Re: [apps-discuss] seeking pragmatic guidelines for content-type 'structure': when to go top-level?
"t.petch" <ietfc@btconnect.com> Thu, 10 November 2011 10:34 UTC
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From: "t.petch" <ietfc@btconnect.com>
To: dcrocker@bbiw.net, Apps Discuss <apps-discuss@ietf.org>
References: <4EBB3CFC.5050608@dcrocker.net> <4EBB5310.6080103@it.aoyama.ac.jp><CAC4RtVBNL_nTCwBsMQpEKS9kXUF7aj9yEstef7yrzwi8qYAQDg@mail.gmail.com> <4EBB7660.6040904@dcrocker.net>
Date: Thu, 10 Nov 2011 10:28:49 +0100
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Subject: Re: [apps-discuss] seeking pragmatic guidelines for content-type 'structure': when to go top-level?
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----- Original Message ----- From: "Dave CROCKER" <dhc@dcrocker.net> To: "Apps Discuss" <apps-discuss@ietf.org> Sent: Thursday, November 10, 2011 7:59 AM > Folks, > > On 11/10/2011 2:02 PM, Barry Leiba wrote: > >> But the fact is that we have a major/minor type system. We can as well make > >> reasonable use of it. > > > > As I said in the other thread (on font/*), we already have the concept > > of saying "This is text," "This is an image," and "This is audio," and > > I see only negative points in insisting that everything other than the > > few TLMTs that we're already defined have to be "application". We > > should do some filtering and apply some judgment, of course, but > > making everything the equivalent to "application/image-jpeg" is silly > > and non-useful. > > That states a basic direction/goal: To have a lower hurdle than perhaps was > there before. > > Does it have any basic downsides? > > My sense from the latest round of postings, including Ned's, is that there is no > current reason to impose a high hurdle on TLCTs. > > Consensus check > =============== > > Is there anyone out there who believes that it is extremely expensive or > dangerous to introduce new, top-level Content-Type and that, therefore, the > barrier to new TLCTs should be (kept) high? Yes. Based on FUD rather than concrete information, but what will all the deployed software do when face with a new top-level Content-Type? And how long will it take for the makers of commercial software to incorporate this in their products (1-2years) and how long will it take for that software to be widely deployed(3-5 years)? I just received an (antisocial) e-mail with .gif's attached, so I edited the Content-Type to be font/various things, and my MUA took no notice, just processed them as .gif. I modified the Content-Description in the same way, same result. Only when I modified the filename (eg to .ttf) did the MUA take any notice and complain that the attachment was not a font, pdf etc. I think we need to know this for commonly deployed platforms before we can say it is not dangerous. Tom Petch > > Assuming the answer and the consensus is no, that still leaves open what > pragmatic guidance is to be used for accepting or rejecting a request for a > TLCT. (We could take the ICANN approach and just filter based on huge gobs of > money, but I doubt that model will transfer to the IETF.) > > So far, the most cogent guidance I've seen seems to be related to the > justification in the model spec (RFC 2077): > > "The important fact is that these > various subtypes can be converted between each other with less loss > of information then to that of other primary types. This fact groups > these subtypes together into the model primary type. All of the > expected subtypes have several features in common and that are unique > to this primary type." > > I had suggested a guideline in terms of "dispatching" to different applications. > Ned's note offered a better framing, in terms of common code among a set of > content sub-types. A particular form of such code, implied by the model > document, is for translating among sub-types. > > Martin pointed out an "administrative" issue quite different from the basic > registration scaling or decentralization I cited, namely the search for related > types by an implementer, where separate sub-tables would be helpful. He noted: > > http://www.iana.org/assignments/media-types/image/index.html > > as a good example. > > > Consensus Check > =============== > > So, I think this leaves guidance in favor of a new top-level content-type > if one or more of the following apply: > > 1. Strong semantic relationship among the sub-types > > 2. Likelihood of some common code for the set of sub-types > > 3. Expectation that implementors will benefit from easily discovering the > current set of sub-types in the registry. > > Does this summarize the guidance that should be offered for justifying a new TLCT? > > d/ > -- > > Dave Crocker > Brandenburg InternetWorking > bbiw.net
- [apps-discuss] seeking pragmatic guidelines for c… Dave CROCKER
- Re: [apps-discuss] seeking pragmatic guidelines f… Martin J. Dürst
- Re: [apps-discuss] seeking pragmatic guidelines f… Barry Leiba
- Re: [apps-discuss] seeking pragmatic guidelines f… Dave CROCKER
- Re: [apps-discuss] seeking pragmatic guidelines f… Barry Leiba
- Re: [apps-discuss] seeking pragmatic guidelines f… t.petch
- Re: [apps-discuss] seeking pragmatic guidelines f… Ned Freed
- Re: [apps-discuss] seeking pragmatic guidelines f… Martin J. Dürst
- Re: [apps-discuss] seeking pragmatic guidelines f… Martin J. Dürst
- Re: [apps-discuss] seeking pragmatic guidelines f… Frank Ellermann
- Re: [apps-discuss] seeking pragmatic guidelines f… t.petch
- Re: [apps-discuss] seeking pragmatic guidelines f… Nathaniel Borenstein
- Re: [apps-discuss] seeking pragmatic guidelines f… Ned Freed
- Re: [apps-discuss] seeking pragmatic guidelines f… t.petch
- Re: [apps-discuss] seeking pragmatic guidelines f… Nico Williams
- Re: [apps-discuss] seeking pragmatic guidelines f… Larry Masinter