Routing Table Compaction for TCAM-Based IP Address Lookup

In this work, we propose a scheme of routing table compaction for IP forwarding engines based on ternary content addressable memory (TCAM). Our scheme transforms the original routing table into a form with only disjoint prefixes. The most prevalent next hop of the routing table is then calculated and the route prefixes corresponding to the next hop are replaced by one TCAM entry. In combination with Espresso-II logic minimization algorithm, the proposed scheme reduces the TCAM storage requirements by more than 75% compared to the original routing tables. We also present an effective approach to support incremental updates