`bgp dampening`

Syntax

bgp dampening {{half-life <HALF-TIME> reuse <LOW-THRESHOLD> suppress <HI-THRESHOLD> max-suppress-time <MAX-TIME>}
| route-map <NAME>}

Description

Enables route flap dampening which reduces the propagation of unstable routes in the network.

Command context

Parameters

These parameters can be configured at the router level for specific address families or the same parameters can be configured under a route map which can be applied to dampening command.

half-life <HALF-TIME>: Specifies the half-life time in minutes. When the time expires, the penalty on a route gets reduced exponentially to half its current value. Default: 15.

reuse <LOW-THRESHOLD>: Specifies the lower threshold of penalty. On a suppressed route, when the penalty on a route falls below this value, the route is unsuppressed. Default: 750.

suppress <HI-THRESHOLD>: Specifies the upper threshold of penalty. When the penalty on a flapping route exceeds this value, the route is suppressed. Default: 2000.

max-suppress-time <MAX-TIME>: Specifies the maximum time to keep a route suppressed in minutes. Once this timer expires, the route is unsuppressed. Default: 60.

route-map <NAME>: Specifies the name of a route map.

Authority

Administrators or local user group members with execution rights for this command.

Usage

The dampening algorithm assigns a penalty of 1000 to a flapping route every time the route gets withdrawn. The penalty values accumulate on the route every time it flaps. However, the penalty decays and is reduced to half its value by the half-life time.

NOTE:

This feature is not applicable on IBGP routes.

Example

switch(config)# router bgp 1
switch(config-bgp)# address-family ipv4 unicast
switch(config-bgp-ipv4-uc)# bgp dampening

switch(config-bgp-ipv4-uc)# bgp dampening route-map abc

switch(config-bgp-ipv4-uc)# bgp dampening route-map xyz

switch(config-bgp-ipv4-uc)# bgp dampening half-life 10 reuse 100 suppress 250 max-suppress-time 45