## 5 Implementation and Simulation Setup
### Description of Simulation Setup  
To compare our multi-interface-capable OF with existing solutions, we simulated an RPL network arranged in an equidistant grid of 25 by 25 nodes, one of which is the root node, as depicted in Figure 7. The distance between nodes (i.e., 50 m) serves no purpose apart from making sure that nodes have two interfaces with different transmission success rates, that is in combination with the values chosen for \(\alpha\) and \(\sigma\). The flow of data transmission events depicted in Figure 8 ensures that medium access (and any attempt thereto) is spread relatively evenly in time across neighboring nodes. The root node also sends data packets back in response. \begin{table}
\begin{tabular}{c c c} \hline
**Constant** & **Interface \#1** & **Interface \#2** \\ \hline \(f\) & 2400 MHz & 868 MHz \\ \hline \(P_{t}\) & 0 dBm & 0 dBm \\ \hline \(S\) & \(-100\) dBm & \(-100\) dBm \\ \hline \(RSSI_{50\%}\) a  & \(-92\) dBm & \(-92\) dBm \\ \hline \(AG_{t}\) & 0 dBi & 0 dBi \\ \hline \(AG_{r}\) & 0 dBi & 0 dBi \\ \hline \(c\) & \(3.0\times 10^{8}\) m/s & \(3.0\times 10^{8}\) m/s \\ \hline \(\alpha\) & 3.0 & 3.0 \\ \hline \(\sigma\)b  & 3.0 & 5.0 \\ \hline \(d_{ref}\) & 1.0 m & 1.0 m \\ \hline \(d_{max}\) & \(\approx 99.648\) m & \(\approx 196.303\) m \\ \hline \end{tabular}  
\(RSSI_{50\%}\) is only used for \(PDR(RSSI)\) calculations; b \(\sigma\) is only used for \(PL(d)\) calculations.  
\end{table} 
Table 2: Overview of the constants used to configure the log-distance path loss model (with log-normal shadowing) in our simulations. Figure 7: View of the simulated RPL network in the Cooja network window. Note that all simulated RPL nodes are arranged in an equidistant grid of 25 by 25 nodes. The RPL root is indicated in green, while the jammer (which is only active during half of the simulation runs) is indicated in red. For the evaluation, we simulated a network wherein all nodes: (1) are dual-interfaced and run DRiPLOF; (2) are dual-interfaced and run POOF; (3) have a single 2400 MHz high-rate/short-range interface and run MRHOF; and (4) have a single 868 MHz low-rate/long-range interface and run MRHOF. Simulations were performed both without and with an external jammer. In the first batch of simulations, no jamming took place and the performance of four OF/interface type configurations was evaluated in ten runs of 20 min each (each with a different random seed). All simulations were then repeated for a scenario wherein a jamming node starts blasting a given frequency band with corrupted data packets for approximately one minute at the 12 min mark (the interfering transmissions do not trigger packet processing). The inter-node spacing, combined with the constants used to configure the path loss model (Table 2) and the routing metric/preferred interface selection criteria, means that both DRiPLOF and POOF tend to favor the 868 MHz long-range/low-rate radio interface. Thus, jamming this interface represents a worst-case scenario when gauging interference resilience. Naturally, the single-interface configurations are jammed on their respective interface types. In addition, the jammer was placed close to the root because nodes closest to the root generally have the largest sub-DODAG. This way, the jammer can disrupt the entire network by forcing a local repair [5]. This makes for a total of 80 simulation runs for both scenarios combined. Table 3 provides an overview of common simulation parameters across all different simulation configurations. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Simulation duration & 20 min/run \\ \hline Simulation runs & 10 runs/config (80 total) \\ \hline Grid size & 5 nodes \(\times\) 5 nodes \\ \hline Inter-node spacing & 50 m \\ \hline Data packet rate & \(\approx\)6 packets/min \\ \hline MAC protocol & CSMA-CA (always-on) \\ \hline \multirow{2}{*}{Data rate} & low-rate: 25 kbps \\  & high-rate: 250 kbps \\ \hline \hline \end{tabular}
\end{table}