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

PROBLEM TO BE SOLVED: To provide a communication system enhancing the safety of a resource sharing network.SOLUTION: The communication system includes: a plurality of communication nodes divided into groups; a switch for connecting the plurality of communication nodes and for processing a packet according to a processing rule to process the packet; and a control device for setting the processing rule to the switch. The control device sets to the switch a processing rule to transfer a broadcast packet, which is transmitted from a communication node to a plurality of other communication nodes subordinate to the same group, whereas the control device does not set to the switch a processing rule to transfer a broadcast packet to a communication node subordinate to a group different from the transmission source communication node of the broadcast packet.