A-label definition

Frank Ellermann hmdmhdfmhdjmzdtjmzdtzktdkztdjz at gmail.com
Fri Jun 20 06:04:15 CEST 2008


YAO Jiankang wrote:

> It is better if we clarify 3 definitions.

> LDH , which is the domain name lable defined in RFC 1034 and 1035

I think we need the RFC 3696 concept "updating" the RFC 1123 idea,
which in turn updated RFC 1034/1035.  It's a subtle point, but the
older definitions had "must start with a letter", that's obsolete.

RFC 1123 fixed that claiming that the <toplabel> can contain only
letters, but that would rule out IDN TLDs.  RFC 3696 finally got
it right, but did not update RFC 1123.  Somebody has to fix this,
we are in the position to do it.  

> U-label , which contains at least a non-ASCII character

Okay, but please without the "standard Unicode encoding" blurb,
it only needs Unicode code points (the numbers, any encoding).

> A-label, which is transformed from U-label with the algorithm
> (punycode), plus a prefix such as XN--  (some lable withe the
> prefix XN-- can not be converted to U-label is not valid A-label)

+1, define A-label based on U-label, and not the other way around.

> LDH label includes A-label.

+1, that is the whole point of this business.

 Frank



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