Fast and Memory-Efficient Traffic Classification with Deep Packet Inspection in CMP Architecture

Traffic classification is important to many network applications, such as network monitoring. The classic way to identify flows, e.g., examining the port numbers in the packet headers, becomes ineffective. In this context, deep packet inspection technology, which does not only inspect the packet headers but also the packet payloads, plays a more important role in traffic classification. Meanwhile regular expressions are replacing strings to represent patterns because of their expressive power, simplicity and flexibility. However, regular expressions mathcing technique causes a high memory usage and processing cost, which result in low throughout. In this paper, we analyze the application-level protocol distribution of network traffic and conclude its characteristic. Furthermore, we design a fast and memory-efficient system of a two-layer architecture for traffic classification with the help of regular expressions in multi-core architecture, which is different from previous one-layer architecture. In order to reduce the memory usage of DFA, we use a compression algorithm called CSCA to perform regular expressions matching, which can reduce 95% memory usage of DFA. We also introduce some optimizations to accelerate the matching speed. We use real-world traffic and all L7-filter protocol patterns to make our experiments, and the results show that the system achieves at Gbps level throughout in 4-cores Servers.