The impact of delayed ACK on TCP variants protocols in wireless network

Abstract

TCP is a connection oriented and reliable protocol of transport layer. TCP receiver generates one acknowledgment denoted as ACK for each data packet that received to acknowledges the sender. If the data packet and ACK uses the same path, then there may be collision between them due to channel contention. Finally TCP throughput is reduced due to huge ACK packet generation. TCP performance is very poor due to wireless channel characteristics. Since the packet loss is always related to path length, choosing appropriate delayed window size is an important parameter in wireless network. This paper, analyzes the impact of delayed acknowledgment on TCP variants say Newreno and Vegas in multi hop wireless networks. However the issues of congestion and loss recovery techniques for these two mechanisms are different. In this paper we study how well the TCP variants react with delayed acknowledgement strategy in multi hop network with different topologies and various flow patterns with respect to throughput, average delay and number of retransmission. The simulation result shows that TCP-Vegas achieve higher throughput, fewer retransmissions and less delay than Newreno. The performance of TCP-Vegas with delayed ack gets best performance among TCP variants.