To configure the Radius Accounting on the the SonicWall please follow the below instructions.
Navigate to SonicPoint | SonicPoints page. Click Edit button for the SonicPoint/SonicWave. Click the Radio Basic tab and choose WPA-EAP, WPA2-EAP or WPA2-AUTO-EAP as authentication type.
Click the Configure button at Radius Server Settings area.
From the popup window, configure the IP, Port and Secret for Radius Accounting Server | Click the OK button to submit the configuration.
NOTE: Radius Accounting Server and Radius (Authentication) Server do not need to be the same.
After completing the configuration, you can logon the radius server to check the accounting log. In this case, the Radius server is set on Windows Server 2008 and the accounting statuses are logged in the local file. Open the local log file, you can find the accounting information as below.