Fast Tcp Congestion Control Mechanism

Rapid inflation of Internet scale and the number of users suddenly growth are not only brought forward a higher request to network equipment, also impelled embedded research in protocol. As a widespread used transmission control protocol, TCP is confronted with more challenges: higher reliability, stability and efficiency. This dissertation based on the national tenth five-year 863 plan - "extensible to T bit high performance IPv4/v6 router basic flat and experiment system", we researched a new kind of congestion control algorithm - FAST TCP after analyzed traditional TCP congestion control mechanism. We improved and optimized Fast TCP, make it suitable for T bit router. We proposed a kind of stable Fast TCP — SW-Fast TCP, then tested and evaluated it's performance.The main work of this paper is as follows:Firstly, we classified and compared the congestion control mechanisms in TCP protocol, and summarize the most studies in this field. We gave the shortcoming and excellence of all kinds of congestion control algorithms, this not only summarizes the congestion control algorithms, but also can offer choice in reason for implementation of TCP congestion control algorithm.Secondly, we analyzed data control, window control, burstiness control and estimation component on current Fast TCP in detail, and tested its performance. Through simulation, we analyzed and compared the throughput, intra-protocol fairness, stability and responsiveness among Fast TCP, HSTCP, STCP and TCP Reno. Fast TCP consistently outperforms other protocols in terms of throughput, fairness, stability and responsiveness.Thirdly, we proposed a stable Fast TCP model — SW-Fast TCP, it overcame the shortcoming in current Fast TCP, e.g., Firstly, when it's current state is far from the balanced state, the window changed too violent. It will lead to congestion on sending queue. Secondly, the position of operating point is unreasonable, it will increase the number of lost packets and queueing delay. Thirdly, the function is unreasonable about window change, it will make window oscillations. The result of simulation proved that the window of SW-Fast TCP is more steady, it reduced the possibility of the queues overflows and oscillation. Compared with the current Fast TCP, the performance of SW-Fast TCP get further promotion, and it can satisfy the requirement of T bit router.Finally, we applied SW-Fast TCP to internal subsystem communication in T hit router, according to the congestion control algorithm principle of design and system structure of T bit router, we proposed a kind of realization plan on SW-Fast TCP in T bit router from the systemdesign, and we divided the function within SW-Fast TCP, defined its the structure and the function which needs in T bit router...