Design of multi-field IPv6 packet classifiers using ternary CAMs

Abstract

Typically, high-end routers/switches classify a packet by looking for multiple fields of the IP/TCP headers and recognize which flow the packet belongs to. Several packet classification algorithms to accelerate packet processing and reduce the memory requirement have been proposed. But it is not easy to implement these algorithms in hardware to lookup these multiple fields in the same time. This paper intends to design a novel packet classification engine capable of simultaneously processing multi-field searching, especially for the IPv6 packets with relative longer addresses (128 bits). To classify the IPv6 packets in wire-speed, the CLM (CAM-Like Memory)-based hardware architecture is considered and five fields (source IPv6 address, destination IPv6 address, source port, destination port, and protocol) are designed as the searching key. Evaluation results indicate that compared with the typical market leading delivering search engines, the proposed hardware architecture provides a 30% speed-up performance. A compact method is also provided to compress the bit-width required to represent the multi-field of an IPv6 packet. This saves the memory space required for the IPv6 rule table for about 20%.