Performance Improvement of Packet Classification by Using Lookahead Caching

Rectangle search is a well-known packet classification scheme which is based on multiple hash accesses for different filter length. It shows good scalability with respect to the number of filters; however, the performance is not fast enough to fulfill the high-speed requirement of packet classification. In this paper, we propose a lookahead caching which can significantly improve the performance of hash-based algorithm. The basic idea is to filter out the un-matched probing case by using dual-hash architecture. The experimental results indicate that the proposed scheme can improve the performance by the factor of two for the 2-dimension (source prefix, destination prefix) filter database.