RE: [idn] Comparisons of the proposals

[Andrew Draper <ADRAPER@altera.com>]

I looked through this and am not sure I would agree with the way that some
of these points were put.  I think this is due to my having a different view
about the interfaces between code modules on the host (DNS is one of those
modules).  

For example, within a host which understands internationalised names I would
expect the particular wire encoding of DNS labels to be hidden within the
resolver and the boxes standard encoding to be used in the interface between
the resolver module and the applications using it.  Clearly none of the
proposals can change the behaviour of the resolver in a
non-internationalised host.

> Protocol overview
> 
> utf-5:  On-the-wire protocol is compatible with today's host names.

utf-5:  On-the-wire protocol redefines the meaning of DNS names which have
        a well-known suffix.

>          No further detail on use in DNS, but will probably be the
>          same as cidnuc.
> cidnuc: On-the-wire protocol is compatible with today's host names.

cidnuc: On-the-wire protocol redefines the meaning of DNS labels which
        have a particular form.

>          Specifies that displayed names should be converted to
>          internationalized characters.
> 8&down: On-the-wire protocol is UTF-8. DNS requests use a new
>          bit in the DNS request packet. Protocols that cannot use
>          UTF-8 directly downcode to an equivalent name that is
>          compatible with today's host names.
> 
> 
> Changes to DNS protocol and resolvers

Changes to DNS protocol and internationalisation aware resolvers

>
> utf-5:  None.

utf-5: For some names DNS resolvers must append well known suffix and
       encode name in utf-5 (or the reverse).  For other names resolver
       sends/decodes as is.

> cidnuc: None.

cidnuc: For DNS labels containing non-ASCII characters DNS resolvers
        must reencode label and prepend identifying prefix.  Reverse
        process for received labels.

> 8&down: Use of new IN bit in requests. 

8&down: Use of new IN bit in requests.  Must upcode names which arrive
        downcoded.
 
> 
> 

Regards,

    Andy