This research focuses on the management of congestion based on flow control. It will include a theoretical study of the paradigm for solving networks with multiple virtual circuit window flow control and will validate the paradigm by simulation, including but limited to Markovian traffic. Particular attention will be given to establishing the validity of the model which is based on the Markovian assumption and other, more realistic traffic models. The research will also include the theoretical study of the application of open queueing networks for modeling input rate regulation as a means of flow control. Another research topic includes the examination and evaluation of fast algorithms for real-time optimization with respect to several network measures including network power, and throughput with queueing time constraints and fairness. The researchers will investigate, either by analytical means or by simulation, several input rate control schemes including average rate control, leaky bucket and promising variations and compare them to window control. They will study the opportunities for using these methods and others described above to influence re- routing and fault recovery.