Re: [tsvwg] Robert Wilton's No Objection on draft-ietf-tsvwg-ecn-encap-guidelines-21: (with COMMENT)

["Rob Wilton (rwilton)" <[e-mail]>]

Hi Bob,

> -----Original Message-----
> From: Bob Briscoe <[e-mail]>
> Sent: Friday, December 1, 2023 12:55 AM
> To: Rob Wilton (rwilton) <[e-mail]>; The IESG <[e-mail]>
> Cc: [e-mail]; [e-mail];
> [e-mail]; David Black <[e-mail]>; [e-mail]
> Subject: Re: Robert Wilton's No Objection on draft-ietf-tsvwg-ecn-encap-
> guidelines-21: (with COMMENT)
> 
> Robert, Thank you for your review. See [BB]
> 
> On 28/11/2023 13:29, Robert Wilton via Datatracker wrote:
> > Robert Wilton has entered the following ballot position for
> > draft-ietf-tsvwg-ecn-encap-guidelines-21: No Objection
> >
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> >
> >
> >
> > ----------------------------------------------------------------------
> > COMMENT:
> > ----------------------------------------------------------------------
> >
> > Hi,
> >
> > Thanks for this document, it is well written and an interesting read.
> >
> > I have just one very minor comment for you to consider please:
> >
> > (1) p 4, sec 1.  Introduction
> >
> >     Therefore, the capitalized terms 'SHOULD' or 'SHOULD NOT' are often
> >     used in preference to 'MUST' or 'MUST NOT', because it is difficult
> >     to know the compromises that will be necessary in each protocol
> >     design.  If a particular protocol design chooses not to follow a
> >     'SHOULD (NOT)' given in the advice below, it MUST include a sound
> >     justification.
> >
> > I would suggest "must include a sound justification", i.e., otherwise it is
> > unclear how the justification affects protocol conformance.
> 
> [BB] I don't understand. Surely it's very clear... If a protocol spec
> does not include a sound justification for why it does not follow any of
> the SHOULD (NOT)s given in this BCP, it does not comply with this BCP-to-be.
> 
> To my mind, conformance is only unclear without the 'MUST' in caps?
[Rob Wilton (rwilton)] 

I mostly think of RFC 2199 language as helping protocol conformance, i.e., will two implementations of a protocol successfully interoperate together.  Hence, I'm struggling to see why, on the wire, whether or not a justification is stated in a document will affect whether two implementations successfully interoperate.

Writing must instead of MUST still requires that they do it, and section 6 of RFC 2119 states:

6. Guidance in the use of these Imperatives

   Imperatives of the type defined in this memo must be used with care
   and sparingly.  In particular, they MUST only be used where it is
   actually required for interoperation or to limit behavior which has
   potential for causing harm (e.g., limiting retransmisssions)  For
   example, they must not be used to try to impose a particular method
   on implementors where the method is not required for
   interoperability.

Also RFC 8174, that updates 2119 states:

   o  These words can be used as defined here, but using them is not
      required.  Specifically, normative text does not require the use
      of these key words.  They are used for clarity and consistency
      when that is what's wanted, but a lot of normative text does not
      use them and is still normative.

   o  The words have the meanings specified herein only when they are in
      all capitals.

   o  When these words are not capitalized, they have their normal
      English meanings and are not affected by this document.

However, having said all of this, this is not a blocking comment, and if you wish to keep it as MUST you may do so.  I just think that it looks odd.

Regards,
Rob



> 
> 
> Bob
> 
> >
> > Regards,
> > Rob
> >
> >
> >
> 
> --
> ________________________________________________________________
> Bob Briscoe                               http://bobbriscoe.net/