**2.3.2.2 Non-INVITE-retransmissions**

This behavior applies to all requests other than INVITE. In this mode the sender retransmits a message if no confirmation was received after T1 seconds. The retransmission timer is then increased exponentially up to a maximum retransmission timer called T2. Once this timer is reached the sender continues retransmitting the request every T2 up to a maximum timer (TimerF). Once this timer is reached the sender drops the message and stops the retransmission.
