Multi-field range encoding for packet classification in TCAM
Yeim–Kuan Chang, Chun‐I Lee, Cheng-Chien Su · 2011
Packet classification has wide applications such as unauthorized access prevention in firewalls and Quality of Service supported in Internet routers. The classifier containing pre-defined rules is processed by the router for finding the best matching rule for each incoming packet and for taking appropriate actions. Although many software-based solutions had been proposed, high search speed required for Internet backbone routers is not easy to achieve. To accelerate the packet classification, the state-of-the-art ternary content-addressable memory (TCAM) is a promising solution. In this paper, we propose an efficient multi-field range encoding scheme to solve the problem of storing ranges in TCAM and to decrease TCAM usage. Existing range encoding schemes are usually single-field schemes that perform range encoding processes in the range fields independently. Our performance experiments on real-life classifiers show that the proposed multi-field range encoding scheme uses less TCAM memory than the existing single field schemes. Compared with existing notable single-field encoding schemes, the proposed scheme uses 12% ~ 33% of TCAM memory needed in DRIPE or SRGE and 56% ~ 86% of TCAM memory needed in PPC for the classifiers of up to 10k rules.