Non-collision Hash Scheme Using Bloom Filter and CAM

Hash tables are fundamental components of several network processing algorithms and applications, including route lookup, intrusion detection, viruses, worms and other malicious code detection and filtering. Collisions exist in common hash tables, which can critically affect the worst-case throughput of an application, since the number of memory accesses required for each lookup can vary. A non-collision hash scheme was presented, assuring at most one memory access for each lookup. Using Bloom filter (BF) and CAM, this new algorithm is flexible and items can be inserted or deleted quickly. Through a combination of analysis and simulations we show that our algorithm achieves better worst-case performance than the BF based hash table using the same amount of memory and a small amount of additional CAM.