Label switching type of packet forwarding apparatus

Abstract

A label switching type packet forwarding apparatus having a routing information table in which a forwarding type of a reception packet, output port identification information, and output routing information of a specific layer in the OSI reference model determined by the forwarding type are defined in correspondence with routing information which is found upon reception of a packet, for converting a header of a reception packet in accordance with the packet forwarding type and the output routing information obtained by a table search.

1 . A packet transmission apparatus for transmitting and receiving packets comprising:
 a plurality of input ports for receiving input packets;   a plurality of output ports for transmitting output packets;   a processing unit which performs a header converting process on an input packet received from one of the input ports in accordance with output routing information pre-defined for the input packet, and outputs a header converted packet to one of the output ports specified by an output port identifier pre-defined in association with the output routing information, wherein the output routing information includes values of a plurality of output header information items.   
     
     
         2 . The packet transmission apparatus according to  claim 1 , wherein the values of the plurality of output header information items included in the output routing information include a value of a Multi Protocol Label Switching (MPLS) header and a value of a Virtual Private Network (VPN) header. 
     
     
         3 . The packet transmission apparatus according to  claim 1 , further comprising a routing information table including a plurality of table entries each of which defines the output routing information and the output port identifier in association with an identifier of one of the input ports and at least one header information item of the input packet to be received from the input port. 
     
     
         4 . A packet forwarding method performed by a packet transmission apparatus having a plurality of input ports and output ports each connected to one of a plurality of communication lines, the method comprising the steps of:
 receiving an input packet by one of the input ports;   performing a header converting process on the input packet in accordance with output routing information pre-defined for the input packet, the output routing information including values of a plurality of output header information items; and   outputting the header converted packet to one of the output ports specified by an output port identifier pre-defined in association with the output routing information.   
     
     
         5 . The packet forwarding method according to  claim 4 , wherein the values of the plurality of output header information items included in the output routing information include a value of a Multi Protocol Label Switching (MPLS) header and a value of a Virtual Private Network (VPN) header. 
     
     
         6 . The packet forwarding method according to  claim 1 , wherein the output routing information and the output port identifier are retrieved from a routing information table including a plurality of table entries each of which defines the output routing information and the output port identifier in association with an identifier of one of the input ports and at least one header information item of the input packet to be received from the input port.