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.
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.
- Short-Reach Mode--After cable length is analyzed, the power usage is adjusted for various cable lengths. If the cable is shorter than 50 meters, the switch 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 globally disabled by default. It cannot be enabled if EEE mode is enabled (see below).
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 when there is no traffic on the port. See the 802.3az Energy Efficient Ethernet Feature section for more information (available on GE models only).
EEE is enabled globally by default. It cannot be enabled if the Short-Reach mode is enabled.
These modes are configured per port, without taking into account the LAG membership of the ports.
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.