Telecommunication system with loop-free switching tables

Abstract

The invention relates to a telecommunication system comprising a plurality of mutually coupled switching centers and at least one coupled control unit. When switching centers assign paths based on switching data stored in switching tables, switchings take place first between the coupled switching centers which have each their own switching tables containing LCR data. The respective switching center recognizes only the beginning and end of the path in the case of an incoming call, so that the call may be permanently switched to and fro between two switching centers leading to an endless loop in the case of a current overload or interruption of the path from the switching table. For realizing an improved switching environment while system features are taken into account, the control unit is provided for forming at least one connection tree which comprises as branches loop-free connections from one switching center and running to other switching centers of the telecommunication system and for converting the connection tree into a switching tree by determining pairs of switching centers in the branches and by erasing at least one branch that contains the respective pair in reverse order. This reduction creates loop-free switching trees from the connection trees, because an endless loop between two nodes is avoided with the switching operation. The respective branches correspond to the possible loop-free connections in the network. Since a switching tree is formed for each switching center, groups of loop-free connections for the whole telecommunication system evolve in this manner.