## 4 What Is NFV?
### Architecture of NFV  
The NFV architecture encompasses several essential components that are employed together to enable the virtualization and management of network functions. Figure 10 represents the NFV reference architecture with essential components that are shown below: \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Category** & **NFV** & **SDN** \\ \hline \multirow{3}{*}{**Concept**} & Abstracts network functions from conventional devices and encapsulates them as software. & Separates the forwarding plane from the control plane to enable automated and programmable network control. \\ \hline \multirow{3}{*}{**Goal**} & Service providers propose replacing distributed network devices with consolidated ones. & To achieve network hardware devices’ programmability and centralized management and control. \\ \hline \multirow{3}{*}{**Key Aspects**} & 1. Established procedure. & 1. An open and programmable control plane \\  & 2. Hardware-based forwarding functions are detached from dedicated hardware. & 2. Hardware-based traffic forwarding, and decision-making within the control plane. \\ \hline \multirow{3}{*}{**Conflict or Not**} & & The fusion of NFV and SDN introduces a novel network model. NFV enables adaptable service orchestration, while SDN realizes unified management and configuration of network functions. \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Differences between NFV and SDN [89]. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Category** & **NFV** & **Proprietary Network Equipment/Devices** \\ \hline \multirow{3}{*}{**Hardware Used**} & Generic x86-based servers, versatile storage devices, and adaptable switching equipment are utilized. & Dedicated devices are used. \\ \hline \multirow{3}{*}{**Hardware-Software Separation**} & Software is separated from hardware and provided as module components. & Hardware and software are closely integrated, with software functions relying on dedicated hardware. \\ \hline \multirow{3}{*}{**Receptiveness**} & Universal hardware foundation and standardized interfaces enable an open ecosystem through collaboration among multiple parties. & Relying on dedicated services results in a closed system, making it challenging to onboard third-party partners. \\ \hline \multirow{3}{*}{**Network Resilience**} & General-purpose hardware and resource virtualization technologies enable dynamic adjustments of both software and hardware resources to meet specific service demands. & Dedicated devices do not align with virtualization technologies, hindering resource-sharing and flexible scaling capabilities. \\ \hline \multirow{3}{*}{**Upgradation**} & Device upgrades occur swiftly, primarily involving software enhancements. & Deployment of network devices is time-consuming, necessitating both software and hardware provisioning. \\ \hline \multirow{3}{*}{**Operation and Management**} & Virtualizes hardware resources and automates operations and management intelligently. & Upgrading and replacing devices is a complex process, as maintenance involves manual or semi-manual preparations and configurations through the CLI or web-based systems. \\ \hline \multirow{3}{*}{**Service Organizations**} & NFV networks are deployed according to service requirements and can be dynamically orchestrated with flexibility. & Traditional networks operate with relative independence. Converting service requirements into network specifications is not swift, resulting in a sluggish network response. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Differences between NFV and proprietary network equipment/devices [89]. 1. **Virtualized Network Functions (VNFs):** VNFs are the virtual instances of network functions implemented as software-based functions that were traditionally implemented using dedicated hardware. Network functions such as routing, firewall, and network optimization can be implemented using software and deployed and managed on the data centers or in the cloud. 2.