Multidrop control network commonly used for carrying network management signals and topology reconfiguration signals

摘要

A data communication system comprises a network management center and switching nodes which are interconnected by regular and spare routes. Each of the regular and spare routes comprises data channels and a control chnanel, the data channels of the regular routes forming a data network for carrying signals to and from user terminals and the control channel of each regular or spare route is connected to the control channels of other regular or spare routes to form a control network of multidrop structure for carrying a network management signal from the center to the nodes as well as network response signals from the nodes to the center. Each of the nodes transmits a request signal through the control network in the event of a line fault in the transmission lines to request permission to establish a new regular route to an adjacent node and transmits a grant signal through the control network in response to receipt of a request signal from an adjacent node indicating that the request is granted if an alternate route is available. The control network is dynamically reconfigured in accordance with the presence and absence of the request signal and the grant signal received from adjacent nodes.