Packet switch and switching method for switching variable length packets

A packet switch, comprising:

• a plurality of input port interfaces;
• a plurality of output port interfaces, and a packet relaying unit for switching variable length packets received from said input port interfaces to one of said output port interfaces corresponding to the destination address of each of said packets,
• wherein each of said output port interfaces comprises:
• a buffer memory for storing transmission packets,
• a transmission priority controller for classifying transmission packets, passed from said packet relaying unit into a plurality of queue groups to which specific bandwidths are assigned respectively, according to the header information of each of said transmission packets and for queuing said transmission packets in said buffer memory so as to form a plurality of queues according to transmission priority in each queue group,
• a packet read-out controller for reading out transmission packets according to the transmission priority while guaranteeing the bandwidth assigned to each of said queue groups, and
• a packet transmission circuit for transmitting said transmission packets read out by said packet read-out controller to an output port associated with the output port interface,
• wherein said transmission priority controller includes a first management table for defining an identifier for each of said queue groups corresponding to a combination of a source network address and a destination network address and a second management table for defining the transmission priority corresponding to a combination of a communication protocol and a packet priority, and
• wherein said transmission priority controller identifies a queue group corresponding to each of said transmission packets by referring to said first management table based on the source and destination network addresses included in the header of the transmission packet and identifies the transmission priority corresponding to the transmission packet by referring to said second management table based on the, communication protocol information and packet priority information included in the header of the transmission packet.