High-Performance IPv6 Lookup with Real-Time Updates Using Hierarchical-Balanced Search Tree

Packet forwarding is the foundation of network communications. Internet routers forward packets by matching the packet destination address against the prefixes in the forwarding information base. Due to the emergence of cloud computing and network function virtualization, more and more applications require high-bandwidth low-latency IPv6 networks. However, most of the current IP lookup algorithms in practice are designed for IPv4 addresses and hard to scale to IPv6 addresses. In this paper, we first propose a novel data structure called hierarchical-balanced search tree (Hi-BST). The compact and scalable data structure built can be stored in on-chip memory. On the basis of Hi-BST, we present a fast IPv6 lookup algorithm and prefix update algorithms. In the worst case, our algorithm can achieve fast lookup and update with the time that is proportional to the logarithm of the number of prefixes. Experiments using real FIBs give an integrated evaluation. Compared with the state-of-the-art algorithms, our algorithm achieves a fast lookup with real-time updates, which is 1.33~6.78 times that of the comparison algorithms respectively. Moreover, Hi-BST saves 4.3%~79.0% memory footprint of the comparison algorithms respectively.