On Designing Fast Nonuniformly Distributed IP Address Lookup Hashing Algorithms

Computer networks have continued to make substantial advances in the past couple of decades through better technologies and methodologies employed. As the usage of the networks continues to increase exponentially, high throughput of the networks has to be maintained with various performance-efficient network algorithms. IP address lookup is one of the processes, the performance of which dearly affects the overall network performance. Hashing has been widely used for fast IP address lookup due to its simplicity, but mostly assuming on hashing from an address set with uniformly distributed key values. Performance from these known hashing techniques is far from optimal due to the high nonuniformity in actual IP address distribution. In this paper, we propose a preprocessing method for the IP address databases to extract certain regularity to allow for design of more efficient hashing algorithms based on XOR operations. Simulation results show an improvement in performance ranging from 35% to 72% on randomly generated addresses and several sample IP address databases. The paper also shows that the proposed algorithms deliver comparable performance to other well-known hashing algorithms such as the CRC and RS hashing while requiring much less hardware to implement and a much shorter time to perform.