Knowledge Base What is DFS (Dynamic Frequency Selection) and how does it work on Deco?
What are DFS channels?
Dynamic Frequency Selection (DFS) enables Wireless routers to switch to another channel if they detect the presence of radar systems, such as weather, military, and airport radars. The DFS channels vary from country to country(https://en.wikipedia.org/wiki/List_of_WLAN_channels). The main benefit of using DFS channels is to increase the number of Wi-Fi channels. It is a legally required Channel Availability Check process to prevent electromagnetic interference at the 5 GHz frequency with the radar.
How does DFS Operate?
Before Operation:
If 5GHz devices with DFS function enabled choose a DFS channel before operation, the devices will detect radar signals for a period of time (about 1 or 10 minutes). And if radar signals are detected on the current channel, the devices will vacate that channel and switch to another channel.
During Operation:
When operating on a DFS channel, 5GHz devices with the DFS function enabled will monitor the operating channel for radar signals continuously. If radar signals are detected on the current operating channel, the devices will also abdicate that channel and choose an alternative channel.
How does DFS affect you?
Some reported Phenomenons on Deco that are related to DFS:
1. A push notification on the Deco APP that "Deco has temporarily switched your Wi-Fi channel width from 160MHz to 80 MHz due to detected radar signals".
160MHz needs 4 consecutive 40MHz 5Ghz channels so it is inevitably working on some of the DFS channels ( U-NII-2A/2C of 5GHz).
It is a legally required Channel Availability Check process to prevent electromagnetic interference at the 5 GHz frequency with the radar. So WLAN devices, like wireless routers need to switch to another channel and drop to 80MHz temporarily.
2. Some mobile devices disconnect when the 5GHz is on 160Mhz and they connect when setting the bandwidth to 80MHz.
As mentioned earlier, the 160Mhz often uses several DFS channels. For WiFi routers, Dynamic Frequency Selection (DFS) enables them to switch to another channel to avoid interference. Wireless NIC manufacturers or software coders might just disable these channels in mobile devices to mitigate liability.