# Re: Why URN is a subset of URL

JC Touvet (Jean-Christophe.Touvet@inria.fr)
Thu, 06 Oct 1994 12:28:28 +0100

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    Message-Id: <199410061128.MAA09958@champagne.inria.fr>

    To: uri@bunyip.com

    Subject: Re: Why URN is a subset of URL

    In-Reply-To: <Pine.3.05.9410060850.A8508-b100000@suna>

    Date: Thu, 06 Oct 1994 12:28:28 +0100

    From: JC Touvet <Jean-Christophe.Touvet@inria.fr>

> Hmm, I'm not so sure. I think that the fact that URLs and URNs may have
> similar syntax _is_ an implementation detail, but the semantics are
> _defined_ to be different and its the semantics that are really the
> important thing (I think its also what Peter was probably getting at).
> URLs are resource _locators_; URNs are _location_ independent names. How
> something which is location independent can be a member of a subset of a
> set of locators is a little beyond me at the moment.

Well, I think this debate will never end. A name is always an address for the
next level of abstraction. For example, we could say that a URL is a name,
since location is resolved by DNS. You can change the IP address of your
host, the URL will still be valid. The same for IP addresses vs Ethernet
addresses etc...

I think that what Roy states is just that a URN is a URL to a service which
gives you URLs. If we have a URN resolution service (let's call it SURP, as
Simple URN Resolution Protocol), we could say that:

urn:object

is equivalent to:

surp://my.prefered.resolver/object

That's exactly the way we have implemented a prototype URN resolution using
User-Friendly Naming (just replace SURP with SOLO ;-)

For those who don't know it yet, all pointers and software (including urn:,
solo: and x500: aware versions of lynx and Mosaic) can be found at:

http://champagne.inria.fr/

Cheers,

-JCT-

solo:touvet,inria,fr?*
x500:touvet,inria,fr?*
solo://champagne.inria.fr:2222/touvet?*
or, with slow gatewaying
http://champagne.inria.fr:8889/%3Ctouvet,inria,fr%3E?*

Relevant paper:

urn:solo-www paper,inria,fr
solo:solo-www paper,inria,fr!URL
x500:solo-www paper,inria,fr!URL
solo://champagne.inria.fr:2222/solo-www paper!URL
or, with slow gatewaying
http://champagne.inria.fr:8889/%3Csolo-www%20paper,inria,fr%3E!URL

- Next message: Peter Deutsch: "Re: Why URN is a subset of URL"
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- Reply: Michael Mealling: "Re: Why URN is a subset of URL"