URN support

Are URNs the best way to describe software collections ?

x-tracker Namespace identifier or FTP Mirror Tracker Unique Identifier
F.e. ftp://ftp.xfree86.org/pub/XFree86/4.0/ 

  urn:x-tracker:57ce083433061aab97c9c2b63759ef2f
will lead to the following results 
 netserv2.chg.ru/pub/XFree86/4.0/
 ftp.radio-msu.net/.2/ftp.xfree86.org/pub/XFree86/4.0/

 caramba.cs.tu-berlin.de/pub/X/XFree86/4.0/
 knecht.mpi-sb.mpg.de/pub/X/mirror/ftp.xfree86.org/XFree86/4.0/

 wizard.freesoftware.com/.0/XFree86/4.0/
 ftp.linux.tucows.com/pub/XFree86/4.0/
Unique, location independent but not time persistent. (Is the content of the software collection time persistent ?)
Copyright © 2000, Martin Hamilton and Alexei Novikov. All rights reserved. This is free slideware, you can redistribute it under the terms of the GNU General Public License, version 2 or later.