Symptom
BFD dampening configured with custom timers causes unexpected behavior with BGP (BGP session is shown established but it is actually not as only one of the peers sends an Open message and no updates are exchanged).
Log message:
*Jul 17 16:23:40.532: %BGP-5-ADJCHANGE: neighbor 10.216.247.58 vpn vrf DAB Up
*Jul 17 16:23:40.533: %BGP-6-MSGDUMP_LIMIT: unsupported or mal-formatted message received from 10.216.247.58:
FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF 0041 0200 0000 1B40 0101 0040 0206 0201
0000 FDEE 4003 040A D8F7 3A80 0404 0000 0000 2001 0A0F 0120 030D 0D0D 2070 0202
02
*Jul 17 16:23:40.533: %BGP-6-MALFORMEDATTR: Malformed attribute in (BGP(0) Prefixes: 1.10.15.1/32 3.13.13.13/32 112.2.2.2/32 ) received from 10.216.247.58
Conditions
BFD dampening custom timers (e.g.dampening 30 20 900 210).
If custom timers are used, BGP is shown as established, however, no routes are exchanged.
In a packet capture can be seen only one of the peers is sending Open message.
Default bfd dampening timers:
dampening 3 1500 3000 5
Workaround
If you want to use bfd dampening use the default dampening timers
Further Problem Description
The "bfd down-monitoring" feature is not supported with this platform.
