in a connection - oriented network , a route table and a network resource table are provided in a source node which updates the network resource table in response to a topology state message which is flooded through the network whenever there is a change in the available network resources . the source node updates the network resource table in response to an early - arriving trouble report message from the network if such a change in the available network resources occurs when a connection is being progressively established or already established from the source node . in response to a connection setup message , the source node fetches a route from the route table and compares a user &# 39 ; s requirement such as quality and / or bandwidth with the resource data of the fetched route stored in the network resource table . a connection is established via the fetched route if the resource data of the fetched route in the network resource table indicates that the fetched route can support the requirement .