Unicode position on local mapping

[Mark Davis]

The Unicode Technical Meeting discussed IDNA at the quarterly meeting. The
following reflects the discussion on the local mapping in IDNA2008:

Given a choice among the different options for mapping in IDNA2008, the UTC
has the following preferences. Note that UTS #46 contains a mapping that is
based on the same principles as IDNA2003, but has exceptions for the special
cases required by IDNA2008 (sharp s, etc.).

1. Any Local Mapping allowed (current situation in IDNA2008) - *Very bad.*
*We foresee that in practice UTS 46 mappings would be used to maintain
compatibility with IDNA2003. However, it could also encourage incompatible
localized mappings, which would cause interoperability and security
problems.*
* *
2. No mapping allowed - *Very bad. And unenforceable*

3. Silent on mapping - *Bad*
*We foresee that in practice UTS 46 mappings would be used to maintain
compatibility with **IDNA2003**. The danger here is the same as for #1; it
is not quite as bad as mentioning local mapping explicitly, thereby
implicitly encouraging it.*
* *
4. Discourage local mapping except for "compatibility with IDNA2003" - *
Better*
*We foresee that in practice UTS 46 mappings would be used to maintain
compatibility with **IDNA2003**. Operationally this is the same as #3,
except that it is more explicit about the recommendation.*

5. Case Mapping incorporated into protocol - *Better*
*The UTC would modify UTS 46 so as to remove case mappings.** We foresee
that in practice the modified UTS 46 mappings would be used to maintain
compatibility with **IDNA2003**.*

6. Case + Width Mapping incorporated into protocol - *Better*
*The UTC would modify UTS 46 so as to remove case mappings and width
mappings.** We foresee that in practice the modified UTS 46 mappings would
be used to maintain compatibility with **IDNA2003**.*

7. UTS#46 Mappings incorporated in protocol - *Best*
*The UTC would discontinue UTS 46, as there would be no need for it.*
*
*Mark
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.alvestrand.no/pipermail/idna-update/attachments/20090213/3239b5d2/attachment.htm