Re: discontinuity timers for Counters

["Randy Presuhn" <randy_presuhn@mindspring.com>]

Hi -

> From: "Wijnen, Bert (Bert)" <bwijnen@lucent.com>
> To: <j.schoenwaelder@iu-bremen.de>
> Cc: "Mreview (E-mail)" <mreview@ops.ietf.org>
> Sent: Tuesday, July 27, 2004 2:01 AM
> Subject: RE: discontinuity timers for Counters
...
> > Looking at the MIB, the question that I have is the interaction of
> > discontinuities with these ZeroBasedCounter32 objects. Does a
> > discontinuity couse these counters to be reset to zero?
>
> I believe that we (MIB doctors) agree that they cannot state that a
> ZeroBasedCounter32 MUST be re-initialized to zero at some point
> in time (they are only required to be zero at creation time).
> So I had them remove that sort of text from an earlier revision.
> So current text is silent about it, meaning that an implementation
> could do anything, right? There is a discontinuity, so we need to
> start with new values and then check at least 2 queries.
...

This seems contrary to the whole motivation for using a zero-based
counter.  I'd think that if they *really* need a zero-based counter,
that the appropriate semantic is for its value to represent the number
of events since the beginning of the epoch defined by its discontinuity
indicator.  If that is so, then the appropriate discontinuity behaviour
would indeed be a reset to zero.  However, I remain sceptical that
zero-based is actually needed here.

What bothers me more is that it specifies TWO discontinuity indicators.
I'd read that as an implicit requirement for management applications
to retrieve BOTH with every query, in order to determine whether either
gives evidence of a discontinuity.

Randy