Packet Switch and Switching Method for Switching Variable Length Packets

Abstract

A packet switch for switching variable length packets, wherein each of output port interfaces includes a buffer memory for storing transmission packets, a transmission priority controller for classifying, based on a predetermined algorithm, transmission packets passed from a packet switching unit into a plurality of queue groups to which individual bandwidths are assigned respectively, and queuing said transmission packets in said buffer memory so as to form a plurality of queues according to transmission priority in each of said queue groups, and a packet read-out controller for reading out said transmission packets from each of said queue groups in the buffer memory according to the order of transmission priority of the packets while guaranteeing the bandwidth assigned to the queue group.

What is claimed is: 
     
         1 . A communication apparatus for forwarding a plurality of packets through input ports and output ports, the communication apparatus comprising:
 a buffer memory;   a classifier which performs a classification of a packet the plurality of packets received through the input ports, by classifying the packet into one of a plurality of queue groups, in accordance with either at least one of a transport layer protocol and a layer protocol of an OSI (Open Systems Interconnection) reference model higher than a transport layer of the packet;   a queuing controller which queues the packet into the buffer memory based on a result of the classification by the classifier;   a packet read-out controller which reads a packet classified into another queue group other than a specific queue group using a bandwidth of a first bandwidth that is unused while guaranteeing the first bandwidth assigned to the specific queue group; and   a packet sending unit which sends each of the plurality of packets read from the buffer memory to one of the output ports.   
     
     
         2 . The communication apparatus according to  claim 1 , wherein the layer protocol higher than the transport layer is at least one of HTTP (Hyper Text Transfer Protocol), FTP (File Transfer Protocol), TELNET (Terminal Connection) and SMTP (Simple Mail Transfer Protocol).