Abstract In this paper, a new data structure, called the classified multi-suffix trie (CMST), is proposed for designing dynamic router-tables. CMST achieves a better performance than existing data structures because each node can store more than one prefix and the longest matching prefix may be found in an internal node rather than on a leaf. Furthermore, with the classification in each node, the dynamic router-table operations can be performed efficiently. To reduce the memory requirement, we store each prefix's corresponding suffix in a CMST node, instead of storing a full binary string. Based on the CMST, we also propose another data structure, called the Partitioning Classified Multi-Suffix Trie (PCMST) to reduce the height of the trie and expedite router-table operations. Experiments using real IPv4 routing databases demonstrate that the proposed data structures are efficient in terms of memory usage and it performs well in terms of the average times of the lookup, insert and delete operations. We report the results of experiments conducted to compare the performance of the proposed data structure with that of other structures using the benchmark IPv4 prefix databases AS4637, AS6447, and AS65000 with 219,581, 296,552, and 226,847 prefixes respectively.

Abstract—High-performance routers require high-speed IP address lookup to achieve wire-speed packet forwarding. This study proposes a new data structure, the Multi-Index Hybrid Trie (MIHT), for dynamic router table designs. This data structure was constructed by combining the useful characteristics of the B+ tree and priority trie. IP lookup operations can be performed efficiently by associating each prefix with a key value in the MIHT. Furthermore, because the required tree height and number of prefixes were reduced, dynamic router table operations were performed efficiently using the MIHT. To reduce the memory requirement, each prefix stored its corresponding suffix in a node of the MIHT, rather than storing a full prefix. Experiments using IPv4 and IPv6 routing databases indicated that the proposed data structure has efficient memory usage and performs well for lookup, insertion, and deletion operations. This study reports the results of the experiments performed to compare the proposed data structure with other structures using the benchmark IPv4 and IPv6 prefix databases AS1221, AS4637, AS6447, AS65000, AS1221*, and AS6447 * with 407,067, 219,581, 417,995, 406,973, 12,155, and 12,278 prefixes, respectively, where AS1221 * and AS6447 * are IPv6 BGP routing tables. Index Terms—Classless inter domain routing (CIDR), dynamic router tables, IP address lookup, longest matching prefix, multi-index hybrid trie. 1