private Set<String> devicesForSpec(DegradedNetworkFaultSpec.NodeDegradeSpec nodeSpec) throws Exception {
        Set<String> devices = new HashSet<>();
        if (nodeSpec.networkDevice().isEmpty()) {
            for (NetworkInterface networkInterface : Collections.list(NetworkInterface.getNetworkInterfaces())) {
                if (!networkInterface.isLoopback()) {
                    devices.add(networkInterface.getName());
                }
            }
        } else {
            devices.add(nodeSpec.networkDevice());
        }
        return devices;
    }
Uses the linux utility <pre>tc</pre> (traffic controller) to degrade performance on a specified network device
trogdor/src/main/java/org/apache/kafka/trogdor/fault/DegradedNetworkFaultWorker.java