RELAY DEVICE AND RELAY CONTROL METHOD

PROBLEM TO BE SOLVED: To suppress deviation produced in a discarded data volume.SOLUTION: A relay device receives from an upstream node a control message including a data communication volume transmitted from a client device located on the upstream side. The relay device also calculates a total communication volume included in the received control message from each upstream node, to notify a downstream node of the calculated total communication volume. Further, the relay device determines the upper limit communication volume of data transfer at the upstream node, by distributing the upper limit communication volume of a channel on the downstream node side, or the upper limit communication volume notified from the downstream node, according to the ratio of the communication volume included in the control message of each upstream node. The relay device also notifies the upstream node of the determined upper limit communication volume.