in reducing the proportion of redundant data in the data transfer process, under the premise of reducing the data transmission delay.The above mechanisms and algorithms were implemented in Java language, the P2P Live Media Streaming System was initially optimized, and it passed the system test, which verified its rationality and effectiveness. In addition, a large number of simulation experiments proved the system's scalability and robustness.