Recently, a friend asked me to explain fog computing. Is it different than cloud computing?
The term Cloud in an architectural diagram, as originally used, meant “it doesn’t matter where the computing is”, i.e., the term Cloud meant vague and undefined. As happens so often, a few big data center operators (you know their names) re-defined it to mean “in our far-away high-up location”. This definition supports their marketing but restricts the original purpose of the term.
Fog is taking back the cloud, by pointing out that clouds can be low to the ground and widely dispersed. Edge-based analytics in the IoT, for example, are near the Things rather than far away.
Fog is still as vague, still a cloud. Is intelligent processing it in each sensor? In each collection of similar sensors? In a single integrated system?
The answer is, it depends.
More and more IOT applications are choosing when to transmit data to the cloud, usually near an event or trend. In 2015, IOT systems collected nearly 8 Zettabytes of data. (A Zettabyte is a billion Terabytes). Most of this data is never reviewed or analyzed. Local storage and local event processing can reduce the ever-growing data collection—as well as the network bandwidth it requires.
Local event processing and local storage can reduce the data that needs to be stored in the [high] Cloud, as well as transmitting the data that is transmitted in more efficient batch transfers. Even some simple systems are now transmitting only the antecedent and proximate data to the event up to the cloud.
In a trivial and easy to understand example, consider the web-enabled doorbell, recording video continuously. It maybe has the capacity to keep a few hours of video locally. When the doorbell rings, it can send the 30 sends before and 30 seconds after to the cloud (transmitting the Antecedent and Proximate data). Before this edge processing, users would see the hat of a delivery person walking away. With this intelligent edge processing, the user sees that face of the person coming onto the porch and ringing the bell.
Now extend this thought to whatever data collection you do. Perform simple analysis locally, and quickly. I say quickly because one principle for good IoT is to “analyze quickly, while it still matters”. This approach can preserve privacy while lessening the need for [mostly] unused zettabytes being transferred to the remote data center.
So, the Fog is the Cloud, just one near the action, on the edge. . .and in the Internet of Things, the Edge is where it’s at.