A Novel Scalable IPv6 Lookup Scheme Using Compressed Pipelined Tries

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.