Re: OSPF Superbackbone Concept

Hi Lejoe,

  I will state my understanding and hopefully experts in the group may add
to it or correct it.Also obviously, you could correct it,if something stated
wrong,

Check the below RFC 2547

http://tools.ietf.org/html/draft-rosen-ppvpn-ospf2547-area0-02#page-3

It states as below,when we may require OSPF Area0(backbone area 0) other
than the MPLS VPN superbackbone area

"

If the OSPF domain has any area 0 routers (other than the PE
   routers), then at least one of those MUST be a CE router, and MUST
   have an area 0 link to at least one PE router. This adjacency MAY be
   via an OSPF virtual link. This is necessary to ensure that inter-area
   routes and AS-external routes can be leaked between the PE routers
   and the non-PE OSPF backbone.
"

Is the above answers your question or I completely misunderstood your
question..Kindly let us know

Thanks

Regards
Anantha Subramanian Natarajan

On Tue, Nov 3, 2009 at 6:22 AM, Lejoe <styran_at_gmail.com> wrote:

> Hi all,
>
> The OSPF superbackbone concept allows to migrate from the traditional
> OSPF concept to MPLS VPN by the use of another backbone, i.e OSPF
> superbackbone. Area 0 is no longer a requirement.
>
> I would like to know when is Area 0 a requirement in MPLS VPN. More
> specifically, if anybody could explain the statement below.
>
> MPLS Configuration on Cisco IOS, Chapter 5 ,Pg 144 states Area 0 is a
> requirement only when the PE router is connected to two different
> non-backbone areas belonging to the same OSPF domain on a PE router.
>
>
> Lejoe
>
>
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Received on Wed Nov 04 2009 - 13:44:33 ART