As the network line rates reach 40 Gbps today and 100 Gbps in the near future, performing deep packet inspection (DPI) in the Network Intrusion Detection and Prevention Systems (NIDPSs) at the such high speed becomes very challenging. The DPI examines every single byte of each incoming packet and matches them against to a set of predefined malicious signatures. One way to achieve such high speed operations is to store all the signatures on the chip. With limited available on-chip memory, we have developed a highly memory-efficient data structure to implement the Minimal Perfect Hash Function (MPHF), allowing us to access the key in the hash table and perform the exact match only once. With our new compacted data structure, we are able to just store 3.5 bits per key to facilitate the access to the key in the on-chip memory. The data structure also simplifies its construction and update operations.
Masanori Bando, N. Sertac Artan, H. Jonathan Chao