digraph G {
    node [ shape=box, fontcolor="#ffffff", color="#40a9e3", style="filled"  ]
    label="IPv4 as a service\nby ungleich"

    subgraph cluster_v6_vm {
        label="IPv6 only VM"
        ipv6onlyvm [ label="IPv6 only VM"  color="#ee1100" ]
    }

    subgraph cluster_roadwarrior {
        label="Roadwarrior"

        notebook [ label="Notebook"  color="#ee1100" ]
        desktop [ label="Desktop"  color="#ee1100" ]
    }

    subgraph cluster_roadwarrior {
        label="Roadwarrior"

        notebook [ label="Notebook"  color="#ee1100" ]
    }

    subgraph cluster_internet {
        label="The Internet"

        ipv4internet [ label="IPv4 Internet" shape=oval ]
        ipv6internet [ label="IPv6 Internet" shape=oval ]
    }

    subgraph cluster_dcl {
        label="Data Center Light in Switzerland"

        vpnserver [ label="VPN Server in\nData Center Light" ]

    }

    ipv6onlyvm->ipv6internet [ label="Connect via IPv6" ]
    {desktop,notebook}->{ipv4internet,ipv6internet} [ label="Connect either way" ]
    {ipv4internet,ipv6internet}->vpnserver [ label="Connect to VPN" ]

    vpnserver->{ipv6onlyvm, desktop, notebook} [ label="Route IPv4 address via VPN" ]


}