RE: XML message format draft

[Graham Klyne <GK@xxxxxxxxxxxxxx>]

At 12:33 PM 2/7/03 +0000, Jon Hanna wrote:

> > My own preference for a urn: form here is a reflection that this
> > specification is intended to closely reflect some IETF
> > specifications, and
> > the URIs used should be within IETF/IANA change-control.  At the present
> > time, as far as I am aware, IETF/IANA are not signed up to the "cool URIs
> > don't change" [3] commitment needed for http: URIs to be sufficiently
> > stable.  Further, I wish to leverage the message header registry proposal
> > [4] that I believe is on its way to being a BCP.
>
> URIs themselves are defined by IETF RFCs. Since the use of URIs as namespace
> names is as opaque identifiers they are immutable for that purpose whatever
> form they take.

I think there's an additional requirement... that the URIs be traceably 
related to the corresponding IETF specifications (e.g. RFC2822, 
etc.).   Currently, I feel that's easier to achieve with urn: forms, by way 
of the IANA registry for URN namespaces.

> Documents obtainable by dereferencing URIs should not be essential to the
> operation of the namespace, as useful as they may be. Hence there is not a
> absolute requirement that the URIs be cool in anyway other than they don't
> change as opaque identifiers. While a change to whether or not the URI can
> be dereferenced may be an inconvenience, it wouldn't break the format
> itself. Hence I don't think that is a reason for avoiding HTTP URLs.

I agree fully with the first sentence, and partly with the rest.  But if 
the URI isn't clearly bound to the specification element it identifies, 
there's a possibility (maybe very remote) that it will end up being used to 
reference a document with completely different purpose.  I think that is a 
potent reason to avoid "uncool" URIs.  Therefore, I see three goals if http 
URIs are to be used for IETF header field identifiers:

(a) the administrator of the domain concerned MUST approve use of the URIs 
concerned for this purpose.

(b) the administrator of the domain concerned MUST be committed to 
maintaining the URIs stable.

(c) the domain used SHOULD be under IETF/IANA administrative control.

#g


-------------------
Graham Klyne
<GK@xxxxxxxxxxxxxx>