Patent ID: 7529251
Filing Date: 2009-05-05
Classification: H04L

Abstract:
1. A data transfer device, comprising: a plurality of input circuits into which a packet is inputted, a plurality of output circuits which output a packet, a routing unit which decides routing information which shows the output circuit of the input packet from data contained in the header of the input packet, and a data relay unit which transfers the packet to the output circuit corresponding to the routing information, wherein said routing unit is a data transfer unit comprising: a forwarding table management unit which extracts part or all of the data contained in a packet header, and performs look-up using this as a look-up key, a forwarding table for outputting data regarding a physical position in which a look-up condition is stored in a memory based on said look-up key, a routing table which stores routing information corresponding to said look-up condition stored at said physical position, and a routing table administration unit which looks up said routing information from said routing table based on said data regarding said physical position, wherein said forwarding table is stored in an array formed by a plurality of physical banks having an identical look-up bit width, and said forwarding table management unit comprises: a function unit which performs calculations for deciding a physical bank to be looked up from said look-up key, and a register which stores numbers for changing an output value of the function unit, and wherein the forwarding table management unit commands the look-up of said physical bank corresponding to the output value from said register.