1.3.2.1 UDP Connection Initialization

In this phase, both endpoints are initialized with mutually agreeable parameters for the connection.

The terminal client initiates the connection by sending a SYN datagram. The terminal client also determines the mode of operation, RDP-UDP-R or RDP-UDP-L, as described in section 1.3.1. The terminal server responds with a datagram with the SYN flag set, along with an ACK flag, to acknowledge the receipt of the SYN datagram. The terminal client acknowledges the SYN datagram by sending an ACK. The terminal client can append the Coded Packets along with the ACK datagram. This datagram indicates that a connection has been set up and data can be exchanged.

All datagrams in this phase – the SYN, SYN+ACK, and ACK – are delivered reliably by using persistent retransmits, irrespective of the mode that the transport is operating in.