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

I'd like to do more than just make sure wsaw:UsingAddressing can be used
in other contexts, I'd like to state that it is appropriate to use it as
a policy assertion.  I'd also like to indicate that the policy assertion
is likely to be preferred as a mechanism once the policy framework
becomes widely adopted.

 

________________________________

From: David Hull [mailto:dmh@tibco.com] 
Sent: Friday, December 02, 2005 8:00 AM
To: Jonathan Marsh
Cc: public-ws-addressing@w3.org
Subject: Re: New Issue: wsaw:UsingAddressing as a policy assertion

 

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
wsdl:required="false".
 
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.