现有的TCP协议采用丢包事件、拥塞反馈信息或往返时延等信息启动拥塞控制,而这些基于单个数据包信息的方法进行丢包区分的能力较弱,使得有线/无线混合网络中的非拥塞丢包影响了TCP的拥塞控制行为.本文提出了一种新的TCP协议,PceReno(Probability of Congestion or Error),它通过对最近一段数据的拥塞概率预测来决定如何响应当前丢包事件,从而避免盲目的启动拥塞控制.这种先应式拥塞感知和后应式拥塞响应相结合的拥塞控制方法不需要增加额外的开销,完全依赖于原有的拥塞控制.实验结果表明PceReno能够较好地对抗随机错误,有效提高TCP在混合网络中的吞吐量.
To decouple congestion control from corruption control is necessary for TCP enhancement over wired-cum-wireless networks. There are dropping events, explicit congestion notice or round trip time etc. that trigger congestion control. While these methods are weak in loss differentiation, and result in error losses misinterface congestion control action. This paper proposed a new scheme called PceReno, in which sender make prediction on probability of congestion or error by ECN marks and act correctly. This new scheme combine reactive feedback and proactive avoidance without extra cost, because it depends on orginal congestion control scheme. Simulate result show that PceReno is immune to lossy links, and the throughput of connection over hybrid networks can be significantly improved.