Improvements in Routing for Packet-Switched Networks

Abstract : Adaptive routing algorithms in store-and-forward communication networks are demonstrated to decrease average message delay, to increase message throughput, and to decrease the number of undelivered messages. Comparisons of existing adaptive routing techniques are presented to provide the basis for extension of the theory in two areas: priority assignment for messages reaching an assigned aging threshold, and prevention of messages looping within the network. Optimization of a defined measurement parameter, throughput factor, phi (t,k) is performed in terms of the priority threshold setting k. A closed form solution for phi (t,k) is obtained on a 3-node network assuming infinite buffers and fixed routing. Included are simulations on damaged and undamaged systems for specific inter-connected networks with finite buffers and adaptive routing. Comparisons are made for the predicted phi (t,k) versus the simulated results on an undamaged network.