Dell S4820T Configuration Manual page 248

bgp dampening [half-life | reuse | suppress max-suppress-time] [route-map
map-name]
Enter the following optional parameters to configure route dampening parameters:
– 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 flapping route's Penalty
value. If the Penalty value is less than the reuse value, the flapping route is once again advertised
(or no longer suppressed). Withdrawn routes are removed from history state. The default is 750.
– suppress: the range is from 1 to 20000. This number is compared to the flapping route's Penalty
value. If the Penalty value is greater than the suppress value, the flapping 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.
– route-map map-name: name of a configured route map. Only match commands in the
configured route map are supported. Use this parameter to apply route dampening to selective
routes.
• Enter the following optional parameters to configure 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 flapping route's Penalty
value. If the Penalty value is less than the reuse value, the flapping 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 flapping route's Penalty
value. If the Penalty value is greater than the suppress value, the flapping 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 specific route.
EXEC Privilege
clear ip bgp [vrf vrf-name] dampening [ip-address mask]
• View all flap statistics or for specific routes meeting the following criteria.
EXEC or EXEC Privilege mode
show ip bgp [vrf vrf-name] 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 in Dell Networking OS 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.
248
Border Gateway Protocol IPv4 (BGPv4)