Service Manual
○ 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 Withdrawn routes are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 EMC 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.
● 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.
To view the BGP configuration, 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 configure 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.
DellEMC(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>
DellEMC(conf-router_bgp)#bgp dampening 2 ?
<1-20000> Value to start reusing a route (default = 750)
Border Gateway Protocol (BGP)
221