A Novel Scalable IPv6 Lookup Scheme Using Compressed Pipelined Tries

Abstract : An IP router has to match each incoming packet’s IP destination address against all stored prefixes in its forwarding table. This task is increasingly more challenging as the routers have to: not only keep up with the ultra-high link speeds, but also be ready to switch to the 128-bit IPv6 address space while the number of prefixes grows quickly. Commercially, many routers employ Ternary Content Addressable Memory (TCAM) to facilitate fast IP lookup. However, TCAMs are power-eager, expensive, and not scalable. We advocate in this paper to keep the forwarding table in trie data structures that are accessed in a pipeline manner. Especially, we propose a new scalable IPv6 forwarding engine based on a multibit trie architecture that can achieve a throughput of 3.1 Tera bits per second.