# An Overview of Fog Computing and Edge Computing Security and Privacy Issues
## 3 Edge Computing Overview  
In the past few years, there has been a change observed in the trend of computing which is pushing the service of clouds towards the edge of the networks. In other words, the computing operations and services are being shifted from network core to the network edge. This emerging technology is referred to as edge computing. Edge computing is different from fog computing technology with respect to the computing location. In fog computing network, local area network (LAN) performs the job of a gateway, whereas in an edge computing network, smart devices such as programmable automation controller  
Figure 2: Cloud, fog and edge interconnection.  
(PACs) perform computing operations. The reason behind the evolution of edge computing concept is to overcome the high latency and energy consumption service issues of Cloud computing, and allow low-latency computation offloading services for resource-constrained devices and Internet-of-Things (IoT) applications. Moreover, it also provides the advantages of content caching and storage services which help in managing high network traffic.  
The key feature of edge computing include:  
* Very low latency.
* Reduced bandwidth limit.
* Flexibility in deployment.
* Automation.  
Edge computing is the main domain which covers a family of related technologies as sub-domains such as cloudlet, mobile cloud computing, and multi-access edge computing. All these sub-domains are based on the concept that computational resources should be present at the edge where network encounters the real demand challenge, which leads to:  
1. Gain of fast access to the computation resources by the end users.
2. Reducing the traffic load on network core significantly.  
Recent estimation shows that in the coming few years, there will be a deployment of tens of billions of Edge devices with exceptionally high processing speeds. This upcoming paradigm is called mobile edge computing (MEC), also referred to as multi-access edge computing (MEC) [13; 15]. MEC is an emerging technology that provides storage and mobile computing resources at the edge of the network, for easy accessibility to the users and increase the efficiency of the edge computing [16]. It offers a low latency, high bandwidth, and real-time service environment that users can enjoy without any computational complexity [17]. In MEC architecture, the cloudlets holding data, also referred to as multitenant data centers, are placed near base stations (BSs) and access points (APs), so that users can easily run real-time applications without any delay and complex computing, on low-resource mobile devices with enhanced quality-of-service (QoS) [18]. Figure 3 shows some of the applications for edge computing.  
While on the one hand, edge computing allows better experience and delay-free services, on the other hand, it also faces numerous challenges such as delay, bandwidth cost, high energy consumption, computational offloading, security, and quality of service (QoS). Edge computing can provide many solutions for different fields including factory floors, telecommunication companies and industrial automation.  
Now that we have a good understanding of the concept of cloud computing, edge computing and fog computing and the difference between each of them in the next chapter we will discuss the security of both fog computing and edge computing and how their unique characteristic highlighted new privacy and security issues.  
Figure 3: Edge computing applications.