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RE: WS-Policy reference indirection

From: Daniel Roth <Daniel.Roth@microsoft.com>
Date: Fri, 22 Sep 2006 14:06:26 -0700
To: Paul Denning <pauld@mitre.org>, "public-ws-policy@w3.org" <public-ws-policy@w3.org>
Message-ID: <E2903CF1E4B5B144B559237FDFB291CE0142E9E1@NA-EXMSG-C117.redmond.corp.microsoft.com>

Hi Paul,

> What if [P1] and [P2] conflict?

Then someone is in effect "lying" about the policy for that endpoint.  It is the responsibility of the policy provider to make sure that the policies are consistent.

> Perhaps an approach that would work is for the WSDL policy reference
> to point to a UDDI tModel, then the UDDI tModel points to the actual
> policy document, say [P1].

Policy references point to policies, not tModels.  You can have your WSDL and your tModel both point to the same policy.  However, this won't have the effect that I think you are implying.

Section 3.1 of the Policy Attachment spec states that you should merge multiple policies attached to the same policy subject using different attachment mechanisms [1].  The merge operation is actually a cross product of the policy alternatives, and P1 x P1 != P1.  When attaching multiple policies to the same subject, these policies should be orthogonal to each other to make sure that the merge results are reasonable.

I hope this helps.

Daniel Roth

[1] http://www.w3.org/Submission/WS-PolicyAttachment/#EffectivePolicy
NOTE: This is a link to the submitted draft.  In the editors draft it looks like the terminology work has cut off some of the text for paragraph 2 in section 3.1.

-----Original Message-----
From: public-ws-policy-request@w3.org [mailto:public-ws-policy-request@w3.org] On Behalf Of Paul Denning
Sent: Wednesday, August 23, 2006 8:49 AM
To: public-ws-policy@w3.org
Subject: WS-Policy reference indirection


Lets say my policy subject is an endpoint [e].

Lets assume two different policy files exist, [P1] and [P2].

I may have a WSDL file for endpoint [e] with an attached policy [1]
that references [P1].

I may also have a UDDI entry for [e] with an attached policy [2] that
references [P2].

So, both [P1] and [P2] are associated with [e].

What if [P1] and [P2] conflict?

For example,
[P1] = endpoint available only Mon-Fri
[P2] = endpoint available only on Sat and Sun

[1]  http://www.w3.org/Submission/WS-PolicyAttachment/#EndpointPolicySubject
[2]
http://www.w3.org/Submission/WS-PolicyAttachment/#EndpointPolicySubjectUDDI
[3]
http://www.w3.org/Submission/2006/SUBM-WS-Policy-20060425/#Policy_Inclusion

It would be nice to avoid this situation.

Perhaps an approach that would work is for the WSDL policy reference
to point to a UDDI tModel, then the UDDI tModel points to the actual
policy document, say [P1].

However, I don't think [3] allows this extra layer of indirection
where WSDL points to UDDI which points to Policy.  I think [3] only
allows WSDL to point to Policy.

Is my reading correct?

Do you agree that the specs should support this extra layer of
indirection to avoid potential policy conflicts and reduce the burden
of synchronizing the WSDL and UDDI policy references?

Paul
Received on Friday, 22 September 2006 21:11:12 GMT

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