Re: URN: vs alternatives

Jon Knight (J.P.Knight@lut.ac.uk)
Sun, 26 Nov 1995 13:11:51 +0000 (GMT)


Date: Sun, 26 Nov 1995 13:11:51 +0000 (GMT)
From: Jon Knight <J.P.Knight@lut.ac.uk>
To: Keith Moore <moore@cs.utk.edu>
Cc: Daniel LaLiberte <liberte@ncsa.uiuc.edu>, fielding@avron.ics.uci.edu,
Subject: Re: URN: vs alternatives
In-Reply-To: <199511260856.DAA10465@wilma.cs.utk.edu>
Message-Id: <Pine.SUN.3.91.951126130224.6883F-100000@weeble.lut.ac.uk>

On Sun, 26 Nov 1995, Keith Moore wrote:
> I'm assuming that as soon as we define URNs we will have multiple 
> registries, because it's clear that there is a lot of feeling both 
> for and against DNS.  (I *wish* we could agree on using a single
> registry for all URNs, but I don't see it happening.)  If we're
> going to be stuck with multiple registries, it's important that
> we be able to register services for any URN in any registry. 

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.

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.  However when the URN namespaces becomes as full as .COM has in the
DNS (which is what is causing all the discussion on the IETF mailing
list), you really need to have a proper searchable directory service like
whois++ sitting there to let you home in on your desired URN(s)

This distinction hadn't really hit me in the face until I read Paul's 
messages in the IETF mailing list earlier today, but now I can see why we 
need _both_ DNS style and whois++/LDAP/SOLO/etc URN resolution.

Jon

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Jon Knight, Researcher, Sysop and General Dogsbody, Department of Computer
Studies, Loughborough University of Technology, Leics., ENGLAND.  LE11 3TU.
* I've found I now dream in Perl.  More worryingly, I enjoy those dreams. *