Research And Implementation Of A P2P Based Heterogeneous Instant Messaging System

P2P technology, as a newly emerging technology on Internet, with its features such as decentralization, high scalability, load balance and robustness, is becoming a hot topic on Internet research rapidly. Now it is developing with each passing day and is considered to be one of the four most influential technologies on Internet in the future. In the instant messaging (IM) field, many companies and organizations have launched their own distinctive instant messaging systems, but most of them cannot communicate with each other for reasons of business, protocol compatibility, etc., which brings a lot of inconvenience to the inter-communication between Internet users. This thesis presents a heterogeneous IM system that addresses the problem. The core idea is to fast locate a proxy node for heterogeneous message transmission.In this thesis, a heterogeneous IM system prototype is designed and then a specific analysis is made on the structure and functions of network entities with the help of previous research and analysis on P2P technology and DHT routing mechanism. A new naming mechanism is developed to meet the application requirements. The system extends the traditional DHT resource location algorithm and brings up a high efficient proxy node discovery algorithm on fully decentralized structured DHT network, based on which the resource location algorithm and the key process of heterogeneous communication are specified. Node joining and quitting algorithm as well as an original system management and updating strategy are proposed in system design.Open souce protocol XMPP based SIP-communicator and Open-Chord are used as upper IM interface and underlying Chord platform respectively, based on which the core system modules for heterogeneous communication are implemented. Because of the limitation of time and experiment environment, the system is simplified to some extent. Results from simulations and tests show that the heterogeneous IM system can guarantee the hit ratio and the load balance at the same time. These merits together with its high stability make the system applicable to large scale network deployment.