TCP-RC增强Ad hoc网络TCP性能

Enhance TCP Performance in Ad hoc Network by TCP-RC

目前改善Adhoc网络中TCP性能的方法通常在路由中断/变化时暂时性地冷冻TCP连接,在路由重建后从冷冻的状态继续TCP传输.但TCP源端和目的端之间的路由在中断前和重建后可能完全不同,所以路由重建后TCP仍从路由中断前的状态继续TCP传输并不一定合适.本文提出了TCP-RC,它在路由重建后重新计算cwnd和ssthresh,使得TCP恢复传输时能根据当前TCP连接上的容量自适应地调整发送速率,降低突发流量造成网络拥塞的可能性.仿真表明TCP-RC在Adhoc网络中取得了更好TCP性能.

By far, there were some approaches proposed to improve TCP performance in Ad hoe network. In generally, they freeze TCP connection temporarily when route is failed, and resume TCP transmission from the ‘frozen’ state when route is reconstructed. However, In fact, the reconstructed route between TCP source and TCP receiver may be very different from the route before failures, so it isn＇t optimal to resume the TCP transmission from the original ‘frozen’ state. In this paper, we propose a new approach, TCP-RC, which re-compute cwnd and ssthresh for the TCP connection after route is reconstructed, thus it can adjust the TCP transmission rate adaptively according to current capacity of TCP connection. Consequently, TCP- RC lowers possibility of bursty traffic and avoids invoking congestion control. Analyses and simulations show that TCP-RC had achieved better TCP performance than Reno in Ad hoe Network.