Abstract: In order to be able to use a smaller routing table (4) and, thus, to reduce the costs and power consumption and to improve the performance of an IP router, it is proposed to extract a destination address identifier (ADR) from a data packet to be forwarded by the IP router, compress the extracted destination address identifier (ADR) by using a lossless data compression algorithm, and compare the compressed destination address identifier with entries stored in the routing table (4) so as to find a correspondence between the destination address identifier and one of the entries of the routing table (4). Each entry of the routing table (4) corresponds to a possible or available forwarding address of the IP router, the forwarding addresses having been compressed with the same data compression algorithm as the destination address identifier.