RE: discontinuity timers for Counters

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

Inline

> -----Original Message-----
> From: Juergen Schoenwaelder [mailto:j.schoenwaelder@iu-bremen.de]
> Sent: dinsdag 27 juli 2004 10:41
> To: Wijnen, Bert (Bert)
> Cc: Mreview (E-mail)
> Subject: Re: discontinuity timers for Counters
> 
> 
> On Mon, Jul 26, 2004 at 11:02:30PM +0200, Wijnen, Bert (Bert) wrote:
> 
> > What do we think about something like this:
> >   "Discontinuities of this counter are indicated by sysUpTime and
> >    ifCounterDiscontinuityTime for the associated ifIndex."
> > 
> > Does that make sense?
> > This is in document draft-ietf-ipcdn-bpiplus-mib-13.tx
> 
> I think it would be extremely helpful to have a discussion what this
> means somewhere in the introductionary text together with a pointer to
> the relevant text in the IF-MIB RFCs (which has some paragraphs about
> this subject that are interesting to know for implementors).
> 
Right, It wasn't clear to me what they mean either. Probably they mean

            Discontinuities in the value of this counter can occur at
            re-initialization of the management system, and at other
            times as indicated by the value of
            ifCounterDiscontinuityTime."
And if so, this text would probably be better.

So the ptr to RFC2863 would be to sect 3.1.5 I assume, specifically
to the text on page 12.
Or did you mean something else?

> 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.

> The TC says that a zero based counter is set to zero(0) on creation and it has
> additional text that the intended usage is in tables where the index
> space is constantly changing. Does this apply here?
> 
Nope, I do not think the index is constantly changing. But that is a 
typical use case, not the only use case is it? At least I never 
considered that to be a pre-requisite for the use of ZeroBasedCounter32.

Bert
> /js
> 
> -- 
> Juergen Schoenwaelder		    International University Bremen
> <http://www.eecs.iu-bremen.de/>	    P.O. Box 750 561, 
> 28725 Bremen, Germany
>