3.1.2 Timers

The following timers are used by the Remote Desktop Protocol: UDP Transport Extension v2 and MUST be implemented:

Retransmit: This timer is used for indicating that no acknowledgment (section 3.1.1.2.3) has been received for a datagram that was transmitted earlier.

Keepalive at the Sender: This timer is used for maintaining an active connection between the endpoints.<2>

Delayed ACK: This timer is used to indicate that an immediate acknowledgment packet needs to be sent if there are data packets received by the Receiver that have not been acknowledged back to the Sender yet.