Space-code bloom filter for efficient traffic flow measurement

Abstract

Per-flow traffic measurement is critical for usage accounting, traffic engineering, and anomaly detection. Previous methodologies are either based on random sampling (e.g., Cisco's NetFlow), which is inaccurate, or only account for the elephants. Our paper introduces a novel technique for measuring per-flow traffic approximately, for all flows regardless of their sizes, at very high-speed (say, OC192+). The core of this technique is a novel data structure called Space Code Bloom Filter (SCBF). A SCBF is an approximate representation of a multiset; each element in this multiset is a traffic flow and its multiplicity is the number of packets in the flow. SCBF employs a Maximum Likelihood Estimation (MLE) method to measure the multiplicity of an element in the multiset. Through parameter tuning, SCBF allows for graceful tradeoff between measurement accuracy and computational and storage complexity. SCBF also contributes to the foundation of data streaming by introducing a new paradigm called blind streaming. We evaluated the performance of SCBF on packet traces gathered from a tier-1 ISP backbone and through mathematical analysis. Our preliminary results demonstrate that SCBF achieves reasonable mea-surement accuracy with very low storage and computational complexity.