{
    "hosts": {
        "h1": {"ip": "10.0.0.1/24", "mac": "08:00:00:00:01:11",
               "commands":["ip route add 10.0.0.0/24 dev eth0"]},
        "h2": {"ip": "10.0.0.2/24", "mac": "08:00:00:00:02:22",
               "commands":["ip route add 10.0.0.0/24 dev eth0"]},
        "h3": {"ip": "10.0.0.3/24", "mac": "08:00:00:00:03:33",
               "commands":["ip route add 10.0.0.0/24 dev eth0"]},
        "h4": {"ip": "10.0.0.4/24", "mac": "08:00:00:00:04:44",
               "commands":["ip route add 10.0.0.0/24 dev eth0"]}
    },
    "switches": {
        "s1": { "runtime_json" : "sig-topo/s1-runtime.json" }
    },
    "links": [
        ["h1", "s1-p1"], ["h2", "s1-p2"], ["h3", "s1-p3"], ["h4", "s1-p4"]
    ]
}