Re: bgp conditional route advertisement

Thanks Narbik nice and clear, I think the reservation that Balaji has it that
when the bgp process resets it causes host route 3.3.3.3 to be advertised
prior to bgp receiving all networks into its rib to me this is an order of ops
where bgp rib will install host route to 1.1.1.1 into global and not yet
learning the 2.2.2.2 route.

Balaji if you're testing I'd imagine not much traffic being forwarded to the
3.3.3.3 network prior to the route being withdrawn.

The answer is this is just the way the feature works.

--
BR
Tony
Sent from my iPad
On 16 Sep 2013, at 18:47, Narbik Kocharians <narbikk_at_gmail.com> wrote:
> Have a look at this lab that I wrote, it might help you:
>
> http://micronics.nl/BGP-Conditional-Adv.pdf
>
>
> On Mon, Sep 16, 2013 at 10:12 AM, Tony Singh <mothafungla_at_gmail.com> wrote:
> 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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> >
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> --
> Narbik Kocharians
> CCSI#30832, CCIE# 12410 (R&S, SP, Security)
> www.MicronicsTraining.com
> Sr. Technical Instructor
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