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

Dan Connolly (
Fri, 24 Oct 1997 17:46:14 -0500

Message-ID: <>
Date: Fri, 24 Oct 1997 17:46:14 -0500
From: Dan Connolly <>
To: Leslie Daigle <>
Subject: Re: The UR* scheme registry, Citing URL/URI specs

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.


> I think you can address some of your concerns/questions with a visit
> to the IETF's URN working group homepage:

Thanks for the reminder... I looked there in April[1],
but not since


> One specific document you don't seem to have been aware of is the URN syntax
> standards-track RFC (RFC2141).

I'm aware of it (I read some of the earlier drafts.) It specifies
a syntax where all the strings start with urn: . I got
the impression urn: would go in the list along with http:
and ftp: and all the rest in places like the IANA registry,
the Java APIs, the Address/Location field in browsers etc.

Not so?

> I won't speak directly to the issue of whether or not the W3C documents
> should refer to URIs or URLs,

I wish you would.

> but there are some specific issues about
> URNs that you brought up that I would like to address.
> On Thu, 23 Oct 1997, Dan Connolly wrote:
> > 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?

>  URNs as they are currently being discussed will have
> need for scheme registration procedures that are different than those of
> URLs -- specifically because URNs aim to (attempt to) provide uniqueness
> and longevity, and also incur some overhead in maintaining registries.
> This is a very key issue, brought up at the Munich URN meeting, and
> hopefully we'll have concrete proposals on the table by Washington.

I'm not talking about the identifers that follow "urn:"
in URNs, but just the one identifier "urn:" itself.

> > And the terms URN and URI either invoke warm fuzzies, cold
> > pricklies, or blank stares, but no hands-on understanding.
> By the way, I think this depends on who you talk to.  Various people
> in publishing and national libraries around the world are clamouring
> for URNs.

Right: the term URN invokes warm fuzzies from those folks.

But I haven't run into one that told me how they're
currently using them (except for PURLs, which use the http:
scheme, and some folks using hdl: . Will hdl: go in the
existin IANA registry?).

> >      Does the process draft cover all URIs or just some?
> >      ("URLs" as of Aug 97) (See Roy's page for latest
> >      process/syntax draft)
> URLs only.
> It has been developed for URLs, and independently of the needs of URNs,
> so if it wants to become the URI process draft, further discussion is
> needed.

I'm game for that. (but I realized a few minutes ago that
I might be on the wrong list. Should I be on

> >      Does the syntax draft cover all URIs or just some? (
> >      "URLs" as of Aug 97)
> URLs.  URNs are discussed in RFC2141.  The syntaxes are intended to be
> compatible.

I keep hearing that, but I look at the standards-track documents,
and I don't see it in black-and-white.

Can I please have an IETF standards-track 
document that specifies
the union of the URL and URN syntaxes?

Larry writes:
>I think that's a good summary of the situation. HTML and XML
>can say they use URIs, and then point to a W3C note that
>says "A URI is defined by IETF, currently it points to URLs,
>and there is some work on URNs".

I'll do that if I have to. But I don't want to.

Back to Leslie...
> >      Syntax draft says "URIs are covered by other specs".
> >      What other specs?
> RFC2141

The term URI does not occur in RFC2141.

> >       spec about URLs, URIs, and URNs, and we
> >       cite RFC1738 and RFC1808 normatively,
> >       and RFC1630 informatively.
> Throw in RFC2141.

Hmm... that's a possibility. I don't really see how
it helps. I still have to define a term for the
union of the RFC2141 syntax and the RFC1808-as-revised

> > I request clear guidance on whether
> >       (1) we can expect the IANA registry to become
> >       known as a URI registry, with the corresponding
> >       change in the syntax and process documents.
> I don't think this is appropriate, as these documents are truly URL
> documents, and haven't been developed in conjunction with the URN
> material.

Can you provide some evidence why it's not appropriate?

> Whether or not there should eventually _be_ umbrella documents is
> a separate question.

I need them. Yesterday.

> >       (2) we can expect the IANA registry to continue
> >       to be known as a URL registry, in which case I
> >       request that the term URI be declared historical
> >       in the syntax/process drafts,
> >       and that any mention of URN set an expectation
> >       that the urn scheme (or schemes) will go in
> >       the URL registry.
> I don't think it would be appropriate to declare this at this time; the
> URN work is real,

I don't dispute that.

> and it has different needs than the URL registry/process.

Would you please be more specific?

> As I said -- check out the URN WG page and the associated RFCs.  We
> are working on sorting out what _should_ be appropriate registration
> processes for URN namespaces (analoguous to but different than URL schemes)
> as that is one outstanding issue that stops URNs from going live.
> Leslie.
> IETF URN WG Co-Chair

Dan Connolly, W3C Architecture Domain Lead