## 4 Results and Analysis
### Network Parameter Evaluation
#### 4.2.1 Study of Transmission Time in SDN Environment  
To measure the delay in this test accurately, the transmission time of 31 messages of varying character length was precisely recorded as illustrated in Figure 16 and Table 2. Messages were transmitted from host h1 to host h4, which were intentionally bridged by several switches in the SDN. This experiment provided valuable insights into the effects of message length and switch interaction on transmission time. In addition, commands were employed to calculate the time of transmission for non-IP packets from h1 to h4. This was a necessary step since it bypassed encryption processing so that the underlying transmission speed in the SDN could be comprehended in a more open way. From the combination of the outcomes of the messages sent and the non-IP packets, an overall view of the efficiency of the SDN in transferring different types and sizes of data was obtained. The transmission time of the IP packets carrying message payloads to be encrypted is, on average, approximately 1.0655 s. A standard deviation of 0.0575 s indicates moderate variability around the mean. The range is from 1.002 s to 1.2304 s, giving a range of 0.2284 s. The range indicates that, even though the transmission times are different, they are different within a reasonably small range. The median transmission time, at 1.0416 s, is slightly lower than the mean, indicating a slight right skew in the data distribution. For non-IP packets, the transmission time for 31 packets that do not require encryption was taken into account, as shown in Figure 17 and Table 3. The average transmission time is significantly lower at 0.024979 s. The standard deviation is just 0.000898 s, reflecting very low variability. Minimum and maximum transmission times are 0.023571 s and 0.026783 s, respectively, with a narrow range of 0.003212 s. Median transmission time is near the mean at 0.024869 s, reflecting symmetry in data distribution. The percentiles also reflect \begin{table}
\begin{tabular}{c c} \hline \hline
**Description** & **Value (s)** \\ \hline Number of Messages & 31 \\ Mean & 1.065513 \\ Standard Deviation & 0.057506 \\ Minimum (Min) & 1.002 \\
25 th Percentile (25\%) & 1.0135 \\ Median (50\%) & 1.0416 \\
75 th Percentile (75\%) & 1.101 \\ Maximum (Max) & 1.2304 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Descriptive statistics of the transmission time. Figure 16: Transmission time (sec) for packets carrying messages that underwent encryption, transmitted from host h1 to h4 in the SDN environment. this uniformity. The low standard deviation and narrow IQR indicate that most non-IP packets have little or no deviation from the average transmission time, demonstrating their consistency in the network. Comparing the two types of packets, it is clear that non-IP packets transmit at a lower and constant time than IP packets. The transmission time for non-IP packets is significantly lower at 0.024979 s than for IP packets at 1.0655 s. This difference indicates the effect of encryption processing on transmission times. The computational cost of encryption is shown by the longer and fluctuating transmission times for IP packets, highlighting a basic trade-off between security and performance that may be examined through Table 4.  
As observed from Table 4, the average encryption latency is 0.5342 s while the average decryption latency is 0.3194 s, as expected due to the increased complexity of encryp \begin{table}
\begin{tabular}{c c c} \hline \hline
**Statistic** & **Encryption Latency Time (s)** & **Decryption Latency Time (s)** \\ \hline Number of Data & 31 & 31 \\ Mean & 0.5342 & 0.3194 \\ Standard Deviation & 0.0393 & 0.0231 \\ Minimum (min) & 0.4895 & 0.2937 \\ Maximum (max) & 0.6399 & 0.3864 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Descriptive statistics for encryption and decryption latency times. Figure 17: Transmission time (sec) for 31 non-IP packets that were allowed to bypass the encryption policy deployed in the SDN environment.