draft-liman-tld-names-00.txt and bidi
tina.dam at icann.org
Mon Mar 9 23:44:45 CET 2009
Just FYI, the leading and trailing digit prohibition we have is for the U-label, because it in certain instances will 'jump the digit'.
The revision of RFC 1123 needs to allow for inclusion of digits in the A-label - whether they can be trailing I don't know....but that has nothing to do with the problem around 'jumping digits'.
There are people that would like digits intermixed with ASCII characters in a TLD. Right now they cannot have that because we don't allow is across scripts, regardless of them being considered IDNs or not. Another reason is that some of these interested parties are looking at labels with 2 characters, one being a digit, which also currently is not allowed, due to confusability against the ISO-list and existing and future ccTLDs. If there are other more technical/DNS specific reasons for making that ban stay as it is I would very much like to hear it.
> -----Original Message-----
> From: idna-update-bounces at alvestrand.no [mailto:idna-update-
> bounces at alvestrand.no] On Behalf Of Vint Cerf
> Sent: Sunday, March 08, 2009 9:08 AM
> To: Andrew Sullivan
> Cc: idna-update at alvestrand.no
> Subject: Re: draft-liman-tld-names-00.txt and bidi
> well, we have already made a rule that labels cannot have leading or
> trailing hyphens...
> others more expert in the punycode algorithm will have to say whether
> it is possible for it to produce a terminating digit. One would think
> so given that digits are an allowed value among the A-Z, 0-9 and "-"
> components of LDH-label subset of ASCII labels.
> Vint Cerf
> 1818 Library Street, Suite 400
> Reston, VA 20190
> vint at google.com
> On Mar 8, 2009, at 11:53 AM, Andrew Sullivan wrote:
> > On Sat, Mar 07, 2009 at 03:43:02PM +0900, Martin Duerst wrote:
> >> You are right that there is a bidi issue. For some very specific
> >> example, please see Example 11 at
> >> http://www.w3.org/International/iri-edit/BidiExamples
> >> (please read the legends or tooltips carefully).
> >> The reason why there are bidi issues is:
> >> - Non-IDN labels turn up in IDNs
> >> - Digits get close to RTL characters, maybe only separated by dots
> >> - In the bidi algorithm, numbers and dots get associated with nearby
> >> text and thrown around
> > Ok. Now the important question is, is it ever possible for Punycode
> > to produce output that ends in a digit? I haven't run into an
> > yet, but I haven't been able to convince myself that's anything but
> > accident. If someone who understands the algorithm better than I
> > says, "No, it can't, and here's why," then we'll be in a position to
> > add to draft-liman-tld-names a restriction that a TLD must both begin
> > _and end_ with an ASCII letter, and the problem will automatically go
> > away. Otherwise, we can't make that rule. Right?
> > A
> > --
> > Andrew Sullivan
> > ajs at shinkuro.com
> > Shinkuro, Inc.
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