digraph G {
    node [ shape="box"];

    rankdir="TB";

    # ORDER OF CREATION IS IMPORTANT FOR ORDERING!

    v6host1 [ label="IPv6 only host" rank="source" ];
    dnsserver [ label="DNS64 DNS server"  ];
    authdns [ label="DNS server\nfor example.com" ];

    nat64   [ label="NAT64 translator" ];
    v4host1 [ label="IPv4 host: 192.0.2.0" ];


    subgraph cluster_dns64 {
        label="DNS request";

        dnsserver;
        authdns;
    }

    subgraph cluster_nat64 {
        label="NAT64 translation";
        nat64;
        v4host1;
    }


    v6host1->dnsserver [ label="ipv4onlyhost.example.com:\nAAAA?" ] ;
    dnsserver->v6host1 [ label="AAAA\n64:ff9b::c000:200" ];
    dnsserver->authdns [ label="ipv4onlyhost.example.com:\nAAAA?" ];
    dnsserver->authdns [ label="ipv4onlyhost.example.com:\nA?" ];
    authdns->dnsserver [ label="NO AAAA record"];
    authdns->dnsserver [ label="A: 192.0.2.0"];

    v6host1->nat64 [ label="Packet for\n64:ff9b::c000:200\ntcp port 80" ];
    nat64->v4host1 [ label="Packet\n for 192.0.2.0\ntcp port 80" ];


}