COMMUNICATION NODE, COMMUNICATION SYSTEM RING CONFIGURATION METHOD, AND RING ESTABLISHING METHOD

摘要

It is possible to obtain a communication node used in a ring-shaped communication system in which communication nodes are connected by the Ethernet (registered trademark) without using a relay device. A plurality of communication nodes (10) are one-to-one connected by the Ethernet (registered trademark) duplexed by a normal-mode ring (1) and a wait-mode ring (2) so as to constitute a communication system in which the communication nodes (10) are connected in a ring shape. Each of the communication nodes (10) includes: an A port (11); a B port (14); and a communication processing unit (17) which receives a frame outputted from the B port (14) and transmits the frame from a normal-mode ring (1) of the B port (14) during normal communication and which performs only a transfer process without receiving a frame from a wait-mode ring (2) of the B port (14) when another communication node performs a loop back process because of a communication failure, so that the frame is transmitted from the A port (11) to the wait-mode ring (2).