Setup Guide

– max-suppress-time: the range is from 1 to 255. The maximum number of minutes a route can be suppressed. The default is
four times the half-life value. The default is 60 minutes.
– route-map map-name: name of a congured route map. Only match commands in the congured route map are supported. Use
this parameter to apply route dampening to selective routes.
• Enter the following optional parameters to congure route dampening.
CONFIG-ROUTE-MAP mode
set dampening half-life reuse suppress max-suppress-time
– half-life: the range is from 1 to 45. Number of minutes after which the Penalty is decreased. After the router assigns a Penalty
of 1024 to a route, the Penalty is decreased by half after the half-life period expires. The default is 15 minutes.
– reuse: the range is from 1 to 20000. This number is compared to the apping route’s Penalty value. If the Penalty value is less than
the reuse value, the apping route is once again advertised (or no longer suppressed). The default is 750.
– suppress: the range is from 1 to 20000. This number is compared to the apping route’s Penalty value. If the Penalty value is
greater than the suppress value, the apping route is no longer advertised (that is, it is suppressed). The default is 2000.
– max-suppress-time: the range is from 1 to 255. The maximum number of minutes a route can be suppressed. The default is
four times the half-life value. The default is 60 minutes.
• Clear all information or only information on a specic route.
EXEC Privilege
clear ip bgp dampening [ip-address mask]
• View all ap statistics or for specic routes meeting the following criteria.
EXEC or EXEC Privilege mode
show ip bgp flap-statistics [ip-address [mask]] [filter-list as-path-name] [regexp regular-
expression]
– ip-address [mask]: enter the IP address and mask.
– filter-list as-path-name: enter the name of an AS-PATH ACL.
– regexp regular-expression: enter a regular express to match on.
By default, the path selection is deterministic, that is, paths are compared irrespective of the order of their arrival. You can change the
path selection method to non-deterministic, that is, paths are compared in the order in which they arrived (starting with the most
recent). Furthermore, in non-deterministic mode, the software may not compare MED attributes though the paths are from the same
AS.
• Change the best path selection method to non-deterministic.
Change the best path selection method to non-deterministic.
CONFIG-ROUTER-BGP mode
bgp non-deterministic-med
NOTE
: When you change the best path selection method, path selection for existing paths remains unchanged until you
reset it by entering the clear ip bgp command in EXEC Privilege mode.
Examples of Working with Route Dampening
To view the BGP conguration, use the show config command in CONFIGURATION ROUTER BGP mode or the show running-
config bgp command in EXEC Privilege mode.
The following example shows how to congure values to reuse or restart a route. In the following example, default = 15 is the set time
before the value decrements, bgp dampening 2 ? is the set re-advertise value, bgp dampening 2 2000 ? is the suppress value,
and bgp dampening 2 2000 3000 ? is the time to suppress a route. Default values are also shown.
Dell(conf-router_bgp)#bgp dampening ?
<1-45> Half-life time for the penalty (default = 15)
route-map Route-map to specify criteria for dampening
<cr>
Dell(conf-router_bgp)#bgp dampening 2 ?
Border Gateway Protocol IPv4 (BGPv4)
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