Packet forwarding device

Abstract

A power-saving packet forwarding device realizing electric power that accords to the number of lines in which communication is performed and a traffic volume inputted from the lines. A header processing unit with which the packet forwarding device is equipped has a plurality of packet processing circuits for performing a packet processing. A line number decision circuit monitors the number of lines in which communication is performed and a traffic volume inputted from the line, and decides presence or absence of an operation of a packet processing circuit. Based on this decision result, a power supply and a clock of the packet processing circuit that does not need to operate are interrupted, and accordingly power saving of the packet forwarding device is realized.

1 . A packet transferring device that has a plurality of input lines and a plurality of output lines, and when a packet is inputted into the input line, forwards the packet to one or more than one output line, comprising:
 a first packet processing circuit which performs a flow process;   a second packet processing circuit which determines output destination of the inputted packet;   a decision unit which determines an operation of the second first processing circuit is to be started or stopped when a flow process is necessary or unnecessary for the inputted packet, and controls operation of the first packet processing circuit.   
     
     
         2 . A packet transferring device according to  claim 1 , wherein the decision unit determines an operation of plurality of the first packet processing circuits is to be started or stopped. 
     
     
         3 . A packet transferring device according to  claim 1 , wherein the decision unit determines number of the first packet processing circuits is to be started and controls operation of plurality of first packet processing circuits to either stop or start operation for each first packet processing circuits on the basis of the number of the first packet processing circuits. 
     
     
         4 . A packet transferring device according to  claim 3 , wherein the decision unit selects at least one of the first packet processing circuits to start operation according to the determined number of the first packet processing circuit. 
     
     
         5 . A packet transferring device according to  claim 3 , wherein the selected first packet processing circuit manages a flow table for performing a flow process. 
     
     
         6 . A packet transferring device according to  claim 1 , wherein the second packet processing circuit is operated in stead of the first packet processing circuit when operation of the first packet processing circuit is stopped. 
     
     
         7 . A packet transferring device according to  claim 3 , further comprises:
 the decision unit determines in response to an instruction from a control terminal, the instruction indicating that a flow process is not needed.