A New Design of Bloom Filter for Packet Inspection Speedup

Bloom filter is a space-efficient randomized data structure for group membership query. It is widely used in networking applications which involve the packet header/content inspection. To provide fast membership query operation, this data structure resides in the main memory in most of its applications. Each membership query consists hashing for a set of memory addresses and memory accesses at these locations. In this paper, we propose a new design of Bloom filter in which every two memory addresses are squeezed into one I/O block of the main memory. With the burst-type data I/O capability in the contemporary DRAM design, the total number of memory I/O's involved in the membership query is reduced by half. Therefore, the average query delay can be reduced significantly. The cost of using this new design is a negligible increment of false positive rate as shown by both analysis and simulation.