On 17/09/2013 2:15 PM, Patrick W. Gilmore wrote:
On Sep 17, 2013, at 12:11 , Martin T <m4rtn...@gmail.com> wrote:
Thanks for all the replies!
Nick,
counting traffic on inter-switch links is kind of cheating, isn't it?
I mean if "input bytes" and "output bytes" on all the ports facing the
IX members are already counted, then counting traffic on links between
the switches in fabric will count some of the traffic multiple times.
Patrick,
how does smaller sampling period help to show more traffic volume on
switch fabric? Or do you mean that in case of shorter sampling periods
the traffic peaks are not averaged out and thus peak in and peak out
traffic levels remain higher?
The graph has a bigger peak, and DE-CIX has claimed "see, we are bigger" using
such graphs. Not only did they not caveat the fact they were using a non-standard
sampling method, they have refused to change when confronted or even say what their
traffic would be with a 300 second timer.
That's easy to counter. just estimate some characteristics of the
distribution from the sample, then apply extreme value theory to
renormalize to 300 s.
(My math background talking. I once got similar stuff written into an
ITU-T recommendation for provisioning trunk groups based on limited
traffic samples.)
Tom T.
