RE: [Policy] RE: PCELS position

Mircea,

The pcimRuleEnabled attribute is defined for the pcimRule class in PCLS, and the pcimRuleEnabled attribute is defined for the pcimPolicyRule. You claim that since the definition of pcimRuleEnabled is the same, there should be no problem.

I disagree because:

1) the semantics of the two defining classes are different

2) the derivation of the two defining classes are different

It's like saying that a Hummer and a Boat both have an engine, so why can't I use the Boat's engine in a Hummer?

regards,
John

John C. Strassner
Chief Strategy Officer
Intelliden Inc.
90 South Cascade Avenue
Colorado Springs, CO 80906 USA
phone: +1.719.785.0648
fax: +1.719.785.0644
email: john.strassner@intelliden.com

-----Original Message-----
From: Pana, Mircea [mailto:mpana@metasolv.com]
Sent: Tuesday, September 23, 2003 1:00 PM
To: 'John Strassner'; 'Wijnen, Bert (Bert)'; 'David McTavish'; 'policy@ietf.org'
Cc: 'Joel M. Halpern'
Subject: RE: [Policy] RE: PCELS position

John,

I agree with you that an attribute should not be used in classes where it would shift semantics. For example, the RulePriority attribute defined in PCLS and used there by the Rule class, is not reused in PCELS. Instead, PCELS defined a new Priority attribute for use in the realization of PolicySetComponent and PolicySetInSystem.

However, the attribute RuleEnabled defined in PCLS is reused in the PolicyRule class defined by PCELS. In both classes the attribute has identical semantics. I see nothing wrong with that.

Mircea.

-----Original Message-----
From: John Strassner [mailto:John.Strassner@intelliden.com]
Sent: Tuesday, September 23, 2003 1:03 PM
To: 'Pana, Mircea'; 'Wijnen, Bert (Bert)'; 'David McTavish'; 'policy@ietf.org'
Cc: John Strassner; 'Joel M. Halpern'
Subject: RE: [Policy] RE: PCELS position

Again, you are trying to determine the validity of an information model based on the concerns of one specific data model. This is backwards.

Furthermore, the argument that you are "reusing" an attribute foo in a new class bar is completely specious, because the new class bar is different than the original class baz that defined foo. The differences are very fundamental - different hierarchies, different attributes, and worse (e.g., the definition of priority). This isn't reuse, this is simply stealing an OID.

So, how about defining a NEW set of classes and attributes? And if you prefixes the new classes and attributes, this would also get around the schema problem that I stated earlier.

regards,
John

John C. Strassner
Chief Strategy Officer
Intelliden Inc.
90 South Cascade Avenue
Colorado Springs, CO 80906 USA
phone: +1.719.785.0648
fax: +1.719.785.0644
email: john.strassner@intelliden.com

-----Original Message-----
From: Pana, Mircea [mailto:mpana@metasolv.com]
Sent: Monday, September 22, 2003 8:21 AM
To: 'Wijnen, Bert (Bert)'; 'David McTavish'; Pana, Mircea; 'policy@ietf.org'
Cc: 'John Strassner'; 'Joel M. Halpern'
Subject: RE: [Policy] RE: PCELS position

Maybe there is no need for such drastic measures. Maybe it is only a matter of interpretation of the PCIMe recommendations. After all PCIMe is quite lenient wrt. that is and what is not used in submodels (see PCIMe section 5.10.).

Some of the structural changes proposed by PCIMe make it difficult for PCELS to be interoperable with PCLS. These are as follows:

1. PCIMe defines a new abstract class, PolicySet, and makes it a superclass of the already defined PolicyRule and PolicyGroup

2. In PCIMe the PolicyRule.Priority property has been deprecated in favor of a new relative priority mechanism.
3. PolicyRepository is deprecated in favor of the new ReusablePolicyContainer.

PCELS could be interoperable with PCLS if it was to interpret these PCIMe changes as follows:
A. there is no need to have an explicit LDAP mapping of the abstract PolicySet. (see also B.)
B. there is no need to have an explicit LDAP mapping of the modified PolicyGroup. Implementations can use (the equivalent of) a PolicyRule with no Actions or Conditions for PolicyGroup objects.

C. implementations SHOULD (as opposed to MUST) use the relative priority mechanism instead of the absolute priority attribute of PolicyRule

D. PolicyRepository SHOULD not be used directly but it is acceptable for instances of this class to occur through inheritance.

So, the question is whether the statements A. through D. violate PCIMe or not. Opinions?

Thanks,
Mircea.
-----Original Message-----
From: Wijnen, Bert (Bert) [mailto:bwijnen@lucent.com]
Sent: Sunday, September 21, 2003 6:14 AM
To: 'David McTavish'; 'Pana, Mircea'; 'policy@ietf.org'
Cc: 'John Strassner'; 'Joel M. Halpern'
Subject: RE: [Policy] RE: PCELS position

W.r.t.
> Is PCIMe considered so complete, that it is beyond modification, if such
> modification could preserve its intent while also adhering to the desires
> of maintaining consistency with PCIM and PCLS?

PCIMe is at Proposed Standard. If, for example because of this effort to try and MAP it onto LDAP, we
find that we did some things in PCIMe that we should not have done, then, with WG consensus,
we can make incompatible changes to PCIMe and then recycle at Proposed Standard.
That is part of the normal standars track process. That is, we get something to PS, then we start
using/implementing (the "using" part is reusing PCIMe definitions in otehr CIM docs (like the
other docs we did in Policy, and like the IPsec work, the "implementing" is sort of mapping onto for
example LDAP I think)... and if we find major issues, then we fix and recycle at PS. If we do not
find major issues, we may advance to DS.

Hope this helps.
Bert