COMMUNICATION SYSTEM, CONTROL DEVICE, CONTROL METHOD FOR CONTROL DEVICE, AND PROGRAM

PROBLEM TO BE SOLVED: To provide a communication system for improving availability.SOLUTION: A communication system includes: a switch which is connected to a communication node and processes a packet according to a processing rule for packet processing; a control device for setting the processing rule to the switch; and a management device which is connected to the switch and manages a redundant system composed of a communication node in an active mode and communication node in a standby mode. When a first packet transfer path between the communication node and the communication node in the active mode disappears because of a connection failure generated between the switch and communication node in the active mode, the control device deletes a processing rule related to the first packet transfer path from the switch and notifies the management device of absence of the first packet transfer path. In response to the notification from the control device, the management device exchanges the communication node in the active mode and communication node in the standby mode of the redundant system.