Abstract: A method for setting up calls in a telecommunications network is disclosed. A call arrives at originating switch A for destination switch B. An attempt is made at switch A to allocate a trunk from the direct trunk group between A and B. If a trunk is available the call is set up. If a trunk is not available (i.e. the trunk group is completely busy) the call is queued for up to Tq seconds to wait for a trunk in the direct trunk group to be released. If a trunk is released, the queue is served in first-come, first-served order, i.e. the call at the head of the queue is set up. When a call has waited in the queue for Tq seconds without obtaining a direct trunk, an attempt is made at switch A to set up the call on an alternate route. The inventive call set-up method provides for operation of a network in which delay is traded off for reduced blocking probability or to carry a relatively small number of customer-specified high priority calls with almost zero blocking probability.

Abstract: A control network for allocating resources (i.e. making routing decisions) in an associated telecommunications network is disclosed. Illustratively, the control network comprises a group of processors arranged in a ring. A database containing information about the exact state of the telecommunications network circulates in a ring-like control network. When an originating switching office in the telecommuncations network wishes to set-up a connection, it seizes one of the processors in the control network and informs it of the desired connection. The processor runs a call set-up algorithm utilizing the database and makes a routing decision which is communicated back to the originating switching office. The originating central office then physically sets up the call in the telecommunications network.