Stability of valid IDN labels
ebw at abenaki.wabanaki.net
Fri Apr 18 23:34:02 CEST 2008
The requirements for labels arises somewhere, and I suspect that for the
IETF's IDN activities, past and present, the author of that requirement
is, at in part, ICANN, in the broad, constituency sense, not the almost
uniformly non-technical members of staff employed by ICANN.
If that is the origin of the requirement for stability, in my opinion,
your requirement that a label be "valid (or invalid) forever" is
stronger than the requirement originating from ICANN for IDNs.
Please consider the 3166 code points in the zone file that the IANA
directly manages. These are not "valid (or invalid) forever", where
there was an alpha-two label "SU" there are now several distinct
alpha-two labels labels. The ISO3166/MA publishes newsletters with
occasional changes to one or more code points, which are eventually
reflected in the validity, or invalidity, of labels in the root zone.
Now it is true that there is no change in the [A-Z][a-z][0-9][-,.] and
length restrictions on labels formed from ASCII characters, but that is
a truth about a production rule, not a truth about any particular label.
Perhaps this is a distinction without difference, as per-character
determinations of label validity may be a production rule for a class of
labels with only one member.
If so, again in my opinion, the ICANN requirement for stability does not
approach the semantics of "forever", there simply is no planning process
in ICANN for any requirement that is as fixed in its intent as that of
the authors of the BCD series of standards, or the ASCII series of
standards, for a present work that cannot, and also need not, be
modified within a few short years, as we are attempting now, on the work
of the earlier IETF IDN WG.
The difference between "for as long as we think this work is used" and
"forever" may allow CONTEXT rules to become more restrictive.
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