Research And Application Of P2P Technology

There is a burning problem that how to mange and utilize the information which increases rapidly everyday in modern network. With the development of hardware and machining technique, P2P can be used in the real-life, which use the network idle resource at the edge of the network as much as possible to enhance the handling capacity of the whole network, eliminating server-centric network bottleneck of client/server mode.Chord is a simple accurate and highly efficient ring model of P2P, which was proposed by MIT. Therefore, the research of Chord has a very important significance. In this thesis, we found that exist certain amounts of unreachable links in the fingertalbe of Chord, when the system occur the operation of join, quit or failure frequently, which make Chord's performance falling badly. In order to address this problem, the thesis advices a K-CAN structural dynamic cache protocol based on Chord, which re-builds the fingertable using the"K-CAN"structure, storaging the real-time dynamic network information when routing or searching, which increases the link's availability for use and enhances the chord's adaptability for dynamic network. Meanwhile, so as to maintain the efficiency of Chord query, ECP(Enhanced Chord protocol) retains the fingertalbe entries which were in the original Chord, which is called"standpoint"and is updated by using on-demand strategy, decreasing the cost of maintenance. The results show that ECP can be applied to a highly dynamic environment with good searching performance.Secondly, study of security strategy about P2P network. Each node use the built-in mechanism to interconnect with each other whthout central organization unit, which form a new network, showing the distribution of small-world and free-scacle characters, which provide a good opportunity for the virus's intrusion. For the purpose of solving the problem, we present a newly developed local search immunization strategy in inhomogeneous networks. On condition that we know the neighbour node degree, our proposed strategy uses max-degree-search way to search and immune stronger node. We use the susceptible-infectious-susceptible epidemic spreading model to demonstrate the efficiency of our proposed strategy on ER, BA scale-free and two real networks., the result shows it can eliminate the virus through immunizing the same dense of infected nodes or requires no more immunization doses than other strategy. We also test the relationship between the strategy and clustering coefficient in BA scale-free network.Finally, P2P concept is introduced into the public traffic query system. Comparing with the traditional way which create a model based on adjacency matrix, our proposed system's modeling object is site. The systems's operation mode is that the source site and the destination exchange information and gradually expand the searching domain to complete the search task. P2P-based public traffic query system not only improves the search efficiency, but also can provide dynamic information, such as real-time traffic, site's busy or idle etc, to meet different needs.