Congestion control in MANET by analyzing network status - New ETCP-Westwood

Abstract

Transmission control protocol provides congestion control mechanisms. These mechanisms work well for mobile adhoc network and wireless networks. TCP provides different mechanisms for both networks. TCP suffers from the packet loss problem in both networks. TCP controls congestion as per type of loss. The mobile adhoc network faces two types of packet loss, 1) loss due to congestion 2) loss due to link failure. TCP can not identify these loss types and it assumes loss as congestion loss. It has existing variants which perform congestion control. One of TCP variant TCP westwood works for congestion control with the help of bandwidth estimation. It works well but has not taken care the value of last Round trip time and estimated round trip time which are the important parameters to analyze network status. The proposed westwood has taken care of these two parameters and controls congestion window based on them. The work proposed in this paper focuses utilization of round trip time for throughput improvement. The proposed algorithm is tested on NS 2.35 and compared with existing variants like TCP Reno, TCP Vegas and TCP westwood and result reveals certain improvements.