Re: URN: vs alternatives

Keith Moore (moore@cs.utk.edu)
Sun, 26 Nov 1995 11:35:06 -0500


Message-Id: <199511261635.LAA10659@wilma.cs.utk.edu>
From: Keith Moore <moore@cs.utk.edu>
To: Jon Knight <J.P.Knight@lut.ac.uk>
Cc: Keith Moore <moore@cs.utk.edu>, Daniel LaLiberte <liberte@ncsa.uiuc.edu>,
Subject: Re: URN: vs alternatives 
In-Reply-To: Your message of "Sun, 26 Nov 1995 13:11:51 GMT."
             <Pine.SUN.3.91.951126130224.6883F-100000@weeble.lut.ac.uk> 
Date: Sun, 26 Nov 1995 11:35:06 -0500

> In a parallel discussion going on over in the IETF mailing list at the 
> moment, Paul Vixie and other DNS gurus have pointed out that the DNS is 
> not a true directory service.  I think this is something that the URN design 
> should bear in mind.  I can see two scenarios here:
> 
> 1) You have a URN given to which you want to resolve to a single URC.  
> This is just like the DNS FQDN -> IP address mapping and so DNS may be 
> appropriate.

Yes, this is the scenario for which I would use DNS.

> 2) You want to know what URN for a certain document written by a
> particular person that has been registered by a particular organisation. 
> Now you could start guessing the DNS-like elements in the URN and in the
> early days when the namespace is small this will probably work most of the
> time.  

If you're assigning URNs and you want them to be persistent over several 
decades, you don't organize your URNs as a hierarchy of human-meaningful 
elements.  So DNS wouldn't even work in the short term for this case.

Even a directory may not make an effective resource discovery tool
for many subject areas.   Effective resource discovery often requires
tools which are tuned to a particular discipline or subject domain.

It might turn out that the most important function that URNs provide 
is to serve as a substrate for good resource discovery tools.

Keith