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Re: SOAP LC Issue 232 -- changing mU default

From: <jones@research.att.com>
Date: Mon, 5 Aug 2002 09:34:33 -0400 (EDT)
Message-Id: <200208051334.JAA27468@bual.research.att.com>
To: hugo@w3.org, jones@research.att.com
Cc: xmlp-comments@w3.org

FWIW, Noah and I discovered an issue related to mU at the f2f.
It has to do with the fact that you might often want to have
headers targeted at 'next' and not marked mustUnderstand="true"
in order to implement some new feature that some, but not
all intermediaries might be revved to look for.  The problem is
that the intermediaries that aren't yet revved will silently
remove the header and not re-insert it according to the current
spec.  It doesn't seem right that intermediaries which don't
understand a header (and aren't required to) would take the
initiative to remove it.  It means that new capabilities have
to be universally deployed or specifically aware of and
independently targetted at all relevant intermediaries.

This arose in the context of thinking about intermediaries
that might want to observe faults on a return path.  The first
problem is that the fault mechanism puts the fault in the body
where it is cannot be targetted at those intermediaries.
The second problem is that even if you added a header for
such faults, you would probably make it mustUnderstand="false"
and target it at 'next'.  But then you have the above issue.

It is rather frustrating that this slipped by for so long,
and it is not clear whether to attempt to fix it now.

Mark Jones
AT&T

	From hugo@w3.org Thu Aug  1 16:37 EDT 2002
	Delivered-To: jones@research.att.com
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	Date: Thu, 1 Aug 2002 16:37:07 -0400
	From: Hugo Haas <hugo@w3.org>
	To: Mark Jones <jones@research.att.com>
	Cc: xmlp-comments@w3.org
	Subject: Re: SOAP LC Issue 232 -- changing mU default
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	Hi Mark.

	* Mark Jones <jones@research.att.com> [2002-08-01 16:18-0400]
	> The XMLP WG has decided to close this issue without any change to the default
	> value of the mustUnderstand attribute.  It was felt that this change would
	> be inconsistent with the current design and would cause mass confusion
	> in the migration from SOAP 1.1 to SOAP 1.2.
	> 
	> If this resolution is unacceptable, please contact the WG asap.

	This is fine.

	A comment though: I think that it would be useful to have some
	examples in the Primer which have headers _not_ marked with
	mustUnderstand="true".

	FWIW, I reread my comment about the wording of the processing
	model[1], and I actually think that it is OK as is.

	Regards,

	Hugo

	  1. http://lists.w3.org/Archives/Public/xmlp-comments/2002Jul/0049.html
	-- 
	Hugo Haas - W3C
	mailto:hugo@w3.org - http://www.w3.org/People/Hugo/ - tel:+1-617-452-2092
Received on Monday, 5 August 2002 09:35:13 GMT

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