Interface Bandwidth widget sampling rate

Question

when FGT is collecting tx/rx traffic for specific interface to draw graph, what is options used in this graph ? [i mean inside FG itself , collected logs not yet exported to FMG / or FAZ ]

what is sampling rate for traffic , is it based on time , packets , etc ? [please provide reference]

--

then when its sent to FMG i see on fresh logs it can show up to 5 minutes distance , then if we explored old graph , distance is compressed to about 30 minutes [please provide reference]

FortiGate

FortiManager

Dhruvin_patel · Accepted Answer

Greetings!

To answer your questions:

When FortiGate is collecting transmit (TX) and receive (RX) traffic for a specific interface to draw a graph internally (not yet exported to FortiManager or FortiAnalyzer), the sampling rate for the traffic is based on time. The bandwidth graph is calculated using data points collected at specific time intervals. For example, in the one-hour graph, there is 1 data point every 3 minutes, and in the 24-hour graph, there is 1 data point every 72 minutes. This means that the sampling rate is time-based, with data points averaged over specific time periods.

When the collected logs are sent to FortiManager (FMG), you may notice that on fresh logs, the data can show up to a 5-minute interval. However, when exploring older graphs, the time interval is compressed to about 30 minutes. This compression of data intervals is due to the way the data is aggregated and displayed in the reporting tools. As mentioned earlier, the longer the reporting period, the fewer data points are displayed, leading to a compression of the time intervals shown in the graph.

For more detailed information, you can refer to the Bandwidth difference between Dashboard interface widget and FortiView > Interfaces section in the provided context.

https://community.fortinet.com/t5/FortiGate/Bandwidth-difference-between-Dashboard-interface-widget-and/ta-p/211842

https://community.fortinet.com/t5/FortiAnalyzer/Technical-Tip-Bandwidth-Over-the-Time-for-specific-interface-in/ta-p/293955

https://community.fortinet.com/t5/FortiGate/Technical-Tip-Interface-Bandwidth-Widget-Displays-Incorrect/ta-p/364434

https://community.fortinet.com/t5/FortiAnalyzer/Technical-Tip-Interface-bandwidth-difference-between-Fortigate/ta-p/286703

Regards!

Dhruvin_patel · Answer

Hello!

To increase the number of data points displayed in a report on FortiGate for more accurate graphs, you can adjust the "top-n" value for the specific chart ID associated with the data you want to visualize. By default, some charts in the local report display only the top 10 items. You can customize this value to show more data points.

Here are the steps to set the number of data points (top-n) for a specific chart ID on FortiGate:
1. Access the FortiGate CLI.
2. Navigate to the report layout configuration:
```
config report layout
edit "default"
```
3. Select the specific chart ID you want to adjust:
```
config body-item
edit <chart ID>
```
4. Set the desired number of data points (top-n):
```
set top-n <value>
```
5. Save the changes and exit the configuration:
```
end
end
```

The default value for the number of data points displayed in a report on FortiGate is set to 10. By following the steps above, you can customize this value to show more data points for a more detailed and accurate representation in your graphs.

https://community.fortinet.com/t5/FortiGate/Technical-Tip-Increasing-value-of-top-to-populate-in-FortiGate/ta-p/201225

https://community.fortinet.com/t5/FortiGate/Customizing-reports-generated-by-FortiGate/ta-p/195461

Best Regards!

Dhruvin Patel

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