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Re: content negotiation flap (resend)

From: <jg@w3.org>
Date: Mon, 27 May 96 10:03:37 -0400
Message-Id: <9605271403.AA06239@zorch.w3.org>
To: Koen Holtman <koen@win.tue.nl>
Cc: Larry Masinter <masinter@parc.xerox.com>, conneg@organic.com, http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com

	Please be aware that as far as I can tell, there is only a few
items in the Content Negotiation chapter (15 in draft 03) as rewritten
by Roy that are normative (i.e. use the words MAY, SHOULD, MUST), and
therefore constrain any future course of action for the content
negotiation facilities.  Please focus on these items.  They look like
reasonable requirements so that things will actually work when Alternates
is introduced to me.

	I plan to err or the side of understandable explanation of the
facilities rather than being silent on items that need explanation to
motivate other facilities in the base specification.  Roy's rewrite,
while not perfect (and I'll certainly go over Koen's rewrite as well
of that section very carefully before I issue a new draft), has made a major
improvement it making the issues clear to the poor reader of this
document.

	Before, the section was not understandable except by those
who had been intimately involved in the content negotiation
discussion; Roy's version even mere mortals like myself could
understand.  This level of clarity is a necessity.  

	Complete silence, as you suggest by deleting the section Roy
wrote on Transparent negotiation, while clearly leaving things
completely open, also leaves the specification open to attack by those
who then don't understand why base facilities exist as they do.  I am
very sensitive to John Klensin's criticism of draft 02 as it looked as
though the design was by committee, rather than there actually being
two real ways for content negotiation to work.  Without some
understandable explanation, we're in for trouble in review outside the
working group, and we must address this kind of criticism.

	The only paragraph in Roy's version in the section on transparent
negotiation that is normative is:

"A cache performing transparent negotiation MUST include the
agent-driven negotiation information along with the response, and MUST
add a Vary header field to the response (defining the dimensions of
its variance) if a Vary field was not already assigned by the origin
server."

	I do not see what is wrong with these requirements, allowing
you complete freedom to specify whatever information you wish to
require, to be processed by any algorithm, unless I am missing
something.

	In any case, I'm going over both Roy's and your messages
on a change by change basis, paragraph by paragraph basis.

			- Jim
Received on Monday, 27 May 1996 07:04:32 EDT

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