# Video Streaming Adaptive QoS Routing with Resource Reservation (VQoSRR) Model for SDN Networks
## 4 Experiments and Results
### Dynamic Rerouting Algorithm Experimental Results  
This section aims to assess the performance of the dynamic traffic rerouting algorithm (DR-RA). The simulation was carried out with the following parameters. The link capacity was set to 50 Mb/s. The majority of links had a loss of 1%, while the links on the longest  
Figure 5: The main topology graph. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Video Name** & **Type** &
\begin{tabular}{c} **Bitrate** \\ **kbps** \\ \end{tabular} & **Size MB** & **Duration** & **Frame/s** \\ \hline \multirow{2}{*}{caminandes\_llamigos\_480p} & SD & \multirow{2}{*}{847} & \multirow{2}{*}{17.5} & \multirow{2}{*}{1:30} & \multirow{2}{*}{24} \\  & (854 \(\times\) 480) & & & & \\ \hline \multirow{2}{*}{caminandes\_llamigos\_720p} & HD & \multirow{2}{*}{1660} & \multirow{2}{*}{32.1} & \multirow{2}{*}{2:30} & \multirow{2}{*}{24} \\  & (1280 \(\times\) 720) & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Videos’ simulated QoE parameters. paths had no loss. There were two hosts with best effort (UDP traffic with 5 Mb/s). For SD and HD, bandwidth constraint metrics were 3 and 10 Mbps, respectively, while packet loss metrics were 0.5% and 0.005%. The controller collected the statistics every 4, 6, or 9 s, whereas the DR-RA execution occurred at t = 5, 7, or 10 s.  
We designed four test scenarios, firstly, videos were sent using the best effort network without using the proposed VQoSRR. Secondly, the VQoSRR had been tested without using the traffic rerouting algorithm (DR-RA), instead only using the TwoLLWPs. The last two scenarios analyzed the effect of the DR-RA. In the first case, the video flow threshold was assigned to the first service group (A), which had had QoS constraints and implied the flow must route over the lowest loss path. In the second case, the flow belonged to the second service group (B), which had soft constraints; in this situation, when no lowest loss path exists, the flow takes the widest path. Figure 6 illustrates a comparison of the four scenarios; it clarifies the effect on video quality by these cases. The results indicate that the SSIM average values of DR-RA provided high quality; the average SSIM of group A was around 0.97 for HD and about 0.96 for SD, and the average SSIM values for group B were close to 0.94 for HD and 0.93 for SD. In comparison, when DR-RA was not applied, the video quality decreased, where the SSIM value of HD's average = 0.92 and SD's average = 0.93. Further, the best effort results (without using the proposed VQoSRR) highly correlated with the degradation of video quality, where SSIM averaged around 0.90 for HD and 0.91 for SD. Figure 7a,b present VMAF and SSIM measured during video delivery using the real-time transport protocol (RTP), with DR-RA, without DR-RA, and without the VQoSRR separately. A video delivered without DR-RA had higher VMAF and SSIM than a video delivered without VQoSRR. Additionally, when delivered using DR-RA, it had a higher quality than both of them. The reason is that DR-RA can reroute video traffic based on network conditions by re-estimating packet loss probability and bandwidth utilization in order to comply with video QoS requirements, which in turn results in better video quality. Figure 6: Average SSIM of the four testing scenarios. DR-RA was executed periodically at predetermined intervals. Hence, this section studies the effect of the execution interval time on ongoing video traffic in order to analyze whether shifting traffic between one path and another affects video quality and which is the most optimal execution interval. In this study, interval times were (5, 7, or 10 s). Figure 8a,b present the achieved results for the received SD video, respectively. The SSIM values are measured every 10 frames in Figure 8a and every 200 frames in Figure 8b. It can be observed from the figures that SSIM was higher when the interval (t = 5 s) compared to (t = 7 s) and (t = 10 s); whereas, there was no significant difference between t = 7 s and t = 10 s in terms of SSIM measurements.