Research And Implementation Of Instant Messaging System

Instant Messaging is currently the most popular way to communicate on the Internet, so that more and more Instant Messaging software kits have been appearing and service providers offer more and more communication ways nowadays. We should believe that Instant Messaging will have a wide use in the near future and is growing up day after day.This thesis focuses on the core issue of software development and gives analysis to some main functions of modules and configurations of servers and clients. In order to introduce the framework in a more intelligible way, we use the rational rose 2002 tool. It's usefull to find mistakes and insufficiency so as to justify designed framework.Based on the exchange function, which is a basic character of instant messaging system, online user management, safeguarding online users and message exchange are designed on main server. The database used for saving chatting message is adopted in client and it is easily to find a message if the clients want. In order to lighten the load of the server, enhance the robustness and efficiency, and expand it easily, we have considered utilizing TCP to transmit messages. In this way, the main server's treatment ability and corresponding tempo of the server have improved sharply. And it's easy to let us add some main functional modules, such as file translating and video conference.By convention customers want to use the clients' window interfaces easily and practicably. This thesis payes a lot of attention to this issue. It is a main subject to design a wonderful interface, and we have made a drawer menu for the interface which looks nice. In another side, in order to improve the beauty of the whole interface, we use the tools of skin care, named Skin Active, and it has proved its feasibility.In order to deal with problems in NAT traverses, this thesis analyzes and resolves some NAT traversal techniques, among which the so called 'Hole Punching', that is simple and robust, will be introduced. And we have discussed three kinds of Hole Punching, especially the communication between various WANs with the TCP protocol.Since communication in LAN is easy to implement, in order to realize the Instant Messaging system perfectly, the main part of this thesis is focused on communication in WAN, not in LAN.By the study and implement of the Instant Messaging system, we have known its development trend and some main questions which are discussed in the thesis..