From: Huan Pham (pnhuan@yahoo.com)
Date: Sun Aug 24 2008 - 02:44:26 ART
Hi,
If you do not have that statement "route-map DAMP permit 50", all other routes that do not match the route-map will not be dampened. This also means they will not be blocked due to this route dampening route-map and will be advertized to other BGP peers (subject to any other policies you may have)
If you do have that statement (i.e "route-map DAMP permit 50") all other routes will be subject to dampening with DEFAULT dampening parameters.
Following commands are usefull in verifying your dampening config (you need to flaps a routes to see the effect of route dampening)
clear ip bgp dampening
show ip bgp dampened-paths
show ip bgp flap-statistics
Command reference is good on explainng the default behaviour of bgp dampening command you are using.
http://www.cisco.com/en/US/docs/ios/iproute/command/reference/irp_bgp1.html#wp1012660
bgp dampening [half-life reuse suppress max-suppress-time | route-map map-name]
route-map map-name (Optional) Name of route map that controls where BGP route dampening is enabled.
Defaults:
---------
BGP dampening is disabled by default. The following values are used when this command is enabled without configuring any optional arguments:
half-life: 15 minutes
reuse: 750
suppress: 2000
max-suppress-time: 4 times half-life
--- On Sun, 8/24/08, Roger Oliver <divineone@divine-wind.net> wrote:
From: Roger Oliver <divineone@divine-wind.net>
Subject: BGP Dampening with Route-maps
To: ccielab@groupstudy.com
Date: Sunday, August 24, 2008, 3:19 PM
Group /Wave
So I think understand the Dampening options I put and this config(see
below)and it makes sense. However do I have to put the third line
"route-map DAMP permit 50?" if I do not put it what happens? other
routes will not flow through the router and be passed on?
When I do a "sh ip bgp dampen para" I see the two route-maps being
applied but there is no other dampening map so that means all other
routes do not get dampened (I'm pretty sure they do not)?
access-list 50 permit 50.5.5.0 0.0.0.255
access-list 55 permit 55.5.5.0 0.0.0.255
route-map DAMP permit 10
match ip add 50
set dampening 20 800 2400 90
!
route-map DAMP permit 20
match ip add 55
set dampening 15 700 2000 60
!
route-map DAMP permit 50
!
router-bgp 500
bgp dampening route-map DAMP
Anyway thanks for the help...back to the next task while I wait
Roger
Blogs and organic groups at http://www.ccie.net
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