how to check bfd logging in cisco sdwan fabric

[palani2010]

how to check bfd logging in cisco sdwan fabric

[Flavio Miranda]

Hi

 Where are teying to see this? vManage ? Or router ?  Which version ?

[palani2010]

Both vmanage (GUI) and vedge (CLI)

Version - 20.3.3

[Flavio Miranda]

"BFD for routing protocols in Cisco SD-WAN cannot be monitored through Cisco vManage. Use CLI show commands for monitoring BFD for Cisco SD-WAN routing protocols."

On the router you can run "show bfd session "

[Kanan Huseynli]

Hi,

you can generally see BFD status via CLI: show bfd session (in IOS XE show sdwan bfd session) or in vManage by choosing device from Monitor page, then Real time > BFD sessions.

However, if you would like to see logs (like BFD down or UP), it can be seen in vManage > Monitor > Logs > Alarms. There can be different BFD alarms. See table 1 from below link:

https://www.cisco.com/c/en/us/td/docs/routers/sdwan/configuration/Monitor-And-Maintain/monitor-maintain-book/m-alarms-events-logs.html

You can do alarm notification to email if needed. From the above doc we see that from 17.6.3 BFD syslog logging is supported (which can be forwarded to external syslog server too). However, this command is not supported in vEdge (I've checked even on 20.11 latest version).

"Starting from Cisco IOS XE Release 17.6.3, the alarms alarm bfd-state-change syslog command is used to view the BFD state change syslog message for any BFD state change event in the device. For complete details, see alarms alarm bfd-state-change syslog command.

Device(config-system)# alarms alarm bfd-state-change syslog 
Device(config-alarm-bfd-state-change)# commit

Here is an example for BFD state change syslog message:

Jul 10 07:09:07.583: %Cisco-SDWAN-vm5-FTMD-5-NTCE-1000009: BFD-session 10.1.15.15:12346 -> 10.1.16.16:12366, 
local-tloc-index: 32775 -> remote-tloc-index: 32777, TLOC- local sys-ip: 172.16.255.15, local color: lte -> remote 
sys-ip: 172.16.255.16, remote color: lte, encap: IPSEC, new state->UP delete:false, reason:

 "

For advanced troubleshooting scenarios you can use debugging BFD (supported on vEdge too) as indicated in this doc:

https://www.cisco.com/c/en/us/support/docs/routers/sd-wan/214510-troubleshoot-bidirectional-forwarding-de.html#anc25