Port Management : Green Ethernet : Green Ethernet Overview
 
Green Ethernet Overview
Green Ethernet is a common name for a set of features that is designed to be environmentally friendly, and to reduce the power consumption of a device. Green Ethernet is different from EEE in that Green Ethernet energy-detect is enabled on all devices whereas only Gigabyte ports are enable with EEE.
The Green Ethernet feature can reduce overall power usage in the following ways:
Energy-Detect Mode—On an inactive link, the port moves into inactive mode, saving power while keeping the Administrative status of the port Up. Recovery from this mode to full operational mode is fast, transparent, and no frames are lost. This mode is supported on both GE and FE ports. This mode is disabled by default.
Short-Reach Mode—This feature provides for power savings on a short length of cable. After cable length is analyzed, the power usage is adjusted for various cable lengths. If the cable is shorter than 30 meter for Tengigabit ports and 50 meter for other type of ports, the device uses less power to send frames over the cable, thus saving energy. This mode is only supported on RJ45 GE ports; it does not apply to Combo ports. This mode is disabled by default.
In addition to the above Green Ethernet features, the 802.3az Energy Efficient Ethernet (EEE) is found on devices supporting GE ports. EEE reduces power consumption when there is no traffic on the port. See 802.3az Energy Efficient Ethernet Feature for more information (available on GE models only).
EEE is enabled globally by default. On a given port, if EEE is enabled, the short reach mode be disabled. The user must disable EEE before enabling short reach mode.
These modes are configured per port, without taking into account the LAG membership of the ports.
The device LEDs are power consumers. Since most of the time the devices are in an unoccupied room, having these LEDs lit is a waste of energy. The Green Ethernet feature enables you to disable the port LEDs (for link, speed, and PoE) when they are not required, and to enable the LEDs if they are needed (debugging, connecting additional devices etc.).
On the System Summary page, the LEDs that are displayed on the device board pictures are not affected by disabling the LEDs.
Power savings, current power consumption and cumulative energy saved can be monitored. The total amount of saved energy can be viewed as a percentage of the power that would have been consumed by the physical interfaces had they not been running in Green Ethernet mode.
The saved energy displayed is only related to Green Ethernet. The amount of energy saved by EEE is not displayed.