## 3 Results and Discussion
### Average Delay Comparison
Figure 9: Comparison of average throughputs across varying traffic PDR and packet sizes. (**a**) PDR with traffic generation; (**b**) PDR with packet size. Figure 9 provides an in-depth comparison of the packet delivery ratio (PDR) for the routing protocols CM-QOS-AODV, CM-GPSR, and IOLSR in city and highway environments across different design metrics, such as traffic generation and packet sizes. The PDR is a critical performance metric in network protocols, representing the percentage of data packets successfully delivered to the destination relative to the number of packets sent. A higher PDR indicates a more reliable network protocol in ensuring data is transmitted successfully despite network challenges. CM-QOS-AODV vs. CM-QOS-AODV: Figure 8a reveals that CM-QOS-AODV performed better in highway environments than in the city, except when subjected to varying traffic generation. This finding indicates that CM-QOS-AODV, which is likely a time-based optimized version of QOS-AODV, is more suited to dynamic and high-mobility environments like highways. This could be due to its reactive nature, where routes are discovered and maintained only when required, making it agile in responding to frequent topology changes that occur in high-mobility scenarios such as highways. However, the performance of CM-QOS-AODV in city environments, though slightly lower than on highways, remains commendable and may still be effective in lower-mobility scenarios with stable network links. On the other hand, CM-QOS-AODV shows only a small difference in average PDR between city and highway scenarios, suggesting that it handles both environments with relatively similar efficiency. This consistency could be due to its underlying design, which might focus on balancing performance across varied network conditions. The stable performance in both environments indicates that CM-QOS-AODV is versatile, making it suitable for applications that need to function reliably in both urban and highway conditions without significant protocol modifications. CM-GPSR: The CM-GPSR protocol stands out by consistently achieving a PDR above 90% across all scenarios, including both city and highway environments. This impressive performance highlights CM-GPSR's capability to effectively route packets in both environments, which can be attributed to the geographical positioning system (GPSR) nature of the protocol, which is optimized for time-based metrics. Its reliance on location-based routing enables it to quickly identify the best routes in a dynamically changing network, such as highways, while still maintaining high PDR in less dynamic city networks. The performance follows a similar trend, although it is more efficient in the highway environment than in the city. The highway's less dense network and fewer obstacles might allow CM-GPSR to better exploit its location-based routing, leading to more efficient packet forwarding and higher PDR. In contrast, the city's more congested network topology could introduce more interference, leading to slightly reduced performance. IOLSR Performance: The IOLSR protocol, which follows a proactive routing approach, managed to achieve an average PDR above 80% in city environments for all scenarios except for high-mobility conditions. This indicates that IOLSR functions effectively when the network topology is relatively stable, as in a typical city scenario with moderate or low mobility. However, as mobility increases, the protocol's performance degrades, which is expected because IOLSR maintains routes continuously, and frequent changes in topology (due to mobility) require constant updates, leading to increased overhead and potential delays in routing adjustments. In highway environments, IOLSR performs slightly better than in the city, managing to achieve more than 80% PDR across all scenarios, including high-mobility situations. This somewhat improved performance in highways can be attributed to the lower density of nodes, which reduces the frequency of route updates.