Subject: Loopback address in Multiple Areas?

From: Jeff <[email-masked]>
Date: Tue, 15 Oct 2002 15:43:23 -0400

Hello,

I have an application which requires a node loopback address to be
advertised in the Router LSA of every active area.  I believe this violates
the practice of assigning each interface (including loopback interfaces) to
an individual area?  Is this done by anyone?  Could this cause potential
problems (beyond extra summary lsas)?

Thanks in advance
Jeff

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From: Acee Lindem <[email-masked]>
Date: Tue, 15 Oct 2002 16:06:40 -0400

Hello Jeff,

Jeff wrote:

> advertised in the Router LSA of every active area.

Out of curiosity - Why do you require it to be explicitly advertised
in the router LSA in every area?

> I believe this violates
> an individual area?

Yes.

> Is this done by anyone?

I've seen implementations that do this with a loopback corresponding to
the router ID.

> Could this cause potential

In general, implementations do not expect it. If an ABR has
implemented a more elaborate incremental SPF computation which does
individual areas incrementally, it may oscillate the route path
between areas.

> Jeff

Thanks,
--
Acee