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

Eric Brunner-Williams ebw at abenaki.wabanaki.net
Sat Jul 26 21:54:09 CEST 2008


that was what i was getting at with "z-labels", anything in the first 
four octets that is inconsistent with the label being an a-label, 
independent of whether anything in octets 5-63 are valid or not.

allowing z-label (but good stuff afterwards) and a-label (with bad stuff 
afterwards) as distinct possible value ranges of disjoint sub-types of 
the (nested def) data label taxa.


Vint Cerf wrote:
> at the risk of making things more complicated, do any of the definitions 
> manage to proscribe the presence of "-" "-" in the 3rd and 4th 
> position from the left in L2R LDH-conforming strings?
> One assumes that despite the possibility of R2L U-labels, the correct 
> associated A-Label expression is still L2R (?).
>
> vint
>
> On Jul 25, 2008, at 6:27 PM, John C Klensin wrote:
>
>> 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 
>> <mailto: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.
>>
>>     john
>>
>> 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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>
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