FW: RFC2279 to Standard

["Wijnen, Bert (Bert)" <bwijnen@lucent.com>]

Form Randy Presuhn (I think he is the best skilled from
the SNMP community w.r.t. UTF-8 and related topics)

So the possible concern would/might be:

  It DOES however mean that some older SNMP entities will 
  accept (and play back) values that would legitimately
  be rejected by newer ones.

So the statement by Ned that we should return an error:
  Actually, I think it is preferable to treat them as 
  protocol errors, due to the need for UTF-16 compatibility.

Does that mean that values above 10ffff should be rejected?
So if my older agents don't do that, is that a problem or
a non-compliance?

Bert
-----Original Message-----
From: Presuhn, Randy [mailto:Randy_Presuhn@bmc.com]
Sent: vrijdag 10 januari 2003 19:42
To: 'Wijnen, Bert (Bert)'
Subject: RE: RFC2279 to Standard


Hi -

I'm not sure why they're talking about UTF-16.  It's bogus,
and the surrogates it uses are not used in the UTF-8 transform.

ISO 10646 and Unicode agreed to go from the full 31-bit range
down to the 0..10ffff range.  I think I raised the question
(along with selecting one of the normalization forms) on the
mailing list.  As I recall, there was only one response, and
the respondant didn't want to open that can of worms.

RFC 3411 says:
       Since additional code points are added by
       amendments to the 10646 standard from time
       to time, implementations must be prepared to
       encounter any code point from 0x00000000 to
       0x7fffffff.  Byte sequences that do not
       correspond to the valid UTF-8 encoding of a
       code point or are outside this range are
       prohibited.

The agreements on Unicode/ISO 10646 just say that those code
points in the 110000..7fffffff range will never be added.  If
the definition of "valid UTF-8 encoding" has been changed to
encompass a smaller range, I believe the the statement "Byte
sequences that do not correspond to the valid UTF-8 encoding
of a code point or are outside this range are prohibited"
remains correct, and gives an implementation grounds to reject
code points outside the 0..10ffff range.  It DOES however mean
that some older agents will accept (and play back) values that
would legitimately be rejected by newer ones.

 ------------------------------------------------------
 Randy Presuhn          BMC Software, Inc.  1-3141
 randy_presuhn@bmc.com  2141 North First Street
 Tel: +1 408 546-1006   San José, California 95131  USA
 ------------------------------------------------------
 My opinions and BMC's are independent variables.
 ------------------------------------------------------