A Game-theoretic Analysis of Tcp Vegas and Fast Tcp

In this paper, we evaluate the impact of selfish behavior through a game-theoretic analysis of TCP Vegas and FAST TCP. By theoretical analysis, we obtain the Nash Equilibrium in these games and study the loss of efficiency under Nash Equilibrium. Our results show that if the users are selfish, then the efficiency of the network as a whole relies on the utility function of individual users. The efficiency of the system degrades under some conditions and remains optimal under other conditions. This motivates us to borrow the notions of Price of Anarchy and Tragedy of the Commons in Game Theory to describe this efficiency loss. We calculate the Price of Anarchy and provide the necessary and sufficient condition under which the TCP Vegas Game (FAST TCP Game) is a Tragedy of the Commons. Finally, we validate the theoretical results by the simulations carried out using NS-2.