Article Applies To: 

Gen5:
NSA E8500, NSA E7500, NSA E6500, NSA E5500, NSA 5000, NSA 4500, NSA 3500, NSA 2400, NSA 2400MX, NSA 240
Gen5 TZ Series: TZ 100, TZ 100 Wireless, TZ 200, TZ 200 W, TZ 210, TZ 210 Wireless,
 
Firmware/Software Version: SonicOS Enhanced 5.5.x. and higher

Problem Definition:

The following error appears on a SonicWALL UTM firewall controller when the SonicPoint Provisioning Profile is configured with a too small Beacon Interval.
"Error: Too small 802.11n Beacon Interval for Virtual Access Point."
This Knowledge Base article aims to be a succint guide to the SonicOS Administrator that needs to configure the beacon interval in the SonicOS wireless settings.

Resolution or Workaround:

If you are not segmenting your wireless network, by using no Virtual Access Points (VAPs) or a provisioning profile with a VAP Group including only one VAP configured, then the beacon interval is to be at least 100 ms, and not greater than 1000ms.
If you are instead segmenting your wireless network, by making use of a provisioning profile with a VAP Group including multiple VAPs, then the beacon interval is to be at least 100ms multiplied by the number of the VAPs added to the VAP Group. For example, if you are using a VAP Group that groups 3 VAPs, then the minimum Beacon Interval is intended to be 300ms (i.e. 3x100ms). When segmenting the wireless network (using multiple VAPs), the maximim value for configuring the beacon interval is anyway set to be 1000ms.

If the administrator configure a too small beacon interval, then the SonicOS Enhanced will show the message: "Error: Too small 802.11n Beacon Interval for Virtual Access Point", not validating the change to the settings.


How to Test:

Step 1: Setting an invalid beacon interval in the SonicPoint provisioning profile radio settings.
Add a new VAP Group "VAP Giovanni", grouping 3 VAPs (e.g. "Gio1", "Gio2" and "Gio3"). 



Access the Provisioning Profile in edit mode, and change the beacon interval from the current value to 200ms: the SonicOS Enhanced will return the message "Error: Too small 802.11n Beacon Interval for Virtual Access Point". This is because the minimum value to be accepted is Nx100ms, where N is the number of VAPs in the Virtual Access Point Group defined in the SonicPoint Provisioning Profile.



Step 2: Setting a valid beacon interval in the SonicPoint provisioning profile radio settings.
Starting from Step 1, access the SonicPoint Provisioning Profile in edit mode, and change the beacon interval to a value included between 300ms and 1000ms. This time the SonicOS will accept the value and validate this setting.
You can verify that this has been saved in the settings from then SonicPoint Provisioning Profile view panel