Hi friends
i newly make a hotspot network with WLAN interface as hotspot interface and one of lan ports connected to WAN with RB951Ui Router Board.
all things are ok and i can ping internet sites, but when i create a user profile and give it 20 minutes session timeout , it counts down to zero and user session ends, and when he again inputs same credentials he can re-use hotspot internet.
thanks to any reply
my problem is solved 
just i change uptime limits to 20 minutes in user properties tab and it works 