## 1 Introduction  
The technical evolution of MANETs has undergone significant technological breakthroughs. MANETs were first developed in the 1970s with DAPRA's packet radio networks and have evolved through phases of enhanced routing protocols, including DSAR and AODV in the 1990s and more sophisticated techniques addressing security, scalability and energy efficiency in the 2000s. The integration of technologies such as the IoT and 5G has expanded the application of MANETs, allowing for modern communication technology for smart cities and vehicular networks [1].  
MANETs are characterized to be deployed on the fly; hence no exclusive infrastructure is needed, and no wires are involved. As in [1, 2], an ad hoc network arrangement can change actively with time, so it could be an appropriate selection for realistic applications such as data sharing in a business meeting or between military soldiers on the move. In mobile ad hoc networks, mobile nodes cooperate to forward data packets from source to destination node; therefore one of the most significant issues in MANETs is the routing mechanism. Several factors need to be considered in MANETs to create an efficient route between a pair of mobile nodes: 1. Dynamic topology: The nodes are mobile devices that are capable of moving freely in a random manner; hence the topology of the network keeps changing with time, and thus the routing protocols for such networks must be adaptive to that variation. 2. Power awareness: since the nodes in MANETs typically run on batteries and deployed in varying environments, they face strained power requirements, which implies that the routing protocols must be able to preserve nodes energy for extended time intervals. 3. Network size: business applications of MANETS such as data sharing in conference meetings or classrooms may go through performance degradation due to overcrowding or vast distribution of mobile nodes while changing network size; this also could apply more constraints on the selected routing protocol. 4. Quality of service (QoS) limitations: ad-hoc networks can handle multimedia applications that need high bandwidth and deal with a diversity of traffic streams; such applications are critically affected by the behaviors of the routing protocols. Finding and maintaining routes that meet specific QoS criteria is more complex than standard routing, as QoS routing protocols need higher computational and communication overhead. 5. Link breakage recovery: Mobility of nodes in MANETs and frequent movement out of communication range cause link breakage in MANETs. Link breakage recovery techniques are necessary to maintain network stability. Proactive and reactive routing protocols also play a role in minimizing the impact of link breakage. 6. Scalability: The increase of the network in size is a major concern in MANETs. To manage a large number of mobile nodes, scalability must be achieved by the chosen routing protocol. Scalability can be achieved by clustering or divide the network to segments. Also, hierarchical architecture can divide networks through segmentation into smaller and easier-to-manage networks. 7. Security: The characteristics of MANETs, especially open-medium wireless communication, dynamic topology and decentralized architecture, require advanced security measures. Robust security measures are challenging in MANETs. Techniques like data encryption, authentication and intrusion detection must be implemented to detect threats as spoofing, eavesdropping, and denial-of-service (DoS) and distributed denial-of-service (DDoS) attacks. 8. Interoperability: Interoperability is vital for seamless integration of MANETs with other communication systems, by ensuring that different protocols and devices can coexist peacefully. Standards-based protocols and interfaces facilitate interoperability, enabling MANETs to use heterogeneous devices and networks.