draft-klensin-idnabis-protocol-04 section 4.5

Simon Josefsson simon at josefsson.org
Thu Mar 27 13:25:48 CET 2008

Harald Tveit Alvestrand <harald at alvestrand.no> writes:

> --On Thursday, March 27, 2008 10:55:04 +0100 Simon Josefsson
> <simon at josefsson.org> wrote:
>> This section reads:
>>    The resulting U-label is converted to an A-label (i.e., the encoding
>>    of that label according to the Punycode algorithm [RFC3492] with the
>>    prefix included, i.e., the "xn--..." form).
>> That assumes that no U-label will be translated into a LDH-label.
>> In IDNA2003 some U-labels are translated to LDH-labels, for example:
>> ToASCII(josefßon) = josefsson
>> ToASCII(dªtªkonsult) = datakonsult
>> Note absence of xn-- prefix and punycode data.
>> Is the intention that these strings will not map to the same LDH label
>> in IDNA200x?
> As long as we keep the "no mapping" principle, the intention is that
> these strings will be rejected by IDNA200x.

Rejected at registration?  Or rejected during lookup?

What I'm trying to understand is what an IDNA200x implementation will do
(i.e., which output string or what error) when the user types 'josefßon'
or 'dªtªkonsult'.


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