Dynamic Scheme for Packet Classification Using Splay Trees

Many researches are about optimizing schemes for packet classification and matching filters to increase the performance of many network devices such as firewalls and QoS routers. Most of the proposed algorithms do not process dynamically the packets and give no specific interest in the skewness of the traffic. In this paper, we conceive a set of selfadjusting tree filters by combining the scheme of binary search on prefix length with the splay tree model. Hence, we have at most 2 hash accesses per filter for consecutive values. Our proposed filter is adapted to easily assure exact matching for protocol field, prefix matching for IP addresses, and range matching for port numbers. Also, we use the splaying technique to optimize the early rejection of unwanted flows, which is important for many filtering devices such as firewalls.