## 6 Evaluation of RPL and RPAL in a Real World Environment
### Testbed Setup  
The localization of the deployed nodes is shown in Figure 5a. It is a prototype of an environmental data collection system based on the Contiki OS and uIPv6 protocol stack, which is located in the garden of the IRSTEA research center (Aubiere, France). Figure 5: **(a)** A plan of testbed deployment; **(b)** Testbed setup: photos of No. 2 and No. 3 deployed IWoTCore node. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Penetration of**} & \multicolumn{3}{c}{**Performance Influenced by Using RPAL SCAOF (+: Increase, –: Decrease)**} \\ \cline{2-5}  & & & **Number of failed** & \\
**Misbehaving** & **Average Packet** & **Average latency (ms) of** & **co-operations for** & **Packet transmission cost** \\
**Nodes (\%)** & **Loss rate (\%)** & ** successful transmission** & **packet forwarding** & \\ \hline
10\% & –11.43 & +9.53 & \(\approx\) –746 & –1.09 \\
20\% & –21.52 & +20.53 & \(\approx\) –1156 & –2.13 \\
30\% & –33.56 & +21.08 & \(\approx\) –2200 & –2.24 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Simulation results of 30 LLN nodes with node state runtime reconfiguration. Currently, this testbed consists of 11 IWoCCore core nodes with Ext_MiLive extend boards, which one of them is directly connected to a laptop (see Figure 6) through a USB port as the sink node, and an adapted version of a collect-view application is running on the laptop for observing different types of measured data. The main objective of this testbed is to monitor the viable states of network, hardware, power supply, and scalar sensing data (air temperature and light intensity). It is to be noticed that one IWoCCore node (tagged by 11 in Figure 5a) is located in an office as a contrast experimental object. To run this testbed system in the real world environment, the boards and their rechargeable power source (Li-Ion Battery Pack from ENIX ENERGIES, Saint Egreve, France) are well encased in hermetical plastic containers (see Figure 6). As shown in Figure 5b, the testbed devices are located where the deployment situation has a certain geographical gradient (little to medium incline) as well as numerous obstacles, like walls, buildings, shruberies, trees, and facilities in the garden. To increase the reliability of transmission, the antenna height is temporarily raised to 45 cm for the testbed devices deployed in the low gradient level area as depicted in Figure 5b. During the setup of this testbed, from the empirical results of our tests, if the antenna's height is lower than that of the obstacles, link quality is very dynamic because the transmission would be mainly based on Non Line of Sight (NLOS) signals, and the link quality would be seriously affected by phenomena like reflection, refraction, diffraction or scattering. The radio chips have to be configured with the same settings like transmission power and identical hardware behaviors, so that most of the radio links are symmetrical in both directions. Even so, the radio channel is intrinsically unstable due to the impacts of various environmental factors and interferences. The easiest observation is that some links can occasionally disappear or reappear, and this phenomenon would imply certain dynamics in the network. Thus, keeping all the testbed devices in a homogeneous situation is significant for the later comparative tests. To deploy the prototype system in the real world environment and organize three comparative experiments, the following simplified considerations and corresponding explanations are defined:  
* Testbed node 1 is the sink node connected to a laptop and used as a data collector and remote controlling message emitter. * Deployed nodes are located at the same positions, at the same relative angles and distances. Figure 6: Testbed setup: sink node and nine IWoCCore Ext_MiLive nodes for outdoor environment experiments. * This prototype system could provide three categories of required measurements (see Table 10).