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Re: Who knows what from where?

From: Francisco Curbera <curbera@us.ibm.com>
Date: Tue, 24 Oct 2006 12:21:09 -0400
To: David Hull <dmh@tibco.com>
Cc: "public-ws-addressing@w3.org" <public-ws-addressing@w3.org>, public-ws-addressing-request@w3.org
Message-ID: <OF395B84F8.E80EA4B3-ON85257211.005463E6-85257211.0059D371@us.ibm.com>
I don't think every spec that uses the (or a) backchannel needs to define 
it, or even use the word itself. As long as WS-A is clear about what 
'backchannel' means for the protocols at hand, and the binding of WS-A to 
each new protocol with backchannel capabilities defines it as well, 
clients are ok. Again, clients don't go fishing for random URLs, so they 
don't need to check them for "backchannel-ness". Instead, clients decide 
to support a set of specs (WS-A, RM, etc.) that define policy assertions 
and URLs among many other things. A client is supposed to understand what 
those definitions mean, otherwise it should not use them. 


David Hull <dmh@tibco.com> 
10/24/2006 10:51 AM

Francisco Curbera/Watson/IBM@IBMUS
"public-ws-addressing@w3.org" <public-ws-addressing@w3.org>, 
Re: Who knows what from where?

Francisco Curbera wrote: 

Supposedly, if the client knows about RM it also knows about the RM anon 
URI as well and what it implies wrt the use of the backchannel, so I 
really don't see the difference. 
The RM anon URI is defined explicitly in the RM spec.  The term 
"backchannel" doesn't appear to be defined anywhere.  Leaving the client 
to make an inference with respect to an undefined term seems risky, to say 
the least.  I think Marc got it right in saying that the RM spec would 
have to provide the definition.

RM says what "http://...wsrm/anonymous?id=...1" means.
The policy assertions say I can put that in my response endpoint.
RM says what "http://...wsrm/anonymous?id=...1" means.
The policy assertions say the server can send responses on the backchannel
RM says, e.g., that in the context of RM, backchannel means regular anon 
or RM anon
In the third bullet, we're basically composing two specs (WSA and RM) that 
have a notion of backchannel.  I wonder how this would scale to composing 
another spec that also had such a notion.

It seems better to worry about whether something is defined and allowed 
than whether it constitutes a "backchannel".


David Hull <dmh@tibco.com> 
Sent by: public-ws-addressing-request@w3.org 
10/23/2006 05:35 PM 

"public-ws-addressing@w3.org" <public-ws-addressing@w3.org> 

Who knows what from where?

Pursuant to CR33:

If I'm a client and I know about WS-RM, and the server says "I support
WS-RM and you can use 'http://.../RMAnon.*' in a response endpoint",
then I know immediately that I can use this facility.  If the server
says "I support WS-RM and I can send responses on the backchannel", then
I need to know, from somewhere, that "backchannel" in this case is
referring to the special WS-RM URI family.

Where would this information appear?
Received on Tuesday, 24 October 2006 16:21:25 UTC

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