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Doc ID: FAQ20256
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OctoBox - How does AP discovery works on 6GHz?
There are 2 types of discovery for 6GHz, each with it's own method(s):
In-Band Discovery (with 3 methods)
Fast Initial Link Setup (FILS) [
] [Octobox uses this option]
FILS uses “discovery announcement frames” which are essentially condensed beacon frames. Only crucial information is sent in a FILS frame: SSID, BSSID, and channel.
If FILS is configured, the 6 GHz AP will broadcast an announcement discovery frame approximately every 20 milliseconds.
Unsolicited probe response (UPR) [
An unsolicited probe response (UPR) frame contains all the same information sent in a beacon.
If used, the 6 GHz AP will broadcast a full probe response frame every 20 milliseconds.
Preferred Channel Scanning (PSC) [
This is actually the only method by which Wi-Fi 6E client devices are allowed to send probe requests.
With PSC, client devices are limited to sending probe requests on every fourth 20 MHz channel.
The full list of 6 GHz PSC channels is 5, 21, 37, 53, 69, 85, 101, 117, 133, 149, 165, 181, 197, 213, and 229.
NOTE: "Fast Initial Link Setup (FILS)" and "unsolicited probe response (UPR)" are mutually exclusive, therefore only 1 can use actively used by the AP
Out-Band Discovery (with 1 method)
Using "reduced neighbor reporting (RNR)" introduced in 802.11v, if the AP is WIFI6E capable, it will send a probe response frame that includes RNR information about its 6 GHz radio.
This RNR will serve as enough information for the client device to roam between 6 GHz and 2.4 or 5 GHz networks.
What if the AP is only broadcasting 6GHz? This is an unlikely condition, but nonetheless a potential one. First, scanning can be reduced by limiting the number of channels to be scanned. This is called Preferred Scanning Channels (PSC). The PSCs are the primary channels (20MHz subchannel) of the 80MHz channels. This works well since 80MHz will often be the preferred bandwidth. If however, lower bandwidth channels are used without RNR or additional support from the methods below, it would be very easy for a client to miss this channel which should be a consideration when using PSC with narrower band channels.
Team, B. (2022, September 22). What are preferred scanning channels (PSC) in 6 GHz WIFI?. ACCESS AGILITY.
Thornycroft, P. (2021, July 24). Wi-Fi 6E: How AP discovery works in 6GHz. aruba networks.
Wi-Fi 6E / 6 ghz channel scanning - accessagility. ACCESS AGILITY. (n.d.).
Dumdei, A. (2023, April 12). Something new: AP discovery methods for 6GHz Wi-Fi - Part 2. Cisco Blogs.
Product : WiFi,OCTOBOX