C ²BF: Cache-based counting Bloom filter for precise matching in network packet processing

Bloom filter is widely used in network packet processing due to its fast lookup speed and small memory cost. However, the non-negligible false positive rate and the difficulty of online update still prevent it from extensive utilization. In this paper, we propose a cache-based counting Bloom filter architecture, C ²BF, which is not only easy to update online but also benefical for fast verification for precise matching. We also present a high speed hardware C ²BF architecture with off-chip memory and fast cache replacement method. This paper includes three contributions: 1) compressed CBF implementation and its updating algorithm; 2) pattern grouping for higher cache hit rate; 3) onchip cache organization and replacement policy. Experiments show that our prototype of C ²BF reduces more than 70% of the verification processing time with cache design compared with traditional schemes without cache.