Subject: [ifmib] IF-MIB questions

From: Massimo Canali <[email-masked]>
Date: Mon, 11 Sep 2000 10:24:44 +0200

Hello,
My colleague and me are defining counter management for an Agent.
We are studying the IF-MIB (RFC2863) and we have some questions about
IfCounterDiscontinuityTime object usage:

   * Has a counter wrapping to be considered as a cause of
     ifCounterDiscontinuityTime object udpated?
   * When the ifAdminStaus and ifOperStatus objects switch to down has
     the Agent to update also the ifCounterDiscontinuityTime object?
   * In the ifCounterDiscontinuityTime definition the only counters
     associated to it are the one inside ifTable and ifXTable. Instead
     it is mentioned also in the the MAU-MIB counters ( e.g.
     ifMauJabberingStateEnters below). Are there any conflicts? Can we
     manage MAU-MIB counters as the IF-MIB ones? Can we envisage only
     one global ifCounterDiscontinuityTime object?
     MAU-MIB:
     ifMauJabberingStateEnters OBJECT-TYPE (…)
     DESCRIPTION " (…) 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."
     REFERENCE   "[IEEE 802.3 Std], 30.5.1.1.6, aJabber.jabberCounter.
     RFC 2233,
     ifCounterDiscontinuityTime."

Thanks in advance.
Regards,

Paolo and Massimo.

---

From: Keith McCloghrie <[email-masked]>
Date: Tue, 12 Sep 2000 17:42:40 -0700 (PDT)

A discontinuity in the value of a counter occurs when the value
changes from X to Y, but the number of new occurrences of the
things it counts was not (Y-X) modulo 2**32.

>      ifCounterDiscontinuityTime object udpated?

No, because of the modulo arithmetic.

>      the Agent to update also the ifCounterDiscontinuityTime object?

No, because the values of the counters do not change just because
the value of ifAdminStaus and/or ifOperStatus changes to 'down'.

>      ifCounterDiscontinuityTime."

I don't think there's anything to prevent other counters from using
ifCounterDiscontinuityTime, even though there are not specifically
mentioned in its DESCRIPION.

The relevant phrase in RFC 2863 is:

  "... relevant counters are the ..."

Now, if it said: 

  "... relevant counters are only the ..."

then I would agree with you.

Nevertheless, it would be clearer if it said:

  "... relevant counters include the ..."

Keith.

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