A relay node functions as a master node or a slave node and includes a status monitoring means, an update requesting means, a master transferring means, and a master accepting means. The status monitoring means monitors a status of a connection related to communication data. The update requesting means transmits a first update request to a first node upon the relay node receiving first communication data while the first node functioning as the master node. The master transferring means determines whether to transfer authority of the master node to a second node in accordance with a status of a first connection upon the relay node receiving a second update request from the second node. The master transferring means transmits a first master transfer notification to the second node. The master accepting means prepares to become the master node upon the relay node receiving a second master transfer notification.