Bidirectional Forwarding Detection (BFD) does not have a peer-discovery mechanism. You must configure BFD for each system.
The following steps give an overview of the BFD workflow.
- The routing protocol registers itself to BFD as a BFD client.
- The BFD timers are negotiated between the two BFD peers by using the periodic exchange of packets.
- The BFD session can go down due to an expiry of the BFD timer or due to a link going down. In such a case, BFD informs all its registered clients about the failure. The clients then take failover action.
- The BFD control packets are exchanged until the BFD session is terminated due to the removal of a BFD client or the removal of the BFD configuration. In either case, the BFD session is torn down.
For more information on how to configure BFD, refer to the next sections in this chapter.