Patent ID: 7450506

Claim:
A communication system for transmitting frames of a plurality of priority levels, the system having a plurality of communication nodes that connect communication terminals, the system comprising: a management entity to set a transmission period of a first priority frame to be sent by a first communication terminal, to a plurality of communication nodes from the first communication terminal which is a source of the first priority frame to a second communication terminal which is a destination of the first priority frame, based on a transmission period notified from the first communication terminal, and to cancel the transmission period set on the plurality of communication nodes in response to a termination of the communication by the first priority frame, wherein each of the plurality of communication nodes comprises: a judging device to judge whether transmission of a second priority frame having a lower priority than the first priority frame can be completed before the transmitting timing of the first priority frame, based on the transmission period set by the management entity and a length of the second priority frame; and a transmitting device to control a transmission of the second priority frame in accordance with a judgment result by the judging device, and wherein each of the plurality of communication nodes through which the first priority frame is transmitted executes the judgment by the judging device and the transmission control by the transmitting device.