Routing algorithms of multiple‐destination telecommunication services

Multiple-destination telecommunication is one of the new services in circuit switching. The telephone conference service, which is already in practical use in Tokyo 03 area, is an example of such a service. This paper assumes the use of a network control data base, and proposes a routing algorithm which is required in the realization of wide-area multiple-destination communication by placing a large number of bifurcations (bridges) in the network. It is required that the algorithm should not only suppress the circuit utilization cost for the determined route but also should determine the route in a sufficiently short time to cope with the immediate call. Five kinds of algorithms are proposed, including the search of the “minimum-spanning tree,” which generally is considered as the basic connection configuration for the multiple-destination communication. The two foregoing items are used as the items for evaluation, and a connection algorithm is presented which is the optimal for the given mumber distribution and the bridge placement. It is shown as a result that there exists an algorithm which is better than the “minimum-spanning-tree” search algorithm.