3.2.4 Controllers in the fog

Sensors collect data and forward that information to the controllers. The controller can forward any information gathered from the sensors to other devices in the Fog, as shown in the figure.

Recall the example of a smart traffic light system. The sensors detect and report activity to the controller. The controller is able to process this data locally and determine optimal traffic patterns. Using this information the controller will send signals to actuators in the traffic lights to adjust traffic flows.

This is an example of M2M communication. In this scenario, the sensors, actuators, and the controller all exist within the Fog. That is, information is not forwarded beyond the local network of end devices.

Processing data in the fog is occurring in less traditional networking environments. New places in networking, or PINs, are created as more things in various industries connect to the network. Field Area Networks (FANs) place hardened equipment in harsh or exposed environments. Smart Grid is an example of a FAN. More detailed information is available from the Cisco website Field Area Network.