Mamo, Mengesha(PhD)Wassie, Keria2018-06-282023-11-042018-06-282023-11-042008-03http://etd.aau.edu.et/handle/123456789/4520TCP is a reliable, connection-oriented and sequence-delivery protocol. All applications which require a reliable delivery of data use TCP. TCP-Reno and TCP-Vegas are some of the TCP types created to give a reliable service in the Network. According to different researchers and results of our simulation, it is observed that TCP-Vegas in isolation has better performance with respect to overall network utilization, stability, fairness, throughput and packet loss, but its performance degrades when TCP-Reno connection exists in the Network. So this thesis is trying to address this incompatibility problem of TCP Vegas while working with TCP-Reno and proposing a solution called Relaxed-Vegas. Using a simulation tool (NS2) we examine the detail behaviours of TCP-Reno and TCP-Vegas while working independently and simultaneously. We propose modifications to the currently working algorithm of TCP-Vegas. From the simulation results we compare the performance of the currently used TCP Vegas and the new proposed solution (Relaxed-Vegas). By using Relaxed-Vegas the number of received packets and the throughput (good-put) is raised by 56.87% and the drop of packets is reduced by 17.0%. Keywords: TCP, TCP Reno, TCP Vegas, Congestion control, Relaxed-VegasenTCPTCP RenoTCP VegasCongestion ControlRelaxed-VegasThesis