Re: bgp conditional route advertisement

Hi Balaji

This is a good question one which I have been scratching my head over, can you confirm if this is in your production environment or is it on gns/IOU or home lab if so please confirm platform/IOS version

--
BR
Tony
Sent from my iPad
On 4 Sep 2013, at 14:58, BALAKRISHNAN Balaji <Balaji.BALAKRISHNAN_at_swift.com> wrote:
> All,
> 
> 
> 
> Any suggestion ?.. Configuration is as below
> 
> 
> 
> ip route 3.3.3.3 255.255.255.255 1.1.1.1
> 
> 
> 
> Router bgp 65000
> 
> Network 3.3.3.3 mask 255.255.255.255
> 
> neighbour 192.168.1.1 remote-as 65001
> 
> neighbour 192.168.1.1 advertise-map  ADVERTISE   non-exist-map  NONEXIST
> 
> !
> 
> Route-map ADVERTISE   permit 10
> 
> Match ip address 50
> 
> !
> 
> Access-list 50 permit 3.3.3.3
> 
> !
> 
> Route-map NONEXIST permit 10
> 
> Match ip address 30
> 
> !
> 
> Access-list 30 permit 2.2.2.2
> 
> !
> 
> 
> 
> Thanx
> 
> Balaji
> 
> 
> 
> From: BALAKRISHNAN Balaji
> Sent: Tuesday, September 03, 2013 5:31 PM
> To: ccielab_at_groupstudy.com
> Subject: bgp conditional route advertisement
> 
> 
> 
> Hello all,
> 
> 
> 
> I have a scenario that I am struggling to address a specific issue and would
> like to hear your recommendation
> 
> 
> 
> Announce the route 3.3.3.3 to the bgp neighbour only under the following
> condition on the routes it receives from the backbone
> 
> 
> 
> -           Only if it  has valid 1.1.1.1/32 route on the bgp table but no
> valid route for 2.2.2.2/32
> 
> 
> 
> It works fine under the normal situation when both 1.1.1.1 and 2.2.2.2  exist
> in the bgp table ( meaning conditional route does not get triggered) .  But
> when the router bounces its bgp connection to the backbone, it  learns the
> route 1.1.1.1/32  fraction of a second earlier than 2.2.2.2/32..    It causes
> the conditional advertisement to  kick in momentarily before withdrawing
> immediately after which is causing some undesirable instability in the
> network..  Can you recommend any work around to resolve this issue.
> 
> 
> 
> Rgds
> 
> Balaji
> 
> 
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