## 2 Literature Review  
In VANETs, the significant contribution of the researchers includes (a) a central service directory architecture [13], (b) directory-less service architecture [14; 15; 16], and (c) distributed directory service architecture [17; 18; 19; 20; 15]. In the first portion, based on central service discovery architecture, the researchers proposed a central discovery server to store the service information and re-join a discovery request with the matched discovery outcomes. [PERSON] et al. [21] discussed a three-way link between 5G technology, Software-Defined Networks, and Vehicular AdHoc Networks. The authors concentrated on creating a network balance by highlighting the mobility, security, and performance of software-defined networks (SDN). Some authors of discussed mystery location-oriented and self-reliance protocols for Mobile AdHoc Network routing [22]. They anticipated their views on a secure packet delivery mechanism in MANETs for vehicular communications. [PERSON] et al. [23] discussed the techniques and methods for providing location-based services for users' tools by requiring assistance from Service-Based Interfaces. Other authors [15] proposed the idea of edge computing in Vehicular AdHoc Networks using bit-blocking protocol infrastructure, and elucidated the use and function of wireless Vehicular AdHoc Networks [16]. They differentiated the structure of MANETs and Cellular Networks. [PERSON] et al. [15] clarified the Vehicle-to-Vehicle (V2V) communications using peer-to-peer networks by employing graph theory and consensus algorithm. In addition, some scholars omitted the Road Side Units and defined the serial communication between vehicles moving along the road, and conducted three focus groups and eight individual interviews to address trust and privacy matters in peer-to-peer networks [17]. [PERSON] et al. [18] provided a visual paradigm of VANET in a 5G technology-based network. [PERSON] et al. [19] described the concept of vehicular cloud by using P2P routing protocols to prevent road accidents, monitor traffic, and ensure fast content delivery, and wrote a survey paper on state-of-the-art vehicular communications and future directions for further studies [19; 20]. [PERSON] et al. [24] proposed a self-organized framework for VANETs. They applied mathematical analysis to their proposed framework to enhance security goals. They also evaluated their framework's performance in terms of computation complexity, storage, and communication overhead. By comparing several schemes, they also tested their framework against several types of external attacks. The authors of [25; 26] evaluated the performance of vehicular communication on P2P wireless networks, while the authors of [27; 28; 29; 30] discussed several security issues and challenges in VANETs with multiple dimensions, including P2P wireless networks. Table 2 lists VANET (Vehicular AdHoc Network) routing protocols based on transmission strategy and route formation, while Table 3 consists of the comparison of previous research over vehicular communication and VANETs. : \begin{table}
\begin{tabular}{c c c} \hline \hline
**Transmission Strategy** & **Route Formation** & **Routing Protocols** \\ \hline Single-hop Broadcasting & Proactive & Beacon-Vector (BV) \\  & & Global Internet Connectivity for Vehicular AdHoc Networks (GLOVE) \\  & & Position-based Opportunistic Routing (POR) \\  & Reactive & Intersection-based Routing (IBR) \\  & & Traffic-aware Routing for Isolated Nodes (TRAIN) \\  & & Emergency Message Transmission Protocol (EMTP) \\ Multi-hop Unicast & Proactive & Distance-Based Clustering (DBC) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Listing VANET (Vehicular AdHoc Network) routing protocols.