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Freund 3/29/2007: WS-Addressing/Policy Questions on Alternatives G (if selected)

From: Monica J. Martin <Monica.Martin@Sun.COM>
Date: Mon, 02 Apr 2007 12:13:30 -0700
To: Tom Rutt <tom@coastin.com>, Bob Freund-Hitachi <bob.freund@hitachisoftware.com>
Cc: Maryann Hondo <mhondo@us.ibm.com>, Fabian Ritzmann <Fabian.Ritzmann@Sun.COM>, Rama Pulavarthi <Rama.Pulavarthi@Sun.COM>, public-ws-addressing@w3.org
Message-id: <461155DA.5020705@sun.com>

Tom,
Several of us have been trying to follow the WS-Addressing WG 
discussions around defining policy assertions. Here are a few comments, 
concentrating on Alternative G that seems to be gaining momentum. Should 
Alternative F be considered, comments could be provided.

Alternative G if chosen:          
http://lists.w3.org/Archives/Public/public-ws-addressing/2007Mar/att-0043/WSA_Policy_-_alternative_G.pdf 


   1. It may be worthwhile to consider revision to the proposal in order
      to clarify that unless there is further specification explicitly,
      there is no behavior implied. It appears the key is that
      WS-Addressing is required or supported. Should other restrictions
      or specific qualification be necessary, consider they are explicit:
          * Proposal states:  "The wsam:Addressing assertion does not
            indicate any restrictions on the use of WS-Addressing unless
            otherwise qualified by assertions in its nested policy
            expression." 
          * Proposal also states: "The wsam:Addressing assertion
            indicates the use of WS-Addressing unless otherwise
            qualified by assertions in its nested policy expression."
                o Note: Therefore the base assumption is what is
                  required explicitly by WS-Addressing core; the
                  baseline here without qualification would be the same
                  would it not? There have been comments that this
                  includes the response types discussed. The WG should
                  clarify.
   2. Email states: "The Addressing assertion without any qualifiers
      (nested assertions) means that the use of WS-Addressing is
      required and has no restrictions."
          * Note: This definition is affected by your baseline assumption.
   3. Email also states: "A subject that requires mixed-mode responses
      can use the Addressing assertion with no qualifiers."
          * Note: We are uncertain this comment is supported by [1] and
            is also affected by the baseline assumption around
            WS-Addressing Core.

Comments by Rutt on Alternative G and those regarding the two use cases 
for back channel and composition may a bit more work (Thanks for the 
hard work Tom). [2]

   1. Example 3-8 proposal: Indicates that specifying addressing infers
      support for all response types. This statement is similar with
      Alternative G and both comments may be affected by the assumption
      around 'no behavior' unless the WS-Addressing Core requires those
      response capabilities.
   2. Composition and split use cases: At first glance, both examples
      seems reasonable. Yet, language proposed:  
          * composition "...empty implies both response types supported..."
          * split "...empty implies support for both response types,..."
                o Suggestion: Delete text, see [1]

More discussion may occur around empty and nested assertions - such as 
intersection of compatible policies, result if any other than 
compatibility, and question surrounding no behavior - as work continues 
on the Primer and Guidelines documents. Thanks.

======
[1] See Framework, Sections 4.3.1-4.3.3. We also indicate in Section 3.2:
  [Definition: A policy alternative is a potentially empty collection
  of policy assertions.] An alternative with zero assertions indicates
  no behaviors. An alternative with one or more assertions indicates
  behaviors implied by those, and only those assertions. [Definition:
  A policy vocabulary is the set of all policy assertion types used in
  a policy.] [Definition: A policy alternative vocabulary is the set
  of all policy assertion types within the policy alternative.] When
  an assertion whose type is part of the policy's vocabulary is not
  included in a policy alternative, the policy alternative without the
  assertion type indicates that the assertion will not be applied in
  the context of the attached policy subject. See the example in
  Section 4.3.1 Optional Policy Assertions.

The guiding language includes "no behaviors" and "assertion will not be 
applied."

[2] Rutt: 
http://lists.w3.org/Archives/Public/public-ws-addressing/2007Mar/0053.html
Composition use case with RM-MC: 
http://lists.w3.org/Archives/Public/public-ws-addressing/2007Mar/0048.html
Split case (faults/responses): 
http://lists.w3.org/Archives/Public/public-ws-addressing/2007Mar/0049.html 
WS-Policy response earlier: 
http://lists.w3.org/Archives/Public/public-ws-policy/2007Feb/0152.html
Received on Monday, 2 April 2007 19:13:22 GMT

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