Analysis Of TCP WestwoodNR Protocol in Congested and Lossy Network

We study the performance of TCP WestwoodNR (TCPWNR), a TCP protocol controls the window using end-to-end bandwidth estimation. This Bandwidth Estimation continuously estimates, at the TCP sender, the packet rate of the connection by monitoring the ACK reception rate. The estimated connection rate is then used to compute congestion window and slow start threshold settings after a packet loss occurred. Resetting the window to match available bandwidth makes TCP-WNR more robust to Random loss as well as in Congestion. Thus Rather than to react unnecessary window reduction after every packet lost, TCP-WNR uses this bandwidth estimation to compute congestion window and slow start threshold. These often cause conventional TCP to overreact, leading to unnecessary window reduction. Experimental studies of TCP-WNR show significant improvements in throughput performance over Reno and SACK, particularly in wired networks. Performance Results are shown that TCP-WNR is the best TCP protocol for link errors as well as congested networks. Performance results also shown that with High Error Rate Environment, TCP-WNR gives the highest throughput among all other TCPs. Analytic results are validated against simulation results.