ATM exchange with band camp-on registration function

An ATM exchange for receiving from terminals call connection requests and camp-on requests in which band values being used are specified, and establishing on a transmission line calls for which the specified band values can be used, wherein the ATM exchange comprises:

• band value storage means for dividing unused band value of the transmission line into an empty band value and a temporarily saved band value, and storing them;
• camp-on request storage means for storing the contents of camp-on requests issued by each terminal, in correlation with the processing rank of these contents;
• connection request response means for establishing on the transmission line the call requested by a connection request when the connection request received from a terminal is one for which the use of a band value below the empty band value stored in the band value storage means has been specified, and notifying the terminal of a refusal to connect when the connection request is such that the use of a band value exceeding the empty band value has been specified;
• camp-on request registration means for establishing, upon receipt of a camp-on request from a terminal, the processing rank of this camp-on request and performing registration in the camp-on request storage means in correlation with the processing rank that identifies the camp-on request data that represent the contents of this camp-on request;
• band value setting means for adding the empty band value stored in the band value storage means to the temporarily saved band value stored in the band value storage means, and setting zero for the empty band value in the band value storage means, when the registration of camp-on request data by the camp-on request registration means is performed with respect to a camp-on request storage means in which no camp-on request data have been registered;
• band value updating means for adding a band value released by a disconnected call to a temporarily saved band value stored in the band value storage means when camp-on request data have been registered in the camp-on request storage means upon detection of the disconnected call in the transmission line, and adding the band value released by the disconnected call to the empty band value stored in the band value storage means when no camp-on request data have been registered in the camp-on request storage means;
• camp-on request response means for establishing a call that corresponds to camp-on request data in the transmission line when the temporarily saved band value stored in the band value storage means exceeds the band value specified for use by the camp-on request data that are stored in the camp-on request storage means and that are assigned the highest processing rank;
• and
• post-processing means for reducing the temporarily saved band value stored in the band value storage means by the band value used to set up a call when it is set up by the camp-on request response means, and erasing the camp-on request data that is stored in the camp-on request storage means and that have been used by the camp-on request response means.