Research Of P2SP File-Distribution System

The traditional C/S network structure can’t meet the public needs of file downloads. P2P transport is appeared in this environment. The P2SP technology absorbs the advantages of P2P and the traditional C/S.As many advantages of P2SP, the important and novel applications have been from the beginning of the file resources, exchange, development to the points collaborative work, distributed storage and computing depth search.there is a Enormous influence on modern network.Under current technical conditions, P2SP document distribution system, there are many problems in P2SP file distributing system that need to be studied in the actual design. First, the study P2SP system architecture based on existing open source P2SP software source code and technical documentation for the actual work processes in P2SP. The P2SP is revealed in the actual work process. A software design method that is streamline the P2SP of file distributing system is proposed.Secondly, studied the working mechanism of the HTTP protocol for the problem to avoid the repeated transmission of files. Solve the problem that breakpoints transfer files are need in HTTP download mode.Finally, Researching the server files load algorithm for upload server connections too much that led to load too high, using the minimum number of connection algorithm is to solve the problem of high load of upload server.The paper proposes the following innovative ideas that the problems encountered in the system design process.(1) The token bucket algorithm has been improved, designes a new speed limit algorithm. The time accuracy is not enough that led to the failure of the speed limit in the existing algorithms.The approach is to expand the unit time to1S.All tokens are put into the token bucket in one unit time.The Method solves that speed limit failure on the lack of precision and that packet loss exceeds the token bucket threshold (2) Designed a single-buffer, single-threaded sub-algorithm. Adhesion problems is solved optimization algorithm for TCP, fast to send packet, receive packet too slow. the problem of TCP stick package is solved that is formating the packets and using a recursive algorithm to get the complete packet.(3) Designed a high-performance communication architecture that is for the existing design of the IOCP that can not record the business status.The status word that the ability is to record the state of the business is added into the IOCP Key and OverLapp property. The prototype system tested that IOCP with the thread pool can completely solve the performance bottleneck of "A thread for the multi-user, or a user".