Symptom
When a single BGP neighbor goes down that has fall over BFD enabled...the BFD logging is complete. In this scenario we see all the expected logs from the BFD state machine:
*Dec 21 16:30:46.162: %BFDFSM-6-BFD_SESS_DOWN: BFD-SYSLOG: BFD session ld:4097 handle:1,is going Down Reason: RX ADMINDOWN
*Dec 21 16:30:46.163: %BFD-6-BFD_SESS_DESTROYED: BFD-SYSLOG: bfd_session_destroyed, ld:4097 neigh proc:BGP, handle:1 active
*Dec 21 16:30:46.183: %BFD-6-BFD_SESS_CREATED: BFD-SYSLOG: bfd_session_created, neigh 10.10.1.2 proc:BGP, idb:GigabitEthernet4 handle:1 act
*Dec 21 16:30:46.187: %BFDFSM-6-BFD_SESS_UP: BFD-SYSLOG: BFD session ld:4097 handle:1 is going UP
When multiple BGP neighbors flap around the same time...the BFD logging is not complete, and logs that show info such as the LD of the BFD session are not logged when the session is destroyed.
Conditions
Multiple BGP neighbors with fall over BFD configured going down around the same time
