Subject: Re: Last Call: draft-ietf-mpls-tp-requirements (MPLS-TP Requirements) toProposed Standard

From: "Tom.Petch" <[email-masked]>
Date: Fri, 10 Jul 2009 11:22:43 +0200

I see some difficulties with the references in this I-D.

a) The security section of this I-D says
see    [I-D.ietf-mpls-mpls-and-gmpls-security-framework]
which is an informative reference.

I believe that security should be normative, not informative, even in this, a
requirements (as opposed to a protocol) draft.

b) The terminology section of this draft overlaps with that in an Informational
Reference [I-D.helvoort-mpls-tp-rosetta-stone] "A Thesaurus for the Terminology
used in MPLS-TP drafts/RFCs and  ITU-T's Transport Network Recommendations."
(now republished as a Working Group Draft)
which will doubtless progress to an RFC but as Informational.  I see this as
problematic; the two may be in step now but I am doubtful that they will be as
and when this last gets amended in the course of its development.  The mpls-tp
list has seen some vigorous debate already about the meaning of terms (eg
associated bidirectional, AIS).  Sometimes, the same concept has a different
term in IETF versus ITU-T (versus IEEE) while the same term may also be used for
a different concept.

RFC4397 is the product of a similar, earlier issue and is another potential
overlap.

The definitions in this I-D may be normative for this I-D but if they
diverge from definitions in other I-Ds, we are storing up problems for the
future.

On balance, I believe that this rosetta-stone should be a Normative Reference,
ideally removing the overlapping definitions.

Tom Petch

Original Message -----
From: "The IESG" <[email-masked]>
To: "IETF-Announce" <[email-masked]>
Cc: <[email-masked]>
Sent: Thursday, July 02, 2009 11:31 PM
Subject: Last Call: draft-ietf-mpls-tp-requirements (MPLS-TP Requirements)
toProposed Standard

> The IESG has received a request from the Multiprotocol Label Switching WG
> (mpls) to consider the following document:
>
> - 'MPLS-TP Requirements '
>    <draft-ietf-mpls-tp-requirements-09.txt> as a Proposed Standard
>
> The IESG plans to make a decision in the next few weeks, and solicits
> final comments on this action.  Please send substantive comments to the
> [email-masked] mailing lists by 2009-07-16. Exceptionally,
> comments may be sent to [email-masked] instead. In either case, please
> retain the beginning of the Subject line to allow automated sorting.
>
> The file can be obtained via
> http://www.ietf.org/internet-drafts/draft-ietf-mpls-tp-requirements-09.txt
>
>
> IESG discussion can be tracked via
>
https://datatracker.ietf.org/public/pidtracker.cgi?command=view_id&dTag=18021&rf
c_flag=0

---

From: Christian Vogt <[email-masked]>
Date: Wed, 15 Jul 2009 17:25:26 -0700

I have been selected as the General Area Review Team (Gen-ART)
reviewer for this draft (for background on Gen-ART, please see
http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html).

Please resolve these comments along with any other Last Call
comments you may receive.

Document..........:  draft-ietf-mpls-tp-requirements
Reviewer..........:  Christian Vogt
Review date.......:  July 15, 2009

Summary:  This draft is basically ready for publication, but has nits
           that should be fixed before publication.

This document specifies protocol requirements for MPLS in packet
transport networks.  The document is of very good quality, with an
elaborate introduction explaining the background for this document.

Two editorial nits that the authors should consider addressing prior
to publication of this document are the following:

- The fourth paragraph on page 6, which is part of the introduction,
   already specifies a requirement.  I suggest moving this to section
   2, since this is the section that is dedicated to requirements.

- The first paragraph of section 2 is a duplicate; it already appears in
   the introduction.  I suggest removing it from section 2.  The
   paragraph is important for the reader to understand the scope of the
   document, and hence should retain its prominent position in the
   introduction rather than the position in section 2.

