LDH-label terminology Iwas: Re: Comments on idnabis-rationale-01)

John C Klensin klensin at jck.com
Sat Jul 26 00:27:43 CEST 2008

This is a very good summary, even though Eric's taxonomy covers
more of the landscape in a little more detail.  Comments below.

--On Friday, 25 July, 2008 00:48 +0200 Frank Ellermann
<hmdmhdfmhdjmzdtjmzdtzktdkztdjz at gmail.com> wrote:

> Tina Dam wrote:
>> I would be ok with a different term as well, but I don't
>> have any good ideas.
> The funny thing is that we all like LDH-label as intuitively
> clear, and then don't agree on the same definition.  Here's
> some simplified ASCII art:
> +--------------------------------+
> | DNS labels (octets)            |
> |                                |
> | +------------------------------+
> | | LDH labels (LDH)             |         
> | |                              |
> | | +----------------------------+     +----------+
> | | | A-labels (IDNAbis valid)   | <=> | U-labels |        
> | | +----------------------------+     +----------+
> | |                              | 
> | +------------------------------+
> |                                | 
> +--------------------------------+
> What I see is "A-labels are a proper subset of LDH-labels,
> as specified in IDNAbis.  LDH-labels are a proper subset
> of DNS labels, as specified in RFC 1123" (or similar).
> What John sees is "A-labels are one thing, and LDH-labels
> are the DNS labels consisting of LDH which are no A-labels,
> as specified in IDNAbis".

> IOW John has no name for the union of A-label and LDH-label
> in his terminology (the middle box in the ASCII art).

I have periodically referred to them as LDH-conforming ASCII
strings, or similar terms.  But, per Eric's note and my prior
one, that box really consists of (my) LDH-labels, A-labels, plus
some stuff that consists of other strings of ASCII characters.

> I've no term for those LDH-labels which are no A-labels in
> my terminology (the middle box excluding the innermost box).

And neither of us have a term for things that fit in the DNS
label box but that are not LDH-conformant.


p.s. I sent a note off earlier today whose purpose is to dump
much of this terminology stuff (and the 1123 clarification and
related issues) onto the DNS experts and/or WG(s) or at least
get them to work with us on it.  Don't know if that will be
successful, but I'm  going to feel better for having tried.

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