Content Switch Rules and Their Conflict Detection

Content switch can be configured as load balancer, firewall, spam mail filter, and virus detection and removal system, by specifying a set of rules. In this paper we present our content switch rule design for a Linux-based content switch, and show how they are translated and downloaded into the switch for packet processing. One common problem in specifying rules for content switches or policy-based networks is the conflict detection problem, where rules may contradict or duplicate each other. We explore the algorithm issues related to conflict detection problem and present some performance results. An algorithm for detecting conflict in rules with regular expression matching is presented and its complexity analyzed. An interactive Java-based content switch rule editor was designed for specifying the rules and detecting the conflicts among rules. Its conflict detection algorithm and performance results are also presented.