draft-liman-tld-names-00.txt and bidi

Andrew Sullivan ajs at shinkuro.com
Fri Mar 6 23:11:47 CET 2009

Dear colleagues,

This is slightly off-topic (although related), but I know some experts
who have thought about this issue are here so I thought I'd better

Over on the DNSOP list, we're discussing draft-liman-tld-names-00.txt.
One of the interesting arguments that has cropped up has to do with
leading or ending digits on a label.

Now, we have some recommendations (and restrictions) on labels in the
bidi document, but of course that is something that restricts IDNs,
and not A-labels.

The question that I have is whether there is a similar bidi issue for
A-labels (or, more importantly, non-IDN LDH labels: think of a label
"123abc", for instance) in a bidi display or entry context.  I've been
assuming "no" because we already have these sorts of labels today and
I imagined whatever is happening now would apply.  But it strikes me
that we wouldn't be introducing bidi restrictions if there weren't
already a problem.  So is there an issue here that might be relevant
to the I-D in question? 

Note that the I-D in question as it stands will not allow all-numeric
labels.  But there is a thread of argument that all-numeric labels
such as "666" ought to be allowed, on the grounds that such a label
could never be part of an IPv4 address anyway.  If there are bidi
issues that are important, then the "no leading digit" rule in the I-D
is strengthened.

Since this isn't strictly on-topic, please send replies off-list.  
Thanks, and sorry for the diversion.  


Andrew Sullivan
ajs at shinkuro.com
Shinkuro, Inc.

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