Mixing of AN and EN (Re: Protocol-08 (and status of Defs-04 and Rationale-06))

Erik van der Poel erikv at google.com
Tue Dec 16 17:24:01 CET 2008


Hi Alireza,

On Tue, Dec 16, 2008 at 12:59 AM, Alireza Saleh <saleh at nic.ir> wrote:
> Would you please test the following examples :
>
> 1) <U+062C>a<U+U0664>-<U+0665>
> 2) <U+062C>a<U+U06F4>-<U+06F5>

There are no dots in these examples, so we cannot test whether any
characters jump over a dot. Also, these labels have different
characters, so they will never be the same, no matter how you re-order
them. See "Label Uniqueness" and "Character Grouping" in:

http://tools.ietf.org/html/draft-ietf-idnabis-bidi-03#section-3

> I'm a little bit confused about what -bidi is aiming at  ?  This is the RFC
> that going to be used to display the labels, or the labels should be tested
> against it during the registration ?

For registration, the IDNA2008 bidi rules are a MUST, but for lookup,
they are a SHOULD:

http://tools.ietf.org/html/draft-ietf-idnabis-protocol-08

The aim of the IDNA2008 bidi draft is to prevent registration of
labels that would cause confusion in the context of a full domain name
(more than one label). As you know, there was a long discussion about
whether or not we can require testing across multiple labels at
registration time, so we now have the wretched compromise of only
requiring testing within a single label.

The IDNA2008 bidi draft is not the only one that is trying to avoid
confusion. I believe the Rationale draft also says that IDNA2008 is
trying to avoid general confusion by restricting labels to letters,
digits and the hyphen:

http://tools.ietf.org/html/draft-ietf-idnabis-rationale-06#section-1.4

Erik


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