RE: bgp conditional route advertisement

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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Received on Wed Sep 04 2013 - 15:58:56 ART