Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) - Manual (Page 128)

100 Multi-Service IronWare Routing Configuration Guide
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Filtering
• 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.
Brocade(config)# route-map DAMPENING_MAP_ENABLE permit 1
Brocade(config-routemap DAMPENING_MAP_ENABLE)# exit
Brocade(config)# route-map DAMPENING_MAP_NEIGHBOR_A permit 1
Brocade(config-routemap DAMPENING_MAP_NEIGHBOR_A)# set dampening
Brocade(config-routemap DAMPENING_MAP_NEIGHBOR_A)# exit
Brocade(config)# router bgp
Brocade(config-bgp)# dampening route-map DAMPENING_MAP_ENABLE
Brocade(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 to neighbor 10.10.10.1. Since the second route map does not contain match clauses for
specific routes, the route map enables dampening for all routes received from the neighbor.
Removing route dampening from a route
You can un-suppress routes by removing route flap dampening from the routes. The device allows
you to un-suppress all routes at once or un-suppress individual routes.
To un-suppress all the suppressed routes, enter the following command at the Privileged EXEC level
of the CLI.
Brocade# clear ip bgp dampening
Syntax: clear ip bgp dampening [ip-addr ip-mask]