## 5 Simulation Results and Discussion
### Discussion of ns-3 Simulation Results  
The simulation results are summarized in Table 3.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{2}{c}{**Observation**} & \multicolumn{3}{c}{**Number of**} & \multicolumn{3}{c}{**Number of Packets**} & \multicolumn{3}{c}{**Total**} & \multicolumn{1}{c}{**Total**} \\ \multicolumn{2}{c}{} & \multicolumn{1}{c}{**Packets Sent**} & \multicolumn{1}{c}{**Received at 170.1.3.2**} & **Number** & **Number** & **Number** & **Number** \\ \hline \multirow{4}{*}{ \begin{tabular}{c} **Start** \\ **Time (s)** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **Stop** \\ **Time (s)** \\ \end{tabular}  } & \multirow{2}{*}{**From Source Interface**} & \multirow{2}{*}{**From Source Interface**} & \multirow{2}{*}{**From Source Interface**} & \multirow{2}{*}{ \begin{tabular}{c} **of** \\ **Packets** \\ **Sent** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **of** \\ **Packets** \\ **Sent** \\ \end{tabular}  } & \multirow{2}{*}{ \begin{tabular}{c} **PDR** \\ **Received** \\ \end{tabular}  } \\ \cline{3-3} \cline{5-10}  & & & **191.168.1.1** & **170.1.2.1** & **191.168.1.1** & **170.1.2.1** & & \\ \hline \multirow{4}{*}{\ \begin{tabular}{c} **Start** \\ **Time (s)** \\ \end{tabular}  } & 0 & 10 & 224 & 0 & 224 & 0 & 224 & 1 \\ \cline{2-10}  & 10 & 20 & 250 & 0 & 250 & 250 & 1 \\ \cline{2-10}  & 20 & 30 & 250 & 0 & 250 & 0 & 250 & 1 \\ \cline{2-10}  & 30 & 40 & 250 & 0 & 250 & 0 & 250 & 1 \\ \cline{2-10}  & 40 & 50 & 250 & 0 & 250 & 0 & 250 & 1 \\ \cline{2-10}  & 50 & 60 & 0 & 250 & 0 & 0 & 250 & 0 & 0 \\ \cline{2-10}  & 60 & 70 & 0 & 250 & 0 & 0 & 250 & 0 & 0 \\ \cline{2-10}  & 70 & 80 & 0 & 250 & 0 & 0 & 250 & 0 & 0 \\ \cline{2-10}  & 80 & 90 & 0 & 250 & 0 & 0 & 250 & 0 & 0 \\ \cline{2-10}  & 90 & 100 & 0 & 250 & 0 & 0 & 250 & 0 & 0 \\ \cline{2-10}  & 100 & 110 & 0 & 250 & 0 & 0 & 250 & 0 & 0 \\ \hline \multirow{4}{*}{ \begin{tabular}{c} **Start** \\ **Time (s)** \\ \end{tabular}  } & 110 & 120 & 249 & 0 & 249 & 0 & 249 & 249 & 1 \\ \cline{2-10}  & 120 & 130 & 251 & 0 & 251 & 0 & 251 & 251 & 1 \\ \cline{2-10}  & 130 & 140 & 250 & 0 & 250 & 0 & 250 & 1 \\ \cline{2-10}  & 140 & 150 & 250 & 0 & 250 & 0 & 250 & 1 \\ \cline{2-10}  & 150  
When the network is simulated for 50 s, since network \(\mathcal{N}_{1}\) is operational, data are communicated over this network from the PMU with an IP address of 191.168.1.1 to the PDC with an IP address of 170.1.3.2. The PMU communicates 1224 packets to the PDC with a packet loss ratio of 0%. Thus, all packets are received at the PDC, which results in a \(PDR\) value equal to 1. This can also be validated using Table 3.  
When the network is simulated for 110 sec, since network \(\mathcal{N}_{1}\) is operational only up to 50 s, data are communicated over this network from the PMU at interface 191.168.1.1 to the PDC at interface 170.1.3.2 up to 50 s only. Further, the PDC receives all 1224 packets sent from the PMU through interface 191.168.1.1, as the packet loss ratio is 0% at the 170.1.3.2 interface of the PDC corresponding to this flow. For the simulation beyond 50 s and up to 110 s, as network \(\mathcal{N}_{1}\) fails, no data can be communicated using this network. In response to the failure of network \(\mathcal{N}_{1}\), the PMU reroutes data through the alternative route at interface 170.1.2.1, which is through network \(\mathcal{N}_{3}\) over the Internet \(\mathcal{N}_{2}\). Nevertheless, network \(\mathcal{N}_{4}\) is disabled to ensure the absence of a backup path between the PMU and PDC. Therefore, PDC does not receive data corresponding to this flow as the packet loss ratio is 100% at the 170.1.3.2 interface of the PDC.