A Longest Prefix Matching Method using Rectangular-Tree

With the rapid growth of Internet traffic as well as the employment of new complex applications, e.g. multimedia, online gaming and social networks, the high-performance devices and routers have become essential requirements in todays computer networks. One of the major bottlenecks in nowadays routers is the lookup of routing tables and finding the appropriate output port for packet forwarding. Because of arbitrary length of Classless Inter-Domain Routing (CIDR) addresses, the packets must be forwarded to the corresponding output port using longest prefix matching (LPM) methods. In recent years, various software and hardware solutions for finding longest prefix matching are proposed. This paper presents a method to implement the IP lookup of the routing table using Rectangle Tree (R-Tree). In this method, prefixes are converted to two-dimensional data in order to be inserted into the R-Tree. Subsequently, searching is performed on R-Tree to find the matched prefixes especially the LPM. The results show that this method reduces the number of memory accesses, significantly.