Re: The UR* scheme registry, Citing URL/URI specs

Leslie Daigle (leslie@Bunyip.Com)
Mon, 27 Oct 1997 14:33:39 -0500 (EST)


Date: Mon, 27 Oct 1997 14:33:39 -0500 (EST)
From: Leslie Daigle <leslie@Bunyip.Com>
To: Dan Connolly <connolly@w3.org>
cc: urn-ietf@bunyip.com, timbl@w3.org, fielding@ics.uci.edu,
Subject: Re: The UR* scheme registry, Citing URL/URI specs
In-Reply-To: <34512536.6FB1@w3.org>
Message-ID: <Pine.SUN.3.95.971027142228.5738I-100000@beethoven.bunyip.com>


[At this point, many other people have replied to several points in this
message, so rather than just adding "me too" to what has been said adequately,
I'll only address points that still seem to be outstanding.  Dan, if
you still want more detail on things I leave out, please let me know. -- LLD]

On Fri, 24 Oct 1997, Dan Connolly wrote:
> Short version:
> 
> Leslie Daigle wrote:
> > >      Syntax draft says "URIs are covered by other specs".
> > >      What other specs?
> > 
> > RFC2141
> 
> Hmmm.... checking...
> The term URI does not occur in RFC2141.
> So that's no help.

Well, I responded to the larger excerpt from the "syntax" draft (which
I assume is draft-fielding-url-syntax-09.txt) which says:

   "The syntax and semantics of other
    URIs are defined by a separate set of specifications, although
    it is expected that any URI notation would have a compatible syntax."

RFC2141 is an appropriate reply to _this_ quote, as it says that _other_
URI specs are defined elsewhere.  I had misunderstood that you had
read it to mean that _URI_ syntax was covered elsewhere.

By the way -- note that this is the 

	"Uniform Resource Locators (URL): Generic Syntax and Semantics"

draft, and it's the "and semantics" parts that concerns me particularly
when talking about sweeping URN syntax into this and calling it the URI
syntax document.

> > > don't reflect that. The IANA registry[1] claims to be
> > > a URL scheme registry, rather than a URI scheme
> > > registry. So I wonder... is it expected that urn: will
> > > appear in that registry?
> > 
> > Not necessarily.
> 
> Can I please have a clear "yes" or "no" from your
> own personal perspective? Do you expect it to
> go in that list or not?

Well, there are 2 separate questions on the table:

	1.  Does "URN:" appear in this registry as one UR{I|L} scheme?

	2.  Do URN namespaces (i.e., that part that appears after the URN:
	    e.g., urn:ietf:<blah>) get registered in that registry.  You
	    suggest not; Larry later suggested he thought they ought.

If the IANA registry is truly to be the URI registry, and an informed
discussion (i.e., by people who know about that registry AND the current
state of URNs) shows this will not restrict the usage of URNs, then sure,
the answer to #1 is yes, urn: can/should appear there (and a ghost of myself 
from a couple of years ago just passed out in shock that I said that ;-)

#2 is a definite "no"; URN namespaces are _not_ just like URL schemes.  THey
have implications of ownership, maintaingin registries and validation
services, and a whole set of requirements centred on uniqueness, etc.  I'm
sorry to be so vague here -- this is exactly the part that the URN WG
is trying to nail down now (and if I could be less vague, I'd be halfway
to having the I-D written :-)

> But I haven't run into one that told me how they're
> currently using them (except for PURLs, which use the http:
> scheme,  [...]

They exist -- if you need specific pointers, I can send them to you
out-of-band.

Leslie.

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