W3C home > Mailing lists > Public > public-ws-addressing@w3.org > December 2005

Re: New Issue: wsaw:UsingAddressing as a policy assertion

From: David Hull <dmh@tibco.com>
Date: Fri, 02 Dec 2005 11:00:23 -0500
To: Jonathan Marsh <jmarsh@microsoft.com>
Cc: public-ws-addressing@w3.org
Message-id: <43906F97.5040504@tibco.com>
WS-BaseNotification delegates many decisions -- as many as we could,
actually -- to the realm of policy.  For example, the core does not
define a way of saying "I don't want to receive more than N
notifications per second".  The core /does/ define a "policy" slot in
the subscription request, but any actual policies one could put there
are defined elsewhere (whether by us or someone else).

We are just starting to pull together all the material that we swept
under the policy rug, but our decision of quite a while ago was
"vocabulary, not grammar."  That is, our policy document would define a
standard element for, say, limiting messages per second, but not talk
about where that would be used or what it would look like as part of a
policy assertion.  Such an element could appear in the "policy" slot of
the subscription, but could just as well appear elsewhere.  This assumes
only that whatever you use to express the assertion uses elements to
convey assertions.  Naturally, we will be careful to make sure that
whatever we define fits easily with WS-Policy.

In the present case, we have to talk about WSDL, so if I understand
correctly, we're mainly talking about making sure that whatever WSDL
markup we define can be used basically unchanged in other contexts,
particularly WS-Policy.

Is this about right, or am I missing something?

Jonathan Marsh wrote:

>The WSDL Binding specification defines both a WSDL extension and a SOAP
>module for indicating the use of WS-Addressing.  Other WS specs that
>Microsoft is implementing such as WS-ReliableMessaging,
>WS-AtomicTransactions, and the various security specifications all rely
>on policy assertions to indicate the use of their respective features.
>In the long term, we'd like to use policy assertions consistently to
>represent all these SOAP extensions.
>As a result, Microsoft sees a need for a policy assertion indicating
>WS-Addressing is in use.  Our preference is to use this marker as the
>primary flag rather than either the WSDL extension or the SOAP module
>even within our short-term products.
>In other standards groups like the OASIS WS-RX TC, the policy assertions
>are developed alongside the spec, by the same experts and on the same
>timeline.  If we were starting WS-Addressing today, I believe we would
>push for a similar ownership regime within the WS-Addressing WG, rather
>than relying on external groups to define such policy assertions after
>the fact.
>Ideally, we would like to see the wsaw:UsingAddressing element converted
>to a policy assertion rather than a WSDL extension.  The semantics of
>this assertion/extension should be virtually identical to what we'd need
>(although it's currently more complicated than we'd prefer), describing
>the engagement of Addressing, the setting of the action values, and the
>consequences on the MEPs.  The main change would be to explicitly
>describe the element as a policy extension.  Some simplification might
>be obtained since the WS-Policy framework defines wsp:Optional through a
>mechanical transformation, reducing the amount of prose needed to
>describe the optional behavior currently defined for
>Secondarily, we'd like the use as a policy assertion sanctioned as on
>option in the spec alongside the WSDL extension.
>We recognize this request poses some timeline challenges, in developing
>a version-neutral policy assertion prior to standardization of the
>policy framework, but feel these issues are tractable.
Received on Friday, 2 December 2005 16:00:32 UTC

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