Subject: Re: FW: Policy Terminology Draft

From: [email-masked]
Date: Tue, 29 Aug 2000 10:23:40 -0400

Yes, in retropspect, I guess it is confusing.  We called it the Policy Core
Model, because it was the core part of policy, which could not be applied
without extensions to specific application domains.  So, the term is relative in
the way it was used.  That is, PCIM is "Core" with respect to the area of
Policy, but it is "Common" with respect to CIM.

Sorry.

Ed Ellesson
Tivoli Systems
Durham, NC
[email-masked]
919-224-2111

Juergen Schoenwaelder <[email-masked]> on 08/29/2000 05:05:07 AM

Please respond to Juergen Schoenwaelder <[email-masked]>

To:   [email-masked]
cc:   [email-masked] (bcc: Ed Ellesson/Tivoli Systems)
Subject:  Re: FW: Policy Terminology Draft

>>>>> Andrea Westerinen writes:

Andrea> [...] so the new AAA explanation reads:

Looks good to me.

Andrea> Here is a rewrite ...

[...]

Andrea> graphical renderings using UML [UML]. Sets of classes and
Andrea> associations represent CIM's Core and Common Models, defining
Andrea> an information model for the "enterprise" - addressing general
Andrea> concepts (in Core), and systems, devices, users, software
Andrea> distribution, the physical environment, networks and policy
Andrea> (in the Common Models). (See also "information model.")

So the "Policy Core Information Model" produced by the Policy WG is a
"Common Model" in CIM terminology, right? Isn't that a bit confusing?

[...]

Andrea> These distinctions are actually not made in any draft
Andrea> and seem to draw arbitrary dividing lines between synonomous
Andrea> terms. The example that you site is listed specifically as an
Andrea> example. We discussed this issue at some length among the
Andrea> PolTerm editors and found that one person's/implementation's
Andrea> view of changing "levels" was another's view of staying at the
Andrea> same level.  We will be happy to add some text that "policy
Andrea> mapping" is another synonym - but the essence of
Andrea> translating/converting/mapping is the "transformation of a
Andrea> policy from a representation and/or level of abstraction, to
Andrea> another representation and/or level of abstraction." This is
Andrea> how the draft is currently worded.

So are we going to kick people out of the door in the future who start
arguing about the differences between translations and mappings? Or
are we just taking the easy way out here?

Sure, the line between translations and mappings will be somewhat
fuzzy - but I generally thought that the distinction is useful. My
understanding is that a translation requires significant additional
input from secondary sources while a mapping just transforms the
primary input into some new output format:

(a)         input
              |
           v
         translation <-- significant secondary input
              |
              v
           output

(b)         input
              |
           v
           mapping
              |
              v
           output

For example, a rule which refers to the accounting department needs
significant secondary information to turn it into concrete device
configurations that use IP addresses to identify traffic to/from the
accounting department while a mapping from a CIM model to an LDAP
schema is basically an algorithmic problem where secondary input is
only needed to fine tune the mapping.

But perhaps you are right that this is just a rathole.

/js

--
Juergen Schoenwaelder      Technical University Braunschweig
<[email-masked]>  Dept. Operating Systems & Computer Networks
Phone: +49 531 391 3289    Bueltenweg 74/75, 38106 Braunschweig, Germany
Fax:   +49 531 391 5936    <URL:http://www.ibr.cs.tu-bs.de/~schoenw/>

---

From: Juergen Schoenwaelder <[email-masked]>
Date: Wed, 30 Aug 2000 10:34:26 +0200

>>>>> Ed Ellesson writes:

Ed> Yes, in retropspect, I guess it is confusing.  We called it the
Ed> Policy Core Model, because it was the core part of policy, which
Ed> could not be applied without extensions to specific application
Ed> domains.  So, the term is relative in the way it was used.  That
Ed> is, PCIM is "Core" with respect to the area of Policy, but it is
Ed> "Common" with respect to CIM.

If we can't fix it, then the terminology document should at least
explain that the interpretation of "core model" depends on the
context. 

I just checked the terminology draft and it seems that there is no
definition of the term "Policy Core Information Model" and the PCIM
acronym only appears as a citation of the PCIM document. I think PCIM
is important enough to be described as an offical term in this
document.

/js

---

From: "Andrea Westerinen" <[email-masked]>
Date: Wed, 30 Aug 2000 02:08:03 -0700

Juergen, I totally agree and will fix this.
Andrea

-----Original Message-----
From: Juergen Schoenwaelder [mailto:[email-masked]]
Sent: Wednesday, August 30, 2000 1:34 AM
To: [email-masked]
Cc: [email-masked]; [email-masked]
Subject: Re: FW: Policy Terminology Draft

/js