Best regards,
- Christian

On Jul 2, 2009, The IESG wrote:

> https://datatracker.ietf.org/public/pidtracker.cgi?command=view_id&dTag=18021&rfc_flag=0

---

From: Christian Vogt <[email-masked]>
Date: Wed, 15 Jul 2009 17:25:26 -0700

Best regards,
- Christian

---

From: Christian Vogt <[email-masked]>
Date: Thu, 16 Jul 2009 20:49:36 -0700

[Resending; the first email didn't make it to this list.  Meanwhile,
Adrian has already replied to my review on the Gen-ART mailing list.]

Best regards,
- Christian

---

From: "Adrian Farrel" <[email-masked]>
Date: Mon, 20 Jul 2009 16:47:25 +0100

Thanks for the input Tom,

> requirements (as opposed to a protocol) draft.

I hear you. Security is fundamental.

draft-ietf-mpls-mpls-and-gmpls-security-framework is targetted as an 
informational RFC because it does not define any protocol mechanisms. It is 
a catalog of existing protocol security mechanisms and reports the current 
state of the art.

In the light of this, do you believe it is necessary to create a downref 
from a requirements document to an informational document?

Could this be handled by strenghtening the text in the security requirements 
section?

> ideally removing the overlapping definitions.

You are right, of course, that terminology needs to be consistent. But 
making a normative reference to the Rosetta Stone draft would put us into a 
nasty non-publication loop because that draft can't be published until 
everything else is completely stable, and nothing else can be published with 
a normative reference to an unpublished I-D.

Would it work for the authors to take a long hard look at the terms they 
have to:
1. make sure they only define terms they really need and cannot defer
   to the Rosetta Stone
2. ensure the Rosetta Stone is up-to-date and includes pointers out to
   the initial definitions so that the terms do not get updated in the 
future?

Cheers,
Adrian

---

From: "Tom.Petch" <[email-masked]>
Date: Tue, 21 Jul 2009 18:44:55 +0200

----- Original Message -----
From: "Adrian Farrel" <[email-masked]>
To: "Tom.Petch" <[email-masked]>
Cc: "ietf" <[email-masked]>
Sent: Monday, July 20, 2009 5:47 PM
Subject: Re: Last Call: draft-ietf-mpls-tp-requirements (MPLS-TP
Requirements)toProposed Standard

> Could this be handled by strenghtening the text in the security requirements

I don't see a good solution to this. I think the text should be strengthened; at
present, it seems a little casual, not quite serious enough.  The referenced I-D
is massive, contains much that I suspect will not be relevant to MPLS-TP and
seems an unsatisfactory companion to this I-D.  I think that
draft-mpls-tp-oam-requirements does a much better job here, and would like to
see something similar, highlighting the key threats (and for MPLS-TP, I do not
know what they are:-(

>    the initial definitions so that the terms do not get updated in the

That sounds like a viable solution.  My sense is that because this has come
first, or at least early on, it has accumulated definitions it does not need.
Technically, I fear we will regret not producing the Rosetta Stone first, but
politically, I suspect that that is unrealistic and so we have to do as you
suggest.

Tom Petch

---

From: "Adrian Farrel" <[email-masked]>
Date: Tue, 21 Jul 2009 22:36:13 +0100

Hi Tom,

> see something similar, highlighting the key threats (and for MPLS-TP, I do 

As luck would have it, a couple of people have just posted 
draft-fang-mpls-tp-security-framework-00.txt

This is in early days, but I think that draft-ietf-mpls-tp-requirements 
should be able to defer to it for security in the same non-normative way 
that it defers to draft-mpls-tp-oam-requirements for OAM and 
draft-mpls-tp-nm-requirements for network management.

Cheers,
Adrian

>> > which will doubtless progress to an RFC but as Informational.  I see 
>> > this
>> > as
>> > problematic; the two may be in step now but I am doubtful that they 
>> > will
>> > be as

---

From: "Tom.Petch" <[email-masked]>
Date: Wed, 22 Jul 2009 18:24:03 +0200

----- Original Message -----
From: "Adrian Farrel" <[email-masked]>
To: "Tom.Petch" <[email-masked]>
Cc: "ietf" <[email-masked]>
Sent: Tuesday, July 21, 2009 11:36 PM
Subject: Re: Last Call: draft-ietf-mpls-tp-requirements (MPLS-TP

> draft-mpls-tp-nm-requirements for network management.

OK

Tom Petch