## 4 Results and Analysis
### Evaluation of System Performance  
To evaluate system performance, monitoring tools were employed to gather detailed insights into the system's behavior during the execution of the emulation process. The primary metrics of interest are CPU utilization and network utilization. These parameters were meticulously monitored to understand resource usage and assess system performance under the given conditions. Figure 23 represents the CPU utilization of 12 cores for a period of one minute. Every colored line indicates the activity of an individual core with the corresponding percentage used indicated in the legend. The data indicate that overall CPU utilization ranges from 0 (0%) to slightly over 20%, which means low to moderate workload levels across the system. Upon examining each core usage individually, utilization observations suggest CPU 1 and CPU 2 with relatively higher peaks of 5.0% and 10.2%, respectively. CPUs such as CPU 3, CPU 5, CPU 6, CPU 8, CPU 12, and CPU 4 are characterized by minimal usage, reaching 1.0% only. CPU 7 and CPU 11 have no significant usage, reading consistently at 0.0% usage. In contrast, CPU 9 and CPU 10 both have much higher activity levels, with their peak usage rates of 18.2% and 14.9%, respectively, indicating that these processors are carrying a greater share of the load. The unevenness in the distribution of CPU load as seen on the graph indicates that the GA-based hybrid encryption mechanism puts different amounts of workloads on different CPU cores and other programs and processes running in the background, as shown in Figure 23, in stark contrast to the unevenly higher utilization of CPU9 and CPU10 compared with most of the other cores that have near-zero activity reported. These observations suggest that, while the system is not overloaded, there exist certain phases where performance can be improved. For improving performances, optimizing the scheduling of loads and  
Figure 23: CPU utilization during emulation process carried out in Mininet and with POX controller for testing and evaluating the GA-based hybrid encryption policy for SDN. fixing any potential bottlenecks in the heavily loaded cores can enhance the overall system performance and efficiency [68]. The network utilization graph, as shown in Figure 24, provides a detailed view of the data transmission rates over a 30 s interval during the emulation process of the GA-based hybrid encryption while keeping all other tasks that utilize the network off. Figure 24 considers both incoming (blue line) and outgoing (red line) network traffic; this is displayed along the \(y\)-axis in KiB/s with respect to time taken along the \(x\)-axis. Analysis of the plot indicates obvious trends and effects to the network performance of the system during emulation runtime. Peaks in network usage at certain intervals show phases of intensive data transfer. The initial small spike is observed around the 50-s mark with subsequent spikes at 30 s and 20 s. The biggest spike of network usage is observed towards the end of the time being monitored, around the 10-s mark, where the rate of incoming data reaches a peak at approximately 30 KiB/s. The rate of outgoing data reaches a peak at approximately 6 KiB/s. These spikes are designed to align specific phases of the GA-based hybrid encryption process involving high data interchange intensity, such as population update, fitness calculations, and outcome dissemination. These peaks and spiking activity at different times also show that the network is not always active, wasting available bandwidth [69]. This can cause network lag or congestion, particularly if the network infrastructure is not optimized to handle such an abrupt spike in data transmission. In the SDN environment, comprehensive performance evaluation requires power and energy consumption analysis.