digraph {
    rankdir=TD
    graph [splines=ortho]
    Switch -> "Internet"
    Switch -> { "4. Thinclient"; "3. Thinclient"; "2. Thinclient"; "1. Thinclient"}
    VBridge -> Switch
    Switch -> FiSiNetz
    subgraph cluster_physisch {
        "4. Thinclient"
        "3. Thinclient"
        "2. Thinclient"
        "1. Thinclient"
    }
    subgraph cluster_virtualisierung {
        label = "Virtualisierung"
        graph[style=dotted];
        Zeus-> VBridge
        Poseidon-> VBridge
        Hades -> VBridge
    }
}