An Enhanced TCP Mechanism for Detecting and Differentiating the Loss of Retransmisssions over Wireless Networks

Abstract

In the current internet, Transmission Control Protocol (TCP) is used as the most popular transport layer protocol. However, the end-to-end throughput of TCP degrades significantly when operates in wireless networks. Frequent retransmission timeout is one of the well-known problems of TCP end-to-end throughput degradation over wireless networks. In wireless networks, a retransmission timeout is inevitable, when the retransmission of a lost packet fails to reach the destination particularly due to changing level of congestion and bit error rate in wireless channel. Existing TCP schemes have no mechanism to detect and differentiate the loss of retransmitted packets. In this paper, we propose a new TCP mechanism, called DDLRP (Detecting and Differentiating the Loss of Retransmitted Packets) which is capable of detecting and differentiating the loss of retransmitted packets and react accordingly without waiting for retransmission timeouts and thereby improve the end-to-end throughput of TCP over wireless networks. DDLRP consists of two schemes, called RL (Retransmission Loss)-Detection and RL-Differentiation. We evaluate the performance of DDRLP through qualnet simulations and demonstrate that our mechanism with two schemes achieve significant improvement than key existing TCP schemes over wireless networks.