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List:       zebra
Subject:    [zebra 5925] Re: on-going NSSA.
From:       Gleb Natapov <gleb () nbase ! co ! il>
Date:       2000-11-29 16:48:13
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Hello !

On Tue, Nov 28, 2000 at 03:36:54PM -0800, dglasspool@csscience.com wrote:
> 
> Is the following "clarification" helpful for OSPF-NSSA?
> 
> ref:  RFC-1587 and "draft-ietf-ospf-nssa-update-09.txt"
> 
> Purpose of "clarification";
> 
> To establish that when there are many connected areas that are all NSSA's
> and that have "shared" AS connections (one ABR), the AS is accessable to all. 
> 
> Add to section 3.4 ??
> 
> In the event one NSSA-ABR has multiple NSSA connections, the ABR could be
> the elected translator for all, for any number, or none of the connected
> NSSAs. 

In the Section 4.1 a new area parameter called the NSSATranslatorState is
described. The fact that this parameter is maintained in the OSPF area data 
structure is emphasised, so IMO it should be clear that the router can be in 
different states for each NSSA area it belongs to.

> Furthermore, in the event it has any attached AS connections, the
> routes to each AS may be advertised by flooding the Type-7 LSA for each AS into
> ALL of the NSSAs connected, but with only the first one with the P-bit set.
>

Why? The same ABR router may generate different Type-7 LSAs into different NSSA areas
for the same network (the forwarding address can be different for instance). thus all 
Type-7 LSAs should be translated to Type-5 LSAs so other routers will be able to pick 
the best route to the destination. Do I miss something?

> For any of the NSSAs for which the ABR is the translator, all the P-bits are
> cleared in the Type-7 LSAs, and the ABR performs the translation as usual. When 
> the ABR is not the translator, only one of all the other elected translators will
> see the P-bit, and translate the Type-7 into a Type-5, for AS-flooding.
> 
I am not sure I understand what do you mean here. Can you give an example please?

--
			Gleb.

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