The CLOSED state exists when no connection exists and there is no connection record allocated.

The CLOSE-WAIT state is entered from either a Close request or from the receipt of an RST segment from the remote site. RDP has sent an RST segment and is waiting a delay period for activity on the connection to complete.

The LISTEN state is entered after a passive Open request is processed. A connection record is allocated and RDP waits for an active request to establish a connection from a remote site.

The OPEN state exists when a connection has been established by the successful exchange of state information between the two sides of the connection. Each side has exchanged and received such data as initial sequence number, maximum segment size, and maximum number of unacknowledged segments that may be outstanding. In the Open state data may be sent between the two parties of the connection.

The SYN-RCVD state may be reached from either the LISTEN state or from the SYN-SENT state. SYN-RCVD is reached from the LISTEN state when a SYN segment requesting a connection is received from a remote host. In reply, the local RDP generates an initial sequence number for its side of the connection, and then sends the sequence number and an acknowledgement of the SYN segment to the remote site. It then waits for an acknowledgement. The SYN-RCVD state is reached from the SYN-SENT state when a SYN segment is received from the remote host without an accompanying acknowledgement of the SYN segment sent to that remote host by the local RDP. This situation is caused by simultaneous attempts to open a connection, with the SYN segments passing each other in transit. The action is to repeat the SYN segment with the same sequence number, but now including an ACK of the remote host's SYN segment to indicate acceptance of the Open request.

The SYN-SENT state is entered after processing an active Open request. A connection record is allocated, an initial sequence number is generated, and a SYN segment is sent to the remote site. RDP then waits in the SYN-SENT state for acknowledgement of its Open request.