Patent ID: 8488621

Claim:
A communication network system for performing time-division-multiplexing communication in which a frame is received in a reception slot to be received by a node in a communication cycle including a data transfer period and an idle period, the communication network system comprising: a network; and a plurality of nodes coupled to the network; wherein at least one node of the plurality of nodes includes: a reception-status-information acquiring unit configured to acquire boundary violation information concerning a current frame received in a reception slot and a respective adjacent frame received in at least one adjacent slot adjacent to the reception slot and to acquire frame state information concerning each of the reception slot and the at least one adjacent slot, the boundary violation information indicating whether a signal is detected within the idle period between two adjacent slots and the frame state information including a reception status of a frame being normal or abnormal; an error-factor verifying unit configured to, when the boundary violation information for the reception slot indicates that the signal is detected within the idle period between the reception slot and a slot of the at least one adjacent slot, determine a cause of a boundary violation based on the boundary violation information and the frame state information, the cause selected from a group of causes including the current frame being located in part within the idle period, an adjacent frame being located in part within the idle period, and noise being located within the idle period; and a frame-use determining unit configured to determine whether data of the current frame is usable based on the cause of the boundary violation determined by the error-factor verifying unit and configured to use the current frame for control when the data of the current frame is usable.