VLSI implementation of routing tables: tries and CAMs

Routing tables for communication networks can be designed using many different approaches, including table lookup, content-addressable memory (CAM), hashing, and tries. The authors compare these approaches in the context of custom VLSI implementation. For tables with a small number of entries and a large address space, CAMs can be very cost effective. If only RAM is available, it is shown that tries, of which simple table lookup is a special case, provide a useful architecture. Also considered is a new variation, table partitioning, which constitutes a useful compromise between the conventional CAM and a trie