Exchange guaranteed to have same terminal identifier information as that of subscriber terminal equipment

摘要

An exchange connects terminal equipment each having terminal identifier information. A layer 3 control unit of the exchange generates a pseudo layer 3 global reception call; and a layer 2 control unit of the exchange terminates the global reception call at the terminal equipment, extracts before link establishment the terminal identifier information of the terminal equipment from a logical link establishment request frame sent from the terminal equipment in response to the termination, and notifies the terminal identifier information to the layer 3 control unit. The layer 3 layer control unit holds the terminal identifier information notified for subsequent termination of calls to the terminal equipment. By this means, matched terminal identifier information is maintained between the exchange and subscriber terminal equipment.