referencing IDNA2008 (and IDNA2003?)
Jeff.Hodges at KingsMountain.com
Thu Oct 21 19:12:16 CEST 2010
In the httpstate, we've almost completed our spec on HTTP Cookies (as they
actually are implemented & deployed). In the process, we've attempted to
properly reference the IDNA specs, but of course with the recent publication of
IDNA2008 and its obsoleting IDNA2003, this presented a bit of head-scratching
WRT how to properly reference them since IDNA2008 is not backwards compatible
and there's going to be a transition period for some time.
Below's what we came up with (the following are relevant excerpts from
How does that look to you folks?
[ httpstate chair & document shepherd ]
5.1.2. Canonicalized host names
A canonicalized host name is the string generated by the following
1. Convert the host name to a sequence of NR-LDH labels (see Section
184.108.40.206 of [RFC5890]) and/or A-labels according to the
appropriate IDNA specification [RFC5891] or [RFC3490] (see
Section 6.3 of this specification)
2. Convert the labels to lower case.
3. Concatenate the labels, separating each label from the next with
a %x2E (".") character.
6.3. IDNA dependency and migration
IDNA2008 [RFC5890] supersedes IDNA2003 [RFC3490] but is not
backwards-compatible. For this reason, there will be a transition
period (possibly of a number of years). User agents SHOULD implement
IDNA2008 [RFC5890] and MAY implement [Unicode Technical Standard #46
<http://unicode.org/reports/tr46/>] in order to facilitate a smoother
IDNA transition. If a user agent does not implement IDNA2008, the
user agent MUST implement IDNA2003 [RFC3490].
10.1. Normative References
[RFC3490] Faltstrom, P., Hoffman, P., and A. Costello,
"Internationalizing Domain Names in Applications (IDNA)",
RFC 3490, March 2003.
See Section 6.3 for an explanation why the normative
reference to an obsoleted specification is needed.
[RFC5890] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework",
RFC 5890, August 2010.
[RFC5891] Klensin, J., "Internationalized Domain Names in
Applications (IDNA): Protocol", RFC 5891, August 2010.
More information about the Idna-update