my comments on draft-ietf-idnabis-bidi-05

"Martin J. Dürst" duerst at
Mon Sep 7 11:21:10 CEST 2009

Hello Mati,

On 2009/09/07 16:47, Matitiahu Allouche wrote:
> Martin J. Dürst asked:
> But then shouldn't BN also be allowed for
> LTR, because some of these characters are needed in Indic scripts?
> The assumption in this document is that the rules for LTR labels are in
> fact rules for LTR labels in Bidi domain names. I don't think that the
> world needs Bidi domain names with some labels written in an Indic script,

But if we think we need domain names with a combination of e.g. Latin 
and Hebrew, or Greek and Arabic, or so, labels, then why should we want 
to exclude the combination of Hebrew and Indic, or Arabic and Indic, 
labels? There is quite a big boundary/overlapping region between Arabic 
and Indic scripts, and according to Wikipedia, there are also Jewish 
communities in India 

> thus banning BN from LTR labels preserves some of the anti-phishing
> effect.

In essence, it only elimintates some very few Indic labels, namely those 
than need these specific characters. If we think that these specific 
characters are needed for the respective Indic scripts (which I think 
the WG does, because otherwise, we wouldn't have contextual rules for 
these) and if we think that combining RTL and Indic labels should be 
allowed (as definitely the current drafts do), then I think we should 
not disallow such an edge case.

> On the other hand, since this anti-phishing effect is already compromised
> for RTL labels, allowing BNs for LTR labels does not make much of a
> difference.
> Bottom line:  I think that allowing BN in LTR labels is not a useful
> extension, but if it is considered better for reasons of principle, or
> others, I will not be outraged beyond recovery.

I herewith formally propose to:

In 1.4, to make things easier to follow, change
"o  BN - Boundary Neutral - control characters"
"o  BN - Boundary Neutral - control characters (in the context of this 
document, ZWJ and ZWNJ)"

In 2., change point 5 from:
"  5.  In an LTR label, only characters with the BIDI properties L, EN,
        ES, CS.  ET, ON and NSM are allowed."
"  5.  In an LTR label, only characters with the BIDI properties L, EN,
        ES, CS.  ET, ON, BN and NSM are allowed."

Regards,    Martin.

> Shalom (Regards),  Mati
>             Bidi Architect
>             Globalization Center Of Competency - Bidirectional Scripts
>             IBM Israel
>             Phone: +972 2 5888802    Fax: +972 2 5870333    Mobile: +972 52
> 2554160

#-# Martin J. Dürst, Professor, Aoyama Gakuin University
#-#   mailto:duerst at

More information about the Idna-update mailing list