Research On Network Coding And Its Application In P2P File-sharing System

Network coding theory is an important break-through in the field of network communication. According to the theory, information can be encoded before it is forwarded by intermediate nodes, and the max-flow bound of network multicast can be achieved, which can not always be achieved by traditional storing and forwarding, i.e. traditional routing. Therefore, network coding has improved the transmission efficiency, capacity and stability of entire network. The theory and application about network coding has become hotspot for communication field to research.Based on understanding the core theory foundation of network coding, this paper has studied encoding and decoding algorithms of linear network coding, and emphasized on the application of linear network coding which is used in P2P file-sharing system. The followings are what have been accomplished in this paper:1. The theory of network coding is briefly summarized, and the principles of coding and decoding and construction algorithms for linear network coding are systematically studied.2. The P2P technique and its application used in file-sharing system are introduced. The most popular file-sharing system BitTorrent is analyzed. The working theory and content of BitTorrent protocol are investigated in detail.3. The mainly problems that BitTorrent system has strong dependency on seed nodes, scheduling algorithm is difficult to achieve the global optimization and etc of BitTorrent file-sharing system are analyzed. Based on the investigation of principle of network coding and its merits, this paper proposes a feasible design for P2P file-sharing system NC_BT based on network coding. Meanwhile, the design methodology, framework, workflow, and communication protocol of NC_BT system are designed and introduced.4. According to the design of NC_BT system, the paper focuses on introduction of all client modules'implementation procedure and the core algorithms of the modules are designed. By testing the download performance of NC_BT in actual network environment, the experimental result proves that NC_BT system can correctly solve these problems of BitTorrent.