Abstract: A node apparatus of such a ring communication network including buffers capable of improving a performance of the ring communication network and yet maintaining a global fairness in use of a ring communication network bandwidth among nodes, and a method for controlling the node apparatus. The node apparatus includes a receiver unit for receiving packets and slots from a ring, an ordering buffering unit for ordering the packets, a receiving queuing unit for temporarily storing messages of the packets to be sent to a host, a trunk buffering unit for temporarily storing packets to be transmitted to other nodes and then relaying the stored packets, a transmitting queuing unit for storing messages to be transmitted to the ring, and a transmitter unit for transmitting packets and messages in a medium access control manner.