Integration of BIDI into the protocol
harald at alvestrand.no
Mon Aug 17 13:14:46 CEST 2009
James Mitchell wrote:
> John, Harald,
> A few observations on the integration of BIDI into the protocol document.
> In the draft-ietf-idnabis-protocol-14 document Section 188.8.131.52:
> If the proposed label contains any characters that are written from
> right to left it MUST meet the "bidi" criteria [IDNA2008-BIDI].
> The above implies that the label must meet the BIDI criteria, however
> BIDI criteria is applied to a BIDI domain name. From
> draft-ietf-idnabis-bidi-04, “The following test has been developed for
> labels in BIDI domain names” and “A "Bidi domain name" is a domain
> name that contains at least one RTL label”. I hesitate to provide
> alternative text for until the following question has been answered._
> The protocol states that the proposed label contains any characters
> written from right to left it MUST meet the bidi criteria. It does not
> impose such requirements on labels containing no right to left
> characters. Consider the registration of label ‘123abc’ in a zone
> containing labels written right to left. The label does not contain
> any right to left characters, therefore does not have to meet the BIDI
> criteria. However this name is a BIDI domain name, yet such a name
> would fail as the first label (LTR) does not begin with BIDI property
> L. Is the label intended to be valid for registration given a right to
> left zone?
In your specific case, registering "123abc" in the RTL zone "ABC" (usual
convention applies) will lead to a domain name (network order:
123abc.ABC) that, on its own, will display as "123abc.CBA" in an RTL
context, but if prepended by "DEF:", forming the network order string
DEF:123abc.ABC, will display as "CBA.abc123:FED" - which may be
surprising to some. (I'm only 90% confident on this - people more used
to bidi in practice may be more confident).
The WG has rejected inter-label tests, therefore all tests defined by
the protocol as normative (MUST or SHOULD) apply only to one label at a
Given the WG decision, I tried to make the BIDI document quite clear
that certain properties can only be guaranteed for domain names where
all the labels meet the test, but this is a case where people have to
read the warnings and do something reasonable, rather than having the
rules define that being unreasonable is forbidden.
"Warning: Contains hot liquids".
> I note also the inconsistent use of the term BIDI. In
> draft-ietf-idnabis-protocol-14 section 184.108.40.206. it is quoted and in
> lower-case, whereas the draft-ietf-idnabis-bidi-04 uses the upper-case
> version extensively. Also, within draft-ietf-idnabis-bidi-04 the term
> "Bidi domain name" in Section 1.4 is inconsistent with “BIDI domain
> names” in Section 2, and the tem “Bidi rule” in Section 10 is
> inconsistent with the several other occurrences in the document.
Thanks, I tried to normalize it to uppercase in an earlier round, but
didn't remain consistent in later edits. Will fix!
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