Scalable route lookup scheme with small forwarding table and fast update capability

We present in this paper a novel and scalable trie-based solution to the longest matching prefix (LMP) problem required in the IP route lookup. By 1) introducing the usage of Binary Content Accessible Memory (BCAM), 2) partitioning the lookup table with adoption of different parameters for prefixes within different length ranges, and 3) furnishing with the Optimized Bitmap Compression (OBC) technique, the proposed BCAM-OBC lookup scheme achieves not only high lookup throughput, small memory requirement and fast update capacity, but also high flexibility and the scalability for IPv6 migration. For a real-life 130K-prefix IPv4 route table, BCAM-OBC can perform up to 200 Million Packets Per Second (MPPS) with only 48.6KB BCAM and 257.3KB SRAM. Furthermore, only 2 memory accesses are needed for each update averagely.