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CISSP 9.11 - Edge & Fog Computing
This episode of the ISC2 Certified Information Systems Security Professional (CISSP) exam prep series asks where computing power should live. Continuing Domain 3, it compares two placement strategies for processing — pushing intelligence all the way out to the devices themselves, or pooling it at a central point inside the local network — and shows why that placement choice shapes both the speed and the security of the systems you design.
What this episode covers
- Edge computing — data and compute sit as close together as possible, cutting latency and saving bandwidth.
- The arc of computing history — mainframe to client-server to cloud, with edge closing the loop.
- Fog computing — scattered devices collect data while a central node in the local network processes it.
- Edge vs fog — distributed processing at the edge versus centralized processing in the fog.
- Shared building blocks — microcontrollers, embedded devices, and connected sensors underpin both designs.
- Placement decisions — choosing where processing happens to fit latency, bandwidth, and trust needs.
Watch the full episode above for the worked examples and detailed explanations of each concept.
Frequently Asked Questions
What is edge computing, and why move processing outward?
Edge computing is a design where data and compute sit as close together as possible. Instead of hauling data to a central brain, each device does its own thinking right where it stands, which cuts latency and saves bandwidth because the work happens near the source.
How does edge computing fit the arc of computing history?
It is the newest turn in a long swing between central and local. First came mainframes, where everything ran on one core machine and thin clients just displayed the results, then client-server pushed real work out to endpoints, then virtualization gave us cloud. Edge completes the loop: control stays central, but execution moves back out to the edge, right next to the user.
What is fog computing, and where does it put the brains?
Fog computing gathers data from many scattered sensors and devices, then hands it to a central point for processing. That processing point sits inside the local network, not out in a far data center, so the intelligence is pooled in the local network, chewing through everything the scattered devices report.
How do edge and fog computing differ side by side?
The split is simply where the thinking happens. In edge computing, each distributed device processes its own data on the spot; in fog computing, the distributed devices only collect, and a central node in the local network does the processing. Edge is many small brains at the ends, and fog is one shared brain in the middle.
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Reference: This article is based on concepts discussed in CISSP 9.11 - Edge & Fog Computing.