Dynamic time windows and generalized virtual clock: combined closed-loop/open-loop congestion control

The authors present mechanisms for congestion control of data traffic in high-speed wide area networks. The network model assumes reservation of resources based on average requirements. The key ideas involve separation of different sources of network congestion, short-term bursts and medium-term load, and using separate mechanisms to address them. Thus, dynamic time window (DTW) admission control is proposed as a mechanism to limit traffic burstiness from sources as a function of the medium-term load on the system, while a new fairness criterion for short-term congestion (Pulse) is proposed as a mechanism for dealing with fair scheduling by switches of short-term bursts. The model of the network is presented. The DTW and Pulse mechanisms are discussed. A detailed analytical and simulation study is presented for static time-windows and various scheduling algorithms. Preliminary results on DTW are discussed