RE: [idn] rederivation of an IDN architecture

["Barr Hibbs" <Barr.Hibbs@Nominum.com>]

Adam--

thank you for your well-considered work!  I have a few minor comments...

>     basic character:  Any of the 128 characters in the ASCII repertoire
>     (not to be confused with the integers or octets mapped to those
>     characters in the ASCII coded character set).
>
...ignoring the ability of DNS servers to transparently handle binary
labels, I think you really mean that a basic character is any one of the
characters which (a) has an associated glyph, (b) is the "non-printing"
space character, or (c) is a diacritical or punctuation symbol.  These
limitations, which essentially are required for characters to be
"human-readable," result in the set of characters being 31-127 of the whole
set.



>     host restrictions (applicable to any sequence of characters):
>     Contains no basic characters other than the letters, digits, and
>     hyphen-minus; and neither begins nor ends with hyphen-minus.
>
...this is not quite correct:  DNS does not make this restriction, although
I believe it is correct for the current standard for host names...

...also, I would observe that certain other characters, such as the
underscore ("_") are commonly permitted in URLs, which many non-experts find
indistinguishable from host names...


>     basic host label:  A basic label that satisfies the host
>     restrictions.  [This is the preexisting standard for host labels.]
>     basic domain name:  A sequence of basic labels (typically separated
>     by full-stop characters).  [This is the preexisting standard for
>     textual domain names.]
>
...one should be very clear that the label element separator (full-stop) is
the x'2E' character (".") and not something similar


> Goal 1 (motivated by facts 1-3 and conjecture 1):  Allow domain names to
> contain additional characters, while still allowing all domains to be
> referred to by all preexisting protocols, interfaces, software, etc.
>
> Requirement 1 (follows from goal 1):  Part of the preexisting namespace
> must be used to represent names containing additional characters,
> which requires altering the semantics of that part of the preexisting
> namespace.
>


--Barr