A Simulation Study of Routing and Control in Communications Networks

In a recent paper 1 the results of some preliminary comparisons of two alternate routing configurations for communications networks were reported. Those results indicated that for small networks (six or fewer nodes) with low traffic densities a symmetrical or unrestricted routing pattern is superior to a hierarchy similar to that in use in the U.S. toll network, while for higher traffic densities there appeared to he little difference in the network behavior in terms of economy and reaction to overloads. Subsequently, a new simulation program has been constructed 2 and substantially larger networks have been examined to provide a more meaningful guide to network design under various circumstances of geography and load level. An additional configuration, called the "gateway," as well as several operating and control variations, has been examined. The latter include stage-by-stage operation with and without crankback (return of routing control to a previous node for rerouting when blocking is encountered at an intermediate switching point), limitation of number of links per call in symmetrical networks, and trunk reservation for first-routed traffic only. * Presented at the Fourth International Teletraffic Conference, London, July, 1904. 2639