Yasir Mehmood 15MSIT12 Supervisor Dr. Imtiaz Ali Halepoto creator Department of Information Technology text Nawabshah QUEST 2019 monographic 26 ABSTRACT TCP is one of the core protocols over the Internet. It provides reliability and guaranteed data transmission across the network. The main theme of this research is to experiment the TCP variants in order to analyze the network congestion. A simulation environment is created for evaluation and the comparative analysis of TCP variants like TCP Tahoe, Reno, New Reno and TCP Vegas by using the wired environment. The performance of aforementioned TCP variants is monitored through multiple values of parameters such as bandwidth and delay. The simulation setup consists of multiple network scenario in which different number of nodes are linked with each other. The scenario contains multiple senders and multiple receivers and they communicate simultaneously. The intermediate discrete routers are also attached with the nodes in order to make it similar to the real world scenario. With different values of bandwidth, delay and loss rate, it is observed that the performance of Vegas is better in comparison other variants. When the loss rate is smaller the throughput of Vegas is greater than the other variants. Whereas, on large value of loss rate there is not much difference in the throughput of the variants.