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
_______________________________________________
DNSOP mailing list
DNSOP@ietf.org
https://www.ietf.org/mailman/listinfo/dnsop
