## 6 Architecture Measurements
### Fault Tolerant Procedure  
This subsection shows the procedure and the connections obtained after a node failure. It is divided into three scenarios to show different cases. The test bench shown in Figure 16 has been used as a starting point. The multisensors have had the same initial parameters as in Subsection 5.1. All multisensors have had the same starting energy for simplicity and they have appeared in the scenario in the same manner as in Subsection 6.1. The traffic obtained in the whole process is not too relevant because there are very few messages transmitted through the network and they cannot be distinguished between the traffic measured. In the first scenario node 3 fails down one second after it sends its update message. Then, we sniffed the open air during 140 seconds (60 seconds was the conFigured dead time interval). This time makes us certain that node 4 had noticed that node 3 had failed. It also gives us enough time to compare the update messages with the ones sent 120 seconds later. Figures 20-22 show the measurements gathered. We observe that there are more broadcasts/s, bytes/s and packets/s sent to the network between seconds 55 and 65 than between 115 and 125. We can see in Figure 20 that there were 18 broadcasts/s in the first range _versus_ 15 broadcasts/s in the second range. Figure 21 shows that the first range has 3,196 bytes/s sent to the network, while the second range has 3,054 bytes/s. In Figure 22, 34 packets were sent in the first range while 32 packets were sent in the second range. The measurements taken let us know that, although there were more broadcasts/s, bytes/s and packets/s, the rise in the first range has been moderated, so when a node fails down, there is very little overhead in the second range. The measurements taken at the first range are shown in Figure 23. The measurements taken at the first range are shown in Figure 24. The measurements taken at  
low impact in the network. It agrees the protocol operation shown in Figure 14. As all nodes have had the same initial energy, taking into account Equation 1, it was deduced that node 4 would be the new CH because it had lower _nodeID_. Figure 23 shows the topology when the network has converged. Because node 3 only had connections as a CH, but not as a CM, when the network has converged, there is just one connection less, so it keeps the same stability. The steps followed to achieve the new topology are shown in Figure 14.  
In the second scenario node 15 fails one second after it sends its update message. Then, we sniffled the open air during 140 seconds (60 seconds was the conFigured dead time interval). This time makes us certain that node 14 had noticed that node 15 had failed. It also gives us enough time to compare the update messages with the ones sent 120 seconds later. Figures 24-26 show the measurements obtained when node 15 fails. There is the same number of broadcasts/s, bytes/s and packets/s sent to the network between seconds 55 and 65 than between 115 and 125. In both ranges, we measured 15 broadcasts/s, 2,958 bytes/s and 30 packets/s respectively. The measurements taken show that a CM failure does not have any impact in the network. Figure 27 shows the network when it has converged. Now, we observed that there were two connections less: the connection between node 14 and node 15 and the connection between node 1 and node 15. It can be seen that there was no other type b node in the cluster CH1 to replace it and there are no other type b nodes close to it to have connections. In the third scenario node 6 fails. After a second, we introduced node 17 in position (100, 125), which is a CM of type c in order to provide a backup for cluster CH3. When we saw the connections in the network (see Figure 28), we discovered that the new node has nodes 10 and 13 with distances lower than 100 meters, but node 5 was at a longer distance (it was not within the coverage area). In this case we don't provide broadcasts/s, bytes/s and packets/s measurements because they were similar to the one obtained when node 15 fails.