Re: Persistent Documents and Locations

Karen R. Sollins (sollins@lcs.mit.edu)
Mon, 21 Aug 1995 19:21:20 -0400


Date: Mon, 21 Aug 1995 19:21:20 -0400
Message-Id: <199508212321.TAA10110@lysithea.lcs.mit.edu>
From: "Karen R. Sollins" <sollins@lcs.mit.edu>
To: lazear@dockside.mitre.org
Cc: uri@bunyip.com, lazear@dockside.mitre.org
In-Reply-To: <9508211941.AA21609@dockside.mitre.org> (lazear@dockside.mitre.org)
Subject: Re: Persistent Documents and Locations

   From: lazear@dockside.mitre.org
   Cc: uri@bunyip.com, lazear@dockside.mitre.org
   Date: Mon, 21 Aug 95 15:41:41 -0400

...

   One problem:  who validates URNs, since they are the 
   longest-lived element in the UR* universe?  Like DNS,
   one can find out that a URN is no longer valid.  The issue
   then is to find out a source from which one can get the new
   form of the URN or an alternate URN or confirmation that the
   URN doesn't exist at all anymore.  This is usually an offline
   task (like calling a friend to learn what the real domain
   name is).

	   Walt

Well, no, I think you've misunderstood RFC 1737.  The intention for
URNs is that they are valid in perpetuity.  If the object is still
around, in 10 yrs, then the URN for it is still "valid".  I can't go
into a long diatribe now, but there is a great deal behind the choice
of making URNs global and long-lived.  But, suffice it to say that
URNs don't expire or become invalid.   The resources they name may be
deleted, but the URN should never be re-used or reassigned.  For each
URN the assigment of it happens no more than once, ever.

			Karen