[mrtg] MRTG methodology

Tyler J. Frederick tyler at sportsline.com
Thu Sep 27 18:41:13 MEST 2001

Hi guys,

I'm new to the list so bear with me if this is answered elsewhere or in
previous posts.  (I've searched the archive and scoured the web page, so I
don't think it is.)

I'm curious as to how MRTG actually works.  I know pretty much what's
going on, but I'm about to use MRTG to graph some information on a
Firewall-1 machine and want a better understanding.  This is assuming the
default interval of 5 mins.

Let's look at a router for example.  It queries the ifInOctets and
ifOutOctets OIDs, which I understand to be cumulative counters of the
amount of bytes that have traversed that interface.

I think my question is this.  What happens if those counters were to be
cleared? (by a 'clear counters' on a Cisco for example).  Would all my
graphs have a spike down to zero on them?  How exactly does the averaging
work?  I know I can put the 'guage' keyword in the options to signify that
the data is a 'current status' measurement and not a cumulative one, but
I'd like to better understand how MRTG does it's data calculation.

Thanks in advance!


Tyler J. Frederick
Systems Engineer/CCSE
Sportsline.com, Inc.

Unsubscribe mailto:mrtg-request at list.ee.ethz.ch?subject=unsubscribe
Archive     http://www.ee.ethz.ch/~slist/mrtg
FAQ         http://faq.mrtg.org    Homepage     http://www.mrtg.org
WebAdmin    http://www.ee.ethz.ch/~slist/lsg2.cgi

More information about the mrtg mailing list