RE: mpls vpn question - pe to ce protocol is OSPF

Hi Andrew,

 You get IA routes because it is the default behavior when you us OSPF as PE-CE routing protocol as Piotr commented. In a normal situation when you redistribute BGP into OSPF you will have a External Route. In this case, OSPF use the concept of Super Backbone inside the MPLS Domain where the Redistribution from MP-BGP into OSPF generates IA routes to avoid the following caveats:

* External routes cannot be summarized.
* External routes are flooded across all OSPF areas.
* External routes could use a different metric type that is not comparable to OSPF Cost.
* Internal routes are always preferred over external routes, regardless of their cost.

            
Ing. Luis Anzola

CCIE # 21959 | e-mail: lanzola_at_desca.com

-----Mensaje original-----
De: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] En nombre de ALL From_NJ
Enviado el: Lunes, 14 de Septiembre de 2009 04:47 p.m.
Para: Cisco certification
Asunto: mpls vpn question - pe to ce protocol is OSPF

Hey yall, ;-)

I hope this email finds you doing well.

Labed up a scenario and have a quick question about OSPF routes on either
CE. They show as IA.

On each PE, I have the same process number and the same domain-id is listed
in the show ip ospf 2 command (I am using process number 2 for my vrf). I
know this would show an E2 route ... but just the same, the configs are
identical. Also ping and everything works fine across the MPLS backbone.

Why would I get IA and not an 'O' ? The little research I did makes this
appear "it is what it is".

Back when I used to actually work w/ MPLS, I forgot if this was ever an
issue ... humm ... don't remember ever being worried about this.

Any thoughts?

I am going to be moving on to EIGRP or RIP tonight, but if anyone has any
thoughts or comments I would love to hear them. Kindest regards team,

-- 
Andrew Lee Lissitz
all.from.nj_at_gmail.com
Blogs and organic groups at http://www.ccie.net