Re: What is T.61 (Was: Chinese Character)

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

At 09:19 AM 11/24/99 -0800, John Kristian wrote:
>"Kurt D. Zeilenga" wrote:
>> I try to add some references. I am sure RFC 1777 provides such.
>But they're not very useful.

I think adding a hyperlink to RFC1345 is useful and will adequately
answer the "What is T.61?" question.

>>> Guess when we convert to UTF8 (8 bit encoding of unicode)we can forget
>>> about T.61.
>> You can forget about T.61 if and when you forget about LDAPv2.
>Or you can forget about T.61 if you use Netscape Directory Server, which
>uses UTF-8 in LDAP v2.

You can forget interoperability, too.  T.61 is an integral part of
LDAPv2 specification.  You might be able to LOCALLY use other
charsets with LDAPv2.  However, in doing so you lose interoperability
with implementations that correctly implement the LDAPv2 specfication.

This is why I state that if OpenLDAP 2.0 does use a non-T.61 charset
with LDAPv2 it will come with a recommendation that LDAPv2 w/o
T.61 be disabled (which may be the default) in deployments that
may include LDAPv2 clients that use T.61.

>> However, if you are deploying software which supports LDAPv2 and LDAPv3,
>> you need to address T.61 vs UTF-8 encoded ISO 10646 charset issues.  You
>> will find that some LDAP implementations (correctly) use T.61 for LDAPv2
>> and other implementations that (incorrectly) use UTF-8 encoded ISO 10646
>> characters for LDAPv2.
>
>Netscape, for example.

Yes.  In a local deployment were all LDAPv2 implementations use UTF-8
instead of T.61, no problem exists.  However, mix in one LDAPv2 client
which correctly uses T.61 as specified by RFC1777 and your directory
will be trashed.

>Some other LDAP implementations use other charsets in LDAP v2.

Yes.  But more to the point is that there are implementations
which correctly use T.61 with LDAPv2 and UTF-8 encoded ISO 10646
with LDAPv3.

Kurt