## 5 Performance Evaluations
### Packet Loss Rate  
#### 5.2.1 Packet Loss Rate with Different Network Topologies  
Figure 10 shows the loss rates of the packets from the mobile node in the network topologies shown in Figure 8. In the 36-node grid network topology, the average packet loss rates of the proposed algorithm, the original trickle algorithm, the E-trickle and the ME-RPL algorithm were found to be 1.7%, 9.6%, 0.3% and 9.1%, respectively, as shown in Figure 10a. Therefore, while the proposed algorithm  
Figure 9: Result of cumulative transfer count with different network topologies. (**a**) Grid topology with 36 router nodes; (**b**) Random topology with 36 router nodes; (**c**) Random topology with 72 router nodes; (**d**) Linear topology with 6 router nodes. has 82.2% and 81.1% lower packet loss rate than the original trickle algorithm and the ME-RPL on average, the E-trickle algorithm was 81.7% lower than the proposed algorithm. In the two random network topologies consisting of 36 and 72 router nodes, the average packet loss rates were found to be 3.0% and 3.1% for the proposed algorithm, 10.9% and 22.2% for the original trickle algorithm, 0.9% and 0.01% for the E-trickle algorithm and 11.9% and 16.6% for the ME-RPL, respectively. This is shown in Figure 10b,c. Therefore, the average packet loss rates of the proposed algorithm were 72.7% and 85.9% lower than those of the original trickle algorithm; the average packet loss rates of the proposed algorithm were 74.9% and 81.2% lower than those of the ME-RPL; and the average packet loss rates of the E-trickle algorithm were 70.5% and 99.6% lower than those of the proposed algorithm. From the results shown in Figure 10b, it can be observed that the standard deviations are 2.1%, 4.7%, 0.3%, and 3.1% for the proposed algorithm, the original trickle algorithm, the E-trickle and the ME-RPL algorithm, respectively. From Figure 10c, it can be seen that the standard deviations are 0.7%, 5.1%, 0.03%, and 4.6% for the proposed algorithm, the original trickle algorithm, the E-trickle algorithm and the ME-RPL, respectively. As shown in Figure 10d, the average packet loss rates in the 6-node linear network topology were found to be 0.6%, 5.1%, 0.6% and 3.8% for the proposed algorithm, the original trickle algorithm, the E-trickle algorithm, and the ME-RPL, respectively. Therefore, the average packet loss rates of the  
Figure 10: Result of packet loss rate with different network topologies. (**a**) Grid topology with 36 router nodes; (**b**) Random topology with 36 router nodes; (**c**) Random topology with 72 router nodes; (**d**) Linear topology with 6 router nodes. proposed algorithm were 88.5%, 2.9% and 84.6% lower than the original trickle algorithm, the E-trickle algorithm and the ME-RPL, respectively. From the experimental results, it can be deduced that the packet loss rate of the packets from the mobile node is lower for the proposed algorithm than the original trickle algorithm and the ME-RPL. However, the packet loss rate of the proposed algorithm is higher than that of the E-trickle algorithm. The original trickle algorithm and the E-trickle algorithm differ in their methods of allocating the redundancy constant \(k\) in addition to the results mentioned in Section 5.1. While the original trickle algorithm defines the \(k\)-value to be a constant, the E-trickle algorithm adjusts the \(k\)-value depending on the interval. Based on this difference, it can be observed from Figure 10 that the E-trickle algorithm is more advantageous than the original trickle algorithm in maintaining a consistent network in an environment where the network topology changes frequently. Unlike the original trickle algorithm and E-trickle algorithms, the proposed algorithm and the ME-RPL do not consider the k-value in searching for the highest OF value, but collects the information of neighboring router nodes. Nevertheless, the proposed algorithm clearly shows lower packet loss rates than the original trickle algorithm and the ME-RPL and an equal or slightly higher packet loss rate than the E-trickle algorithm.