Billion BIPAC 8500 User Manual page 72

Billion BIPAC-8500 / 8520 SHDSL VPN Firewall Bridge / Router
Mode: You may select Stateful or Stateless mode. The key will be changed every 256
packets when you select Stateful mode. If you select Stateless mode, the key will be
changed in each packet.
Idle Time: Auto-disconnect the VPN connection when there is no activity on the
connection for a predetermined period of time. 0 means this connection is always on.
Click Apply after changing settings.
Chapter 4: Configuration
68