Patent ID: 7287061

Claim:
A data transfer apparatus for determining transmission priorities of data frames transmitted from plural queues, comprising: a forwarding table generator that generates a forwarding table in which data for determination of said transmission priorities is registered and which is sequentially transferred to said plural queues; a data update unit that, if a priority of transmission queue to which said forwarding table has been transferred is higher than that of a next transmission queue registered in said forwarding table as a transmission queue from which a data frame is to be transmitted next, updates said next transmission queue with said transmission queue; a data arbitration unit that causes transmission of data frame from a queue registered as said next transmission queue in the forwarding table which has been transferred through all said plural queues; means for generating a queue information table for each said queue; means for providing a flag, indicating data frame transmission possible status or data frame transmission impossible status from said queue, in said queue information table; means for closing said flag to indicate the transmission possible status, if a data frame is stored in said queue and if a transmission rate of said data frame is lower than a rate set by transmission rate control on said queue; and means for comparing a priority of a transmission possible queue for which said flag indicates a transmission possible status with that of the next transmission queue registered in said forwarding table, wherein each of said plural queues independently updates the forwarding table.