Technology Research, Based On The Wan, Fine-grained Dynamic Drift

With network scale expanding and network applications developing, people pay more and more attentions to service availability in network environments. In order to get high availability, We not only improve a single server's performance, but try to change the system architecture. For a system with the same servers, Dynamic migration technique can enhance its performance by altering the system architecture. By means of service migration, the technique may implement continuous data transmission under server breakdown.After analyzing the disadvantages of the traditional realizations of dynamic migration technique, we focus on our work on the pivotal implementation technology of WGCTEM (based-on-WAN, fine-Grained, no-Controller, Transparent-to-client and Equal-among-servers dynamic Migration). The following contents are discussed in the thesis.1) Based on the analysis and comparison of traditional implementations of dynamic migration technique, An idea of WGCTEM is presented;2) The related protocols such as TCP and SCTP are mainly discussed;3) Fine-grained TCP connection migration technique is discussed deeply, and assistant technologies in migration system are implemented;4) WGCTEM prototype based on HTTP are designed and implemented;5) The overall designs for combining WGCTEM prototype with the emergency-response and fault-recovery system are put forward.The WGCTEM prototype based on HTTP is significant to the improvement of the system survivability and has been applied into the emergency-response and fault-recovery system, which lays the foundations for the final examination of 863 experts.There are totally six chapters in this paper. In chapter one, the background of our project, application background of dynamic migration technique and the main research areas are introduced. In chapter two, various realizations of dynamic migration technique are discussed. In chapter three, fine-grained TCP connection migration technique based on WAN and its various implementations are discussed. In chapter four, a new idea, namely WGCTEM, is presented, and dynamic migration architecture based on TCP connection migration is discussed. In chapter five, the implementation technology of WGCTEM prototype is discussed, and the overall designs for combining WGCTEM prototype with the responding and recovering system are presented. At last, the work and contributions of this paper are summarized, and the future work is put forward.