Symptom
After reloading a A9K-1x100GE-SE linecard, BFD may fail to initialize with fib_mgr correctly leaving bfd not operational on the line card.
The show bfd session will show the bfd session state as Unknown while the bfd agent on the line card shows the session in Retry.
RP/0/RSP0/CPU0:router#sh bfd agent loc 0/1/cpu0
Tue Jun 14 08:00:14.344 UTC
IPV4 Sessions Up: 0, Down: 0, Standby: 0, Unknown: 0, Retry: 1, Total: 1
show bfd trace verbose on the line card displays the error "fib_connection NOT up"
Jun 14 06:51:31.452 ip_bfd/events 0/1/CPU0 t1 Create session [intf=HundredGigE0/1/0/0 (ifh=0x60000c0), Dst=10.3.28.26, Src:0.0.0.0], parent i/f: NULLIFHNDL (0x0), detect 300000 us, mult 3, app/state 4294967295
Jun 14 06:51:31.452 ip_bfd/events 0/1/CPU0 t1 Session subtype PR/V4/SH, bundle ifh 0x0, caps 0, iftype 0, create type 0
Jun 14 06:51:31.455 ip_bfd/fib 0/1/CPU0 t1 Doing FIB register for 26.28.3.10, ifh:HundredGigE0/1/0/0 (0x60000c0), table id 0xe0000000, fib_connection NOT up
Conditions
This issue is rarely seen after the line card is reloaded.
Workaround
There is no workaround.
Reload the line card again to recover from this condition.
Restarting the bfd_agent process on the affected line card will also recover from the failure.
