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Re: Policy expressions with no wire manifestation

From: Sergey Beryozkin <sergey.beryozkin@iona.com>
Date: Wed, 20 Sep 2006 18:46:48 +0100
Message-ID: <003e01c6dcdc$beed5ae0$3901020a@sberyoz>
To: "Maryann Hondo" <mhondo@us.ibm.com>
Cc: "Anthony Nadalin" <drsecure@us.ibm.com>, <public-ws-policy@w3.org>, <public-ws-policy-request@w3.org>
Hi Maryann, others

this is most helpful...

"I would note that if you're "using the assertion for selection", it could 
imply that you know what it is."

Ok, I think I start understanding it (fingers crossed :-)). A requester runtime may be required to select services which are highly available. It expects providers to advertize well-known <oasis:HighlyAvailable/> assertions. If a provider advertizes a policy which have no <oasis:HighlyAvailable/> assertions then the intersection will fail. I think it's reasonable.

Now consider a different case.
A requester runtime has no priori policy requirements. However it understands all well-known security assertions but no others ones. It has found a service which requires that a requester supports some security policies. 

Futhermore, a provider wishes to advertize some of its capabilities, namely that it's the best service around. A requester does not know yet about such assertions and is not even planning to use assertions like this for services selection.

How would we do it ?

Like this  ? :

<wsp:Policy> 
   <wsp:ExactlyOnce> 
      <wsp:All>
         <!--- security assertion -->
         <sp:HttpsToken/>
      </wsp:All>
      <wsp:All>
         <!-- capability assertion -->
         <oasis:QOSGuarantee> 
            <TheBestServiceInThisCategory verifiedBy="..."/> 
         </oasis:QOSGuarantee> 
         <!--- security assertion -->
         <sp:HttpsToken/>
      </wsp:All>
   <wsp/ExactlyOnce> 
<wsp:Policy>

Thanks, 
Sergey Beryozkin
Iona Technologies

  ----- Original Message ----- 
  From: Maryann Hondo 
  To: Sergey Beryozkin 
  Cc: Anthony Nadalin ; public-ws-policy@w3.org ; public-ws-policy-request@w3.org ; Sergey Beryozkin 
  Sent: Wednesday, September 20, 2006 2:17 PM
  Subject: Re: Policy expressions with no wire manifestation



  Sergey, 
  I responded to your other mail ...so this is a bit of a repetition. 

  In the guidelines document, Umit and I have attempted to capture "observations" about the use of optional, and this might 
  be a case where it would be useful.  I would note that if you're "using the assertion for selection", it could 
  imply that you know what it is. Whether or not it is required on the wire is a facet of the behavior associated with the assertion. 
  Each set of authors is given a set of tools by the specifications, but the authors need to craft the assertions. 

  Maryann 



        "Sergey Beryozkin" <sergey.beryozkin@iona.com> 
        Sent by: public-ws-policy-request@w3.org 
        09/20/2006 05:35 AM 
       To "Sergey Beryozkin" <sergey.beryozkin@iona.com>, Anthony Nadalin/Austin/IBM@IBMUS  
              cc <public-ws-policy@w3.org>, <public-ws-policy-request@w3.org>  
              Subject Re: Policy expressions with no wire manifestation 

              

       



  Hi there 
    
  That was a response in a hurry so I take it back. Before flooding the group concalls with trivial issues I'd rather attempt to make my question as clear as possible. Note that I may indeed be confused, but if so then I'd appreciate an answer which would help. 
    
  Consider this example : 
    
  <wsp:Policy> 
     <wsp:ExactlyOnce> 
           <oasis:QOSGuarantee> 
                <NeverFails/> 
                <TheBestServiceInThisCategory verifiedBy="..."/> 
           <oasis:QOSGuarantee> 
     <wsp/ExactlyOnce> 
  <wsp:Policy> 
    
  This is an example of a policy with a single alternative. This alternative contains non-optional assertions 
  defined by a policy profile spec published a month ago. These assertions have no wire manifestations. 
  A ws-policy aware (requester) entity whose runtime has not been updated yet to recognize <oasis:QOSGuarantee> is about to start communicating with the service which advertizes this policy. 
    
  Given the fact that it's likely ws-policy aware requesters will refuse to start talking to a service should they fail to support the above policy and that the fact whether this requester supports this policy or not will have no effect on the actual communication with the service this policy attached to, my understanding is that such assertions with no wire manifestations SHOULD be marked as wsp:optional : 
    
  <wsp:Policy> 
     <wsp:ExactlyOnce> 
           <oasis:QOSGuarantee wsp:optional="true"> 
                <!-- --> 
           <oasis:QOSGuarantee> 
     <wsp/ExactlyOnce> 
  <wsp:Policy> 
    
  This means a requester may use this policy for a service selection but doesn't need to refuse talking to this service should it fail to recognize the policy. 
    
  Does it make sense ? 
  What is the group's position on this issue ? 
    
  Thanks 
    
  Sergey Beryozkin 
  Iona Technologies 
    
Received on Wednesday, 20 September 2006 17:45:58 GMT

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