RE: 3553: Policy Compatibility Check must account for level of Nesting of Policy Alternatives

For you convenience, I marked up the distinction in Section 4.4 using two different colors in the attached HTML document. If the distinction is insufficient, please let us know.

> what constitutes a "policy alternative" is not precisely defined.

I'll address this in my response to issue 3554.

Regards,
 
Asir S Vedamuthu
Microsoft Corporation

________________________________________
From: Prasad Yendluri [mailto:prasad.yendluri@webmethods.com] 
Sent: Tuesday, August 01, 2006 6:02 PM
To: Asir Vedamuthu; Prasad Yendluri; public-ws-policy@w3.org
Subject: RE: NEW ISSUE: Policy Compatibility Check must account for level of Nesting of Policy Alternatives

Hi Asir,

In section 4.4 Section 4.4 I do not see any text that distinguishes between policy and nested policy (I am looking here: http://dev.w3.org/cvsweb/~checkout~/2006/ws/policy/ws-policy-framework.html?content-type=text/html;%20charset=utf-8#Policy_Intersection)

However the main issue as I see it is that, what constitutes a "policy alternative" is not precisely defined. More specifically an alternative in am embedded policy expression is not ruled out to constitute an alternative of the parent policy also. We need more precise definitions of policy, policy alternative etc. IMO.

Thanks.

Prasad 


________________________________________
From: public-ws-policy-request@w3.org [mailto:public-ws-policy-request@w3.org] On Behalf Of Asir Vedamuthu
Sent: Tuesday, August 01, 2006 5:06 PM
To: Prasad Yendluri; public-ws-policy@w3.org
Subject: RE: NEW ISSUE: Policy Compatibility Check must account for level of N esting of Policy Alternatives

RE "There is scope however for interpretation, that if an alternative (at any nesting level) in one matches the alternative (at any nesting level) in the other, the two policies can be considered compatible."

In Section 4.4, the requested distinction is called out at the policy level:

- 'policy' vs. 'nested policy', and
- 'an alternative' vs. 'the alternative in the nested policy'

This distinction is consistently maintained throughout Section 4.4 which seems to clarify any ambiguity raised by this e-mail.

PS: I'll update your entry in Bugzilla.

Regards,
 
Asir S Vedamuthu
Microsoft Corporation
________________________________________
From: public-ws-policy-request@w3.org [mailto:public-ws-policy-request@w3.org] On Behalf Of Prasad Yendluri
Sent: Wednesday, July 26, 2006 4:10 PM
To: public-ws-policy@w3.org
Subject: NEW ISSUE: Policy Compatibility Check must account for level of N esting of Policy Alternatives

Title: Policy Compatibility Check must account for level of Nesting of Policy Alternatives
 
Description: Section 4.4 of the WS-Policy 1.5 - Framework specification states:

* "Two policies are compatible if an alternative in one is compatible with an alternative in the other. If two policies are compatible, their intersection is the set of the intersections between all pairs of compatible alternatives, choosing one alternative from each policy. If two policies are not compatible, their intersection has no policy alternatives."

However, per section 4.3.2 (Policy Assertion Nesting), a policy Assertion may contain a nested Policy. 

The intent of the above text is to check compatibility of alternatives at the top level of the subject policies only. There is scope however for interpretation, that if an alternative (at any nesting level) in one matches the alternative (at any nesting level) in the other, the two policies can be considered compatible.

In addition section 2.3 terminology defines a policy to be "collection of policy alternatives "only. 
No further constraints on the origin of alternatives in the collection.

Similarly section 3.3 (Policy) defines a policy to be: "a policy is a potentially empty collection of policy alternatives"

Justification:
There is scope for interpretation that needs to be eliminated. 
 
Target: WS-Policy 1.5 - Framework
 
Proposal - 

1. Tighten up the definition of policy to be specific about the (nesting level / origin of) "collection" of alternatives it groups. 
     I am Opening a separate new issue for it. If that is properly resolved, this issue is automatically resolved.
2.  Rephrase the policy compatibility statement to say "Two policies are compatible if a top level alternative in one is compatible with a top level alternative in the other."

Regards,
Prasad Yendluri