A comparison and analysis of congestion window for HS-TCP, Full-TCP, and TCP-Linux in long term evolution system model

TCP performance over high bandwidth network still represents the major challenge, since the large numbers of data flows through bottleneck, TCP forces a high packet loss rate and that causing delays that users are likely to notice. Congestion window (cwnd) is maintained, which indicates the number of Transmission Control Protocol (TCP) segments that the existing connection is capable of holding safely. In high bandwidth networks, such as 4^th Generation (4G) Long Term Evolution (LTE) systems, we expect a high rate of traffics, and then each TCP variants perform a different behavior of cwnd. In this study, three TCP's variants: TCP-Linux, FullTCP, and High Speed TCP (HSTCP), observed and the cwnd of each variant analyzed and compared with other two variants, over a model of high bandwidth network topology using network simulator (NS-2). All these TCP's tested under high rate of data transferred through a bottleneck. We found that each variant can provide a good cwnd size performance and stability but the differences was in cwnd phases such as slow start threshold (ssthresh), congestion avoidance, slow-start, and maximum congestion points.