DCS and DFS


Userlevel 2
Hi,

I have a quick question regarding DCS and DFS.

Are they independent of eachother?

The scenario being, setting DCS to monitor mode and configuring APs with static a channels.

If the AP uses a DFS channel, would it change if it detected RADAR without DCS in active mode?

I assume it would but just wanted to clarify.

We've had a Wi-Fi survey done of our site and have details re specific channels for each AP.

Thanks
Ian

4 replies

Userlevel 4
Hi Ian,

Dynamic Channel Selection (DCS)
  • DCS allows a Wireless AP to monitor traffic and noise levels on the channel on which the AP is currently operating. DCS can operate in two modes:
  • Active: When DCS is enabled in active mode and traffic or noise levels exceed the configured DCS thresholds, an alarm is triggered and an information log is generated. In addition, the AP ceases operating on the current channel and ACS is employed to select an alternate channel for the AP to operate on. DCS does not trigger channel changes on neighbouring APs.
  • Monitor: When DCS is enabled in monitor mode and traffic or noise levels exceed the configured DCS thresholds, an alarm is triggered and an information log is generated. The DCS monitor alarm is used for evaluating the RF environment of your deployed AP.
However when in the scenario described, whereby the AP detects radar, it will be forced to change to a non-DFS channel, regardless if DCS is in active or monitor mode.

https://gtacknowledge.extremenetworks.com/articles/Solution/Identifi-access-points-moving-from-their...

For more control over what non-DFS channel is selected an option is to give the DFS configured AP’s a predetermined non-DFS channel to switch to in the event of a positive radar scan.

Please take into consideration that the weather channel includes 5600-5650MHz sub-bands and requires a 10-minute listening period before the AP can provide wireless service.

Hope this helps.

- Sam
Userlevel 2
How do we do this? I have not come across this option in the controller AP set up.
"For more control over what non-DFS channel is selected an option is to give the DFS configured AP’s a predetermined non-DFS channel to switch to in the event of a positive radar scan."
Userlevel 5
Hello Taylor,

the channel config is a per AP and per Radio configuration (see picture below).
DFS to avoide Radar signals is only relevant in 5 GHz.

You can select for example "All Non-DFS-Channel" or a "Custom" plan. Push the "Configure" button after choosing "Custom"!!! to select the appropriate channels.



Regards
Stephan
Userlevel 5
Hello lan,

Here is one script to explain DFS channel when you create a 5GHz WiFi Channel Plan.

https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-create-a-5GHz-WiFi-Channel-Plan/

Best regards,
Bin

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