Hi Gurpreet:
      Since X, B and C all are in back bone area, It may have happened
that B has already flooded that particular LSA to router C.

       Thanks.
                         -Samvid

----- Original Message -----
From: "Singh, Gurpreet" <Gurpreet.SinghSPIRENTCOM.COM>
To: <OSPFdiscuss.microsoft.com>
Sent: Wednesday, September 26, 2001 8:52 AM
Subject: Re: Intra Area Routes

> Hi Xie
>
> Just one thought crossed my mind. Is it not that since Router X is
ABR
> so it also belongs to the backbone. So lets say additionally Router C is
> connected to Router C in the backbone. Since backbone is also considered
to
> be an area with area id 0.0.0.0, then when Router X gets a Summary-LSA
from
> Router B it should flood it to Router C, since Router B and Router C are
in
> the backbone.
> And for Router A it should regenerate the Summary LSA with same Link State
> ID but with Advertising Router as Router X.
>
> Gurpreet
>
> -----Original Message-----
> From: Xie, Feng [mailto:Feng.XieMARCONI.COM]
> Sent: Tuesday, September 25, 2001 6:56 PM
> To: OSPFDISCUSS.MICROSOFT.COM
> Subject: Re: Intra Area Routes
>
>
> Hi, Gurpreet:
>
> It seems to me that router X is an ABR which connects to both backbone
> area and area 1. If so, for router X, the route to router A is an
intra-area
> route because router X derives this route from a router lsa instead of a
> type-3 lsa. In fact, this can be used as a criteria of determining
> intra-area and inter-area routes.
> If router X derives a route based on a type-3 lsa it gets from router
B,
> then this route is an inter-area route for Router X and it will generate a
> type-3 lsa and send it to Router A. But the type-3 lsa wouldn't be sent
back
> to the backbone area.
> Hopefully this will help.
>
> Feng Xie
>
> -----Original Message-----
> From: Singh, Gurpreet [mailto:Gurpreet.SinghSPIRENTCOM.COM]
> Sent: Tuesday, September 25, 2001 3:34 PM
> To: OSPFDISCUSS.MICROSOFT.COM
> Subject: Intra Area Routes
>
>
> Hi
>
> According to RFC 2328 Setion 12.4.3
> "only intra-area routes are advertised into the backbone, while both
> intra-area and inter-area routes are advertised into the other areas."
>
> This means that intra-area routes are advertised into backbone as well as
> non-backbone areas and inter-area routes are not advertised to backbone
> areas.
>
> If a router X is connected to a router A (AS Boundary Router) in Area1 and
> also router X is connected to Router B in the backbone area.
>
> Then the route to Router A will be considered as inter-area or inter-area
> with respect to router X ? i.e. Should the router X advertise the route to
> Router A in a Summary LSA to Router B ?
>
> Also if the router X should advertise the RouterA to Router B then what
will
> be considered as a inter-area route such that router X will not advertise
it
> to router B.
>
>
> Gurpreet
>

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