## 5 Results and Discussion
### Experimental Details
First, we divide our result and test case according to the protocol. We use TCP- and UDP-based protocol traffic. Another variable that we change in our test case is the number of hosts starting from 500 and reaching 2000 hosts. Cross-traffic and without cross-traffic conditions are also tested. Another test case we test is forming permanent groups without changing their service rate. For that, 5, 10, 15 groups are formed to perform this test case. Without fixing the cluster group number, we also run experiments. In this scenario, the service rate of the controllers are not fixed, so forming cluster groups can vary. Finally, we test this framework under different bandwidths of the controller. The bandwidth of controllers is set at 2 Gbps, 5 Gbps 10 Gbps. We also test a case where random bandwidths are assigned to different controllers. The last test case is about bandwidth utilization when a simple mechanism is implemented to test AARNET at a 10 Gbps bandwidth. Below are the results of the experiment, and an analysis of the result is presented in the next subsection of this paper. ### Discussion of Experimental Result

Based on the simulation, the experiment's findings were made. Changing the host count and bandwidth allowed us to obtain different outcomes. Additionally, a simulation with a fixed homogeneous group count was conducted. Results of AARNET on both protocols are shown in Figures 8 and 9. In Figures 10 and 11, the DFN network topology results for both protocols are shown. First, we analyzed the result of both topologies in both protocols at 10 GB bandwidth. The results in Figures 8c, 9c, 10c and 11c are very similar to those obtained by [13]. They consider the unlimited bandwidth of the controller, but in Mininet, if the controller bandwidth link is not defined, it takes around 10 GB bandwidth by default. The throughput of both topologies decreases when their controller bandwidth is decreased. The important point is that in every bandwidth case, the throughput follows the same linearity means; as the number of hosts increases, the throughput decreases. The throughput is reduced from 30% to 35% when a 2 Gbps bandwidth is set. For 5 Gbps, the bandwidth is decreased by 16% to around 20% as compared to the results of [PERSON] et al. [13]. The 10 Gbps results are approximately the same. Based on the results, it seems that heterogeneity affects the QoS. The decrease in throughput is linear, which means that the throughput does not deviate too much as the number of hosts increases. The other thing we observed is that as the number of cluster groups is increased in the system, the throughput is greater. When we fix the service rate and form constant groups, for example, 5, 10 15, the throughput is increased when the number of groups is greater, which means that this strategy impacts the heterogeneous network performance. When we do not fix the number of groups, the throughput is maximal in every test case. It indicates that grouping based on the service rate and, after some interval time, changing groups based on their current service rate is the most efficient way. We also implement one method based on throughput to change the interval time of the service rate, but it does not show any significant changes in the average throughput of the system. We need further investigation to see this method's effectiveness on other controller resources. When the bandwidth consideration technique is applied, we see some increase in the throughput when the hosts increase and and decrease in the available bandwidth value due to more traffic. In this scenario, the throughput is increased from 2% to 4% as shown in Figure 12 compared to the results of [PERSON]. [PERSON] et al. [13]. It shows that there is potential in this framework to become more efficient in terms of QoS while alleviating heterogeneity. Our proposed model focuses on all traffic, not only on control traffic, as presented in [28; 29]. Figure 8: AARNET throughput at different bandwidths TCP. (**a**) AARNET throughput at 2 GB bandwidth TCP.