Packet distributing apparatus and packet distributing method

Abstract

In a packet distributing apparatus and a packet distributing method which, in a situation in which a link can be allocated to a specific user or a specific traffic with priority, can effectively utilize any unoccupied link, a packet inputted via first through Nth the input interface circuits 203 1 through 203 N is provided by a transfer destination searching unit 205 with a transfer destination port and a transfer-admissible port. Usage detecting units 211 1 through 211 N check the usage of a transfer-admissible port matching the pertinent one of first through Nth output buffer units 209 1 through 209 N , and distribute the packet to a transfer-admissible port bearing a less load than a prescribed level (less loaded transfer-admissible port). If there is no less-loaded transfer-admissible port, the packet is distributed to the transfer destination port for which it is destined in its own right.

1 . A packet distributing apparatus for distributing each of packets inputted from a plurality of input ports to one of a plurality of output ports, comprising:
 a port information searching unit for searching, on the basis of information written in said packet, for a transfer destination output port to be selected with priority as an output port and for transfer-admissible output ports;   packet storage buffers for temporarily storing said packet;   a transfer-admissible port loaded state judging unit for searching for a less loaded one of said transfer-admissible output ports in which the quantity of buffered packet data is less than a prescribed value, on the basis of the usage of the matching one of said packet storage buffers; and   a packet sending unit for sending, when the load on said transfer destination port is heavy, said packet stored in said packet storage buffer to said less loaded one of said transfer-admissible output ports which has been detected.   
   
   
       2 . The packet distributing apparatus as claimed in  claim 1 , wherein:
 said packet storage buffers include low priority buffers and high priority buffers, from which read-out is given priority over the low priority buffers.   
   
   
       3 . A router comprising the packet distributing apparatus claimed in  claim 1 . 
   
   
       4 . A network comprising a plurality of routers connected to one another, wherein each of said routers comprises the packet distributing apparatus claimed in  claim 1 . 
   
   
       5 . A packet distributing apparatus for distributing each of packets inputted from a plurality of input ports to one of a plurality of output ports, comprising:
 a port information searching unit for searching, on the basis of information written in said packet, for a transfer destination output port to be selected with priority as an output port and for transfer-admissible output ports;   packet storage buffers for temporarily storing said packet;   a transfer-admissible port loaded state judging unit for searching for a less loaded one of said transfer-admissible output ports in which the quantity of buffered packet data is less than a prescribed value, on the basis of the usage of the matching one of said packet storage buffers; and   a packet sending unit for distributing, if said less loaded one of said transfer-admissible output ports is detected, the packet stored in said packet storage buffers to said less loaded one of said transfer-admissible output ports or, if said less loaded one of said transfer-admissible output ports is not detected, the packet stored in said packet storage buffers to said transfer destination port.   
   
   
       6 . The packet distributing apparatus as claimed in  claim 5 , wherein:
 said packet storage buffers include low priority buffers and high priority buffers, from which read-out is given priority over the low priority buffers.   
   
   
       7 . A packet distributing method for distributing each of packets inputted from a plurality of input ports to one of a plurality of output ports, comprising:
 a port information searching step of searching, on the basis of information written in said packet, for a transfer destination output port to be selected with priority as an output port and for transfer-admissible output ports;   a transfer-admissible output port loaded state judging step of searching for a less loaded one of said transfer-admissible output ports in which the quantity of buffered packet data in packet storage buffers each provided on said output port side for temporarily storing said packet is less than a prescribed value, on the basis of the usage of the matching one of said packet storage buffers; and   a packet sending step of sending, when the load on said transfer destination port is heavy, the packet stored in said packet storage buffer to said less loaded transfer-admissible output port which has been detected.   
   
   
       8 . A packet distributing method for distributing each of packets inputted from a plurality of input ports to one of a plurality of output ports, comprising:
 a port information searching step of searching, on the basis of information written in said packet, for a transfer destination output port to be selected with priority as an output port and for transfer-admissible output ports;   a transfer-admissible output port loaded state judging step of searching for a less loaded one of said transfer-admissible output ports in which the quantity of buffered packet data in packet storage buffers each provided on said output port side for temporarily storing said packet is less than a prescribed value, on the basis of the usage of the matching one of said packet storage buffers; and   a packet sending step of distributing, if said less loaded transfer-admissible output port is detected, the packet stored in said packet storage buffers to said less loaded transfer-admissible output port or, if said less loaded transfer-admissible output port is not detected, the packet stored in said packet storage buffers to said transfer destination port.