Patent ID: 7788714

Claim:
A packet transfer apparatus which can be connected to a plurality of input lines and a plurality of output lines, and transfers a packet received from each of the input lines to one of the output lines specified by header information, comprising: a reception circuit to receive the packet through the input line; a flow retrieval section to obtain a priority based on the header information of the received packet; a relay section to transfer the packet; and an output circuit to output the packet transferred from the relay section through the output line, wherein the flow retrieval section includes: a determination section to execute, in accordance with previously set setting information or a previously determined header information item of the header information of the packet, a first process of outputting a plurality of header information items for identifying a flow or a second process of outputting a header information item indicating a priority extracted from the header information of the received packet; a first retrieval unit that inputs the plurality of header information items from the determination section, identifies the flow of the packet by using the plurality of header information items as a retrieval key, and obtains a priority previously specified for each flow; and a second retrieval unit that includes a conversion table in which priorities are previously stored correspondingly to header information items indicating priorities, inputs the header information item indicating the priority from the determination section, refers to the conversion table to obtain the priority by using the header information item indicating the priority as a retrieval key, and power consumption of the second retrieval unit is lower than power consumption of the first retrieval unit, and the packet transfer apparatus transfers and controls the packet in accordance with the obtained priority.