I have encountered similar results. What I did to narrow it down was to
collect on the mibs (ifInOctets, ifOutOctets and ifSpeed) separately at the
same polling frequency as the ifBit expression. That way, whenever the ifBit
expression shows an unreasonable value, I can see what the separate values
of the mibs were. From there, it's anyone's guess what caused the anomaly.

J.P. Giuliotti  - Massachusetts Financial Services
(617) 954-5684
JPG AT MFS DOT COM

        -----Original Message-----
        From:   Adibah Mohamed [SMTP:bmadibah AT NCS.COM DOT SG]
        Sent:   Monday, November 09, 1998 10:54 PM
        To:     NV-L AT UCSBVM.UCSB DOT EDU
        Subject:        Re: Utilisation graphs

        Hi,

          Thanks for your replies.

          I've double-checked the speed and am calculating incoming and
outgoing
        separately, using the formula :

           (ifInOctets * 8 / ifSpeed ) * 100% and ifOutOctets for outgoing
        utilization.

          Although data collection is done sequentially, it still does not
        explain how it can be above the speed.  How do I check the counter?


        Diba

        Douglas Stevenson wrote:
        >
        > I've run into this...
        >
        > Check to ensure that the Spped is set to the proper setting on the
device
        > itself...  ie.. it is possible on some devices to set the speed of
an
        > Ethernet (within the agent) to say 56000...  While the actual
speed may be
        > 10,000,000...
        >
        > Also, if you are looking at utilization on full duplex interfaces,
each
        > side must be calculated separately as it can transmit and receive
        > simultaneously.
        >
        > HTH,
        >
        > Doug...
        >
        > At 08:45 AM 11/9/98 -0800, Connie Logg wrote:
        > >I have run into this anomaly occasionally.  I explain it by
observing that
        > >the data taking is sequential and thus not simultaneous, thus in
high
        > >utilization scenarios, the utilization can calculate out to be
greater than
        > >100%.
        > >
        > >Also one must be careful about counter wrapping.
        > >
        > >
        > >At 09:18 AM 11/9/98 +0100, you wrote:
        > >>What is your expression for the utilization ?
        > >>
        > >>Uwe
        > >>
        > >>>===== Original Message From Adibah Mohamed
<SMTP:NV-L AT UCSBVM.UCSB DOT EDU>
        > =====
        > >>>Hi,
        > >>>
        > >>>  Has anyone encountered instances where utilisation goes
beyond 100%?
        > >>>I know my formula is correct but why do I get a spike in my
utilisation
        > >>>which goes above 100%.  Is there a way to cap it at 100%?
        > >>>
        > >>>Diba
        > >>
        >
>*********************************************************************
        > >" Of course the opinions expressed here are my own. "
        > >
        > >Connie Logg    CAL AT SLAC.Stanford DOT Edu  ph: 650-926-2879
        > >Network Management and Performance Analyst
        > >SLAC (MS 97), P.O. Box 4349, Stanford, CA 94309
        > >
        > >"Happiness is found along the way, not at the end of the road."
        > >
        >
        > ___________
        > Douglas W. Stevenson
        > Managing Consultant - Enterprise Management
        > Predictive Systems Inc.
        > 620 Herndon Parkway
        > Suite 360
        > Herndon, VA 20170
        > (703)925-1600
        > (703)925-1899 (Fax)
        > http://www.predictive.com