# A Proposal for IoT Dynamic Routes Selection Based on Contextual Information
## 4 Performance Assessment and Results
### Network Scenario and Used Metrics  
The network scenario for simulation was built in order to validate the approach proposed in this paper. It simultaneously includes features from applications aimed at environmental monitoring, tracking and localization. The network topology is shown in Figure 3 and considers 11 sensor nodes, 6 tags (RFID), 2 reader nodes (RFID) and 1 sink node. There are 20 devices within a fixed network topology.  
There is data flow for upward and downward. The sink node transmits DODAG Information Object (DIO) messages whenever there is a change of application and it is located as shown in Figure 3.  
The use of RFID tags within the simulated scenario is justified because they can play an important role in IoT solutions and it is needed a realistic IoT scenario. According to [29], excess messages exchanged between readers and RFID tags have strong influence on the network's performance, as well as in application QoS requirements. In the studied scenario, the packets received by the readers are forwarded to the sink, which processes the information sent by readers and by sensor nodes in a consolidated manner.  
The total simulation time was 35 min. To ensure that simulations converge to a steady state, each simulation experiment was repeated five times because, after the fifth experiment, no change was observed in the results. However, to evaluate the dynamic change between objective functions, the simulated time was about 140 min, since each application remains for 35 min. The messages were simulated with packets of 30 bytes (Contiki standard). The choice of the parent node for route establishment was based on the Fuzzy System-Based Route Classifier proposed in this work. The initial power of the nodes was adjusted to 200 joules above the Contiki Energest energy consumption  
Figure 3: Topology of the network simulation scenario.  
model [28]. In this work, the variation in the number of sensor nodes was not considered since, during the study, it was observed that there was no variation of the results changing the number of devices during the use of the proposed objective functions associated to route classifier based on fuzzy system. This is justified because the route selection process of the proposed approach uses only aspects related to energy, position in the routing tree and number of transmission estimates.  
The following four metrics used by the RPL (RFC 6551), suitable for 6 LoWPAN environments, were chosen for evaluation of this approach: Energy Consumed (_EC_), Number of Hops (_NH_), Delivery Ratio (TX) and Expected Transmission Count (ETX). The Expected Transmission Count (ETX) is equal to the average number of required transmissions (including retransmissions) so that a package is duly delivered to its destination.  
Four applications were considered for this study. The first application requires priority in terms of reliability (represented by the delivery ratio). The second application requires a shorter delay (represented by the number of hops). The third application requires a long lifetime (represented by the energy consumed) and the fourth application requires QoS for data delivery (represented by the ETX).