Effects of a Priority Discipline in Routing for Packet-Switched Networks

This paper addresses itself to some comparisons of adaptive routing algorithms in store-and-forward Communication nets. The intent here is to demonstrate how some relatively simple add-ons to already existing adaptive algorithms can decrease the average message delay and increase message throughput in the network. The overview of many existing routing algorithms is intended to point out that, although an algorithm may be adaptive, it is not necessarily good in terms of the performance measures addressed in this paper. The basic objective of this study is to assess the effects of endogenous priority assignment to messages that have reached some specified aging threshold while in the network and to note the effects of Such priority assignment on network performance. The performance measures are average message delay, throughput, and number of messages undelivered. The routing techniques are demonstrated via simulation on an 8node highly connected network and a 19-node Advanced Research Projects Agency (ARPA) network. The routing algorithms are applied with and without network element destruction on the selected networks.