Sampled NetFlow collects NetFlow data for a subset of traffic on the interface(s) being monitored. Instead of collecting every packet, Sampled NetFlow collects only 1 packet in every N number of packets.
Flow data from protocols like NetFlow are a very light load, typically less than 0.5% of total bandwidth consumption. But Sampled NetFlow helps lower CPU utilization (and to a lesser extent bandwidth) if these are concerns for your monitored device. The trade-off is you’ll lose a bit of granularity in your data. The loss is minimal but increases as your N value increases.
These are the NetFlow sample rates we recommend:
|Data volume (95th percentile)||Recommended sampling rate|
|< 25 Mb/s||1 in 1|
|< 100 Mb/s||1 in 128|
|< 400 Mb/s||1 in 256|
|< 1 Gb/s||1 in 512|
|< 5 Gb/s||1 in 1024|
|< 25 Gb/s||1 in 2048|
If you set a sampling rate on a device, you must set the same sampling rate for the device in Auvik.
Some devices don’t have a setting for sampling rate. For these devices, you’ll need to set a sampling rate of 1 in Auvik.