digraph G {
  bgcolor=transparent

  // Must use the cluster_* prefix
  subgraph cluster_toxo {
    label="desktop @ home";
    color=lightgrey;
    firefox;
    steam;
    pacman;
  }

  subgraph cluster_popho {
    label="server @ OVH";
    color=lightgrey;
    unbound;
    pf;
  }

  internet;

  firefox -> unbound -> pf -> internet [label="domain" fontsize="9" color="darkorange4" fontcolor="darkorange4"];
  firefox -> pf -> internet [label="low BW http(s)" fontsize="9" color="green" fontcolor="green"];
  pacman -> unbound [color="darkorange4"];
  pacman -> internet [label="high BW https" fontsize="9" color="green" fontcolor="green"];
  steam -> unbound [color="darkorange4"];
  steam -> internet [label="high BW udp/?" fontsize="9" color="darkblue" fontcolor="darkblue"];
}