A decentralized control strategy for dynamic routing

A decentralized controller for dynamic routing in multidestination data-communication networks is presented. A dynamic model, which can incorporate arbitrary, differing processing delays at different nodes, is developed to describe the network dynamics. The structure of the controller is motivated by an optimal control problem. It is shown that the controller has many desirable properties; it does not direct messages around a loop, and, in the absence of external input flows, it guarantees that the queues are cleared. Some simulation results are presented to illustrate the controller performance in a number of practical cases. They verify that the queue lengths remain reasonable when the input flow rates are moderate compared to the link capacities. The control strategy can also cope easily with modifications, expansions, and failures in the network.