Deduced message sequence for setting up VRPN connections

connectionsetup.msc

msc {
    hscale = "2";
    
    a [label="Server"], b [label="Client (UDP Capable)"], c [label="Client (TCP Only)"];
    # A little vertical space
    |||;
    a box a [label="Listen on TCP port 3883", linecolor="red"];
    a box a [label="Bind to UDP port 3883", linecolor="orange"];
    ...;
    |||;
    # Start of client trying to connect.
    --- [label="Client starts trying to connect to server, with UDP permitted"];
    b box b [label="Start listening on arbitrary TCP port X\nvrpn_get_a_TCP_socket", linecolor="blue"];
    b->a [label="Send 'clientip X' to UDP 3883", linecolor="orange"];
    a->b [label="Connect to clientip X over TCP", linecolor="blue"];
    b->a [label="Send client VRPN magic cookie over TCP", linecolor="blue"];
    a->b [label="Send server VRPN magic cookie over TCP", linecolor="blue"];
    b box b [label="Bind to arbitrary UDP port Y\nvrpn_Endpoint_IP::finish_new_connection_setup", linecolor="purple"];
    b->a [label="Send 'clientip Y' over TCP for low-latency connection request\nvrpn_Endpoint_IP::pack_udp_description", linecolor="blue"];
    b->a [label="Send type/sender descriptions", linecolor="blue"];
    b rbox b [label="status: connected"];
    a->b [label="Lossy, low latency (tracker) messages now sent over UDP", linecolor="purple"];
    
    ...;
    |||;
    # Start of client trying to connect.
    --- [label="Client starts trying to connect to server with TCP-only"];
    c->a [label="Connect to server over TCP", linecolor="red"];
    a box a [label="Accepts connection and notes that endpoint is TCP-only."];
    a->c [label="Send client VRPN magic cookie over TCP", linecolor="red"];
    c->a [label="Send server VRPN magic cookie over TCP", linecolor="red"];
    c rbox c [label="status: connected"];
    
}