Re: Usage of the DateAndTime TC

[Steve Moulton <moulton@snmp.com>]

On Tuesday, November 6 2001, Juergen Schoenwaelder <schoenw@ibr.cs.tu-bs.de> wr
ote:

> (a) Fix all MIB modules and their implementations which violate the
>     DateAndTime TC to use '0000010100000000'H. This has its costs.
> (b) Clarify the DateAndTime TC that '0000000000000000'H is indeed a
>     special legal value. This legalizes current practice and fielded
>     implementation and this is the approach taken in
>     <draft-ietf-sming-modules-02.txt>.
> (c) Silently keep things as they are and rely on book authors to
>     explain the folklore. ;-)
> 
> In this particular case, I believe that (b) is the cheapest way to
> move ahead for existing MIBs. This does of course not answer whether
> new MIBs should use '0000010100000000'H or '0000000000000000'H as a
> "NULL" value. ('0000000000000000'H has some slight advantages from a
> purist point of view since you can never confuse it with a legal point
> in time. But it is a de-facto standard standard violation.)

I have no argument with either a or b.   Juergen, I would like to 
know what costs approach a has; initially it would have been the
approach I would have favored.

The only time I have dealt with DateAndTime is in implementing host
resources MIB, and it was simply not a problem there (since the
targets I was working with had some concept of date).  So I
am a bit puzzled about how to represent this value in a management
application.  Should this be something like "00-0-0,0:0:0.0"
(not very readable, but clearly communicates the idea), "00-1-1,0:0:0.0" 
(both following the display hint) or maybe "no date"?  

This is a timely question for me, as we are currently looking at an issue 
tangent to this.

A different issue: Please pardon my cultural ignorance on this question.  
Americans tend to say that 2/5/2001 is February 5, where Europeans say 
that it is May 2nd.  Is 2001/2/5 unambiguously yyyy/mm/dd or would some 
consider it yyyy/dd/mm?  I know the usage is spelled out in RFC2579, but
I'd like to make sure what a management app displays is ambiguous de
facto, as well as de jure.

        - Steve
---
Steve Moulton        SNMP Research, Inc            voice: +1 865 573 1434
Sr Software Engineer 3001 Kimberlin Heights Rd.    fax: +1 865 573 9197
moulton@snmp.com     Knoxville, TN 37920-9716 USA  http://www.snmp.com