Flow smoothing
The sFlow-RT real-time analytics engine includes statistical smoothing. The chart above illustrates the effect of different levels of smoothing when analyzing real-time sFlow telemetry.The traffic generator in this example creates an alternating pattern: 1.25Mbytes/second for 30 seconds followed by a pause of 30 seconds. Smoothing time constants between 1 second and 500 seconds have been applied to generate the family of charts. The blue line is the result of 1 second smoothing and closely tracks the traffic pattern. At the other extreme, the dark red line is the result of 500 second smoothing, showing a constant 625Kbytes/second (the average of the waveform).
There is a tradeoff between responsiveness and variability (noise) when selecting the level of smoothing. Selecting a suitable smoothing level depends on the flow analytics application.
Low smoothing values are appropriate when fast response is required, for example:
- DDoS detection
- Leaf and spine traffic engineering using segment routing and SDN
- Internet router using merchant silicon
- Real-time traffic visualization using Netflix Vizceral
- Real-time web analytics
- Real-time visibility and control of campus networks
Generating the chart
The results described in this article are easily reproduced using the testbed Continue reading








