RE: Route Selection in BGP

Hi there,

It's only 75F now so not a real "hell" YET!

Anyway, there is big difference between these 2 attributes. Actually I
can't think of many real world/CCIE examples that you've got both
options available to you. The local-pref feature does get propagated
across your BGP peers in your AS and it influences the decision of how
my BGP nodes go out. The Weight attribute on the other hand, is a local
feature only so can be configured on your BGP boxes that have 2
(logical/physical) connections. This attribute affects your local
decision only (local on that particular box).

For instance, you have a router with 2 connections one goes to ATT and
the other one goes to SPIRINT you want to use ATT as long as it's
available; in this case I'd configure the Weight (if do I have Cisco
gear). But let's say you have 5 BGP routers with various connections and
you'd like to let your BGP peers in your AS know that in order to get to
any IP ranges within MSN they're better off taking the path offered by
RTR101 which is connected to SPIRINT as long as it's up. But for the
rest of the prefixes you don't really care. In this case I'd configure
the local-pref for the customer.

Please read through the volume 2 of TCP/IP by Jeff Doyle for more
information on this.

HTH

--------------------------
Kambiz Agahian
CCIE (R&S), CCSI, WAASSE, RSSSE
Technical Instructor
CCBOOTCAMP - Cisco Learning Solutions Partner (CLSP)
Email: kagahian_at_ccbootcamp.com
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-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
oluwaseyi ojo
Sent: Monday, May 03, 2010 4:04 PM
To: Cisco certification
Subject: Route Selection in BGP

Hell,

In the lab if you are given a task to influence route selection based on
weight and local pref.

Can you use both weight and local pref attributes to influence route
selection or use either?

Comments will be deeply appreciated.

Thanks in advance.

Ojo Oluwaseyi O.

Blogs and organic groups at http://www.ccie.net
Received on Mon May 03 2010 - 16:34:50 ART