Re: Question about Type2 redistribution in to OSPF

[Nikhil Sama <[e-mail]>]

R1 will have a cost of 5 to the type-2 external route mentioned.

The reason is, as you mentioned ..
"Type 2 metrics are assumed to be larger than the cost of any intra-AS
path."

If there was another type-2 external route available to the same
destination prefix via another internal ASBR/Next-Hop, then your
decision on which route to pick should be independent of your cost to
the different internal next-hop's but based solely on the type 2
metrics.
This would not "necessarily" be the case had you added the internal
cost(of getting to the next-hop) to the type-2 metric.

Hope this helps !
/ns

On Wed, 2002-08-21 at 11:21, Mani Devarajan wrote:
> RFC 2328:
> =========
> Section - 12.4.4.  AS-external-LSAs
>
> Type 2 metrics are assumed to be larger than
> the cost of any intra-AS path.
>
> In one other document I read ,it says that for type 2
> it will be always external cost irrespective of inter
> area cost.
>
>                           type 2
>       -----     -----     -----
>      |     |   |     |   |     |
>      | R1  |   | R2  |   |ASBR |
>      |     |   |     |   |     |
>       -----     -----     -----
>           |10   |   |10    |  |
>            -----     ------    ----|
>                                    | External Network
>                                    |
> If ASBR redistributes route for external network at a
> cost of 5, R1 will have a route to external network
> with cost == 5 or cost > 10.
>
> Thanks in advance,
> <Mani
>