"SRV-Style" labels and "IDN"

[Mark Andrews]

In message <49D4A23B.2060205 at alvestrand.no>, Harald Alvestrand writes:
> Mark Andrews wrote:
> > In message <8BC845943058D844ABFC73D2220D4665081E4704 at nics-mail.sbg.nic.at>,
>  "Al
> > exander Mayrhofer" writes:
> >   
> >> Hi,
> >>
> >> I'm currently reading through the idnabis-Documents, and didn't find a
> >> clear answer to the following issue:
> >>
> >> 2.3.2.3 of draft-ietf-idnabis-defs-08 defines an IDN as "name that may
> >> contain any mixture of NR-LDH-labels, A-labels, or U-labels".  From what
> >> i read, that means that an IDN may not contain a "SRV-style" label,
> >> starting with an underscore. A few lines later, it is clarified that
> >> such a label is not an "Internationalized Label". There's no text about
> >> those labels in the definition of "IDN". Therefore, from the definition,
> >> the following example:
> >>
> >>    _sip._tcp.<A-Label>.<tld>
> >>
> >> Would not be an IDN. My questions now, unless i have missed something:
> >>
> >> - Is my assumption correct that the example is not an IDN?
> >> - If it is not an IDN, what is it? 
> >>     
> >
> > 	This reflects the mis-use of DOMAIN in IDN.  In reality
> > 	IDN's should be named IHN's (International HOST Names).
> > 	LDH is a HOST NAME restriction, not a DOMAIN NAME restriction.
> >
> > 	In general you won't ever enter _sip._tcp.<A-Label>.<tld>
> > 	in a application.  You will enter <A-Label>.<tld> and
> > 	_sip._tcp will be prepended as part of the discovert process.
> >
> > 	_sip._tcp.<A-Label>.<tld> is not a host name the same way
> > 	that _sip._tcp.example.net is not a host name but both are
> > 	legal domain names.
> >
> > 	Mark
> >
> >   
> we lost this fight (for rational use of "host" vs "domain" in the 
> original IDN group back around 2000.

	and it keeps coming back to bite us.
 
> in _sip._tcp.<A-label>.<tld>, it's rational to consider <A-label>.<tld> 
> an IDN. I don't have a name for the assemblage.
> 
>                   Harald
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org