Subject: [Supa] Benoit's AD Comments on SUPA

From: "Adrian Farrel" <[email-masked]>
Date: Sat, 1 Aug 2015 17:34:06 +0100

Hi Benoit,

Thanks for typing up your thoughts in more detail than there was time for in
Prague. What you say makes a lot of sense (to me). Comments in line.

> There are no instructions that the IETF must only be working on data 
> models as opposed to information models. If the group wants to work on 
> information models, and can justify why this is important, fine.  In this 
> case, if it helps to connect with other SDOs that use information 
> models, fine. IMO, I think a case for developing an information model 
> has been made for SUPA.

Right. And my comment at the mic was to the effect that I see no value, but I
can hardly object. If there is a group of people who believe this will be useful
(and a number of reasons have been put forward including the one you give) and
are willing to do the work, then that's great and it seems to form a clear work
task.

> However, we have to understand that the end goal is data models. Talking 
> to some operators, their feedback is: "I can't do much with an 
> information model, provide me with data models". And this is right, the 
> end goal is more programmability and manageability for our networks, and 
> this comes from data models. So if a group spends too long on an 
> information model at the cost of delaying the rest of the work, there is 
> something wrong.

I'd go a step further since the policy data models are  not much help in
isolation, but will require follow-on work to tie them in to specific use cases.

This is a nice and "correct" step-by-step approach which may look good to the
pointy-haired boss, but to be effective it requires considerable momentum
otherwise it will be left behind. So I hope this effort can be kicked off
without further delay. Indeed, I'd encourage those who are behind the work to
pursue the information model drafts with all their energy while the details of
the charter are finalised.

[snip]

> - If SUPA could specify some reusable policy components, and some 
> standard ways to manage policies, that could be beneficial for our 
> industry.  So there is something into SUPA. However, we also have to 
> acknowledge that there is some experimental aspects to SUPA, at least in 
> the intent based part of the work (as opposed to the Event - Condition 
> - Action, which can be compared to the old RMON MIB). Indeed, what does 
> it mean for "do what I mean" in a YANG model object? (Note: feel free to 
> replace "do what I mean" with whatever intent-based example you want). 
> This is why I repeatedly asked the question to the SUPA community: I 
> wonder what we have in those YANG models?

Well, we should see this come clear from the information models (I naively doubt
that there is a big effort to turn an info model into a YANG model).

But, while this is definitely an experiment (can it be done? will it be useful?)
I'm hoping that it will produce useful, generic, re-usable policy models that
can be picked up and incorporated into other work.

[snip]

> - We had some balanced hums on the following two questions.
>     Does the community think that the problem statement is clear, 
>     well-scoped, solvable, and useful to solve?
>    Is there support to form a WG with the charter presented at the BOF 
>    (with edits)?
> This is the most difficult situation for an AD.

For me, these questions were problematic because there is a degree of edits
necessary. Depending on how those edits go, the charter could end up saying
something dumb or something valuable.

Listening to some of the debate in the BoF (we fairly whizzed through the
charter text at a rate faster than I could read!) I suspect that a lot of the
concerns come down to "use of language". For example, the word "translate"
caused a fair amount of debate, but I think a synonym would have suited the
authors and been much clearer.

[snip]

> - I've been trying to get feedback from different vendors regarding 
> SUPA, as we have to observe that this SUPA effort is mainly pushed by a 
> single vendor. This is absolutely not a problem, but I need to 
> understand why other vendors were not involved. From my discussions, I 
> gathered feedback such as "no interested", "this is a terrible idea", 
> "no harm".

I'm somewhere more positive than "no harm", but it depends what actually
happens. I feel that this work undertaken four years ago would have set us up
nicely for all of the YANG work we have been doing for the last year. Maybe it
is not too late, and maybe the concept will be valuable.

> What are the next steps?

As I read what you said in the rest of your email, I should sit on any proposed
edits until I see your revised charter text.

Thanks again,
Adrian