Re: UTF-8 in SNMPv3

From: Randy Presuhn (rpresuhn@peer.com)
Date: Mon Jul 07 1997 - 13:25:15 EDT


Hi -

> Date: Fri, 4 Jul 1997 12:16:02 +0200 (MET DST)
> From: "Martin J. Duerst" <mduerst@ifi.unizh.ch>
> To: Randy Presuhn <rpresuhn@peer.com>
> Cc: Multiple Recipients of <unicode@unicode.org>
> Subject: Re: UTF-8 in SNMPv3
> Message-Id: <Pine.SUN.3.96.970704114736.253k-100000@enoshima>
...
> > 1) Is there any merit to the argument that the "non-printable
> > stuff" in 10646 is any better or worse than the NVT ASVII
> > definition?
>
> Because you are using UTF-8 and because many of the things mentionned
> in your excerpt of RFC 1903 rely on properties of lower-level
> protocols (e.g. CR NUL comes from telnet,...), I would clearly adwise
> you to keep these as they are. This means that a lot of the software
> doesn't have to be changed.

Seems reasonable.

> > 2) Can we use standard character properties to identify a
> > "printable" subset that would not break for any language?
> > (The folks that want these also want to have CRLF...)
> >
> > Background information:
> > In the SNMP protocol notions of equality and ordering have no
> > "locale" component. There is no notion of character equivalence.
> > It is very much a "bits is bits" environment.
>
> That's similar to the situation with URLs. Can you give some info
> on where and how equality or sorting is used, and where it is crucial?

I like the analogy. The matching for equality is important when an
attribute is used as an index into a table. Sorting is important in the
same situation, in the context of the "GET-NEXT" operator. The rules
for representing an OCTET STRING (the only data type SNMP has that can
hold this kind of information) as an INDEX and GET-NEXT processing admit
no possibility of alternative collation sequences.

> > The concerns of working group members appear to be arising from:
> > 1) what does it mean to "support 10646"
> > 2) how to display "wierd stuff"
> > 3) how to input "wierd stuff"
>
> What do you mean with "wierd stuff"? Some codepoints can lead to
> rather complicated display or input code, but they are absolutely
> necessary for the display of certain languages.

Understood. A few of us in the working group have had some contact
with internationalization issues; many have not. The concerns seem
to be motivated by the fear that supporting 10646 would require them
to junk command line and character-mode interfaces. (Such a requirement
would probably kill whatever support UTF-8 has within the working group.)

> The question is how to come up with a rather flexible display requirement
> clause without breaking the base functionality of the protocol. For HTML,
> for example, it was rather easy to say that a browser is not required
> to display a character, but that it should indicate the characters it is
> not able to display in a suitable way ("missing character glyph",...).
> Something equivalent may be possible for SNMP. Maybe one would have
> to require that the Hex number of the character is given in a suitable
> form.

What standards for the display and entry of "undisplayable stuff" would
be good hints for developers?

> > 4) the old CR/LF problem
>
> As I said, stay with it, don't change things unnecessarily.

Folks like to hear advice like this. :-)

> Regards, Martin.
>

Thanks!

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 Randy Presuhn BMC Software, Inc. (Silicon Valley Division)
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