一种动态门限变速增加的TCP慢启动算法

A dynamic threshold and varying rate TCP slow-start algorithm

提出了一种动态门限变速增加的慢启动算法,将Vegas和TCP Westwood的关键技术应用到了TCP首次慢启动过程,并提出了动态设定慢启动门限和分段的窗口增加粒度的算法.动态门限变速增加通过对链路可用带宽的估计来设置慢启动门限,使其不会出现多包丢失,从而过早地进入拥塞避免阶段,所以动态门限变速增加能够迅速到达稳态.利用Vegas瓶颈链路队列长度的值,对窗口增加粒度进行分段控制,能够根据瓶颈缓冲区的队列情况来调整窗口增加粒度.该算法能够在多种网络环境下,避免慢启动阶段的多包丢失,迅速到达稳态,提高了慢启动阶段的吞吐量.同时该算法对链路瓶颈缓冲有较好的鲁棒性,对WEB业务适应性强,对现有网络协议保持友好性,只需在发送端修改.

DSVR, a dynamic threshold and verying rate TCP Slow-Start algorithm, is proposed. The key technologies of Vegas and TCP Westwood are applied to the first slow start process in DSVR, which dynamically configures the TCP Slow-Start threshold and adaptively adjusts the increasing rate of TCP transmitting windows. DSVR can reach the steady state rapidly because its configuration of the slow-start threshold is based on the bandwidth estimation, and thus the lost packages will be limited and the entrance of congestion avoidance stage will not be too early. Simulation result proves that this alogrithm can avoid the loss of data packets, reach the steady state quickly, and improve TCP throughput in the complex network. This algorithm is robust to the bottleneck buffer, adaptable to WEB service, and compatible with the present TCP protocol It is simple and practical in that it only modifies the sender of TCP.