NAF conversion: An efficient solution for the range matching problem in packet filters

The coexistence of range based and prefix based fields within the filtering rules is one of the most important cause that makes the packet classification problem difficult to resolve and the proposed hybrid solutions hard to implement. How to effectively support such complex filtering rules is really a challenge. Most of the cases range-based fields need to be converted into a set of standard prefixes. Actually, there is a manifested need to have new expressive conversion techniques to process efficiently multiple type of conditions. In this context, the problem of limited scalability is encountered and must be resolved to avoid the range to prefix blowout. In this paper, we propose the NAF conversion technique (Non-adjacent form) which is able to expand an arbitrary range or multiple ranges into an optimal set of signed prefixes. The proposed technique is flexible enough and let us the possibility to reach a better compression ratio than the previous proposed solutions.