3554 2006-07-31 21:27:04 +0000 "Policy Alternatives" and "Policy" need proper definition 2006-08-31 14:34:27 +0000 1 1 1 Unclassified WS-Policy Framework FPWD All All RESOLVED FIXED http://lists.w3.org/Archives/Public/public-ws-policy/2006Jul/0113.html editorial P2 normal --- 1 prasad.yendluri prasad.yendluri asirveda Daniel.Roth prasad.yendluri public-ws-policy-qa oldest_to_newest 10903 0 prasad.yendluri 2006-07-31 21:27:04 +0000 From: public-ws-policy-request@w3.org [mailto:public-ws-policy-request@w3.org] On Behalf Of Prasad Yendluri Sent: Wednesday, July 26, 2006 4:16 PM To: public-ws-policy@w3.org Subject: NEW ISSUE: "Policy Alternatives" and "Policy" need proper definit ion Title: "Policy Alternatives" and "Policy" need proper definition Description: Section 2.3 terminology defines a “policy” to be, “a collection of policy alternatives” No further constraints on how these alternatives are grouped, i.e. on the origin of alternatives in the collection. Similarly section 3.2 (Policy) defines a “policy” to be: “a policy is a potentially empty collection of policy alternatives.” This “collection” does not account for level of nesting of a specific policy alternative. Section 2.3 terminology defines a “Policy Alternative” to be “a collection of policy assertions” only. No further restriction on how these assertions are grouped (or) the origin of the assertions in the collection. Similarly section 3.2 (Policy Alternative) defines a policy alternative to be: “A policy alternative is a logical construct which represents a potentially empty collection of policy assertions. An alternative with zero assertions indicates no behaviors.” This “collection” again does not account for level of nesting of a policy assertion included. Justification: There is scope for interpretation that needs to be eliminated. “policy assertion” and “policy” definitions need to account for level of nesting of the collection they define. Target: WS-Policy 1.5 - Framework Proposal – Tighten up the definitions of “policy” and “policy assertion”. Sorry I have not come up suggestion for a specific replacement text at this point. Hope to follow-up later. Regards, Prasad Yendluri 10904 1 Daniel.Roth 2006-08-01 00:01:57 +0000 I’m having difficulty understanding this issue. Some examples that demonstrate how the current definitions are ambiguous would be helpful. 10926 2 prasad.yendluri 2006-08-01 03:52:31 +0000 (In reply to comment #1) > I’m having difficulty understanding this issue. Some examples that demonstrate > how the current definitions are ambiguous would be helpful. > See Example here: http://lists.w3.org/Archives/Public/public-ws-policy/2006Aug/0000.html 10987 3 asirveda 2006-08-02 00:21:02 +0000 Hi Prasad, Thank you for writing down these examples. Let us look at the two policy expressions in your e-mail below. Policy 1 has two alternatives: A1 = {assertion 6, assertion 8} A2 = {assertion 7, assertion 8} Policy 2 has six alternatives: A3 = {assertion 1, assertion 4} A4 = {assertion 2, assertion 4} A5 = {assertion 1, assertion 5, assertion 6} A6 = {assertion 1, assertion 5, assertion 7} A7 = {assertion 2, assertion 5, assertion 6} A8 = {assertion 2, assertion 5, assertion 7} Two policy alternatives are compatible if each policy assertion in one alternative is compatible with a policy assertion in the other and vice-versa. None of the above policy alternatives are compatible. Two policies are compatible if a policy alternative in one is compatible with a policy alternative in the other. Policy 1 and Policy 2 are incompatible because none of the policy alternatives in Policy 1 is compatible with a policy alternative in Policy 2. Just as expected, these two policies are incompatible. I noticed that your example policies do not use any nested policy expression. I hope this helps. Regards,   Asir S Vedamuthu Microsoft Corporation 10991 4 prasad.yendluri 2006-08-02 01:08:35 +0000 (In reply to comment #3) > Hi Prasad, > > Thank you for writing down these examples. Let us look at the two policy > expressions in your e-mail below. > > Policy 1 has two alternatives: > A1 = {assertion 6, assertion 8} > A2 = {assertion 7, assertion 8} > > Policy 2 has six alternatives: > A3 = {assertion 1, assertion 4} > A4 = {assertion 2, assertion 4} > A5 = {assertion 1, assertion 5, assertion 6} > A6 = {assertion 1, assertion 5, assertion 7} > A7 = {assertion 2, assertion 5, assertion 6} > A8 = {assertion 2, assertion 5, assertion 7} > > Two policy alternatives are compatible if each policy assertion in one > alternative is compatible with a policy assertion in the other and vice-versa. > None of the above policy alternatives are compatible. > > Two policies are compatible if a policy alternative in one is compatible with a > policy alternative in the other. Policy 1 and Policy 2 are incompatible because > none of the policy alternatives in Policy 1 is compatible with a policy > alternative in Policy 2. > > Just as expected, these two policies are incompatible. I noticed that your > example policies do not use any nested policy expression. > > I hope this helps. > > Regards, > > Asir S Vedamuthu > Microsoft Corporation > Hi Asir, > I noticed that your example policies do not use any nested policy expression. Section 4.3.3 defines: Equivalence wsp:Policy is equivalent to wsp:All So, for readability, I have not explicitly put wsp:policy brackets around things and used wsp:All. If my examples have been, Example Policy 1: <wsp:All> <!