Peter,

> On 13 Feb 2018, at 22:49, Peter Shute <psh...@nuw.org.au> wrote:
> 
> Simone Mainardi wrote:
> 
>>> I have this running now, so I can't try creating host pools unless I undo
>> those changes.
>>> 
>>> One thing I've noticed with dynamic interfaces is that if I select one, then
>> click on the chart icon, the traffic peaks seem way too  high. Eg 85Mbps when
>> we only have a 14Mbps link.
>> 
>> Peaks you are seeing are very likely due to the quantized nature of flows.
>> Your netflow exporters do periodic exports of active flows -- say every 2
>> minutes -- so the ntopng/nProbe pair is not able to know what happened
>> during the 2 minutes, it just receives the exported flow at the end of the
>> period. This translates into a potentially high volume of traffic in a very 
>> short
>> period that determines the peak. However, total values over time must be
>> consistent.
> 
> That makes sense. I wonder if it would be helpful to add a note about that on 
> the charts so that people understand their limitations.

Correct, we will add it.

> 
> Does this mean I can still use those charts to look for periods of high 
> usage, but should take the vertical scale with a grain of salt?

Correct. The interface chart with 1-second data points -- say the latest 10 
minutes -- should be taken with a grain of salt on configurations that involve 
flows collection. 
Selecting wider time ranges will automatically average out short peaks and will 
provide you more accurate information.

> 
> Peter Shute
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