{
    "hosts": {
        "h1": {"ip": "10.0.1.1/24", "mac": "08:00:00:00:01:11",
               "commands":["route add default gw 10.0.1.10 dev eth0",
                           "arp -i eth0 -s 10.0.1.10 08:00:00:00:01:00"]},
        "h2": {"ip": "10.0.2.2/24", "mac": "08:00:00:00:02:22",
               "commands":["route add default gw 10.0.2.20 dev eth0",
                           "arp -i eth0 -s 10.0.2.20 08:00:00:00:02:00"]},
        "h3": {"ip": "10.0.3.3/24", "mac": "08:00:00:00:03:33",
               "commands":["route add default gw 10.0.3.30 dev eth0",
                           "arp -i eth0 -s 10.0.3.30 08:00:00:00:03:00"]},
        "h4": {"ip": "10.0.4.4/24", "mac": "08:00:00:00:04:44",
               "commands":["route add default gw 10.0.4.40 dev eth0",
                           "arp -i eth0 -s 10.0.4.40 08:00:00:00:04:00"]}
    },
    "switches": {
        "s1": { "runtime_json" : "pod-topo/s1-runtime.json" },
        "s2": { "runtime_json" : "pod-topo/s2-runtime.json" },
        "s3": { "runtime_json" : "pod-topo/s3-runtime.json" },
        "s4": { "runtime_json" : "pod-topo/s4-runtime.json" }
    },
    "links": [
        ["h1", "s1-p1"], ["h2", "s1-p2"], ["s1-p3", "s3-p1"], ["s1-p4", "s4-p2"],
        ["h3", "s2-p1"], ["h4", "s2-p2"], ["s2-p3", "s4-p1"], ["s2-p4", "s3-p2"]
    ]
}