Packet transfer device and method adaptive to a large number of input ports

摘要

A packet transfer device that can be easily realized even when a number of input ports is large. Each input buffer temporarily stores entered packets class by class, and outputs packets of a selected class specified by the control unit, while the control unit determines the selected class of packets to be outputted from the input buffers according to a packet storage state in the packet storage units of the input buffers as a whole for each class. Each input buffer can temporarily store entered packets while selecting packets to be outputted at a next phase, and the control unit can specify packets to be selected in the input buffers according to an output state of packets previously selected in the input buffers as a whole. Packets stored in the buffer can be managed in terms of a plurality of groups, and each packet entered at the buffer can be distributed into a plurality of groups so that packets are distributed fairly among flows. The packets belonging to one of a plurality of groups are then outputted from the buffer toward the output port. A packet transfer at the buffer can be controlled by issuing a packet transfer command according to a log of packet transfer commands with respect to the buffer and a packet storage state of the buffer.