I-D ACTION:draft-ietf-conneg-feature-sets-at-urls-00.txt

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A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Content Negotiation Working Group of the IETF.

	Title		: Syntax extensions for abbreviating media feature 
                          sets with URLs
	Author(s)	: W. Newman
	Filename	: draft-ietf-conneg-feature-sets-at-urls-00.txt
	Pages		: 7
	Date		: 01-Mar-99
	
   Other Internet Drafts from the CONNEG working group describe a
   syntax[SYNTAX] and vocabulary[FEATURES] for negotiating media feature
   sets which can be used for transmission of a message. For example, a
   feature set may specify that full color output up to 800x600 pixels
   is supported, or that output can have up to 300 dots per inch. These
   feature sets can be arbitrarily complex, and typical feature set
   expressions may be hundreds of bytes in length. It would be
   relatively costly to transmit such long feature set expressions, and
   this cost could be a significant obstacle to the use of the CONNEG
   standard to negotiate capabilities for Internet transactions. The
   problem is likely to particularly severe for low-bandwidth wireless
   connections to the Internet.
 
   This document describes an extension to the CONNEG syntax[SYNTAX]
   which allows a feature set expression to be represented as an
   absolute URL, which can then be looked up over another channel, which
   is not necessarily the channel between the negotiating parties. By
   using this extension, content negotiation between two parties can
   proceed with a relatively small exchange of data over the channel
   between them. Of course, the contents of the URL must still be found
   through some channel. However, the channel used to find the contents
   of the URL may have greater bandwidth than the channel between the
   negotiating parties, and may further benefit from HTTP or other
   caching mechanisms.
 
   This extended syntax is only applicable when the receiver of the
   feature set has the capability to fetch the contents of absolute
   URLs.  In contrast, the base, unextended syntax[SYNTAX] is applicable
   to any transmission channel, without requiring any external resources
   for the feature set transmitter or the feature set receiver.

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