Re: [idn] Adding "optional" characters in draft-ietf-idn-nameprep

[Patrik Fältström <paf@cisco.com>]

At 09.53 +0800 00-08-14, James Seng wrote:
>No, I dont believe UTR15 handles what we are discussing here. Please
>read UTR15 and come back to read this thread again.

If TR#15 doesn't then we have 2 options:

- Ask the Unicode people to please resolve this issue aswell, and we 
will only use whatever TR#15 talks about. This means that optional 
characters in Hebrew will be significant in DNS names -- as they are 
according to Unicode specifications.

- Do our own extension to TR#15 for Hebrew and other scripts which 
"are missing" from TR#15.

I see that we will need one and only one algorithm for doing 
"nameprep" and it should definitely build on what the Unicode 
Consortium has done.

What we need to build is a definition for "hostname" (bad word, but 
anyway) using Unicode characters. Other protocols (LDAP for example) 
might have the need for other definitions of "allowed strings". This 
includes two things:

- Characters which are to be translitterated to other characters, 
i.e. they are forbidden in a canonical domainname, but we tell how to 
map to other characters (1-N mapping)

- Characters which are forbidden

I hope that the first can be the same for Unicode strings in Internet 
protocols, while the second is specific for each protocol.

Note that the transformation in the first rule might _introduce_ a 
character which is forbidden according to second rule.

   paf