# Advancing the State of the Fog Computing to Enable 5G Network Technologies
## 5 Overview of Fog Computing
### Fog Physical Network Architecture
#### 5.2.2 Emerging Technologies for Fog Networks  
FC accommodates and allows three kinds of network connections, as given below; the wireless connections between edge devices and fog nodes, the wireless and wired connections among the fog nodes, and the wireless and wired connection between fog nodes and cloud data centers. These wireless communication technologies sustain fog applications. However, mobile fog computing supports the operation of Bluetooth, ZigBee, Wireless Local Area Network (WLAN), and 3G/4G. Fog computing architecture also supports many other communication technologies, and these technologies are further explained in the following subsections. Network Function Virtualization (NFV)  
NFV offers a novel approach towards creating, managing, and delivering network services. One of the prominent functions of NFV is that it detaches the activity of networks from the owned device by abstracting the device through virtualization techniques. It makes it possible for resource management of network services by delivering flexible services as well as fully ensuring the growth and improvement of new services [41]. NFV integrates varying virtualized parts or components like switches and gateways. These components can be virtualized and kept on fog nodes for easy resource management, storage, computation, communication of geographically dispersed fog networks as well as harmonizing other functions [42; 43; 44]. Software Defined Networking (SDN)  
It is an emerging platform for networking that was designed to control programs via software applications intuitively. Its physical architecture allows it to delink the data component from its control component. It controls communication via centralized server route nodes [45]. Moreover, its physical structure allows flexibility, scalability, and capability of being programmed. SDN removes dependentembedded network devices such as switches and routers. It can also rid varying stemming from different network devices. Users are empowered to lay down their own rules and regulations of routing and transmitting networks, which provides flexible communication [46]. SDN plays a vital role in fog computing by competently managing diverse fog networks as well as offering solutions to reoccurring challenges [47]. These challenges include uneven connectivity and increased loss in packet data [48]. SDN can overcome the challenges in fog computing vehicle networks. It was proposed in the study [49], which suggests that SDN and fog computing supported a novel ad hoc network design known as FSDN for vehicles. The proposed study was aimed to improve the scalability, flexibility, uneven and poor connectivity-related network problems, and this is done by optimizing the use of resources and lessening latency. Long-Reach Passive Optical Network (LRPON)  
Long-reach Passive Optical Networks (LR-PON) technology is a better and improved version of the conventional Passive Optical Network (PON). The reason is that it saves costs to deploy fiber optics that are used in home buildings, offices, and roadways. LRPON network reaches stretched up to 100 km using several Optical amplifiers. It makes it easy for the consolidation of network processes over a wide area [50]. LRPON has a special use in fog computing, especially with regards to applications that are sensitive to latency and bandwidth, such as smart homes and smart industry services [43]. It is suggested that the enhancement of network design should assimilate fog computing and LRPON. Content Distributed Network (CDN)  
CDN is the bulwark that delivers content via proxy servers located at the edge of the Internet. It is an Internet-based cache network that takes the users and loads distance as factors of every node, as well as the connection status. The content that is in proximity to the user is then transmitted to the proxy server. Thus, this can curtail the information retrieved from either users or readers from faraway sites and improve the response speed [51].