1.3.2 RDP-UDP2 Data Transfer Phase

In this phase, which follows the Connection Initialization Phase, data generated by the users of this protocol is exchanged between the endpoints as shown in the figure "The RDP-UDP2 bidirectional endpoints connection" in section 1.3. The Sender sends a data packet on behalf of the upper layer in the transport stack, and the Receiver receives the packet by sending an acknowledgment (ACK) packet back to the Sender to indicate that the packet has been received. The ACK packet need not be sent as soon as receiving the data packet; the timing for sending the ACK packet can be optimized for best performance. The Sender informs the Receiver of the extent to which the ACK can be delayed and the Receiver can optimize within those parameters. A lack of receiving the proper ACK packets is interpreted by the Sender as a packet loss, and it will retransmit the same packet. This phase ends when either the connection is terminated by the user, or when an endpoint determines that the remote endpoint is no longer present. No protocol-specific messages are exchanged to communicate that the endpoint is no longer present.