## 6 Performance Evaluation
### Evaluation Results
#### 6.3.4 Total Energy Consumption  
Wireless transmissions in terms of Interest and Data packet disseminations account for the majority of a node's energy consumption. Figures 10 and 11 show the comparative analysis of total energy consumed in Interest and Data packet transmissions in GIF, NDN, and CIDF-WSN. 1. **Interest Energy consumption:** To study the impact of Interest energy consumption, CIDF-WSN vary the Interest packet frequency between 5 and 30 packets/sec and compute the total Interest energy consumption of all schemes, as shown in Figure 10.  
Figure 9: Total Packets processed as a function of Interest frequency. It is evident from the results that the overall energy consumption in all the schemes increases with an increase in the Interest packet frequency. However, the CIDF-WSN lowers more than 50% of energy consumption compared with GIF, while reducing the energy consumption several times in comparison with the vanilla NDN. This is because that the CIDF-WSN avoids the blind Interest broadcasts by utilizing the ICT of the neighboring node(s) of the nominated relay to forward the Interest packet in vulnerable conditions. If the designated node fails to reply to the Interest packet, the immediate neighbors of the designated node forward the Interest packet by consulting their ICT to avoid the blind broadcast of the Interest packet. These procedures highly reduce the retransmissions and conserve the transmission energy of the node. In GIF, if the forwarder fails due to a certain reason, the content consumer restarts the Interest transmissions upon the Interest timeout. In addition, If a node receives an Interest packet and there is no information on sender in its neighbor table, the node re-initiates the neighbor table development procedure which involves multiple Interest packets transmissions which enhances the overall energy consumption of underlying nodes. Moreover, there is no procedure provided by the GIF which may allow the immediate neighbors of the selected relay to continue the Interest forwarding process in traffic-intensive conditions. All these factors result in increasing the total Interest energy consumption of the network. Analyzing the Interest energy consumption of vanilla NDN (shown in Figure 10) compared with the CIDF-WSN, the energy consumption of vanilla NDN increases with the increase in Interest frequency. In vanilla NDN, the recipient node(s) blindly forward the Interest packets if they do not have the requested content in their CS. This induces the Interest broadcast storm due to several Interest transmissions and increases the overall Interest energy consumption of the network. Figure 10: Interest energy consumption as a function of Interest. 2. **Data Energy consumption:** Data packets have a major impact on total energy consumption due to their large size. Figure 11 shows that in all the schemes, the energy consumed by the Data packets is greater than that of the Interest packets. The rationale is that the size of the Data packet is almost double that of the Interest packet. In comparison with vanilla NDN and GIF, the CIDF-WSN produced better performance results in terms of total Data packets energy consumption. The reason is that the robust Data forwarding mechanism allows the immediate neighbors of potential Forwarder nodes in the lower layer directing towards the consumer to temporarily utilize their TCT and continue the packet forwarding process in case Data packet transmission stops due to designated node failure. The collaboration of immediate neighbors in the Data packet forwarding process reduces the overall Data packet retransmissions and conserves the energy of the nodes. In contrast, the GIF starts over the entire communication process when the packet has failed to receive at the consumer end. Another important reason is that the lack of involvement of immediate neighboring nodes of the potential forwarder to carry the Data packet forwarding in case of designated node failure leads towards frequent packet retransmissions and consumes a substantial amount of energy.