Research And Realization Of The Instant Messenger System On The Basis Of P2P

With the development of network technology, as an important application of P2P technology, instant messaging has become the indispensable means of communication in people's daily life. This thesis has explained the principle of instant messaging based on P2P networks in detail, and researched the JXTA architecture and its application. On this foundation, I designed and implemented a fully distributed instant messaging system based on P2P. The system improves the network interoperability and the collaboration performance of network nodes,for it does not need to depend on any particular node and removes the obvious difference between the client and server.JXTA platform released by Sun company is applied in this paper to develop instant messaging system, the JXTA platform has the advantages of cross-platform, cross-operating system and cross-programming language, and these features provides fast support for the realization of completely distributed instant messaging. Through some instant messaging software analysis and comparison, the paper aims at discovery mechanism of P2P communication, designs a new type of hybrid P2P network model,which uses the discovery mechanism based on rendezvous. The model introduces the trust assessment mechanism of P2P nodes, and the trust value of nodes which involved in the communication can be assessed, then according to the level of trust value to select the rendezvous. This thesis has researched the problem of streaming media transmission under the JXTA platform, and conducted a useful attempt of multimedia development and implemented the audio signal transmission. The major functions of the instant messaging system that designed in this paper are the instant text message and audio message transmission between nodes, and the management of peer group as well as members of group, resource sharing and so on.In addition, the paper has structured a simulated test environment according to the characteristics of current network, and carried out abundant tests on the model that this thesis put forward in this environment, the questions that appear in the process to conduct a detailed analysis and demonstration. The system has been basically reached the requirements of the overall design, and each module can work normal.