Fog computing vs. edge computing: What's the difference?

Fog computing vs. edge computing -- while many IT professionals use the terms synonymously, others make subtle but important distinctions between them.

Fog computing vs. edge computing -- the difference between these two IoT-related concepts depends largely on whom you ask. Here, we break down three ways you might hear these emerging terms used.

1. One and the same. Many IT pros use the terms fog and edge computing broadly and interchangeably to refer to the distribution of compute and storage resources at or near the periphery of the network.

A decentralized edge or fog model enables data to be processed at or near its point of origin rather than at a distant, in-house data center or cloud. This results in lower latency for mobile and IoT devices and less network congestion overall.

2. Separate, but related. Other users use more precise definitions that distinguish between fog computing and edge computing.

The OpenFog Consortium -- an industry group that includes Cisco, Intel, Microsoft and Princeton University -- argues that fog refers to a broad IT architecture that creates a complex web of dynamic interconnections. These interconnections can extend from edge devices to the cloud; shared local compute and storage resources, such as IoT gateways; and other edge devices.

According to OpenFog, fog computing, which is also called fog networking and fogging, standardizes cloud extension out to the edge, encompassing all the space and activity between the two.

Edge computing, in this case, is more limited in scope, as it refers to individual, predefined instances of computational processing that happen at or near network endpoints. With this paradigm, edge computing cannot create direct network connections between two endpoints or between an endpoint and an IoT gateway on its own; for that, it needs fog.

Edge computing infographic

In OpenFog's view, fog computing always uses edge computing. Edge computing, however, might or might not use fog computing. Also, by definition, fog includes the cloud, while edge does not.

3. Location, location, location. Still other IT pros say the use of fog computing vs. edge computing depends specifically on the location of the distributed compute and storage resources. If processing capabilities are embedded directly within a connected endpoint, they call that edge computing. But if intelligence resides in a separate network node stationed between an endpoint and the cloud, such as a local node or IoT gateway, then it's fog.

This was last published in April 2019

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