Re: What we want to accomplish

["John Strassner" <jstrassn@cisco.com>]

"Everything should be as simple as possible, but not
simpler" - Einstein

more specific comments inline.

regards,
John
----- Original Message -----
From: "Durham, David" <david.durham@intel.com>
To: "'Randy Bush'" <randy@psg.com>; "Andrea Westerinen"
<andreawest@mindspring.com>
Cc: <nim@ops.ietf.org>
Sent: Tuesday, April 18, 2000 11:01 AM
Subject: NIM: What we want to accomplish


> I agree with Randy (because he has his reality hat on) and
vote for inherent
> simplicity, methods notwithstanding. Fundamentally, we
want a model that is
> easy to grok and is attractive to the subject experts such
that THEY can
> move relevant information out of their heads and into the
model. This is
> verses having modeling experts have to learn what's in all
the subject
> matter experts heads and try to integrate this into a
model.
>
> To me this means:
>
> 1. Avoid excessive hierarchy

Why? Modeling == Classification. Classification needs
hierarchIES (not just inheritance, but also aggregation) to
properly protrary knowledge.

Please understand that I do agree with the overall goal of
simplification. But let's not rush into cutting things out
without proper examination that it doesn't hurt the model.

> 2. Avoid class REFERENCE explosion (Perhaps by avoiding
aggregations and
> instead using good-o'l-fashion containment and by creating
some short-hand
> notation for the real associations)

Aggregation is a modeling construct, containment is an
implementation...

> 3. Reusability of ALL constructs (existing and future).
Model it once
> (extend it many), so that we don't keep re-inventing the
wheel.

??? Don't grok what you mean here

> 4. Scope the model... People tend to only be interested in
a particular
> subject area, so have mechanisms where the relevant subset
of the model can
> be easily identified (Andrea's requirement methinks)
> 5. Model it precisely yet succinctly (constraint language
will help oodles
> here)

And a constraint language will complicate things too, both
in adding classes and relationships as well as language
constructs. So be careful what you ask for...

> 6. Don't think WE have to model the Universe: Instead
provide (decide on) an
> appropriate tool set and conventions such that those in
the Universe can
> effectively (and consistently) model themselves. This is
what I see NIM
> fundamentally accomplishing.
>
> 1+2+3+4+5+6 = 24x80 (for what you are interested in
anyway).
>
> Cheers,
> -Dave
>
>
> > -----Original Message-----
> > From: Randy Bush [mailto:randy@psg.com]
> > Sent: Monday, April 17, 2000 11:36 PM
> > To: Andrea Westerinen
> > Cc: nim@ops.ietf.org
> > Subject: RE: Closing on NIM requirements
> >
> >
> > > The data/relationships/methods must be modeled enough,
but
> > not too much.
> > > So, I always start with the problems being solved
> > (requirements), and move
> > > to the nouns and verbs.  I never start with a
predefined
> > model in mind.
> >
> > well, policy framework started with cim handed down from
> > dmtf, and has been
> > trying to recover 'ere since.
> >
> > so, what are the requirements here?  for what purpose(s)
are
> > we trying to
> > model what?  can we get it on one 24x80 screen?
> >
> > randy
> >
> >
>
>
>
>