multiple URI elements per Service in XRDs

Peter Davis peter.davis at
Thu Jan 19 17:40:50 UTC 2006

On 1/18/2006 7:35 PM, "Johannes Ernst" < at>

> This question is really for the XRI guys whose XRD/S format/subset we
> are using for YADIS. Fortunately, some of you (you know who you are!)
> do seem to monitor this list ...

Yeah we do ;-)

> The question is: is it really necessary to allow multiple URI
> elements within the same XRD element?

Assuming s/XRD/Service/g:

There are many motivations for supporting multiple URIs for a service:
- convey multiple URI encodings (eg URI vs IRI).  Esp in the near term, some
applications will not be able operate on IRIs

- convey multiple URI schemes, eg FTP HTTP HTTPS URN MAILTO GOPHER (heh,
yeah there are still gopher servers out there!!) etc etc...  This is perhaps
the most important motivation, IMHO

- load distribution, etc...

It's likely, at least for YADIS, you'll have at least 2 (HTTP and HTTPS)

And FWIW, the processing rules over the selection are rather arduous, but
the TC choose to be fairly explicit to avoid interop issues.

=peterd  (

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