Design & Implementation Of TCPv6 In The High-Performance IPv6 Router

More requirements are brought forward on routers as the fast development of Internet to broader band and the IPv6 technology. As a key point of the router software framework, TCP protocol is confronted with,more challenges. On the one hand, TCP must provide offer higher throughput, on the other hand, it must sustain IPv6. This dissertation is devoted to the researches of the theory and implementation of TCPv6 according to the requirements of 863 IPv6 router project. The main work of this dissertation is as follows:Firstly, according to the characteristics of TCP, we designed sub-modules and defined the functions of each module for TCPv6 using the modularization idea. The interfaces are also detailedly designed between each module.Secondly, implementation schemes of three modules input module, output module and congestion control module are detailedly designed for TCPv6 module. In the input module, this dissertation adopts the dynamic delay acknowledgement tactic and quick acknowledgement tactic in the slow start phase, which improves the ability of real time and throughput of TCP. In the congestion control module, according to the relations of congestion events, we define a congestion state machine (CCSM). Its state responds to different input congestion events and fulfills different congestion algorithms. This implementation scheme simplifies the process of congestion and its expansibility is good.Thirdly, considering the problem of mass lose of packets in the slow start phase and congestion avoidance phase and the problem of fairness against traditional TCP in High-Speed TCP, this dissertation proposes an improved High-Speed TCP congestion control algorithm (DA-HSTCP) based on dual congestions. The analysises indicate that DA-HSTCP inherits the merit of High-Speed TCP. It can reach high throughput and make the utilization of the bandwidth to the most. Moreover, DA-HSTCP is sensitive to the congestion. It can promptly limit the increasing speed of congestion window in the early phase of the congestion. In addition, it can achieve good fairness with traditional TCP when they are sharing the same link.Finally, the performance of TCPv6 implemented in this dissertation is tested in a simply environment. The results indicate that the average throughput can reach 87.46Mbps, which is enough for IPv6 router.