Re: MPBGP ip vrf name

Just think of RTs along the same lines as tags in IGP redistribution. When
you export you are setting the target/tag and when you import you are matching
the target/tag. It's the same concept but just different terminology.
(export/import vs set/match)

Brian Dennis, CCIEx5 #2210 (R&S/ISP-Dial/Security/SP/Voice)
bdennis_at_ine.com<mailto:bdennis_at_ine.com>

INE, Inc.
http://www.INE.com<http://www.ine.com/>

From: Tauseef Khan
<tasneemjan_at_googlemail.com<mailto:tasneemjan_at_googlemail.com>>
Date: Thursday, December 27, 2012 7:41 AM
To: Brian Dennis <bdennis_at_ine.com<mailto:bdennis_at_ine.com>>
Cc: Cisco certification
<ccielab_at_groupstudy.com<mailto:ccielab_at_groupstudy.com>>
Subject: Re: MPBGP ip vrf name

Many Thanks for the explanation Brian, So as long as what ever I am exporting
on one site connecting PE, I should import on the other sites connecting PEs
and vice versa it should work. Vrf name and RD values could be different
however i should keep RT values unique per customer perfix other wise routes
could leak into other customers vrfs.
Regards

Regards
On 27 December 2012 00:18, Brian Dennis
<bdennis_at_ine.com<mailto:bdennis_at_ine.com>> wrote:
The VRF name does not matter as it's not exchanged between PE's. Also the
RD's do not need to be "reciprocal".

From RFC 4364 - BGP/MPLS IP Virtual Private Networks (VPNs)

An RD is simply a number, and it does not contain any inherent
   information; it does not identify the origin of the route or the set
   of VPNs to which the route is to be distributed. The purpose of the
   RD is solely to allow one to create distinct routes to a common IPv4
   address prefix.

A Route Target attribute can be thought of as identifying a set of
   sites. (Though it would be more precise to think of it as
   identifying a set of VRFs.) Associating a particular Route Target
   attribute with a route allows that route to be placed in the VRFs
   that are used for routing traffic that is received from the
   corresponding sites.

http://www.ietf.org/rfc/rfc4364.txt

So remember that RD has nothing to do with RT and RT likewise has nothing
to do with RD. They serve two different purposes as stated above.

The configuration below will do the same as your configuration in regards
to the two sites.

Router-Manchester_pop
ip vrf CUST_100
rd 100:100
route-target export 11:11
route-target import 22:22

++++++++++++++++++++++++++++++++++++++
Router-Birmingham_pop
ip vrf CUST_200
rd 200:200
route-target export 22:22
route-target import 11:11

HTH,

Brian Dennis, CCIEx5 #2210 (R&S/ISP-Dial/Security/SP/Voice)
bdennis_at_ine.com<mailto:bdennis_at_ine.com>

INE, Inc.
http://www.INE.com

On 12/26/12 7:50 PM, "Tauseef Khan"
<tasneemjan_at_googlemail.com<mailto:tasneemjan_at_googlemail.com>> wrote:

>Would it matter if i have different vrf names on PE routers routers as
>long
>as I have reciprocal rd values.
>
>so on one PE router connecting customer site i have
>
>Router-Manchester_pop
>ip vrf CUST_100
> rd 20:20
> route-target export 20:20
> route-target import 20:20
> route-target import 10:10
>
>++++++++++++++++++++++++++++++++++++++
>Router-Birmingham_pop
>ip vrf CUST_200
> rd 10:10
> route-target export 10:10
> route-target import 10:10
> route-target import 20:20
> ip vrf forwarding site-a
>
>
>both vrf CUST_100 and CUST_200 belong to the same Customer
>
>in the mpbgp table when i do which sounds strange as rd vlaues are
>different on bot PEs (20:20 and 10:10)
>show ip bgp vpnv4 all i can see the routes populated. appreciate if some
>one could clarify.
>regards
>
>
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Received on Thu Dec 27 2012 - 11:07:52 ART