[DNSOP] namespace and substring reservations (was Re: Another look - draft-ietf-dnsop-attrleaf-05.txt)

[Dave Crocker <[e-mail]>]

On 3/26/2018 12:07 AM, Paul Vixie wrote:
> 
> 
> John C Klensin wrote:
>>    it is not clear to me that
>> the set of labels starting with "_" constitute a namespace, any more
>> than the set of labels starting with "xn--" do. It is just a naming
>> convention that identifies the labels as keywords with defined
>> meaning.


1. This seems to require a very precise definition of the term 
namespace, but doesn't cite it.  Here's mine -- although it's different 
from Wikipedia's:

    An integrated (probably contiguous) range of values from which names 
can be chosen.

And elaborated:

      A set of rules for assigning names out of a common space of values.


2. If "_" at the beginning of a DNS label does not define a namespace in 
the current DNS, then it can't be subject to any distinct set of rules. 
In actual practice, the use of "_" as the first character is now fully 
entrenched.  Debating what to call the space it controls doesn't change 
established practice.


3. I don't understand how xn-- can be any less reserved for exclusive 
use. That is, I believe the convention of using xn-- has reserved that 
string for only that use and that the document choosing that string has 
formally made that restriction.


The goal of the current draft is to bring the space of names starting 
with underscore under unified control.  With the publication of a draft 
like this, the use of underscore as the first character makes its use 
reserved.

All of this has to do with name /assignment/, but makes no changes on 
name /resolution/.  Name resolution remains blissfully unaware of any 
rules about name assignment or 'meaning'.

d/

-- 
Dave Crocker
Brandenburg InternetWorking
bbiw.net