RE: URI for XML schema and namespace

Martin Duerst <> Sat, 05 January 2008 02:08 UTC

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Date: Sat, 05 Jan 2008 11:03:27 +0900
To: Chris Newman <Chris.Newman@Sun.COM>, David Harrington <>, "'Julian Reschke'" <>
From: Martin Duerst <>
Subject: RE: URI for XML schema and namespace
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At 08:46 08/01/05, Chris Newman wrote:
>As Applications Area Director, I'm not aware of anyone ever asking for that.
>I'm holding a discuss position on:
>   draft-narten-iana-considerations-rfc2434bis-08
>because the present text forbids use of IANA URLs and I consider that an unacceptable new restriction for IANA considerations.

Great, thanks. Please hold on firmly to this discuss until things
are fixed.

>Current IETF practice discourages use of IANA URLs in IETF specifications. However, we have one case, RFC 4790, where stable http URLs are provided to registry elements and that was done with IANA's permission.

I wanted to bring up this case, but I'm glad Chris has done it.

>In that case, the registry was created to be useful to both the IETF and the W3C. The stable http URLs make the W3C happier so it was worth doing that way.

Yes indeed. The W3C uses URIs for a lot of things. One reason is that
it helps to avoid registries, or allows decentralized registration,
depending on the way you look at it.

>I would support a similar approach for http XML namespaces if someone spent the time to write up the rules and get IANA's consent.

Great to know. I'd probably be able to help, or can try to make
sure somebody from the W3C can help.

Regards,   Martin.

>Using an http URIs for XML namespaces is a bad idea.  The IETF has deliberately kept the registry function for our standards separate and I consider that a feature.  Also, is operated by the Secretariat function so using that domain for registrations would require additional (and more expensive) coordination than  It _might_ be feasible to set up a redirect from to for XML namespaces, but I worry that's just one additional level of complexity where things could break (especially if we transition the secretariat function between vendors periodically as we're in the process of doing now).
>To summarize the options:
>1. URNs for XML namespaces -- present IETF common practice
>2. non-IETF http URLs for XML namespaces -- acceptable
>3. http URLs for XML namespaces -- nobody has tried this, seems feasible to me.
>4. http URLs for XML namespaces -- nobody has tried this.  I think it's a bad idea.

#-#-#  Martin J. Du"rst, Assoc. Professor, Aoyama Gakuin University