In allocating bandwidth using a Resilient Packet Ring (RPR) fairness mechanism in a node connected to an RPR network, when congestion occurs, an amount of traffic that the node has transmitted to a ring during one aging interval is stored together with its own identifier in a fairness message as a fairness transmission rate to be advertised to its own upstream nodes. The amount of traffic transmitted from the upstream node during the aging interval is measured and stored. When the congestion has been solved, an available bandwidth is calculated with reference to the fairness transmission rate and the amount of traffic transmitted from the upstream nodes, and the fairness transmission rate is calculated to fairly allocate the available bandwidth to the upstream nodes so that the fairness transmission rate is transmitted to the upstream nodes.