HOST TO HOST CONGESTION CONTROL USING TCP ENHANCED NEWRENO

Todays Internet is relying on using efficient congestion control[1] mechanisms which has got lot of importance in controlling congestion problems. Congestion control is required not only to prevent congestion collapse in the network, but also to improve network utilization.Without congestion control, a sending node may continue transmitting packets that may be dropped later due to congestion collapse[1]. This paper presents a modified fast recovery algorithm to enhance the performance of the most widespread congestion control protocol[1] TCP- NewReno.Transmission Control Protocol (TCP) is an important transport layer protocol for reliable data transfer over the Internet. It supports most of the popular Internet applications, such as the World Wide Web, file transfer and e-mail. However, the rapid growth of the Internet and the increasing demand of different traffics over the Internet lied to a serious problem called congestion collapse.After observing a series of congestion collapse, several congestion control algorithms are proposed and incorporated into the TCP to resolve the congestion collapse problem. In 1988, several innovative congestion control algorithms were introduced into TCP . This TCP version is called TCP Tahoe. It includes three algorithms namely Slow Start, Congestion Avoidance[2] and Fast Retransmit. A Fast Recovery algorithm was added to Tahoe to form a new TCP version called TCP Reno. TCP Reno is a reactive congestion control scheme that uses packet loss as an indicator for congestion. In order to probe the available bandwidth along the end-to-end path, the TCP congestion window (cw) is increased until a packet loss is detected, at which point the congestion window is halved and a linear increase algorithm takes over until further packet loss is experienced. TCP newReno reduces its window size to half irrespective of the congestion in the network. On the other hand TCP EnewReno adjusts its window size based on the network status. It also transfers more packets to the destination.