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

Michael Mealling (
Sun, 26 Oct 1997 15:53:10 -0500 (EST)

From: Michael Mealling <>
Message-Id: <>
Subject: Re: The UR* scheme registry, Citing URL/URI specs
In-Reply-To: <> from Keith Moore at "Oct 26, 97 02:17:13 pm"
To: (Keith Moore)
Date: Sun, 26 Oct 1997 15:53:10 -0500 (EST)

Keith Moore said this:
> > As it stands, I'd just as soon see URN schemes in the same
> > registry as URL schemes (no conflicts allowed), and just annoted
> > as to whether the scheme implies URN-ness. 
> This much would be reasonable, if only to avoid confusion.
> > I'd also like to
> > see "urn:" turned into a more universal URL prefix, e.g., 
> > allow "urn:" as a means of indicating
> > "I intend this usage of to be treated
> > as a permanent name rather than as just the current location".
> This is a rathole.  Let's not go there.

But do-able by simply registering the 'http' namespace as a URN
namespace. Now whether or not the URN namespace registration process
lets you do that is another question we're currently trying to answer. ;-)

> So, back to the question of what to call the resource identifiers 
> that appear in HTTP.  I'd say there are two choices:
> 1. Say: these may be either URNs or URLs.  Cite appropriate documents
> for each category.
> 2. Say: these are URIs, where URIs can be URNs or URLs, and other
> kinds of URIs as might be defined later by IETF or W3C.  Cite 
> appropriate documents for URNs and URLs.
> Either one seems easy to me.  Or did I miss something?

My opinion is to go for #2. The problem with it, as Larry pointed out,
is whether the syntax documents specify a global URI syntax framework
or simply one for URLs and/or URNs. If they specify a syntax framework
for all URIs then we end up limiting future work in other areas. It's
still to be determined if that limitation is a good thing or a bad thing.

I'll throw out a fairly concrete hypothetical that the IRTF IIIA group
has partially identified as an important area of work: User Friendly Names.
There are already informal URLs used that qualify as a UFN. Netscape
uses the "keyword:" scheme to handle their version of a UFN. If someone
were to attempt to identify a class of identifiers that qualified as
User Friendly Names, would they be URIs or not? If they are URIs then are
they limited by the current URL(I?) syntax frameworks?

My suggestion is that the URL syntax framework applies to those things
that call themselves URLs. The URN syntax framework applies to those
things that call themselves URNs. URIs don't have a syntax framework
because its more of a much larger framework that merely has a set of
identified principles for what makes a good identifier.

How would that last paragraph sit with the W3C?


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