Performance evaluation and cache behavior of LC-trie for IP-address lookup

Many IP-address lookup software algorithms use a trie-like data structure to perform longest prefix match. LC-trie is an efficient algorithm that uses level compression and path compression on tries. By using realistic and synthetically generated traces, we study the performance of the LC-trie algorithm. Our study includes trie search depth, prefix vector access behavior, cache behavior, and packet lookup service time. The results show that for a realistic traffic trace, the LC-trie algorithm is capable of performing 20 million packet lookups per second on a Pentium 4, 2.8 GHz computer, which corresponds to a 40 Gb/s link for average sized packets. Further, the results show that LC-trie performs up to five times better on the realistic trace compared to a synthetically generated network trace. This illustrates that the choice of traces may have a large influence on the results when evaluating lookup algorithms.