## 3 Problem Statement  
The issue of misbehaving and selfish nodes, which leads to network efficiency deterioration when no measures are taken against them, is addressed in this article. A case study was performed that used the NS2 simulation tool [43] to demonstrate the effect of these nodes on the output of VDTNs. A map-based depiction (\(4000\times 3200\) m\({}^{2}\)) is included in the simulation. During a 48-hour simulation, these network nodes interact via IEEE 802.11b (at 8 Mbps) and Omni-directional antennas with a communication range of 300 m. Ten terminal nodes, including a buffer capacity of 120 MB, serve as traffic sources and sinks. There were five relay nodes located at five road crossing points to increase the number of network connections. Each relay does have a 120 MB buffer space. A group of 25 to 120 mobile nodes travels across map paths at a speed of 40 km/h with a buffer space of 60 megabytes. The amount of selfish nodes begins at 0% (when there are no selfish nodes) and progressively increases up to 80% of all the nodes throughout the entire simulations (20 for each juncture). No selfish node identification frameworks were taken into account to better explain their effect on the network.  
The work begins with the assessment of the effect of selfish nodes on the percentage of bundles distributed that can be seen in Figure 1. As can be shown, the number of distribution packages gradually decreases when the number of selfish nodes increases rapidly. This activity emphasizes the significance of identifying such nodes so that measures can be taken toward them (e.g., punishing selfish nodes). These selfish nodes affect the time it takes for packages to reach their intended destination. This occurs because selfish nodes compel cooperative nodes to almost double their efforts to produce packages. Cooperative nodes, for instance, will also have to deliver packages for longer periods before delivering them to their intended destination or some cooperative node. The time it takes for a package to move in between the source and recipient nodes would increase dramatically in this process, as can be seen in Figure 1. Buffer congestion occurs when packages are placed on nodes over long periods, causing a greater ratio of dropped packages because nodes should keep their cooperative activities to not diverge from the underlying protocol. Nodes can, however, drop packages and thus save resources and sustain the integrity of data. The presence of selfish nodes within a network does have a significant effect not just on several nodes but also on routing schemes.  
The energy consumption parameter, which represents a routing protocol's energy efficiency, can be seen in Figure 1. As can be shown, the presence of selfish nodes within a network increases the routing protocol energy consumption substantially, owing to inadequate network efficiency. The number of packages dropped as a result of the presence of selfish nodes can be seen in Figure 1. The implications of selfish nodes within the network, as mentioned in this section of the article, could result in a disastrous scenario that can be seen in Figure 1. For this, it is essential to provide nodes with specialized models that can identify and prevent any misbehaving or selfish node. As a result, an EMS for VDTNs is introduced as a solution for coping with the existence of such selfish nodes in the network.  
Figure 1: _Cont._