CTS 108: Useful Wi-Fi Metrics To Track

From Clear To Send: Wireless Network Engineering Rowell Dionicio and François Vergès

Which Wi-Fi metrics are worth tracking and what can you do with those metrics?
This episode was sponsored by Metageek

Useful Wi-Fi Metrics To Track
Today’s Wi-Fi networks are the main point of access to network resources and have become mission critical service to employees. To monitor the Wi-Fi network, which metrics should you track to show the Wi-Fi network is performing optimally? We list our six useful Wi-Fi metrics worth tracking.
RSSI

* Most looked at metric
* Determines the strength of the signal
* Good to get both from AP and client perspective. Client may hear AP loudly but not the other way around

SNR

* Indication of signal quality
* Difference between the signal and noise
* Example: concert, kids talking over parents

Channel Utilization

* How busy the channel is
* Both 802.11 and non-802.11 traffic
* Congestion and capacity
* If youre seeing high channel utilization you may need to add more capacity
* Tells us if CCI is an issue

Data rate

* Especially useful on the client side
* Tells us how well the client is able to decode the Rx signal
* Tells us how the driver is handling data rates

Retry Rate

* Does it correlate with high channel utilization
* Are basic data rates too high
* If you’re seeing too high (10-15%) retry rate look into lowering data rates, look at potential interference, maybe even hidden nodes or devices with bad drivers

Association Time

* Why would it take a long time to associate
* Bandsteering could cause long association times because of delayed probe responses
* Are devices scanning DFS channels
* Can client and AP hear each other