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