INTRANETWORK SUBSCRIBER STATE REPORTING SYSTEM

PURPOSE:To provide the intranetwork subscriber state reporting system for which report processing is simplified by normally periodically reporting a subscriber state to an opposite subscriber storage exchange. CONSTITUTION:The subscriber state of end-end (a state between subscribers 300 and 301) is reported by exchanging frames in a fixed cycle between call originating and incoming subscriber storage exchanges 200 and 203. Assuming that the state report frame is lost in the middle, non-coincidence is not generated in the subscriber state management information of end-end by reporting the state with the state report frame in the next cycle. Sometimes, the state management information is easily lost when restarting or breaking the exchange, and it is difficult to recover the non-coincidence by the report depending on an event such as a fault or congestion. Even at the time of this restart or fault, the state of end-end can be made coincident by the periodical report after the exchange is recovered.