Efficient IP routing table lookup scheme

Abstract

One of the pertinent issues in IP router design is the IP routing table lookup. With high-speed multi-gigabit links required in the Internet, the lookup has become a great bottleneck. The authors propose a lookup scheme that can efficiently handle IP route lookup, insertion and deletion inside the routing table. This method is less complex in comparison to other schemes. By using careful memory management design, each of the IP routes are only stored once instead of the range that is used conventionally. Therefore, the required memory is reduced. In addition, a novel skip function is introduced to further decrease the memory size. The proposed scheme, which furnishes approximately 75×106 lookups/s, needs only a small memory size of 0.59 Mbyte. This scheme can be implemented in a pipeline hardware design and thus achieves one route lookup for every memory access. This lookup scheme can also be easily scaled to IPv6 in the future.