Re: U-labels and draft-obispo-epp-idn-00

I agree that _technically_ both A-label and U-label are not required. However by requiring both U-label and A-label a registry can guarantee that the registrar knew the corresponding U-label prior to registration. Registrars may choose to generate the U-label from the A-label (that they somehow derived), however it is also their choice to send a create command to the registry where the U-label is not what the registrar or the registrant expected. In this case the registry has done all it possibly can to ensure that the correct name has been registered. You will find that a few ccTLDs will have this hat on.

As an example, consider the U-label of U+03C2 (final sigma) which has a corresponding A-label of xn--3xa. Using IDNA 2003 based processing however the derived ACE-label for U+03C2 is xn--4xa, which is a valid A-label, however for the U-label U+03C3 (non-final sigma). A registrar can send the registry one of these A-labels, and the registry can programmatically determine the corresponding U-label, however is this the same U-label that the registrar was expecting to register?

James

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On
> Behalf Of Patrik Fältström
> Sent: Wednesday, 15 February 2012 2:41 PM
> To: Jay Daley
> Cc: [email protected]
> Subject: Re: [provreg] U-labels and draft-obispo-epp-idn-00
> 
> 
> On 15 feb 2012, at 04:19, Jay Daley wrote:
> 
> > On 15/02/2012, at 4:09 PM, Patrik Fältström wrote:
> >
> >>> I agree that this might come in handy in many cases
> >>
> >> Mention one.
> >
> > In .nz we expect both the U and A labels and that the A label is
> correctly derived from the U.  The reasoning for this is that
> registrants are not in their minds registering the A label, they are
> registering the U label and we want to guard against a processing error
> that would not provide what the registrant wants.  With only an A label
> we can't trap this.
> 
> And you have factual errors where a U-label and an A-label does not
> match? You do not talk about cases where they believe they can register
> some unicode string that is not a U-label?
> 
> Note, the discussion is about U-labels and A-labels, not unicode
> strings and A-labels.
> 
>    Patrik
> 
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