Hi Kamlesh
that ISE error still exists in ISE 2.3 and it was not due to any misconfiguration in the NAD. For many years Cisco has been preaching that the WLC/NAD is sending Accounting Interim updates too frequently and to avoid that, one should set Interim-Updates to 0 seconds in the Cisco WLC 8.x - this has the effect of only sending Interim-Updates if the client association also involves a DHCP event (i.e. client requests DHCP or the IP address of client changes). In the past we used to hard code Interim-Updates to be like 600 seconds or whatever. But if you don't care about the bytes in/out contained in the Accounting updates, then you can save yourself some processing on all systems concerned. But I quite like the Interim updates once in a while so that ISE knows that the session is still alive.
Accounting Start tells ISE the session has started. Accounting Stop tells ISE the session has ended and also releases a Base license. But if the time between these events is more than 24 hours, I don't quite know what happens to the Session table, or to the Licensing table.
