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Viewing Network Deviations
The Home > Network Deviations page provides graphs that track your network's Client and Usage information and draw attention to unusual network usage patterns. These graphs can show you, for example, if heavy network traffic is occurring during off hours, or they can be used to detect the time(s) of day when your network traffic peaks.
By default, the graph lines display, in five-minute intervals, the previous 2 hours of client and usage information for the current day of the week averaged out over the last 40 weeks. The shaded area indicates the standard deviation, which defaults to 1. So, for example, if you launch this page at 9:00 am on a Friday, then a 2-hour graph will show the current and average number of connected clients and usage between 7:00 AM and 9:00 AM on all Fridays over the last 40 weeks, with plot points showing the number of clients for every five minutes. You can also select/drag a set of plot points to zoom in and view a more precise time range. Click the Reset zoom button to return to the specified time range. You can change the time range of the graphs to 4 hours, 8 hours, or 1 day using the time-range options in the upper-right corner of this page, and AirWave will remember the new setting the next time the page is launched.
The left graph shows client information - specifically the current and average number of clients over the last 40 weeks during the selected time range. The right graphs show usage information - specifically the current and average incoming and outgoing bits-per-second over the last 40 weeks during the selected time range. The shaded/gray color within the graphs indicates the standard deviation. Any blue lines (Avg Clients, Avg Out Usage) or green lines (Avg In Usage) that appear outside of the shaded/gray area can be considered deviation points because the value does not come within the range of the calculated standard deviation.
This operation can consume a significant amount of CPU capacity as it parses through large amounts of data. Larger deployments you may have to wait up to a minute before seeing the initial graph plot points. In addition, this page does not automatically refresh, rather it refreshes each time this page is selected and/or each time you click Refresh. As a result, if you click this page, navigate away, and then return to this page, the page will begin to load again. If your network includes a large amount of data, then a best practice is to open this page in a new tab before navigating to another page. In this case, the Network Deviations page will continue to load while you continue to work in AirWave.
Figure 1 Home > Network Deviations page
The first time this page is launched, the graphs will display information for all devices in the Top folder. To specify a different folder, simply select one from the folder drop down in the upper-right corner, and then refresh the page. AirWave will remember the new setting the next time that the page is launched.
By default, the graphs display average and standard deviation information for the current time over the last 40 weeks. Click the gear icon in the upper right corner to change these defaults. AirWave will remember the new setting the next time that the page is launched.
The Thresholds button is disabled while the page is loading. The Folder drop down is disabled until the first plot points display.
Figure 2 Network Deviations Threshold
How Standard Deviation is Calculated
Plot lines may or may not display outside of the shaded, standard deviation range depending on the SD value specified from Thresholds button. Refer to the following example to review the way that standard deviation is calculated.
Standard Deviation Example
Assumptions:
Mean: 5
Standard Deviation: 2
SD(1):
-------
1*SD +- Mean
1*2 +- 5
2 +- 5
Normal Range: 3 - 7
SD(2):
-------
2*SD +- Mean
2*2 +- 5
4 +- 5
Normal Range: 1 - 9
SD(3):
-------
3*SD +- Mean
3*2 +- 5
6 +- 5
Normal Range: 0 - 11 (-1 is not considered, so 0 is taken)
Given the information above, if the Average Client Count over the last 40 weeks is 5, then this is not an anomaly (deviation) for any SD value. On the other hand, if at one point the client count was 8, then this would be an anomaly for SD1, whose normal client range is from 3-7. The plot point would appear outside of the shaded area when the standard deviation is set to 1, but it would be normal from a standard deviation of 2 or 3.
