## 6 Performance Evaluation
### Simulation Results
#### 6.4.5 Permanent Node Failure Rate Test (Fifth Simulated Scenario)  
In order to simulate the permanent node failure rate, we set each sensor node to fail for a fixed instance of time. The start of each sensor node failure rate was chosen randomly at the start of the simulation using the uniform distribution of the failure rate start time against the time of failure occurrences [24, 40, 41, 51, 52, 53]. In this scenario, we consider a sensor network of size equal to 600 nodes. We set the transient link failure rate at 20%, and the source communicating nodes to be 10, 20, and 40 in order to ensure the protocol's performance under high and low network traffics. We varied the permanent failure rate from 10% to 60% in step of 10% in order to obtain the routing performances at different percentages of the permanent node failure rate. We conducted three different sets of simulations with a different number of seeds, and varied the number of source communicating nodes in each simulated scenario. The results of the permanent node failure rate with 95% confidence intervals are illustrated in Figures 10-12, which show the results of the permanent node failure rate performance evaluation of ASAART compared with the SHR and SSR protocols. Figure 10: _Cont._Figure 10a-d show the three routing protocols under permanent node failure rates with source communicating nodes of size equal to ten. Here we can observe that because of less traffic congestion in the network, the three protocols compete very closely in terms of the end-to-end packet delivery ratio. All three protocols attain 90% to 95% efficient packet delivery with a permanent node failure rate between 40% and 60%. The ASAART protocol shows slightly higher end-to-end delay and low packet delivery rate compared with the SHR and SSR protocols. However, this is compensated by having a lower MAC layer packet transmission and low energy consumption. ASAART achieves lower MAC layer transmission because of its flooding control technique that attempts to reduce the retransmission of redundant network packets. Figure 10: Permanent node failure rate test (fifth simulated scenario) with source node = 10: (**a**) Average packet delivery rate (success rate); (**b**) End-to-end delay; (**c**) Energy consumption; (**d**) Transmitted MAC layer packets. Figure 11: _Cont._  
From Figure 11a-d, we can observe an increase in the packet end-to-end delivery rate exhibited by the three routing protocols when the source communication nodes equal 20 compared with the source node being equal to 40 nodes. The three routing protocols achieve a success rate above 80% when the permanent node failure rate is between 40% and 60%. This is attributed to less network traffic, which helps reduce the packets' contention and collision in the network. ASAART shows a higher end-to-end delay compared with the SHR and SSR protocols; this is because of its strategy of combined local and global network state information. However, ASAART exhibits better MAC layer packet transmission and energy efficiency compared with the SSR and SHR protocols. In Figure 12, we can observe that the ASAART technique slightly outperforms both the SSR and SHR protocols. In Figure 12b, the SHR and SSR protocols exhibit higher end-to-end delay compared with the ASAART protocol. The ASAART protocol shows slightly lower end-to-end delay that remains almost stable when the permanent node failure rate is between 10% and 60%. ASAART uses slightly lower energy consumption compared with SSR and SHR, particularly at higher permanent node failure rates. This is because of its efficient route repair technique that ensures reliable end-to-end packet delivery. However, we can observe that ASAART uses the least number of delivered MAC layer packets at different percentages of the permanent node failure rate because of its efficient flooding control technique and faster routing decision that quickly converges to the minimum routing paths.