The half-life parameter species the number of minutes after which the penalty for a route becomes half its value. The route penalty
allows routes that have remained stable for a period despite earlier instability to eventually become eligible for use again. The decay rate
of the penalty is proportional to the value of the penalty. After the half-life expires, the penalty decays to half its value. A dampened route
that is no longer unstable can eventually again become eligible for use. You can congure the half-life to be from 1 through 45 minutes.
The default is 15 minutes.
The reuse parameter species how low a penalty for a route must be before the route becomes eligible for use again, after being
suppressed. You can set the reuse threshold to a value from 1 through 20000. The default is 750 (0.75, or three-fourths, of the penalty
assessed for a one ap).
The suppress parameter species how high the penalty for a route can be before the device suppresses the route. You can set the
suppression threshold to a value from 1 through 20000. The default is 2000 (more than two aps).
The max-suppress-time parameter species the maximum number of minutes that a route can be suppressed regardless of how
unstable it is. You can set the maximum suppression time to a value from 1 through 255 minutes. The default is 40 minutes.
This example shows how to change the dampening parameters.
device(config-bgp-router)# dampening 20 200 2500 40
This command changes the half-life to 20 minutes, the reuse threshold to 200, the suppression threshold to 2500, and the maximum
number of minutes a route can be dampened to 40.
NOTE
To change any of the parameters, you must specify all the parameters with the command. To want to leave any parameters
unchanged, enter their default values.
Using a route map to congure route ap dampening for a specic
neighbor
You can use a route map to congure route ap dampening for a specic neighbor by performing the following tasks:
• Congure an empty route map with no match or set clauses. This route map does not specify particular routes for dampening
but does allow you to enable dampening globally when you refer to this route map from within the BGP4 conguration level.
• Congure another route map that explicitly enables dampening. Use a set clause within the route map to enable dampening.
When you associate this route map with a specic neighbor, the route map enables dampening for all routes associated with the
neighbor. You also can use match clauses within the route map to selectively perform dampening on some routes from the
neighbor.
NOTE
You still need to congure the rst route map to enable dampening globally. The second route map does not enable dampening
by itself; it just applies dampening to a neighbor.
• Apply the route map to the neighbor.
To enable route ap dampening for a specic BGP4 neighbor, enter commands such as the following.
device(config)# route-map DAMPENING_MAP_ENABLE permit 1
device(config-routemap DAMPENING_MAP_ENABLE)# exit
device(config)# route-map DAMPENING_MAP_NEIGHBOR_A permit 1
device(config-routemap DAMPENING_MAP_NEIGHBOR_A)# set dampening
device(config-routemap DAMPENING_MAP_NEIGHBOR_A)# exit
device(config)# router bgp
device(config-bgp)# dampening route-map DAMPENING_MAP_ENABLE
device(config-bgp)# neighbor 10.10.10.1 route-map in DAMPENING_MAP_NEIGHBOR_A
Conguring route ap dampening
FastIron Ethernet Switch Layer 3 Routing
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