Connection-level dynamics in networks: Stability and control

This paper studies the dynamics of the number of active end-to-end connections (flows) in a network, assuming individual flow rates are determined by standard models of TCP congestion control. We consider different scenarios as to the degree of control applied to such connections. In the first case, connections are driven by exogenous loads, and the only control is over routing: we generalize characterizations of the stability region. Secondly, we consider a highly controlled case, where numbers of connections per route are actively controlled with feedback from the network, to serve a global notion of user welfare; we prove results on global stability for proposed decentralized control laws. Finally, an intermediate situation concerns exogenous loads subject to admission control by the network, with or without routing. In this case we characterize the equilibrium achieved by the proposed admission control laws.