CEF — FIB, Adjacency & Why Process Switching Died

CEF is the default forwarding engine: no per-packet CPU work. Two precomputed structures: FIB — optimised copy of the RIB, longest-prefix entries, best path per prefix. Adjacency table — the rewritten L2 header per next-hop (MAC + outgoing interface), built from ARP/ND. Flow: RIB → FIB → Adjacency. Both update event-driven on routing or ARP […]