## 5 RC-LARR: RSU-Assisted Cloud-Based Location-Aware Hybrid Routing
### Route Discovery
In Figure 17, the average end-to-end delay is shown against the communication range. In this simulation, the vehicle speed was taken to be 40 km/h. The delay time for this routing method is smaller than the delay time for the other two routing methods. Figure 18 illustrates the effect of vehicle speed on the end-to-end delay. For this, a communication range of 300 m and 10 packets per second as data rates were assumed. Likewise, Figure 19 evaluates the EED of RC-LAHR based on different data packet rates. RC-LAHR gives priority to the nodes that have a higher chance of being in range. Hence, the route selected is more likely to be stable. Therefore, once the route is set up, there is very little delay in packet delivery. It is observed that RC-LAHR performs better in both cases. Figure 16: Packet delivery ratio vs. data packet rate. Figure 17: End-to-end delay vs. communication range. ### Network Traffic Analysis

Network traffic density is a measurement of the quantity of data transmitted or received on a network during a given time interval. The data packets, route requests, and request replies to packets were taken as parameters to analyze the traffic density. Initially, in the proposed routing protocol, the routing packets were sent frequently by all vehicles to the RSU for the initialization process. Because of this, the traffic density in the initial phase took more time. After the establishment of all the vehicles and the RSU's routing table, the topology of the network was stored on the SDN controller (RSUs). Hence, whenever the route was required by any vehicle, the route was determined immediately and sent to the vehicle. Due to this, the route reply and route request times were reduced. This resulted in a lower average traffic density. In Figure 20, the impact of the traffic density during the simulation is analyzed. Figure 19: End-to-end delay vs. data packet rate. Figure 20: Average traffic density vs. time. Figure 18: End-to-end delay vs. vehicle speed. ### Route Calculation Time Analysis

It is necessary to evaluate the suggested routing protocol according to the amount of time needed to find the route. Initially, the information about the topology was not stored at the SDN controller. Therefore, the route calculation took more time. Once the SDN controller stored information about the overall topology, the route determination time was reduced. Figure 21 compares the amount of time spent route-finding to the amount of time spent simulating, while Figure 22 compares the average amount of time spent to find the route to the total number of connections. The simulation used 30 nodes with the speed of 40 km per hour. ### Load Analysis

The proposed routing protocol heavily relies on the use of the RSU and the cloud as major resources. Consequently, conducting an examination of the traffic load on the RSUs and the cloud infrastructure throughout the process of route determination has paramount importance. Figure 23 shows a comparison between the loads that the RSUs and the cloud experienced in relation to the total number of connections. Figure 21: Average route calculation time vs. time. Figure 13:0 Average route-finding time vs. connection rate. ### Network Reliability Analysis

VANETs may experience frequent changes in network topology due to the mobility of vehicles. Network reliability in VANETs involves assessing the likelihood that vehicles within the network are able to maintain connectivity with each other and with roadside infrastructure, even as they move through the network. RC-LAHR selects the node that has the highest probability of staying in the network and has a smaller number of hops. To select such hops, RC-LAHR uses the priority zone as discussed in Section 4.1. Figure 24 shows the result of network reliability with the number of connections. ## 8 Discussion

In the dynamic environment of VANETs, where vehicles are frequently moving and network topology changes rapidly, maintaining a high PDR is challenging. The result shows that the PDR has increased significantly.