Re: [idn] Transparent vs. ACE representations (was We are quibbling about WHAT?)

[Dave Crocker <dhc@dcrocker.net>]

At 02:13 AM 8/9/2001, David Hopwood wrote:
>But, you may say, that encoding wasn't UTF-8. Doesn't matter.

well, actually it does.


>Suppose for
>the sake of argument that the message had contained characters outside the
>US-ASCII repertoire (in a domain name or elsewhere).

If the text switches from one character set to another, then no, it is 
unlikely the processing software will handle that well.  If you mean that 
the text is all in the UTF-8, then, no, it isn't.  Mine is in ASCII.  Hence 
your suggestion means we would have mixed Ascii, UTF-8.

The real point is that you appear to be assuming a much more simplified and 
consistent processing environment for characters, across applications, than 
actually exists.


>Call a domain name representation within
>some surrounding text (or other protocol elements) "transparent", if the
>representation is of a character string such that each character in the
>string stands for the same character in the domain name.

By that definition, UTF-8 is not transparent.  It is an encoding scheme, as 
is ACE.


>The thesis behind the ACE-only proposals seems to be that most existing
>protocols, formats, and implementations assume that domain names only
>use US-ASCII characters, and so using a non-ASCII representation will 
>break them. he vast majority of cases, that simply isn't true

The premise has been present in the design of Internet protocols from the 
beginning.  Much has changed since then, but not everything.

The premise that all software will correctly process UTF-8 has been 
demonstrated to be false.


> > As to predictions of the future, well, they are always wrong.
>
>That's obvious nonsense. It is a perfectly safe prediction that the
>default encoding (often the only encoding) used in almost all Internet
>protocols in the near future will be UTF-8.

I do not know how many such confident predictions of the future you have 
suffered through, but many of us have watched them made repeatedly over the 
last 25 years and, I am sorry to say, they are usually incorrect.  Not 
always, no.  But frequently.


>  In a sense there is nothing
>to predict; the decision has already been made in RFC 2277 / BCP 18, and
>the process of making the necessary modifications to existing standards
>is already well underway.

You should review the history of "decisions" that were made around the 
world, by businesses and governments, for many other technical choices, 
such as ADA, OSI, CMIP, ATM, ...

Nothing is over until it is over.  No decision is firm until it is in the past.

d/

----------
Dave Crocker  <mailto:dcrocker@brandenburg.com>
Brandenburg InternetWorking  <http://www.brandenburg.com>
tel +1.408.246.8253;  fax +1.408.273.6464