Make sure that the session timeout is greater than the client idle timeout, otherwise the sleeping client entry would not be created.
After entering the appropriate login credentials for web-auth, the client get authenticated and moves to RUN state.
Now if the client configured is idle for 300 seconds (default idle timeout value) or disconnects from the WLAN it is connected to, then the client will move to sleeping clients.
Once the client is moved to the Sleeping Clients, the timeout session starts and the remaining time before the client entry is deleted/cleared is displayed.
If the client wakes up or joins back to the same WLAN, it doesn't require re-authentication.
the number of sleeping clients that are remembered has increased to 25000 from the previous 9000. A larger number of sleeping clients are remembered even after waking up, on the wireless network with high-scale Cisco WLCs. This eliminates the need for user intervention to re-enter credentials for a greater number of clients.
