Re: common method to count traffic volume on IX

["Patrick W. Gilmore" <patrick () ianai net>]

On Sep 17, 2013, at 12:11 , Martin T <m4rtntns () 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.

-- 
TTFN,
patrick


> On 9/17/13, Nick Hilliard <nick () foobar org> wrote:
> > On 17/09/2013 14:43, Patrick W. Gilmore wrote:
> > > And yes, DE-CIX is more than well aware everyone thinks this is .. uh ..
> > > let's just call it "silly" for now, although most would use far more
> > > disparaging words. Which is probably why no serious IXP does it.
> >
> > It's not silly - it's just not what everyone else does, so it's not
> > possible to directly compare stats with other ixps.  I'm all in favour of
> > using short (but technically sensible) sampling intervals for internal
> > monitoring, but there are good reasons to use 300s / ingress sum for
> > prettypics intended for public consumption.
> >
> > Nick

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