Configuring BGP Route Dampening

Use the following commands to configure BGP route dampening.

BGP route dampening maintains a history of flapping routes and prevents advertising these routes.

A route is considered to be flapping when it is repeatedly transitioning from available to unavailable or vice versa.

Syntax:

set bgp dampening

{off | on}

suppress-above {<2-32> | default}

reuse-below {<1-32> | default}

max-flat {<3-64> | default}

reachable-decay {<1-900> | default}

unreachable-decay {<1-2700> | default}

keep-history {<2-5400> | default}

Note - BGP route dampening is only supported for External BGP (EBGP).

Parameters:

Parameter	Description
`{off \| on}`	Specifies whether to enable or disable BGP route dampening.
`suppress-above <2-32>`	Specifies the value of the instability metric at which route suppression takes place. A route is not installed in the forwarding table or announced even if it reachable during the period that it is suppressed.
`suppress-above default`	Specifies an instability metric value for suppressing routes of 3.
`reuse-below metric <1-32>`	Specifies the value of the instability metric at which a suppressed route becomes unsuppressed if it is reachable but currently suppressed. The value assigned to the reuse-below metric must be lower than the suppress-above value.
`reuse-below metric default`	Specifies an instability metric value for announcing previously suppressed routes of 2.
`max-flap <3-64>`	Specifies the upper limit of the instability metric. The value must be greater than the suppress-above value plus 1. Each time a route becomes unreachable, 1 is added to the current instability metric.
`max-flat default`	Specifies the upper limit of the instability metric as 16.
`reachable-decay <1-900>`	Specifies the time for the instability metric to reach half of its value when the route is reachable. The smaller the value the sooner a suppressed route becomes reusable.
`reachable-decay default`	Specifies a value of 300.
`unreachable-decay <1-2700>`	Specifies the time for the instability metric to reach half its value when the route is NOT reachable. The value must be equal to or higher than the reachable-decay value.
`unreachable-decay default`	Specifies a value of 900
`keep-history <2-5400>`	Specifies the period for which route flapping history is maintained for a given route.
`keep-history default`	Specifies a value of 1800.