This counter tallies packets that CEF itself dropped, as opposed to punting them elsewhere, for whichever switching path this instance represents. Because these are drops attributable specifically to the CEF fast path, not interface errors or ACL denies, a rising value here points an admin toward FIB-level forwarding failures, like no route to a destination, rather than a physical-layer or access-list problem. If this counter climbs sharply right after a routing change, it may mean CEF briefly had no valid FIB entry for some destinations during reconvergence and dropped their packets rather than forwarding them.