Bidirectional Forwarding Detection (BFD) is supported on the 7705 SAR. In the case of BFD for RSVP-TE, an RSVP-TE enabled link is registered with the BFD state machine, and if a failure occurs the RSVP-TE interface is taken out of service. The BFD implementation on the 7705 SAR works on a hop-by-hop basis, and if BFD detects a link failure, only the two directly connected MPLS nodes are aware of that failure. If the node that detects the link failure is an LSR node, it generates PATH-ERR messages to the originators (the LER nodes) of the failing LSPs. If FRR is configured, the detecting node takes corrective action itself. See LSP Redundancy and RSVP-TE Fast Reroute (FRR) for more information on these topics.