Subject: RE: [idn] ietf london idn wg meeting minutes

From: Yves Arrouye <[email-masked]>
Date: Sun, 26 Aug 2001 13:14:46 -0700

> I am not sure what you discussed to do in the pre-processing 
> step. The minimum mandatory pre-processing step should be 
> normalisation to Uncode form C.

I am not sure either but there seems to be a need for common rules that
would apply to the whole domain name, and not the hostname/label which is
what IDN works on. A common example is the need to map U+3002 IDEOGRAPHIC
FULL STOP (and others like U+FF0E FULLWIDTH FULL STOP) to U+002E FULL STOP
which is the only label separator.

> In the context of nameprep some talk about canonicalisation. 
> What is a canonical name? In RFC 1035 a CNAME record defines 
> the canonical name for an alias. From this I get that the 
> canonical name is not the same as the form-folded name. A 
> canonical name may include mixed case and other forms not 
> significant in matching.

Pretty sure it's not a CNAME but the end result of Nameprep. Its "canonical"
as reduced to its "canonical form" which is (according to Merriam-Webster)
"the simplest form of something," an internationalized DNS label in our
case.
 
YA

---

From: Dan Oscarsson <[email-masked]>
Date: Tue, 28 Aug 2001 14:15:10 +0200 (MEST)

>> >ACE EVALUATION WITH IDNs ALREADY REGISTERED, Yoshiro Yoneya
>> >
>> >- Most important evaluation criterion to study is to maximize number
>> >   of characters, raw speed is less important because nameprep is the
>> >   slow stage.
>>
>> This is not correct in general. At my site which uses the Latin-1
>subset
>> of UCS, most ACE encodings are a very expensive step compared to
>nameprep.
>
>I am curious about this statement. Do you have any numbers for this?
>
>You see, all datas from other sources, from Verisign, i-DNS.net, JPNIC
>etc who have done Nameprep-ACE/UTF-8 have clearly shown that Nameprep ~=
>10xACE in terms of CPU time.

The nameprep step for Latin-1 is as simple as for ASCII. Even larger sets
of UCS where simple alphabets are used will have a very simple and
quick nameprep step.
For Latin-1 it is like for ASCII - it can be done with a simple table lookup.
To do ACE with compression includes much more work - just look at some of
the algorithms.

Note that I said subset. At my site I do not need to support more
than Latin-1. host names outside that scope will remain ACE. And if I implement
this support in my DNS server, it will also only need to support
Latin-1 when comparing names as I will only have latin-1-names in
my authorative domains.

   Dan