Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 461)

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 configure route flap dampening for a specific
neighbor
You can use a route map to configure route flap dampening for a specific neighbor by performing the
following tasks:
• Configure 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 configuration level.
• Configure 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 specific 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 configure the first 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 flap dampening for a specific 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
In this example, the first command globally enables route flap dampening. This route map does not
contain any match or set clauses. At the BGP4 configuration level, the dampening route-map
command refers to the DAMPENING_MAP_ENABLE route map created by the first command, thus
enabling dampening globally.
The third and fourth commands configure a second route map that explicitly enables dampening. Notice
that the route map does not contain a match clause. The route map implicitly applies to all routes. Since
the route map will be applied to a neighbor at the BGP4 configuration level, the route map will apply to
all routes associated with the neighbor.
Although the second route map enables dampening, the first route map is still required. The second
route map enables dampening for the neighbors to which the route map is applied. However, unless
dampening is already enabled globally by the first route map, the second route map has no effect.
The last two commands apply the route maps. The dampening route-map command applies the first
route map, which enables dampening globally. The neighbor command applies the second route map
Using a route map to configure route flap dampening for a specific neighbor
FastIron Ethernet Switch Layer 3 Routing Configuration Guide 461
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