220.127.116.11 Disconnect-Related Timers
There are two timers related to disconnect processing:
The first timer is started by an SSTP peer when it has initiated a disconnect by sending the Call Disconnect message to the SSTP far end. If the SSTP peer receives a Call Disconnect Acknowledge message from the SSTP far end before the timer expires, then it MUST cancel the timer and immediately clear the connection state to clean up the connection.
When the SSTP far end receives a Call Disconnect message, it responds with a Call Disconnect Acknowledge message and then starts the second timer (that is, TIMER_VAL_DISCONNECT_STATE_TIMER_2). This timer ensures that the SSTP peer receives the Call Disconnect Acknowledge message that is sent by the SSTP far end.
The first timer SHOULD be set to 5 seconds. The second timer SHOULD be set to 1 second.