From: Chad Hintz (ccie_2b2004@yahoo.com)
Date: Thu Apr 07 2005 - 10:30:38 GMT-3
Exactly, if you want to prefer a route out of ur local as best bet would be using local preference.
HTH,
Chad
Paresh Khatri <Paresh.Khatri@aapt.com.au> wrote:
This is normal behaviour - as-prepending is only possible on EBGP updates.
It's also a bad thing to change the AS-PATH on iBGP updates... if the AS-Path is prepend on IBGP updates to some iBGP peers but not all of them, there is a serious potential for routing loops.
HTH,
Paresh.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
gladston@br.ibm.com
Sent: Thursday, 07 April 2005 01:16 AM
To: ccielab@groupstudy.com
Subject: Prepend does not work with iBGP
Have you seen this?
bb1 prepends AS 200 on routes that it originated.
R9 is iBGP with BB1
R6 is eBGP with BB1
R6 receives the prepend AS on the route.
R9 does not.
Is it normal behavior?
bb1# sh run
router bgp 1
no synchronization
bgp router-id 8.8.8.8
network 210.1.2.0
network 210.2.2.0
network 210.3.2.0
network 210.4.2.0
network 210.5.2.0
neighbor 10.10.10.9 remote-as 1
neighbor 10.10.10.9 route-map Test out
neighbor 150.100.1.6 remote-as 1600
neighbor 150.100.1.6 route-map Test out
no auto-summary
!
route-map Test permit 10
set as-path prepend 200
r6#sb
*> 210.1.2.0 150.100.1.254 0 0 1 200 i
*> 210.2.2.0 150.100.1.254 0 0 1 200 i
*> 210.3.2.0 150.100.1.254 0 0 1 200 i
*> 210.4.2.0 150.100.1.254 0 0 1 200 i
*> 210.5.2.0 150.100.1.254 0 0 1 200 i
r6#
r9#sb
*>i210.1.2.0 10.10.10.11 0 100 0 i
*>i210.2.2.0 10.10.10.11 0 100 0 i
*>i210.3.2.0 10.10.10.11 0 100 0 i
*>i210.4.2.0 10.10.10.11 0 100 0 i
*>i210.5.2.0 10.10.10.11 0 100 0 i
r9#
Thanks to any feedback.
My intention is to generated a route on BB1 that contains AS200. This route is propagated to R9 and R6. R9 propagates this route to R6 too.
R6 should filter any route with AS 200.
The problem I am facing is that route receive from R9 by R6 does not have AS200, so it is permitted. It is because R9 receives the route without AS prepend from BB1.
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