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

    v4host [ label="IPv4 hosts" ]
    v6host [ label="IPv6 hosts" ]

    nat64gw [ label="P4 switch: NAT64" ];
    controller [ label="P4 Controller" ];

    nat64gw--v4host;

    v6host--nat64gw;

    nat64gw--controller [ label="custom protocol" ];

    { rank="same" nat64gw, controller };


}