-- assertion 5 --> <wsp:ExactlyOne> <!-- assertion 6 --> <!-- assertion 7 --> </wsp:ExactlyOne> </wsp:All> Example Policy 2: <wsp:All> <wsp:ExactlyOne> <!-- assertion 1 --> <!-- assertion 2 --> </wsp:ExactlyOne> <wsp:ExactlyOne> <!-- assertion 4 --> . . . . <wsp:policy> <!-- assertion 5 --> <wsp:ExactlyOne> <!-- assertion 6 --> <!-- assertion 7 --> </wsp:ExactlyOne> </wsp:policy> . . . . </wsp:ExactlyOne> </wsp:All> Would you not then have the same policy alternates for Policy 1 and the nested policy in policy 2? I understand the way you came up with the production of the alternatives for each policy and agree that is the correct way to arrive at them. The point of the issue however is that, the text of the specification is not explicit enough for this. What makes a nested alternative in a Policy specification not an alternative of the parent policy, when policy is only defined to be “a collection of policy alternatives”? The nested policy and hence the embedded alternative is part of the same “collection” is it not? Regards, Prasad 10994 5 asirveda 2006-08-02 14:13:26 +0000 RE the text of the specification is not explicit enough for this A full worked out example that demonstrates how the current definitions are ambiguous or not explicit enough is the best way to move forward on this. Regards, Asir S Vedamuthu Microsoft Corporation 11003 6 asirveda 2006-08-02 21:11:31 +0000 In the example above, it is not clear to me where assertions start and end. As described in Section 4.3.2 [1], a nested policy expression is a policy expression that is a child element of a policy assertion element: "Any policy assertion MAY contain a nested policy expression. The schema outline for a nested policy expression is: <Assertion …> … ( <wsp:Policy …> … </wsp:Policy> )? … </Assertion>" In the example above, it does not look like any of these assertions have nested policy expressions. Was this intentional? The normative text in Section 4.3.2 seems to be clear that this must be the case. [1] http://www.w3.org/TR/2006/WD-ws-policy-20060731/#Policy_Assertion_Nesting Regards,   Asir S Vedamuthu Microsoft Corporation 11006 7 prasad.yendluri 2006-08-03 03:21:11 +0000 (In reply to comment #6) > In the example above, it is not clear to me where assertions start and end. As > described in Section 4.3.2 [1], a nested policy expression is a policy > expression that is a child element of a policy assertion element: > > "Any policy assertion MAY contain a nested policy expression. The schema > outline for a nested policy expression is: > > <Assertion …> > … > ( <wsp:Policy …> … </wsp:Policy> )? > … > </Assertion>" > > In the example above, it does not look like any of these assertions have nested > policy expressions. Was this intentional? The normative text in Section 4.3.2 > seems to be clear that this must be the case. > > [1] http://www.w3.org/TR/2006/WD-ws-policy-20060731/#Policy_Assertion_Nesting > > Regards, > > Asir S Vedamuthu > Microsoft Corporation > Hi Asir, Yes the example above does have a nested policy. I used … around the <wsp:policy> elements on purpose, to skip some unnecessary detail, that are not needed to illustrate the issue at hand. The point is that the nested policy in “Example Policy 2” has policy alternatives that are identical to the policy alternatives in “Example Policy 1”. With the current (somewhat loose) specification of a policy to be a collection of policy alternatives, one can deduce that the alternatives in the nested Policy specification are alternatives of the parent policy also, which match the alternatives in “Example Policy 1” (and hence the two policies are compatible etc.). It would be helpful to have more concrete definitions. Regards, Prasad 11059 8 prasad.yendluri 2006-08-08 23:07:34 +0000 Hi, >Prasad, do you think we should describe these concepts with illustrative >examples in the Primer? Asir, Dan and I had an offline discussion on this and I am happy to close this issue and issue 3553 with the resolution to explain / clarify these aspects in the primer. Thanks. Prasad 11074 9 prasad.yendluri 2006-08-09 18:08:50 +0000 This issue was Resolved in the Aug 09, 2006 WS-Policy WG meeting (minutes: http://www.w3.org/2006/08/09-ws-policy-minutes.html) with the resolution to retarget the issue at the primer. The primer will incorporate the explanotory text to clarify the definitions.