From the "help" guide on the controller....
- Session lifetime — Specify a session lifetime, in hours, for the new guest account. The default 0 value specifies no limit to the session lifetime. The session lifetime is the allowed cumulative total in hours spent on the network during the account lifetime.
So if he is doing nothing for an hour the account is not longer valid as the user consumed his one hour session lifetime (active time).
Might be that this one helps to unterstand it better.....
![eddc1ad5960a4e09ab7b9f92b144ad89_RackMultipart20151021-30144-18zqjhr-guest_ticket_times_inline.png eddc1ad5960a4e09ab7b9f92b144ad89_RackMultipart20151021-30144-18zqjhr-guest_ticket_times_inline.png](/t5/image/serverpage/image-id/826i40D43DAEDE079C6C/image-size/large?v=v2&px=999)
-Ron