[mrtg] MRTG methodology

[Tyler J. Frederick]

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!

tf.



-- 
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