Comparative analysis of TCP congestion control mechanisms

TCP (Transmission Control Protocol) is the most used transport protocol for wired and wireless networks. It provides many services (reliability, end to end delivery ...) to the applications running over the Internet, but to be able to manage traffics with a huge quantity of data, TCP must have robust congestion control mechanisms. Many researchers have agreed that despite the existence of some congestion control algorithms, TCP still suffers from disappointing performances for short and long flows. For that, researches are still launched by the network community in order to have the suitable mechanism ensuring fair and efficient bandwidth allocation. The works already carried out in this subject has elaborated several congestion control mechanisms. In this paper, we discuss, identify, analyze and compare the behavior of some congestion control mechanisms under congested wireless mech networks, in order to identify their advantages and their respective limits. For the simulation, we used the well known network simulator ns2. Simulation results show that TCP Tahoe, TCP Reno, TCP New Reno, Sack are loss-based, they are beneficial for latency-sensitive flows, while TCP Vegas which is delay-based, it is recommended for applications that don't endure the loss of information but suffers from fairness problems when sharing a bottleneck with competitive flows.