Résumé: The di.culty of e.ciently reordering the rules in an Access Control List is considered and the essential optimisation problem formulated. The complexity of exact and sophisticated heuristics is noted along with their unsuitability for real time implementation embedded in the hardware of the network device. A simple alternative is proposed, in which a very limited rule reordering is considered following the processing of each packet. Simulation results are given from a range of tra.c types. The method is shown to achieve savings thatmake its use worthwhile for lists longer than a given number of rules. This number is dependent on tra.c characteristics but generally around 25 for typical network conditions.

Langue: Anglais