MVALID (was Re: M-Label or MVALID, and dangers with mappings?)

John C Klensin klensin at
Mon Apr 13 22:25:42 CEST 2009

--On Monday, April 13, 2009 15:42 -0400 Vint Cerf
<vint at> wrote:

> if this is to be a separate document, this document still
> needs to be considered a part of the specifications because
> that is what we agreed to do in the last face/face working
> group meeting: ie. to map on lookup while not mapping on
> registration.

I would still argue for a separate document on the grounds that
we should define the canonical forms and protocol is a way
calculated to be as stable as possible with as much opportunity
for conformity as possible.  The mapping activity appears to me
to be likely to be appreciably less stable.  We've had multiple
examples on the list of situations in which implementations may
wish to apply alternate mappings and, if we subdivide
compatibility mappings as my earlier note suggested, it seems to
me that, unless  the mappings are compatibility-only, they will
need much more review with new versions of Unicode than the
basic rules.

> In other words this mapping function is not distinct from the
> IDNA2008 spec at least that is how I read our conclusion at
> the meeting.

I didn't make quite that inference, but I don't think it makes
very much difference and will happily accept your judgment.  It
is clear to me that, if we are going to have standardized
mapping, the WG must take some responsibility for its context
and framework.


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