Disclosed are, inter alia, methods, apparatus, computer-storage media, mechanisms, and means associated with Bidirectional Forwarding Detection (BFD) on multilink bundled interfaces. A packet switching device communicates with another packet switching device through a multilink bundled interface configured for communicating over a plurality of bundled communication links. A separate BFD session is conducted over each link of the multiple bundled communication links, and in response to a BFD-detected failure condition, the use of the one or more links or the entire bundled interface is removed from service.