RE: [wsdm] WS-Addressing Effects on WSDM

["Vambenepe, William N" <vbp@hp.com>]

A related concern I've heard is that WSDM uses 2 different versions of WS-Addressing. More precisely, WSDM uses one version of WS-A (2004/08) but it also uses WS-BaseNotif 1.2d3 which uses another version of WS-Addressing (2003/02). This is true and of course everyone agrees that it is less than ideal.

 

But while this creates a little bit of added complexity for some implementations, in no case does it result in interoperability problems. Each message exchange described by WSDM which uses an EPR (including those inherited from WS-BaseNotif) specifies unambiguously what version of WS-A is used in the EPR. So yes you might have to support more than one version but you always clearly know what version to use when.

 

Here is an example:

 

Using WSDM, I learn that my manageable resource A depends on a manageable resource B. Through the WSDM relationship mechanism, I get an EPR (version 2004/08) that points to a manageability endpoint for B. Since I care about the health of A, I decide to register for notifications on B so that I'll be alerted when something goes wrong with B that could affect the health of A. To do so, I use the EPR I have for B (again, using WS-A version 2004/08) to send a "subscribe" message to B. The response to this message contains an EPR to the newly created subscription. This EPR uses the 2003/02 version of WS-A. So I now have two EPRs, one (version 2004/08) to the manageability endpoint to B and the other one (version 2003/02) to a subscription. These are used for different interactions and address different endpoints. There is no confusion as to what version of WS-A to use for what EPR.

 

And in any case, smart implementations such as the ones in Apache will be, as the saying goes, "liberal in what they consume and conservative in what they produce". From my understanding, the Apache Hermes code will accept any version of WS-addressing.

 

Those who have concerns about these problems are warmly invited to join us in the WSDM interop effort.

 

Regards,

 

William

---

From: Heather Kreger [mailto:kreger@us.ibm.com]
Sent: Monday, February 28, 2005 12:59 PM
To: wsdm@lists.oasis-open.org
Subject: [wsdm] WS-Addressing Effects on WSDM

I just thought I'd try to correct 
any misunderstandings from Martin's post.  In his post 
he makes a set of assertions and I'd just like to clarify 
one or two.   The assertion that 
the changes to WS-Addressting are disruptive to the WSDM V1.0 
specifation. 

"In
particular WS-Addressing is 
currently being worked on and looks like
the final version when it finally 
emerges will be significantly
different from its various antecedent 
proprietary versions. In
particular the debates and changes surrounding 
reference properties
and parameters will mean the use of different schema 
types and usage
patterns. None of these changes will mean that it can't be 
used by
these higher level specifications, e.g. WSDM, etc., but they will 
need
to be modified. The current Working Draft of the W3C WS-Addressing 
Working
Group [2] includes this status section:" 

"This is a draft document and may be updated, replaced or obsoleted 
by  other documents at any time.
It is inappropriate to cite this 
document
as other than work in progress." 

Because WSDM treats the entire EPR as opaque. We only use 
the EPR as a unit. 
We do not suggest how 
to create the EPR or ever suggest information be extracted from EPRs. 

Therefore, WSDM V1.0 is unaffected 
by changes in the WS-Addressing specification in the W3C. 
WSDM V1.0 does not reference the WS-Addressing Working 
Draft, it references the submission:

http://www.w3.org/Submission/2004/SUBM-ws-addressing-20040810/. The submission itself is stable.

It is not changing during development of the specification.  It does not have the same text quoted above in the status section.

WSDM V2.0 is already scoped to include making whatever changes are necessary to use the standard
versions of WS-Addresssing, WS-Notification, and WS-Resource Framework.

Heather Kreger
STSM, Web Services Lead Architect for SWG Emerging Technologies
Author of "Java and JMX: Building Manageable Systems"
kreger@us.ibm.com
919-543-3211 (t/l 441)  cell:919-496-9572