Huge difference in incoming traffic counters after upgrade

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Peter Eriksson

Jan 19, 2021, 11:54:40 AM1/19/21
to FastNetMon user group

After upgrading FastNetMon community version from 1.1.4 to 1.1.9 there is a huge difference in incoming traffic counters. The outgoing traffic counters seem to be correct and are the same as before the upgrade. The incoming ones are now about 20% too high, across all hosts, networks and total counters, for both PPS and BPS.

I am using sampled Netflow with a sample ratio of 1024, with both v5 and v9 packets coming from Cisco and Juniper routers respectively.

Anyone have any idea what is going on or have experienced something similar?

Best regards,

Pavel Odintsov

Jan 19, 2021, 1:45:06 PM1/19/21
to Peter Eriksson, FastNetMon user group

We did quite a serious number of changes between these versions and we completely reworked Netflow / IPFIX processing logic but we did not make any changes for traffic calculation logic. 1.1.4 has the only option to manually configure sampling rate in configuration. In 1.1.9 we can read it directly from your routers and in this case you may expect issues when it does not match or you have multiple samplers.

Big number of hosts to monitor can cause such behavior too. Any overloaded cores in htop output?

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Pavel Odintsov
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