# A Smart Collaborative Routing Protocol for Reliable Data Diffusion in IoT Scenarios
## 4 Validation and Discussion
### Analysis of Simulation Results  
Based on the above contents, the simulation results of the three parameters (i.e., delay, loss packet ratio and throughput) are discussed respectively. For the delay aspect, it is related to the number of sensor nodes and the packet size. As shown in Figure 9a. With continuous expansion of the network scale, the delay of all protocols gradually increases. Due to a large number of data forwarding in the flooding method, the delay problem is particularly serious. Its delay is higher than that of other protocols. From the 40 nodes to 200 nodes, the delay in flooding protocol has increased proportionately. When there are 200 nodes in the network, the delay is even higher than 200 ms. This result has far exceeded that of the other three protocols. While, the latency of the other three protocols is almost identical between the 40 nodes and 80 nodes. The delay performances of them are all below 50 ms. Starting from 120 nodes, the gap of the three protocols has gradually emerged. The growth rate of GPSR starts to accelerate. In short, the GIN protocol outperforms the other three protocols in the delay aspect. It utilizes the least time to obtain monitoring information and maintains a stable growth of delay. In Figure 9b, the delay is affected by the size of packet. The packet size is divided into five scenarios (i.e., 1024 KB, 2048 KB, 3072 KB, 4096 KB and 5120 KB). We can see that the flooding still exists in the largest delay, which is much larger than that of others. Starting from 1024 KB, the delay of flooding exceeds 200 ms and continues to grow. When the packet size approaches to maximum, the delay of that is more than 400 ms. While, the delay of other three protocols is only around 200 ms at the maximum packet size. Moreover, the delay levels of GEAR and GIN protocols are very similar. The difference is that the GIN is equipped with the IN mechanism. Among the four protocols, the GIN protocol consumes the least time to complete data collection, which can improve transmission efficiency and reduce the number of retransmissions. For the packet loss ratio, it is related to the packet length and the transmission frequency. In terms of the packet length, there are five cases (i.e., the packet length is divided into 1000 KB, 2000 KB, 3000 KB, 4000 KB and 5000 KB). As the packet length increases, the packet loss ratio continues to deteriorate as shown in Figure 10a. Especially in the case of the flooding, the packet loss ratio increases steadily between 1000 KB and 3000 KB. However, this number is seriously higher than other protocols. After the 3000 KB line, the packet loss ratio of flooding protocol becomes worse. When the packet length is 5000 KB, the packet loss ratio approaches 0.05. At this stage, the performance of GIN in packet loss ratio is still a preferred one. The maximum packet loss ratio in GIN protocol is almost equal to that of the minimum value in flooding method, i.e., it is approximately 0.01. Moreover, the value gap of GIN and GEAR protocols is almost similar to the gap of GEAR and GPSR protocols in the packet loss ratio. The gap of them is about 0.008. Due to the IN mechanism, the GIN protocol rarely encounters the selective dropping packet attacks. Therefore, it is the safest one of the four protocols. Figure 10b illustrates that the packet loss ratio is inversely proportional to the transmission frequency of packet. When the transmission frequency of packet is 10 Mbps, the packet loss ratio of the four protocols is at their respective maximum. Between 10 Mbps and 20 Mbps, the packet loss ratio of flooding, GPSR and \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Number of Sensor Nodes & 40/80/120/160/200 \\ Network Size & 200 m \(\times\) 200 m \\ Packet Size & 1 M/2 M/3 M/4 M/5 M \\ Inspection Nodes & 4 \\ Cluster Head & 4 \\ Number of Packets & 1000 \\ Frequency of sending packets & 10 Mbps/20 Mbps/30 Mbps/40 Mbps/50 Mbps \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Simulation parameters. GEAR protocols drops significantly.