As an engineer, I have always known that you do not adjust RX-SOP unless you know what you are doing, as it can cause unpredictable behavior if this is configured improperly. Here are some of the things I've learned on how to optimize RX-SOP value in the real-world high-density deployments:
In a high-density wireless deployment, you will run across co-channel interference no matter how you design your channels and RF. In order to reduce co-channel interference/overall channel utilization, RX-SOP works great to optimize the RF environment.
The way RX-SOP works, the AP can still hear the distance AP noise which are operating in the same channel, but the AP will ignore the energy if it is coming from a distance AP. Adjusting RX-SOP threshold is therefore tricky because it can help reduce the co-channel interference from distance APs, but it could also impact clients who are a little bit further away from communicating to the AP if RX-SOP is adjusted too aggressively. Here are some of my tips to adjust RX-SOP threshold:
- Choose client devices (ideally the devices which are common in your environment) and the areas to test where you'd like to adjust RX-SOP threshold.
- Create a temporary SSID on ONE AP in the test area, so your client doesn't roam between neighboring APs.
- Monitor the AP's view of the test client throughout the cell and the farthest distance where the intended coverage area is for the AP.
- Use the RSSI value to adjust your initial RX-SOP value. Ideally, pad the worst reading by another 15 dB or more, and then make smaller adjustments as needed.
RXSOP is not generally a configuration that you adjust every day or do it on all of the APs, but in any areas where further optimization is needed, this configuration is great to reduce the co-channel interference.
To give a real-world example, with the same number of clients in an AP coverage cell, we were able to reduce the channel utilization from 37% to 17% during a Cisco Live event by adjusting RX-SOP. I hope this is helpful!