**4. Fog computing characteristics**

Fog Computing is a highly virtualized platform that overcomes the limitation of interaction between end devices and the cloud. Fog computing devices are mostly located at the edge of the network; they bring the paradigm of cloud computing, such as computing, networking, and storage services, to the edge of the network. It provides all the benefits of the cloud to the edge devices and compensates for the limitations of the edge and IoT devices. Fog computing enhances the performance of edge computing by reducing the time, bandwidth, and energy requirements that would have been expended in IoT-Cloud communication. In this section, the characteristics of fog computing from the works of [12, 21, 27–30] are highlighted below:

#### **4.1 Edge location**

One of the major characteristics of fog computing is that it contains fog nodes located at the edge of the network. The FNs are in the same environment and location where the IoT devices generate their data [31]. From the perspective of the Communication Service Provider, FNs are the cloudlets attached to the base stations that are distributed with the service masts/tower [31]. These fog nodes enable the computational ability of the cloud to be performed at the edge of the network.

#### *4.1.1 Location-awareness*

Fog computing supports location awareness applications. The ability of an edge device to be aware of its location through an application is known as location awareness. Location awareness enables location-specific services and information to be available for users when a device enters or leaves a geographical region. This is particularly important for mobile edge IoT devices in applications like the automotive, drone, and health industries. Location-awareness features of the FC network provide important information in resource planning and distribution for equitable, even, and fair service distribution.

#### *4.1.2 Low latency*

The issue of high latency gives rise to the need for FC due to the distance between edge devices and cloud systems. FC alleviates this high latency by providing the network's edge fog nodes. FN supports end devices with cloud services at the network's edge, including applications with low latency requirements (e.g., gaming, video streaming, and augmented reality). FNs make the cloud's robust computational and storage capacities available to the edge devices in the shortest time possible since they are located almost in the same network and environment as the IoT and other edge devices needing their services [32].

#### *4.1.3 Geographical distribution*

The cloud is more centralized, while in contrast, FC uses services and applications that requires vastly distributed deployments. FC contains varieties of FN, which are widely distributed, and are placed in different places such as highways, tracks, network infrastructure, and even in residential buildings. Therefore, fog computing

consists of widely distributed fog nodes that enable data processing, storage, and computing with IoT devices.
