BFD/Dampening Template question

krock · ‎07-12-2017

HI All,

I have a question about BFD template with dampening

I have the following configured on my ISR router

bfd-template single-hop Template1
interval min-tx 150 min-rx 150 multiplier 3
dampening 15 750 2000 60

I know the thresholds that you can apply to the template are Half-life, Value to unsuppress, Value to start suppressing, Maximum duration to suppress. However when I do show run I see the following value added to the template

bfd-template single-hop Template1
interval min-tx 150 min-rx 150 multiplier 3
dampening 15 750 2000 60 >>> 300 <<<

what to me seems like the restart penalty of 5 minutes, I cant figure out how this value is calculated. I was not able to find a supporting document that explains why the restart value is being added to the template or how it's being calculated.

If I take the same dampening config and apply it to the interface only, the restart value does not show up under the interface. However under the interface itself I do have the option to enable the restart process and specify the value.

LAB1(config)#int gi0/0/1
LAB1(config-if)#dampening 15 750 2000 60
LAB1(config-if)#dampening 15 750 2000 60 ?
restart Enable restart penalty
<cr>
LAB1(config-if)#dampening 15 750 2000 60
LAB1(config-if)#end
!
LAB1#sh run int gi0/0/1
Building configuration...

Current configuration : 187 bytes
!
interface GigabitEthernet0/0/1
description BLAH
dampening 15 750 2000 60
ip address 10.1.1.1 255.255.255.252
load-interval 30
negotiation auto

So basically my question is does anyone know how the restart value is being calculated under the template? regardless of your half life and other values under the template the restart value seems always to be 300.

Thanks

network_baba · ‎11-30-2022

I think some of the verbiage here is confusing. It seems as though in your example you are mixing both BFD dampening (which is the template above) and works much differently than just Cisco IP Event dampening (which is applied to the interface in your example). IF you look up these two different dampening techniques/technologies it may clear up the questions regarding timers etc.. hope that helps.