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

From: Alia Atlas <[email-masked]>
Date: Tue, 12 Apr 2016 16:06:02 -0400

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.

   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.

Thanks!
Alia

---

From: Alia Atlas <[email-masked]>
Date: Tue, 12 Apr 2016 18:49:56 -0400

On Tue, Apr 12, 2016 at 4:06 PM, Alia Atlas <[email-masked]> wrote:

>    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.
>

Thanks to Les for politely pointing out the sentence I'd skimmed over in
RFC 7770. The behavior for unrecognized types is in Sec 2.3 so this draft
should just reference it.

Thanks,
Alia

---

From: "Carlos Pignataro (cpignata)" <[email-masked]>
Date: Wed, 13 Apr 2016 16:39:41 +0000

Hi Alia,

Thanks for this review! Please see inline.

> On Apr 12, 2016, at 4:06 PM, [email-masked] 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.

---

From: Alia Atlas <[email-masked]>
Date: Wed, 13 Apr 2016 15:08:20 -0400

Sounds great.   Do submit it.    Version numbers are cheap.

Thanks,
Alia
On Apr 13, 2016 12:39 PM, "Carlos Pignataro (cpignata)" <[email-masked]>
wrote:

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