Re: ASBR Selection

Tony,
It's not a selection but an election. Within each area an RDR (Redistribution
Designated Router) is elected. The RDR is responsible for external route
redistribution within an area. Stub and totally stub areas do not have an
RDR since no redistribution occurs in these types of areas. When there is
only a single point of redistribution within an area there isn't any
election but once you have multiple points of redistribution the RDR is
elected.

Under the OSPF process configure the preferred router to become the RDR as
such:

router ospf 1
area X redistribution priority 100

If there is a tie with the redistribution priority between routers, the
router with the longest host-id (aka hostname) wins. To disable this
behavior use the command below:

router ospf 1
no redistribute compare host-id

If you can't find these commands it could be because they are only in the
newer IOS versions.

As a side note in production environments watch out for Juniper routers.
 They will make a lot of pre-redistribution election promises but never
follow through once elected. Once again they over promise but under
deliver.

Hope this helps!

On May 28, 2012, at 1:54, Vincent Tay <vtay.75_at_gmail.com> wrote:

Hi all,
If there are two ASBRs redistributing routes, will there be any selection?
From what i have try, the router that i clear the ospf process will end up
advertising the type 5 routes. I am quite confuse with it.
                         EIGRP
____________________________________
     | |
     | |
     | |
R3(ASBR)------------------------------R2(ASBR) !
Redistributing EIGRP into OSPF
    | |
    | |
    | |
              OSPF Area Routers
___________________________________
Thanks.
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Received on Tue May 29 2012 - 10:45:56 ART