DEVICE AND METHOD FOR ROUTING TABLE RETRIEVAL

摘要

PROBLEM TO BE SOLVED: To enable fast retrieval by reducing the frequency and memory capacity of routing table retrieval. SOLUTION: Retrieval is carried out in two stages; and 1st retrieval is performed by a 1st-stage process part 1 by using CAM and 2nd retrieval is performed by arranging a tree at a 2nd-stage process part 2. All Prefix's entering a table are divided into a range determined by Prefix length and Prefix's generated by shortening the Prefix's to the minimum Prefix length in the range are stored in the CAM. The 1st-stage process part 1 compares an input IP address with the Prefix's stored in the CAM and outputs the address of a tree storage memory part 3 corresponding to a matching Prefix. The process moves to the node corresponding to the output of the CAM halfway in a tree, retrieval is carried out in the limited range, and at the end of the retrieval, information in a NextHop information storage memory 4 is outputted as a final result.