Subject: draft-ietf-ospf-hitless-restart-03.txt

From: "Manral, Vishwas" <[email-masked]>
Date: Fri, 25 Oct 2002 07:23:58 -0400

Hi Acee/Padma,

I have the following comments on the latest draft besides the earlier
comments: -

1. We could specify the Destination address to be used for packets to in
case of an unplanned hitless restart. I guess we should send packets to all
AllSPFRouters multicast address in case of broadcast links(we dont know the
interface state DR/BDR/nonDR). This would be different from whats specified
in the base RFC and hence may need to be put it down in the document.

2. "Robusness variable" would also mean we delay the sending of hellos, for
sending the Grace LSA after sending a hello would not help. I think we
should send the LSA in MinLSArrival a few times before we start sending
hellos. May be that could be clarified, we may be violating the
MinLSInterval in this case.

Thanks,
Vishwas

---

From: Acee Lindem <[email-masked]>
Date: Fri, 25 Oct 2002 10:14:21 -0400

> in the base RFC and hence may need to be put it down in the document.

Hi Manral,

Good catch. If the restarting router is DR then this is absolutely
necessary for unplanned restart.

> MinLSInterval in this case.

Ok. The only consequence of re-flooding the LSA sooner is that the
routers that previously received the LSA will ignore it.
My concern is that I'd hate to delay the business of sync'ing up the
databases. In practice, the neighbor adjacencies are re-established very
quickly (even with thousands of LSAs).  Am I missing something?

--
Acee

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From: Padma Pillay-Esnault <[email-masked]>
Date: Fri, 25 Oct 2002 09:51:38 -0700

> necessary for unplanned restart.

Actually this is what our implementation does ..
I'd even go further to say that this is what we should always do even
in a planned restart.

> quickly (even with thousands of LSAs).  Am I missing something?

I think that flooding a few times before sending the hellos is fine and we do
not really need to delay the hellos.
The interval between resending the grace lsa is something like 2 secs in
our implementation. The grace lsa are scheduled to be retransmitted
at least twice before unblocking sending the hellos.

Padma

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From: Acee Lindem <[email-masked]>
Date: Fri, 25 Oct 2002 13:07:55 -0400

> I'd even go further to say that this is what we should always do even

Why would you send to AllSPFRouters if you know your DR
state (which would be the case in a planned restart) and
you're not DR?

> at least twice before unblocking sending the hellos.

I agree here - I just don't want to wait N * MinLSInterval seconds (where
N is the number of retransmissions).

--
Acee

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From: Padma Pillay-Esnault <[email-masked]>
Date: Fri, 25 Oct 2002 10:33:31 -0700

Acee

> state (which would be the case in a planned restart) and

Why not ? The goal is to notify everyone on the BCAST segment.
If they have a full adjacency with the restarting router
DR or not we need them as helpers.

Padma

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From: Acee Lindem <[email-masked]>
Date: Fri, 25 Oct 2002 13:37:03 -0400

> DR or not we need them as helpers.

Would you argue the same for all flooding on a broadcast
segment? The fact is we shouldn't need to change base
flooding if it is a planned restart and we are not
DR.

--
Acee

---

From: Padma Pillay-Esnault <[email-masked]>
Date: Fri, 25 Oct 2002 10:48:43 -0700

> flooding if it is a planned restart and we are not

I understand  your point.
But I think of grace lsa as a signal.

Padma