Re: [OSPF] AD review of draft-ietf-ospf-sbfd-disciminator-03

"Carlos Pignataro (cpignata)" <cpignata@cisco.com> Wed, 13 April 2016 16:39 UTC

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From: "Carlos Pignataro (cpignata)" <cpignata@cisco.com>
To: "akatlas@gmail.com" <akatlas@gmail.com>
Thread-Topic: AD review of draft-ietf-ospf-sbfd-disciminator-03
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Date: Wed, 13 Apr 2016 16:39:41 +0000
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Cc: OSPF List <ospf@ietf.org>, "draft-ietf-ospf-sbfd-discriminator@ietf.org" <draft-ietf-ospf-sbfd-discriminator@ietf.org>
Subject: Re: [OSPF] AD review of draft-ietf-ospf-sbfd-disciminator-03
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Hi Alia,

Thanks for this review! Please see inline.

> On Apr 12, 2016, at 4:06 PM, akatlas@gmail.com wrote:
> 
> First, thanks very much to the authors Manav, Carlos, Sam, and Trilok for their work on this document.
> 
> As is customary, I have done my AD review before requesting IETF Last Call.  In this case, I have a couple minor comments that I would like the authors to address during IETF Last Call.
> 
> In addition to IETF Last Call, I am requesting a Routing Directorate review.  I expect that both of these will conclude by April 27 and that this draft will be on the IESG telechat on May 5.  During this period, it is critical that the authors be extremely responsive and update the draft as appropriate so that the process runs as smoothly and quickly as feasible
> 
> 
> Minor comments:
>    1) Draft references RFC 4970 instead of RFC 7770 which obsoleted it.  In addition to updating the reference, please reread RFC 7770 and be certain that there are no surprises that can come from multiple RI LSAs being allowed or other nuances.  I personally don't see any right now.

Great point. Working copy updated. I also re-read RFC 7770 and I do not think there’s any additional considerations or implications.

> 
>    2) In Sec 2.1, it specifies "Routers that do not recognize the S-BFD Discriminator TLV Type MUST ignore the TLV."  I don't think that this document can mandate what routers that don't implement it do.  I went back through RFC 7770 and don't see any description *sigh* for the expected router behavior if a sub-TLV isn't recognized.  This might be a very useful errata to add to RFC 7770 - unless someone else can find where the behavior is specified.  For this draft, please think about what "ignoring the TLV" means and what routers that do not know about this draft are likely to do - and then update this sentence.

True, this doc cannot say “MUST ignore”. However, RFC 7770 S2.3 already says “Unrecognized types are ignored.”

I will change
"Routers that do not recognize the S-BFD Discriminator TLV Type MUST ignore the TLV.”
to:
"Routers that do not recognize the S-BFD Discriminator TLV Type will ignore the TLV [RFC 7770], and therefore will not learn S-BFD Discriminators via OSPF.”

Changes made in our working copy, and can submit when signaled.

Feedback most welcome.

Thanks,

— Carlos.

> 
> Thanks!
> Alia