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<DIV>In the case of domain names containing right-to-left characters, the
requirements in the Bidi Rule and those of the rest of IDNA2008 seem to
conflict.</DIV>
<DIV> </DIV>
<DIV>RFC 5893, which defines the Bidi Rule, says that the rule "applies to
labels in Bidi domain names", which are defined as domain names with "at least
one RTL label", that is, "a label that contains at least one character of type
R, AL, or AN". Therefore, ASCII-only labels (and particularly those that
start with a digit, which do not satisfy the Bidi Rule) that occur in Bidi
domain names are subject to the rule. </DIV>
<DIV> </DIV>
<DIV>(Note that the rule itself redefines "RTL label" and "LTR label". In
a future update, it would be worth rewording the rule so as not to use these two
terms. But this issue is not as important as the applicability
conflict.)</DIV>
<DIV> </DIV>
<DIV>However, RFC 5891 sec. 4.2.3.4 says, "If the proposed label contains any
characters from scripts that are written from right to left, it MUST meet the
Bidi criteria". (Note that this does not necessarily mean "characters of
type R, AL, or AN".) Therefore, even ASCII-only labels that occur in a
domain name with another label with right-to-left characters would not be
subject to the Bidi rule. RFC 5890 sec. 2.3.2.1 also says that a U-label
is "subject to ... the Bidi constraints in [RFC 5891] if it contains any
character from scripts that are written right to left."</DIV>
<DIV> </DIV>
<DIV>But that conflicts with the statement in the Bidi Rule that "even ... pure
ASCII labels have to be tested" for conformance to the rule, and pure ASCII
labels are not RTL labels.</DIV>
<DIV> </DIV>
<DIV>And the Bidi Rule conflicts with the statement in the same section of RFC
5890 that says that "IDNA is defined for labels, not for parts of them and not
for complete domain names", and the Bidi Rule applies to "domain names", not
"labels", at least in the sense that labels in only some domain names are
subject to the rule.</DIV>
<DIV> </DIV>
<DIV>(I am aware that some pure-ASCII domain names contain labels that start
with a digit. Those domain names are unaffected by this conflict.)</DIV>
<DIV> </DIV>
<DIV>I would like some discussion on how to resolve this conflict best.</DIV>
<DIV> </DIV>
<DIV>--Peter</DIV></DIV></DIV></BODY></HTML>