nanog mailing list archives

Re: MRTG in Fourier Space


From: Rubens Kuhl <rubensk () gmail com>
Date: Fri, 24 Apr 2009 01:07:37 -0300

As IP traffic is assumed to be self-similar, my EE origins tell me to
look for parameters that could measure it from stochastic process
theory. On a Google search this paper sounded interesting:
http://www.sparc.uni-mb.si/OPNET/PDF/IWSSIP2007Fras.pdf
(...) We estimated
the Hurst parameter (H) for the arrival process, and the
fitted distributions for the measured data (packet size and
inter-arrival processes). Using the autocorrelation function of
the process, we determined long-range or short-range
dependence.
distribution and its parameters. The Hurst parameter was
estimated using three graphical methods (variance, R/S,
and periodogram methods). Distribution and its parameters
were estimated using fitting tools. (...)

Doing it in RRD-time seems like a challenge, though.

It might be easier to plot fractals from the data source if your
target audience is made of humans, because they will spot patterns
real fast with much less number crunching.


Rubens


On Tue, Apr 21, 2009 at 9:12 PM, Crist Clark <Crist.Clark () globalstar com> wrote:
Maybe a slightly off topic math-geek kind of question to
take time out from the ARIN/death-of-IPv4/IPv6-evangalist
thread of the week.

Has anyone found any value in examining network utilization
numbers with Fourier analyses? After staring at pretty
MRTG graphs for a bit too long today, I'm wondering if
there are some interesting periodic characteristics in the
data that could be easily teased out beyond, "Well, the
diurnal fluctuations are obvious, but looks like we may
have some hourly traffic spikes in there too. And maybe
some of those are bigger every fourth hour."

A quick Google search turned up nothing at all. With many
EE-types who find their way into network operations and
wannabe-EEs already there, I found that maybe a little
surprising. I know the EEs love Fourier transforms.





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