MAYBE-TRANSITIONAL, a historical tale (was: Re: Additional thoughts on TRANSITIONAL)

Mark Davis ☕ mark at
Fri Dec 4 22:45:31 CET 2009

I agree with you that there are many similarities between the MAYBE and
TRANSITIONAL. MAYBE at the time wasn't suitable because it was applied to a
huge number of characters. However, applying the concept (with a few
changes) to these 4 characters for a transitional period is, I think,


On Fri, Dec 4, 2009 at 12:40, John C Klensin <klensin at> wrote:

> Once upon a time, not really that long ago, there was a proposal
> to differentiate what is now PVALID by including MAYBE YES and
> MAYBE NO categories.   Anyone interested should try to find a
> copy of draft-klensin-idnabis-issues-06.txt and earlier.  The
> general model, in today's vocabulary, was to put characters (and
> groups of characters) that we weren't sure about into categories
> that would encourage different handling on registration and
> looking from characters about which we were more certain, to
> permit later reclassification, and to arrange for controlled
> transitions.  There was consensus for removing those categories
> because they made things too fragile, because they would require
> that all registries and applications check for updates and
> changes frequently (which would be too fragile), and so on.
> In practice, the only real difference between MAYBE and the sort
> of implied TRANSITIONAL you imply (or the explicit versions
> others have suggested) is that MAYBE would have laid out the
> "this is likely to change" aspect of the situation more clearly,
> while the idea you outline above raises all of the issues that
> the WG has discussed about transitions from DISALLOWED to PVALID
> (and decided that reclassification should require a catastrophic
> situation).
> If I remember correctly, both you and Mark were at the meeting
> at which the decision to drop MAYBE was made and were among
> those pushing for that decision, pretty much on the basis
> outlined above.
> While I don't object to revisiting that general idea -- under
> the identification of TRANSITIONAL or otherwise-- if the WG
> really feels that it wants to go there and that the old model
> might be worth the aggravation that caused it to be dropped the
> last time around, I hope that everyone does understand that
> TRANSITIONAL, as you and others have described it, is very close
> to that old and discarded idea... close enough that we might
> even be able to borrow text from documents that are now more
> than 18 months old.
> best,
>   john
> p.s. I'm not going to comment at any length on the "global
> mappings" part of your proposal because I think everything has
> been said already.  Having required global mappings is
> equivalent to _almost_ having U-label <-> A-label symmetry.
> And, of all mappings, "map to nothing" is the worst: while part
> of the problem with a mapping between "ß" and "ss" is that one
> cannot tell by looking at "ss" afterward whether the registrant
> intended "ss" or "ß", one at least knows that "x" or "ab" was
> not intended.  With "map to nothing", the character that was
> eliminated could, in principle, have appeared in any position in
> any domain name label.
> --On Friday, December 04, 2009 04:11 -0800 Erik van der Poel
> <erikv at> wrote:
> > Here is another proposal that is dead simple, yet allows
> > implementations to take advantage of a machine-readable file,
> > and does not involve "flag days" (dates at which we change
> > something).
> >
> > Instead of having a machine-readable file at each host, we
> > have two global files at One file is similar to
> > Patrik's table with entries like:
> >
> >
> > There is no new value called TRANSITIONAL. The infamous 4
> > characters (above) start with the value DISALLOWED. Later, we
> > change them to PVALID (or CONTEXTJ for 200C/200D). We
> > encourage ICANN to redelegate TLDs the registries of which
> > flout our rules.
> > The other file is for global mappings. Not language-specific
> > mappings. The format might be similar to RFC 3454's:
> >
> > 0041; 0061; Case map
> > 00AD; ; Map to nothing
> >
> > The absence of a character from this file means that there is
> > no mapping for that character. It maps to itself. The infamous
> >...
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