An Adaptive TCP Protocol for Lossy Mobile Environment

TCP has been designed and tuned as a reliable transfer protocol for wired links. However, it incurs end-to-end performance degradation in wireless environments where packet loss is very high. TCP HACK (Header Checksum Option) is a novel mechanism proposed to improve original TCP in lossy links. It presents an extension to TCP that enables TCP to distinguish packet corruption from congestion in lossy environments. TCP HACK performs well when the sender receives the special ACKs correctly, but if many ACKs are also lost, the efficient of TCP HACK will not be prominent. In this paper we present an extension to TCP HACK, which can perform well even if the ACKs are severely corrupted. We use OPNET to simulate our proposal. The results have shown that our proposal performs substantially better than TCP HACK when corruptions occur on both data transmission path and acknowledgement path.