Re: Clarification in changing the router id dynamically!!

Acee Lindem <acee@REDBACK.COM> Sat, 05 July 2003 01:27 UTC

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Date: Fri, 04 Jul 2003 21:25:48 -0400
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From: Acee Lindem <acee@REDBACK.COM>
Subject: Re: Clarification in changing the router id dynamically!!
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kamatchi soundaram wrote:
> Hi,
>
>   If the router id of the router R1 is changed on the fly (dynamically),
> what factor triggers the adjacent router R2 connected to R1 via point to
> point link, to generate the new Router LSA???
>
>  From the RFC i could infer that R1 will flush all his self originated lsas
> when it's router lsa has been changed.
>   But i couldn't find, how the R2 triggered to generate the new router lsa
> with the changed router id as is neighbor id in its router lsa??

Kamatchi,

Actually, since neighbors are identified by router ID on P2P links (as per
RFC 2338 section 8.2), R2 shouldn't recognize R1 with the new router ID and
should bring down the old adjacency with R1 and form a new one. A more
interesting question is what would happen on a broadcast or NBMA network
(where neighbors are identified by source address).
This case isn't explicitly handled by RFC 2328 and there is some variance
between implementations. At a minimum, the DR must recognize the change
in router ID and originate a new network LSA. I found that one popular
implementation required the router with the router ID change to bring its
adjacencies down (by sending a hello w/o any neighbor IDs) in order to
interoperate.

Thanks,
Acee

>
> Thanks in advance,
> Kamatchi.
>


--
Acee