| BT As the representative of P2 P technology, though it has a good performance, when faced with a complex network environment, the efficiency of its distribution may be greatly affected: the policy of priority for local scarce resources may be that local scarce resources are not the globally scarce resources, Leads to a lot of duplication of scarce resources are not be done in time and reduce the efficiency of document distribution; nodes will communicate each other for Resource information before downloading, This content collaborative downloading will not only increase network traffic and content than spend additional processing; tracking server of BT network has not organized nodes, Random network may lead to uneven distribution of resources, which affects the efficiency of the distribution. Recent research results show that, P2 P file sharing system based on network coding can avoid the complex and inefficient content negotiation and resource scheduling algorithm and ensure uniform distribution of resources, and in the case of that network coding system does not affect the speed of transmission speed, it improve system performance. In this paper, based on network coding and the idea "download while uploading”, Author design new way for download and add the function of network organization in tracking, with new scheduling algorithm scheduling algorithm then design and implement a file distribution system. The main the study of author are as follows:1. Research of P2 P technologies. Study various structures of P2 P network and analyzes the advantages and disadvantages, study the BT download protocol. According to the technical specifications, analysis of the issues that they might face in complex network environments and demonstration network coding will make it more efficient and stable distribution.2. The proposed use of GF(p) domain to realize network coding algorithm in file sharing, and design pipelined resource scheduling algorithms. Studied the structural principle of linear random network coding and related content finite field, recent analysis based on network coding file sharing system papers and found that it encodes are based on GF(28) domain, which is not high for the utilization of computer word shortcomings, the paper used in GF(p) domain to achieve coding algorithm, and proved theoretically using GF(p) can significantly improve the encoding and decoding speed; proposed organization to join the network function in BT tracking server, enabling streamlined resource scheduling, improve download stability.3. Design and implementation of network coding algorithms and achieve streamlined download on GF(p) domain file distribution system. Resource scheduling algorithm uses a pipelined data transfer time before its GF(p) domain of the random linear network coding, and change the way resource requests, tracking server to join the network organization functions, so that the node download; this paper system uses a centralized P2 P structure Select the other nodes in the network to download.4. Make the codec and distribution system based on network coding file test. Test results show that: under the same conditions, the use of GF(p) as the number of bits for network coding algorithm more time processing, so the speed in terms of encoding and decoding are about three times using GF(28) when; together with the new After the resource scheduling method, not only has a higher download speed in a stable network, and node dynamically leave will not cause significant impact on the system nodes in download speeds, with high stability. |
