Telecommunication connections that are to be set up are provided with a signaling information (SI) that has an originating information (UI) for identifying the originating node, a destination information (ZI) for identifying the destination node and a network authorization information (NB) for an identification of restricted node connections specifically associated to the transmitting subscriber. Stored in the node itself is a correction information (KI) that can have at least one of inhibit and enable indicators for the node connections dependent on the originating and destination information (UI, ZI) of a telecommunication connection to be set up. A node authorization information is formed in the node controller from the network authorization information (NB) and from the correction information (KI), a node connection to be traversed thereupon by the telecommunication connection that is to be set up being calculated on the basis of this node authorization information. Network loops and inadmissible network interworkings can thus be prevented.
A requesting terminal signals a call request (CALL) to a control unit of a first communications network. The control unit then determines whether sufficient capacity is available in the first communications network to establish the connection requested by the call request. In the event of insufficient capacity, the control unit transmits an overload message (DAT) to the requesting terminal. It only initiates an alternative establishment of the requested connection via another, second communications network after it receives an acknowledge message (ACK) issued by the requesting terminal.
The routing of calls from one network (100) to another network (170) may be accomplished by tracking the call completion history over each trunk group (174.sub.1 -174.sub.2) connecting the networks. From a knowledge of the call completion history for each route, a Completion Rate Factor (CRF), representing the ratio of completed calls to all calls attempted is computed. The route having the CRF representing the highest number of completions is then selected. Typically, the process is dynamic, so that if the selected route no longer has the highest number of completions, then the route previously found to have the highest number of call completions is selected. The concept of completion rate factor routing can be extended to multiple carriers to yield a carrier completion rate feature routing technique. Routing may also be completed in accordance with network congestion to route advance a call.
A method enables each node in a multi-nodal network to construct a routing table to all other nodes in the network. Each "home" or originating node performs a method which includes the steps of: transmitting a query to all immediate neighbor nodes and recording in a routing table, responses received which identify the neighbor node at the terminus of each link; transferring to each neighbor node, home node routing table entries and receiving routing table entries from each neighbor node; and, for each routing table entry to a node that is received from a neighbor node, if the route indicator is already present in the home node routing table, ignoring the entry; if the new entry indicates a route to a new node, entering the new node and a route identifier; and if the entry indicates a route to a node for which there is already an entry in the home node routing table, noting the new entry as a lower priority route to the node. Once the aforementioned procedure is repeated a number of times, each node in the multi-nodal network includes routes to all nodes in the network, with the routes having automatically been prioritized in accordance by sequence of receipt.
