A perfect-hashing scheme for fast IP lookup

IP lookup is widely performed in many network applications, including route lookup, packet classification and network monitoring. Hashing scheme is an important technology for it and can gain O(1) average memory access per lookup. But collisions exist in common hash scheme, which need multiple memory accesses, affecting the worst-case throughput critically. A perfect-hashing scheme was proposed. By combining bloom filter (BF) and contend addressable memory (CAM) together, it eliminated collisions at a low price. Through a combination of analysis and simulations we show that this algorithm is significantly faster than common hash scheme in the worst case performance.