This section describes how to configure a dynamic BFD session to detect faults in links between RSVP neighbors.
BFD for RSVP is used with TE FRR when a Layer 2 device exists on the primary LSP between a PLR and its downstream RSVP neighbor.
The interval at which a neighbor is declared Down is three times as long as the interval at which RSVP Hello messages are sent. This allows devices to detect a fault in an RSVP neighbor in seconds.
If a Layer 2 device exists on a link between RSVP nodes, an RSVP node cannot rapidly detect a link fault, which results in a great loss of data.
BFD rapidly detects faults in links or nodes on which RSVP adjacencies are deployed. If BFD detects a fault, it notifies the RSVP module of the fault and instructs the RSVP module to switch traffic to a bypass tunnel.