PacketShaper and Netflow.

[moneyworks]

Hi there,

Recently, I checked on the utilisation graph of PacketShaper(PS) and Netflow(NF), found that WAN output for both are not tally.

We only have PS connected to the WAN router. Hence, the router WAN interface traffic should be the same as PS WAN interface right?

Connection as below:

(LAN)-(PS)-(Router)-(WAN)

Does anybody has the formula for PS and NF? Appreciate for your answer. Thanks.

[b.speltz]

Does the frequency (how often) at which the packet shaper sample the data match with the frequency of Netflow. Because by default the Netflow samples the data after a different threshold when compared with the packet shpaer. That may be the reason you are seeing different ouput values for the same WAN interface on the packet shaper when compared to Netflow

[moneyworks]

I did tried to plot the graph based on the same frequency (one day) but still seems to be different. Do you know the formula behind the calculation?

[moneyworks]

Hi there,

Found Netflow peak utilisation data giving some reading more than the physical bandwidth. How could this be possible? Is there any reason for this? What is the formula used to calculate the utilisation?

[smcarthur]

Netflow uses flows. This usually requires data from switching cache which means that it comes in one interface and leaves via another. You may have traffic which PS sees but which is not actually switched through router and does not appear in netflow.

You may have to check the interface index to see thaqt the info matches. The utilisation usually is calculated by the Management software and this info may be incorrect.