Troubleshooting Tip: FortiAP are unable to broadcast a SSID on 6E band

[Adolfo_Z_H]

Description

This article describes how to troubleshoot FortiAP unable to broadcast an SSID on the 6E band.

Scope

FortiAP 6E.

Solution

Ensure both FortiAP and FortiGate are using the latest GA version of each of these products, FortiAP v7.4.4 and FortiGate v7.2.5 or higher. Check that there are no regionalization conflicts and resolve them appropriately (country code mismatch): Technical Note: Changing country setting on a wireless controller 

The most likely reason a 6GHz SSID cannot be observed being broadcast is because SSID broadcasting in the 6GHz band works differently from the conventional 2.4GHz and 5GHz bands.

There are two ways WiFi 6E channel discovery works: Out-of-Band Discovery and In-Band Discovery.

• Out-of-Band Discovery: Uses a method called Reduced Neighbor Report. Essentially, it broadcasts the 6GHz SSID channel through the 2.4GHz and 5GHz beacon frames.
• Enable the 2.4GHz and/or 5GHz band and  6GHz channels will be discoverable.
• Check the beacon frames in an over-the-air packet capture, the 6GHz SSID will be announced there.
• This discovery method is preferred by client devices and access points.

• In-Band Discovery: Client devices scan the 6GHz band directly but only on a Preferred Scanning Channel (PSC) set. This method is unreliable because it varies between different client device vendors. For example, some Apple devices capable of 6E only perform Out-of-Band Discovery to discover 6GHz SSIDs.

• For 6GHz SSIDs to be directly detectable, they need to be on a Preferred Scanning Channel (PSC).
• PSC channels: 5, 21, 37, 53, 69, 85, 101, 117, 133, 149, 165, 181, 197, 213, 229.
• If Wi-Fi device supports the In-Band Discovery method, please specify that the 6GHz SSID channel is channel 5 or one of these.