Subject: DR change.

From: prashant desai <[email-masked]>
Date: Tue, 25 Jun 2002 16:31:59 -0700

In case of a DR going down, BDR becomming DR and a new network lsa being
originated..
What should other routers in the domain do with the old network lsa ?
It can lie around(age out) in the lsdb or can be purged explicitly ...
Cisco seems to purge it..Is it an implementation issue.

Thanks
Prashant

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From: Sina Mirtorabi <[email-masked]>
Date: Wed, 26 Jun 2002 01:55:04 -0700

Prashant,

> Cisco seems to purge it..Is it an implementation issue.

It is actually mentioned in RFC

------
        A router may only prematurely age its own self-originated LSAs.
        The router may not prematurely age LSAs that have been
        originated by other routers.
------

----
            A router that has formerly been the Designated Router for a
            network, but is no longer, should flush the network-LSA that
            it had previously originated.  This LSA is no longer used in
            the routing table calculation.  It is flushed by prematurely
            incrementing the LSA's age to MaxAge and reflooding (see
            Section 14.1). In addition, in those rare cases where a
            router's Router ID has changed, any network-LSAs that were
            originated with the router's previous Router ID must be
            flushed. Since the router may have no idea what it's
            previous Router ID might have been, these network-LSAs are
            indicated by having their Link State ID equal to one of the
            router's IP interface addresses and their Advertising Router
            equal to some value other than the router's current Router
            ID (see Section 13.4 for more details).

-----

Sina

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From: Amit Srivastava <[email-masked]>
Date: Wed, 26 Jun 2002 03:35:17 -0700

Hi prashant!!
     There can be two parts to your problem i try to
discuss both of them

Part 1) Suppose the DR crashes and another router
becomes the DR fatre some time if the crashed router
restart it would flush its own self originated LSA.

Part 2) If the crash router does not restarts then the
LSA has to be there till the MAX age i don't think you
can do any thing for that!!!

Regards
Amit

--- prashant desai <[email-masked]>
> http://photos.msn.com/support/worldwide.aspx

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