2.1.2 Content Negotiation (conneg)

NOTE: This charter is a snapshot of the 43rd IETF Meeting in Orlando, Florida. It may now be out-of-date. Last Modified: 25-Nov-98


E. Hardie <hardie@equinix.com>

Applications Area Director(s):

Keith Moore <moore@cs.utk.edu>
Patrik Faltstrom <paf@swip.net>

Applications Area Advisor:

Keith Moore <moore@cs.utk.edu>


A. Mutz <andy_mutz@hp.com>
G. Klyne <GK@ACM.ORG>

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Description of Working Group:

A number of Internet application protocols need to indicate recipient capabilities, characteristics, and preferences when the resources they handle can vary in form. This working group will finalize registration procedures for distinguishing attributes which cause the media delivered to vary in form. The registration of these "media features" will provide a supplement to the MIME registration of media types and enable the development of a cross-protocol vocabulary for exchanging information on recipient capabilities, characteristics, and preferences. Since these distinguishing attributes commonly occur in related sets, this working group will also describe at least one method for referring to composite media feature sets. Experimental methods for using these features and feature sets within specific protocol contexts may be developed within this group or within the groups standardizing the relevant protocols.

The working group is aware of applications which desire to negotiate what content is delivered as well as the form in which it is delivered. As much as possible, the group will endeavor to create a framework for exchange sturdy enough to handle the later addition of this type of negotiation. It will not, however, address this need directly nor will it limit its design choices based on the possible later addition of this negotiation.

Goals and Milestones:

Feb 98


Submission of registration procedure draft as BCP

Feb 98


First draft of Requirements and frameworks document.

Feb 98


Submission of feature scenarios draft as Informational RFC

Mar 98


Revised draft of Requirements and frameworks document.

Mar 98


First draft of composite feature set draft.

May 98


Requirements and frameworks document to Information RFC

May 98


Revised feature set draft

Jul 98


Feature set draft to Informational RFC

Aug 98


Working Group Closes


No Request For Comments

Current Meeting Report

Minutes, CONNEG Working Group
Dec 13, 1998
Ted Hardie, Chair
Reported by April Marine

The chair first clarified the focus of the group for first time attendees, highlighting its mission to create a registry for elements of exchange and a syntax for senders and recipients to use in identifying the intersection of capabilities and available features.

Graham Klyne reviewed the current syntax docs. Recent issues on the mailing list have focused on q-values and set notation; those and editorial changes were considered and the room approved of the proposed changes. These will be folded into a final draft and that draft will be last called on the mailing list.

During the course of discussion, two architectural principles for registered features emerged. The first principle is that the semantics of a feature should not depend on the value of any other feature. For example, if you have a feature "cloth" which can be equal to "cotton", "wool", or "blend" and second feature "washtemp" which can be equal to "hot", "cold", or "warm", the values of "hot" should not change in a washing context depending on the cloth chosen. The related architectural principle is that absolutely determined features make it easier to reuse the same terms independently; "washtemp", in other words, should be the temperature in degrees celsius, not tokens like "hot", "warm", and "cold".

The group briefly considered the CCPP crosswalk draft and noted that the primary difference between the frameworks is that the CCPP draft presumes an aggregated feature set based on device; the CONNEG framework presumes that feature sets get built out of individual feature collections at the time of exchange. The two groups have agreed to use the same uri syntax for uri-based features; the CCPP may eventual use registered feature sets, when they have been fully specified.

Larry Masinter presented a possible resolution to the color issue in the media-features draft; he will issue a new draft, which will be last called on the list. The group recognizes that this document is not meant to be comprehensive, but merely a basic set of useful media features; the color model and other aspects here are, therefore necessarily limited.

The group heard a presentation from Lloyd McIntyre and Graham Klyne on the FAX feature document; this is being considered in the FAX working group and those interested in that arena should follow the document there.

Some final questions on IANA considerations were discussed and Larry Masinter identified as an Area Expert for the IANA to consult in the area of feature collections.

Further work on feature set aggregation is needed; Chris Burke has tenatively volunteered to edit that draft. 2/28/99 set as a potential date for that work.


None received.