Single-letter names

John C Klensin klensin at
Sat Jul 5 19:03:30 CEST 2008

--On Saturday, 05 July, 2008 12:55 -0400 Vint Cerf
<vint at> wrote:

> no, I was specific that my remarks were oriented solely to the
> IDN   question. I do not believe that our work on IDNs deals
> with the ASCII   LDH question except insofar as we are
> constrained to assure that our   mapping of IDN's expressed in
> some form of UNICODE does not conflict   with established
> practices associated with ASCII domain names. It is   clear
> that a valid IDN is a minimum of some 6 ASCII characters I  
> believe, and that means none of the IDN work will directly
> implnge on   questions about single character ASCII domain
> names at top level or   elsewhere.


There is also an almost-separate discussion of whether there
should be minimum length requirements on the U-label form of
IDNs (as well as LDH labels).   The current ICANN
recommendations apply such minimums to TLDs, as discussed on
this list and somewhat more extensively on the IETF list.

I interpreted your note as indicating that such minima were not
an agenda item for the IDNAbis WG, whether LDH, U-labels, or
A-labels.  For the latter, as you point out, the prefix length
plus some punycode encoding implies that we are well above the

Is that correct?


More information about the Idna-update mailing list