一种改进的基于延迟的TCP拥塞避免算法

An Improved DCA Algorithm for TCP

基于延迟的 TCP 拥塞避免算法(DCA)提高了系统的吞吐量,但在某些情况下 DCA 表现出较差的性能。通过对 RTT 的分析发现,变化的传输延迟和延迟 ACK 将对使用 RTT 指示拥塞引入明显误差,从而影响 DCA 算法的准确性。为此提出了一种改进的 DCA 算法,在判断网络是否拥塞时,先消除这些明显误差。仿真试验表明,该算法更加准确地监测到网络拥塞,改进了 TCP 性能,提高网络的吞吐量。

The delay-based congestion avoidance（DCA）algorithms for TCP increases system＇s throughput. But in some cases,the DCA presents bad performance. By analyzing RTT＇s component, it is found that various transmitting delay and delayed ACK bring obvious errors in using RTT as the signal of network congestion, and affect DCA algorithms＇ veracity. In order to solve the problem,an improved DCA algorithms is proposed,which eliminates these errors before estimating network whether or not to be congestion. The performance of the algorithm has been tested and evaluated on NS simulator. The simulation results demonstrate that the algorithm inspects network congestion more exactly. So it enhances TCP efficiency and increases good throughput of TCP flow.