A dynamic readjustment of an energy efficient network control policy parameters in an optical network unit based on a Service Interoperability in Ethernet Passive Optical Network (SIEPON) protocol. The access link between the OLT and ONU has distinct properties that can be used to enhance the energy efficiency control policy on the network facing side of the ONU. In one embodiment, an adjustment mechanism can be based on the receipt, by an optical interface in an ONU, of a control command from an upstream OLT, wherein the control command is configured to provide a limitation on an available time period during which the ONU can communicate with the OLT over an optical fiber cable.