Hybrid trie based approach for longest prefix matching in IP packet processing

Abstract

A hybrid trie based approach for longest prefix match (LPM) search scheme is proposed in this paper to handle the current prefix growth in an efficient manner. The proposed scheme is built around two sub-schemes, the first one is the tree bitmap structure and the second one is the trie based data structure. The main idea of this approach is to simplify the required prefix operations, viz., insertion, deletion, LPM search and update operations in the routing tables. The prominent characteristics of this scheme is the inherent ability to find the best matched prefix during the search operation itself instead of the requirement of dedicated LPM search algorithm. It is also to be noted that this scheme consumes less amount of memory to store prefixes unlike conventional and existing LPM solutions. The simulation result shows that in comparison to TBM based approach, the proposed hybrid based LPM scheme exhibits similar lookup performance with significant improvement in terms of memory requirement.