# Enhancing Energy Efficiency in IoT-NDN via Parameter Optimization
## 6 Evaluation
### Discussion of the Results  
This final subsection of the evaluation addresses the meaningfulness of the previously presented results. We assess how significant the statements about the measured energy efficiency actually are.  
Previously, it was established that the savings of relative energy consumption are not particularly substantial: The energy difference between a packet size of 8192 and 1024 is only approx. 2 to 4%. The relative energy deviation for the other variable parameters is even smaller, with about 0.08% to 0.0006% depending on the parameter. This is a less impactful result than was expected. Nevertheless, there are many reasons why the results are still interesting and deliver a substantial contribution to the field.  
First, it has to be noted that when the nodes in the network did not transmit during the simulations, they were in the idle state, not in the sleep state. The difference in electric current between idle and sleep is huge: Assuming the Wi-Fi energy model from this work, the idle current is 273 mA, while the sleep current is 33 mA. Hence, sleeping consumes only ca. 12.1% of idle power. If the sleep behavior of the nodes had been factored in, the energy consumption differences might have been orders of magnitude greater. Future work may add this sleep behavior to the simulator.  
Furthermore, even though the relative amount of saved energy is relatively low for most parameters, in absolute numbers, a sizable quantity may be saved by employing the best caching schemes and caching strategies in the appropriate situation. Many nodes in IoT networks run over a long time, e.g., temperature sensors or smart home devices. Over the runtime of several weeks or months, the saved energy in joule may add up to a large amount. Figure 5 shows an example with graph size 64, grid topology, and linear random sequence type. The absolute difference in energy between probabilistic 50% and no caching is 0.2658 J on average per node. The simulation simulated 100 s of network communication, but if, for example, 30 days of runtime were simulated, this difference would increase to approx. 6891.661 J per node. The corresponding difference for the entire network would be 441.006 kJ. This amount is already considerable, and this can be achieved by modifying only the caching scheme.  
Finally, it should be argued that even if the energy savings of a particular combination compared to another are not huge, implementing the best caching scheme or strategy in a given setup is not difficult. In Section 5.3, it has been explained that the implementation, particularly of the probabilistic caching scheme, is straightforward. Concerning the packet size, it has been clarified before that its energy footprint is quite substantial. Reducing the packet size is not necessarily easy or even possible. However, sometimes it is feasible for the sender to compress data and for the receiver to uncompress data. Assuming that the vast majority of energy is consumed by communication, rather than computation, data compression presumably saves energy overall. However, further work should investigate this issue in more depth.