Subject: draft-farrell-ft-01.txt -- what signal are we attempting to sense?

From: Ted Hardie <[email-masked]>
Date: Wed, 5 Dec 2012 09:22:10 -0800

Reading through Stephen's draft and the discussion to date, I think there
is some confusion/disagreement about what it is having an implementation
at this stage signals.

One way to break up the work of the IETF is:

Engineering--making decisions about the trade-offs related to
             different approaches to solving a problem.

Specification--producing text that describes how to inter-operate with
others.

Standardization--describing the applicability of a specification or
         its suitability as the basis of other work

(Since we reflect all of these in the same document production, it's
really muddier than this, but bear with me)

My experience is that people implementing during the working group
discussion phase generate really useful data about the engineering;
they can tell you the real impact of different trade-offs, so that
this isn't based on general experience.  But it's not such a great
signal about the specification itself, since the spec is designed to
be usable by folks who were not part of the working group process.

Stephen's draft says:

   Note also that this experiment just needs an implementation that
   makes it possible for the WG chairs and responsible AD to verify (to
   the extent they chose) that the implementation matches the draft.

and later:

   An implementation of the draft (ideally open-source) is required
   for fast-track last-call.  If there is no implementation or if the
   implementation is unavailable or does not implement the draft
   sufficiently closely then the document needs to be returned to the
   WG.  This only requires one implementation, not two and the WG
   chairs and responsible AD decide themselves how much validation is
   required for this.

Given the "sufficiently closely" and the timing of production, I
assume that the signal we're looking for here is confirmation of the
engineering choices.  I think that's fine (though I'm not sure this
needs formal experiment status).  But I believe we need to be really
careful that it isn't mistaken for signal about the specification's
quality.  It can happen that a working group has "lore" about what to
do that gets folded into the implementations done by those
participating, but which never quite makes it into the spec "because
everyone knows it".  An implementation written during the working
group process is potentially subject to this effect.

An interoperating implementation written to the spec by a non-working
group participant would be great signal about the specification quality,
but it  is not likely to be available at the stage of the process this
draft
targets.

Again, not objecting to the experiment; I just want to be clear about
what signal we believe we're getting from the implementation.

Just my two cents,

Ted

---

From: Stephen Farrell <[email-masked]>
Date: Wed, 05 Dec 2012 17:58:25 +0000

Hi Ted,

> be usable by folks who were not part of the working group process.

Good point.

> needs formal experiment status).  

I hadn't thought about this in terms of signals, but its an
interesting way to look at it.

BTW, others have also said (and I agree) that lots of the things
suggested in the draft don't need to be a formal experiment,
but I think doing it that way has merit in any case.

> But I believe we need to be really

That's very true.

I guess I'd be a bit reluctant to try to add text to the
draft about this though, since it might be a bit of a rathole
to try discuss generic good/bad aspects of implementations
and specs. I could see that discussion running and running
and getting nowhere;-)

But maybe it'd be a good idea to maintain a wiki as the
experiment runs where such things could be captured that
could feed into later evaluation of how things went.

If that sounds useful, I'm willing to start that (maybe
once the draft's gotten past IETF LC) and add a bit of text
to the draft pointing at the wiki page. I'm also happy to
do some maintenance on that as things progress, if they do.

If you think some other changes would help instead or
as well, I'll gladly take text of course, or suggestions
for how to (re-)structure the text.

Cheers,
S.

---

From: Ted Hardie <[email-masked]>
Date: Wed, 5 Dec 2012 11:36:37 -0800

Hi Stephen,

Some further comments in-line.

> and specs. I could see that discussion running and running
I don't think it needs to be a rat-hole.  Let me suggest the following
text:

OLD:

   Sometimes, it can take a long time to get a Proposed Standard
   produced in the IETF.  This memo proposes an optional way to speed up
   the parts of the process that happen after a WG has done its job by
   building a "reward" for having an implementation (ideally open-
   source) available into IETF processes.

NEW:

Implementations developed during the production of an Internet-draft
can indicate that a working group has had the opportunity to get
early confirmation of its engineering choices.  This memo proposes
an optional way to parallel process some final stage reviews when
the working group management and area directors believe that the
implementation can itself serve as a practical review of the engineering
choices.

Does that make sense?

> for how to (re-)structure the text.
I think it might generally useful to talk about this in terms of
parallel processing review, rather than issuing a reward, but
that may be simply a a style preference.

regards,

Ted Hardie

---

From: Stephen Farrell <[email-masked]>
Date: Wed, 05 Dec 2012 21:55:07 +0000

Hi Ted,

Thanks that change looks good to me. I'll whack it in thanks. I do
still like the word "reward" though so I'll tag that on too:-)

Cheers,
S.