Re: URNs: syntax and registries

William Y. Arms (warms@CNRI.Reston.VA.US)
Tue, 28 Nov 1995 09:17:10 -0500


Message-Id: <v02130500ace0c7df2760@[132.151.1.217]>
Date: Tue, 28 Nov 1995 09:17:10 -0500
To: Jim Conklin <conklin@info.cren.net>
From: "William Y. Arms" <warms@CNRI.Reston.VA.US>
Subject: Re: URNs: syntax and registries
Cc: uri@bunyip.com

At 4:35 PM 11/27/95, Jim Conklin wrote:
>Bill,
>  I find your proposal to be very appealing, but I have a concern:  The
>idea of explicitly naming a Naming Authority, which you've eliminated in
>favor of explicitly naming a Naming Scheme.  Now, the Naming Scheme may
>correspond closely to the Naming Authority, but I believe that it might
>also encompass multiple naming authorities.
>  In the latter case, is it not necessary for the r-name to specify the
>Naming Authority in order to ensure that the r-name is unique?
>
>Jim

Jim,

We are in agreement here.  The naming-scheme has an obligation to ensure
that names are unique.  In all the principal URN proposals, this is
delegated to naming authorities and the format of <r-name> is of the form:

  <r-name> := <naming-authority><separator><locally-unique-string>

My reasons for not spelling this out in the posting were:

(a)  To allow for the inclusion of naming schems where there is only one
naming authority (e.g., social security numbers), or where the naming
authority is buried in the name (e.g., ISBNs).  Thus, the following might
be a valid URN.

  URN:SSN:012-34-5678

(b) In the hope that it will be possible to for naming-schemes to select
their own separators.


Bill