Re: OSPF Superbackbone Concept

Hi Anantha,

Thank you for the response. However,the paragraph in RFC highlights
the extension of area 0, if one of the links on the CE belongs to Area
0.

Well reading the RFC cleared the murkiness. I believe, the statement
in the book means, if the CE has one more links belonging to different
OSPF areas, then the link between that CE and PE belonging to same
OSPF domain must be in Area 0.

Thank you once again for your response.

Regards

Lejoe

On Thu, Nov 5, 2009 at 6:44 AM, Anantha Subramanian Natarajan
<anantha.natarajan_at_gravitant.com> wrote:
> 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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>>
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Received on Thu Nov 05 2009 - 13:35:10 ART