Users Guide

– 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 [vrf vrf-name] 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 [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.
• 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 Conguring a Route and Viewing the Number of Dampened Routes
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 ?
<1-20000> Value to start reusing a route (default = 750)
Dell(conf-router_bgp)#bgp dampening 2 2000 ?
<1-20000> Value to start suppressing a route (default = 2000)
Dell(conf-router_bgp)#bgp dampening 2 2000 3000 ?
<1-255> Maximum duration to suppress a stable route (default = 60)
Dell(conf-router_bgp)#bgp dampening 2 2000 3000 10 ?
route-map Route-map to specify criteria for dampening
<cr>
208
Border Gateway Protocol IPv4 (BGPv4)