Re: [idn] Re: [idn-nameprep] nameprep back-compatibility

[Patrik Fältström <paf@cisco.com>]

--On 08/02/2001 5:49 PM +0000 Mike Astle <astle@new.net> wrote:

> The silence from the idn-nameprep list is leading me to believe that I
> might be asking a stupid question here, but I'll give it a go nonetheless.
> 
> Please see below...

As myself and Mark came up with section 6, I will respond to this.

> On Mon, 30 Jul 2001, Mike Astle wrote:
> 
>> I agree that the handling of newly assigned codepoints is very sensible
>> and will ease the adoption process.  I'm interested in what happens to
>> "reassigned" codepoints.  To use the language of Section 6 of the draft,
>> what if a character in MN changes mappings between two versions of
>> nameprep?

According to Unicode Consortium, this will not happen. Yes, it happened a
few months ago, but that was a change that was agreed could be made at that
point in time as the tables are not referenced by any standard (yet). The
same decision would be different if IDN/Nameprep was a done deal.

I got this as a response when I as liason from IETF asked this very
question.

>>  That is:
>> 
>> nameprep_version1( X ) = A
>> nameprep_version2( X ) = B
>> 
>> where X is in MN and A and B are in AO.  X remains in MN.
>> 
>> If I'm a client with a resolver that uses nameprep_version1, I expect X
>> to always map to A.  When I upgrade my resolver to nameprep_version2, X
>> now maps to B - possibly leading me to a different IP address than what I
>> intended.
>> 
>> Is this kind of remapping forbidden by the draft or an associated
>> document?

See above, forbidden in the Unicode Consortium.

   paf