Abstract: In a telecommunications network in which a plurality of switching nodes are interconnected via links each composed of a plurality of trunks and are each connected to a network control center via a control signal link, the network control center determines for each switching node a predetermined number of alternate routes for each first route on the basis of traffic data in the telecommunications network and supplies them as a set of available alternate routes to the switching node. The switching node assigns one or more of the available alternate routes in advance. The switching node responds to a call-connection request to try to connect the call to the first route, and when having failed in the call connection, the switching node retries the call connection through one of the assigned routes.