BGP path manipulation

From: Suplepo (suplepo@yahoo.com)
Date: Sun Apr 22 2007 - 13:21:09 ART


I'm working through a sample lab and have hit a snag.

R1 Is advertising networks 1.1.1.1/32 and 2.2.2.2/32
into BGP. Instructions state

1) Configure R3 so that it's the preferred path for
traffic network 1.1.1.1/32

2) Configure R2 so that it's the preferred path for
traffic to network 2.2.2.2/32

I can easily do this with AS-path prepending or MED,
but since both of these must be configured on the
non-desireable path I'm stuck. Is there anything I can
do on the desired inbound path (R3 for 1.1.1.1) to
ensure it's the best path. Since R1 is advertising the
routes to both R2 & R3 conditional advertisement from
R3 and R2 will not work.

This all has me thinking I looking at a mistake in the
question, but thought I'd bounce it off the collective
to make sure there's not another option.

Topology below,
iBGP peerings R1<->R2, R1<->R3, R3<->R2
eBGP peerings R3<->R4, R2<->R4

             |
   AS1 | AS2
             |
R3--------eBGP-----------R4
 |\ |
 | \ |
 | R1 |
 | / |
 | / |
 R2---------eBGP----------|



This archive was generated by hypermail 2.1.4 : Tue May 01 2007 - 08:28:36 ART