W3C home > Mailing lists > Public > public-ws-resource-access@w3.org > April 2009

RE: [Bug 6692] New: Remove Mode from the specification

From: Kemp, Devon <Devon.Kemp@cda.canon.com>
Date: Fri, 17 Apr 2009 13:05:40 -0700
Message-ID: <02954887D466F24D9F3FC9F47466DEF00BBF756F@cdaexchange.sc.rd.canon.com>
To: <public-ws-resource-access@w3.org>


Canon is also very concerned about the proposal to remove the Delivery
Mode attribute, and defined delivery modes, from the WS-Eventing


1)    Canon has several products currently in the market that contain
implementations of DPWS, which relies on the Push Mode of event
delivery. Should the WS-Eventing specification remove the delivery mode,
our investment in DPWS will be at risk.

2)    It appears that you're not requiring any specific type of delivery
mode. We have learned that in order to assure interoperability, there
must be at least one defined type of delivery modes. Push mode has been
used in several applications of DPWS and has proved (at least to us) to
be an easy to implement, common denominator, for eventing messages.

3)    The lack of a formal extension point ("Delivery Mode") prevents
easy adoption by other specifications in the industry, reducing
WS-Eventing's usability.

4)    Nothing appears to be gained by the removal of the Delivery Mode
attribute. (Don't fix something that isn't broken.)


We ask that you please reconsider your proposal to remove the Delivery
Mode attribute, and keep this in the WS-Eventing specification.


Best Regards,

-Devon Kemp





From: public-ws-resource-access-request@w3.org
[mailto:public-ws-resource-access-request@w3.org] On Behalf Of Asir
Sent: Sunday, March 29, 2009 7:59 PM
To: public-ws-resource-access@w3.org
Subject: RE: [Bug 6692] New: Remove Mode from the specification


Last week, on the WG conference call, I mentioned that we will provide
some clarity on the concept of delivery mode (in WS-Eventing) and
related use cases.


Delivery mode [1] provides a subscriber with a mechanism to specify the
means by which an event is delivered. Delivery mode is represented as a
URI in a Subscribe message [2]. The semantics indicated by a delivery
mode are:


1)  Rules for the delivery of events

a)  Semantics and lifecycle of a Notification delivery

b)  Message Exchange Pattern used (One-way, Request-Response, etc.) and
how the delivery mode binds to those Message Exchange Patterns

c)  Format of a response (if any)

d)  Configuration parameters or context data (if any) to support the
Message Exchange Pattern

e)  Rules for the delivery or other disposition of faults generated
during a Notification delivery

2)  Delivery mode specific protocol information (if any) to guarantee

3)  Supported delivery formats.


Some portion of the above semantics are captured by an EPR, in a
machine-readable form, but certainly not all. So, there is value added
by a formal mechanism to indicate a delivery mode. 


The delivery mode is an extension point in WS-Eventing. The WS-Eventing
specification defines a single built-in delivery mode, Push Mode. Other
delivery modes may be important for external groups or other W3C Working
Groups and are delegated to those groups. This is similar to SOAP
Bindings. The W3C XML Protocol WG defined SOAP Protocol Binding
Framework as an extension point and a concrete binding, SOAP HTTP
Binding (is also identified using a URI [3]). Other groups defined SOAP
bindings such as SOAP-over-JMS and SOAP-over-UDP.


The DMTF WS-Management WG defined three new delivery modes [4] and these
delivery modes have been widely adopted.


Furthermore, based on the WS-RA WG charter [5], the WG deliverables need
to satisfy the following requirements as well:


1)  Charter scope - "Mechanisms to allow a subscriber to specify the
means by which an event is delivered and the definition of a push-based
delivery mode".

2)  Charter scope - "In order to avoid disrupting the interoperability
of existing implementations, WS-MetadataExchange
<http://www.w3.org/Submission/2008/SUBM-WS-MetadataExchange-20080813/> ,
<http://www.w3.org/Submission/2006/SUBM-WS-Transfer-20060927/> ,
<http://www.w3.org/Submission/2006/SUBM-WS-Eventing-20060315/>  and
should remain compatible with protocols and formats that depend on them,
and offer a smooth migration path from the submission to the standard."
We are aware of two dependant protocols - DPWS [6] (uses Push Mode) and
WS-Management [4] (uses Push Mode and, as mentioned before, defines
three new delivery modes).


[1] http://www.w3.org/Submission/WS-Eventing/#Delivery_Modes 

[2] http://www.w3.org/Submission/WS-Eventing/#Subscribe 

[3] http://www.w3.org/TR/2003/REC-soap12-part2-20030624/#http-bindname 

[4] http://www.dmtf.org/standards/published_documents/DSP0226.pdf -
Section 7

[5] http://www.w3.org/2008/11/ws-ra-charter.html#scope

[6] http://specs.xmlsoap.org/ws/2006/02/devprof/ 


We hope this helps. 




Asir S Vedamuthu

Microsoft Corporation


-----Original Message-----
From: public-ws-resource-access-notifications-request@w3.org
[mailto:public-ws-resource-access-notifications-request@w3.org] On
Behalf Of bugzilla@wiggum.w3.org
Sent: Thursday, March 12, 2009 8:37 AM
To: public-ws-resource-access-notifications@w3.org
Subject: [Bug 6692] New: Remove Mode from the specification




           Summary: Remove Mode from the specification

           Product: WS-Resource Access

           Version: CR

          Platform: PC

        OS/Version: All

            Status: NEW

          Severity: major

          Priority: P2

         Component: Eventing

        AssignedTo: public-ws-resource-access-notifications@w3.org

        ReportedBy: david.Snelling@UK.Fujitsu.com

         QAContact: public-ws-resource-access-notifications@w3.org



The concept of Mode is redundant in the current version of the

All events can be thought of as being delivered. There is no actual

of "Push Mode" and no other recommended modes. We even have a

strategy to allow clients behind NATs to fetch events. Likewise,
strategies for

complex queuing and distribution are supportable without adding

modes and are outside the scope of this specification.


Proposal: Remove /s:Envelope/s:Body/*/wse:Delivery/@Mode from the

and all references to Push Mode. A simple explanation of the delivery
idea and

a pointer to some of the techniques available will be needed.




Configure bugmail:

------- You are receiving this mail because: -------

You are the QA contact for the bug.

You are the assignee for the bug.


Received on Monday, 20 April 2009 18:42:20 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 20:34:48 UTC