Abstract: A forwarding table 7 where a next transmission queue is registered is sequentially transferred within a queue chain 30 as a group of queues 131. If a priority of a queue to which the forwarding table 7 is transferred is higher than that of a queue registered in the forwarding table 7 as a next transmission queue, a next transmission queue number or the like is updated. Further, an arbiter 8 outputs a transmission command to a queue registered as the next transmission queue in the forwarding table 7 which has been transferred through all the queues, to transmit the next data frame from the queue having the highest priority. By this arrangement, it is possible to determine data frame transmission priorities among plural queues easily and efficiently while insuring a minimum guaranteed rate defined in each queue.

Abstract: A forwarding table 7 where a next transmission queue is registered is sequentially transferred within a queue chain 30 as a group of queues 131. If a priority of a queue to which the forwarding table 7 is transferred is higher than that of a queue registered in the forwarding table 7 as a next transmission queue, a next transmission queue number or the like is updated. Further, an arbiter 8 outputs a transmission command to a queue registered as the next transmission queue in the forwarding table 7 which has been transferred through all the queues, to transmit the next data frame from the queue having the highest priority. By this arrangement, it is possible to determine data frame transmission priorities among plural queues easily and efficiently while insuring a minimum guaranteed rate defined in each queue.