fully-qualified domain names containing differently-encoded labels ?

[=JeffH]

AFAIK, this is a true statement:

   a fully-qualified domain name (FQDN) is comprised of individual labels,
   each of which can potentially be allocated via a different registrar,
   and that some registrars/registries may or may not be supporting IDNs,
   and if they are, they may support IDNA2003 or IDNA2008.

Yes?

Thus, it seems we may encounter domain names comprised of a mixture of label 
types (beyond just the obvious two-level mixture of 
"<IDNA-label>.<NR-LDH-TLD-label>" where TLD == "top level domain"), e.g...

   <IDNA2008 A-label>.<IDNA2003 Punycode-encoded label>.TLD

..or possibly even..

   <IDNA2003 Punycode-encoded label>.<NR-LDH>.<IDNA2008 A-label>.<U-label TLD>

..and obvious ad-infinitum variations thereof.


Though this (obviously common) case (that I have various in-the-wild samples of)..

   <NR-LDH label>.<IDNA2003 Punycode-encoded label OR IDNA2008 A-label>.TLD

..eg..

   www.xn--xample-9ua.org   (registered by Paul Hoffman :)


..would seem to be arguably the most common case, at least for a while.


But in any case, it would seem that any specification of conversion operations 
on a multi-label domain name, that takes into account IDNA{2003,2008}, needs to 
properly allow for and accomodate label-by-label type diversity, yes?

thanks,

=JeffH