**3.2 Energy consumption analysis**

For computing energy consumption, only the edge devices of the network is a concerning issue because energy consumption by the PON channel is negligible. Thus, the total energy consumption is computed as:

$$
\Delta E = E\_{\text{Edge\\_Fog}} + E\_{\text{Optimal\\_Fog}} + E\_{\text{cloud}} \tag{5}
$$


The proposed framework computes most of the computations at the Optical-Fog layer which reduces the overhead on the cloud data centers. Thus, QoE is improved by minimizing the overall energy consumption.
