referencing IDNA2008 (and IDNA2003?)

Vint Cerf vint at
Fri Oct 22 01:22:07 CEST 2010

i am a big fan of the canonical A-label form for all comparison and
processing purposes, converting to U-label format when display is


On Thu, Oct 21, 2010 at 6:21 PM, Andrew Sullivan <ajs at> wrote:
> On Thu, Oct 21, 2010 at 05:45:51PM -0400, John C Klensin wrote:
>>       (2) The application insists that all IDNs, including
>>       especially what is stored in cookies, use A-labels and
>>       then behaves in a fashion that is as ignorant as
>>       possible as far as details & versions of IDNA are concerned.
> I will note that my personal preference is very much this option.  I
> think it would be an excellent idea to suggest that this is the best
> option, because it's the most interoperable (IDNA-ignorant systems
> don't spit up on it, for instance), because it's always possible to
> get the U-label back out, and because it means that you do the
> A/U/A/U-label dance only one time, at the end, when it's time to
> display.  But if people are going to put U-labels anywhere, I agree
> with John that the best advice we can give is "follow the rules".
> A
> --
> Andrew Sullivan
> ajs at
> Shinkuro, Inc.
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