Achieving network stability and user fairness through admission control of TCP connections

This paper studies a network under TCP congestion control, in which the number of flows per user is explicitly taken into account. We present a control law for this variable that, in combination with congestion control, induces as equilibrium the maximization of social welfare measured at the level of users, rather than the level of TCP connections. We use fluid flow models to prove stability theorems on the dynamics of the overall system, combining the dynamics of flows with the dynamic rates and prices of congestion control. We then develop an admission control policy for discrete TCP flows, that emulates the continuous behavior, and is modeled as a Markov chain. We present simulation studies of the overall system, which exhibit its stability and the desired user-level fairness behavior.