Enhancing transmission control protocol tcp performance in wireless networks

Abstract

Today in this pervasive world, anything can be connected with anything through networking. Wireless technology leads the major part of pervasiveness. There is an exhaustive collaboration between wired and wireless networks. In late 700s after the invention of internet, TCP is the de facto standard protocol meant for reliable data transfer. TCP is a predominant traditional protocol developed for the wired network. When TCP is operated in wired-cum-wireless networks its performance gets reduced. The reason behind this issue is that most of the losses occurring in wired networks are due to congestion. But in wireless networks, losses are due to the wireless characteristics and most of them are random losses. When there is a wireless loss, TCP assumes that it is because of congestion and triggers the congestion control algorithms unnecessarily by mistaking wireless losses as congestion losses. Hence, the performance of TCP reduces drastically. There needs to be a mechanism to differentiate these losses. According to the loss, congestion window can be adjusted respectively. For random loss, there is no need to reduce the congestion window. Hence there is a need to improve the performance of TCP. This is the motivation for the thesis. Extensive literature study is done. There are various TCP variants which have been developed to accommodate the changing needs such as Reno,Westwood, Log Westwood, MMLR. Reno did not differentiates the type of loss. Log Westwood protocols are based on the bandwidth estimation techniques which fails to address the retransmitted lost packets and did not consider wireless channel behavior. Westwood and MMLR protocol did not receiver capacity with respect to the channel behavior. newline