Energy Efficient Ethernet
Encyclopedia
Energy-Efficient Ethernet is a set of enhancements to the twisted-pair and backplane Ethernet
family of computer network
ing standards that will allow for less power consumption during periods of low data activity. The intention was to reduce power consumption by 50% or more, while retaining full compatibility with existing equipment. The Institute of Electrical and Electronics Engineers
(IEEE), through the IEEE 802.3az task force developed the standard. The IEEE ratified the final standard in September 2010. Some companies introduced technology to reduce the power required for Ethernet before the standard was ratified, using the name Green Ethernet.
The first study group had its call for interest in November 2006, and the official standards task force was authorized in May 2007.
In , 1 gigabit
and speed data links energy is used to keep the physical layer
transmitters on all the time. If they could be put into "sleep" mode when no data is being sent that energy could be saved. By sending a low-power-idle (LPI) indication signal for a specified time the transmit chips in the system can be turned off. LPI is sent periodically to refresh the sleep mode. When there is data to transmit a normal idle signal is sent to wake the transmit system up before data is due to be sent. The data link is considered to be always operational, as the receive signal ciruit remains active even when the transmit path is in sleep mode.
In addition, a new lower power mode was added to Ethernet over twisted pair
, which reduces power supplies required for each interface.
Green Ethernet technology was a superset of the 802.3az standard. In addition to the link load power savings of Energy-Efficient Ethernet, Green Ethernet works in one of two ways. First, it detects link status, allowing each port on the switch to power down into a standby or ‘sleep’ mode when a connected device, such as a computer, is not active. Second, it detects cable length and adjusts the power accordingly. Previous standard switches provide enough power to send a signal up to 100 metres (328.1 ft). However, this is often unnecessary, especially in the home, where 5 to 10 m (16.4 to 32.8 ft) of cabling are typical between rooms.
Green Ethernet also encompasses the use of more efficient circuitry in Ethernet chips, and the use of "off-load engines" on Ethernet interface cards intended for network servers.
scheduler using Wireless N Gigabit routers automatically determines when Wi-Fi
radio signals are turned on and off to further reduce energy consumption.
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
family of computer network
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
ing standards that will allow for less power consumption during periods of low data activity. The intention was to reduce power consumption by 50% or more, while retaining full compatibility with existing equipment. The Institute of Electrical and Electronics Engineers
Institute of Electrical and Electronics Engineers
The Institute of Electrical and Electronics Engineers is a non-profit professional association headquartered in New York City that is dedicated to advancing technological innovation and excellence...
(IEEE), through the IEEE 802.3az task force developed the standard. The IEEE ratified the final standard in September 2010. Some companies introduced technology to reduce the power required for Ethernet before the standard was ratified, using the name Green Ethernet.
Potential savings
In 2005, all the network interface controllers in the United States (in computers, switches, and routers) used an estimated 5.3 terawatt-hours of electricity. According to a researcher at the Lawrence Berkeley Laboratory, Energy-Efficient Ethernet could save an estimated a year in energy costs in the U.S. Most of the savings from homes , and offices , and the remaining from data centers.The first study group had its call for interest in November 2006, and the official standards task force was authorized in May 2007.
Concepts
The power reduction is accomplished in a few ways.In , 1 gigabit
Gigabit Ethernet
Gigabit Ethernet is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second , as defined by the IEEE 802.3-2008 standard. It came into use beginning in 1999, gradually supplanting Fast Ethernet in wired local networks where it performed...
and speed data links energy is used to keep the physical layer
Ethernet physical layer
The Ethernet physical layer is the physical layer component of the Ethernet family of computer network standards.The Ethernet physical layer evolved over a considerable time span and encompasses quite a few physical media interfaces and several magnitudes of speed...
transmitters on all the time. If they could be put into "sleep" mode when no data is being sent that energy could be saved. By sending a low-power-idle (LPI) indication signal for a specified time the transmit chips in the system can be turned off. LPI is sent periodically to refresh the sleep mode. When there is data to transmit a normal idle signal is sent to wake the transmit system up before data is due to be sent. The data link is considered to be always operational, as the receive signal ciruit remains active even when the transmit path is in sleep mode.
In addition, a new lower power mode was added to Ethernet over twisted pair
Ethernet over twisted pair
Ethernet over twisted pair technologies use twisted-pair cables for the physical layer of an Ethernet computer network. Other Ethernet cable standards employ coaxial cable or optical fiber. Early versions developed in the 1980s included StarLAN followed by 10BASE-T. By the 1990s, fast, inexpensive...
, which reduces power supplies required for each interface.
Green Ethernet
Green Ethernet was a marketing term for Ethernet power-saving technology in 2007 and 2008.Compared to IEEE Standard 802.3az
Some energy-efficient switch-integrated circuits were developed before the IEEE 802.3az standard was finalized.Green Ethernet technology was a superset of the 802.3az standard. In addition to the link load power savings of Energy-Efficient Ethernet, Green Ethernet works in one of two ways. First, it detects link status, allowing each port on the switch to power down into a standby or ‘sleep’ mode when a connected device, such as a computer, is not active. Second, it detects cable length and adjusts the power accordingly. Previous standard switches provide enough power to send a signal up to 100 metres (328.1 ft). However, this is often unnecessary, especially in the home, where 5 to 10 m (16.4 to 32.8 ft) of cabling are typical between rooms.
Green Ethernet also encompasses the use of more efficient circuitry in Ethernet chips, and the use of "off-load engines" on Ethernet interface cards intended for network servers.
Routers
In April 2008, the term was used for switches, and, in July 2008, introduced into wireless routers. A Wireless LANWireless LAN
A wireless local area network links two or more devices using some wireless distribution method , and usually providing a connection through an access point to the wider internet. This gives users the mobility to move around within a local coverage area and still be connected to the network...
scheduler using Wireless N Gigabit routers automatically determines when Wi-Fi
Wi-Fi
Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...
radio signals are turned on and off to further reduce energy consumption.
Power savings
Green Ethernet was first employed on home products. However, low port counts mean that significant cost savings are not going to be made using this technology only in the home. Turning off existing devices when they are idle is likely to provide a more immediate saving. Projected power savings of up to were estimated using Green Ethernet switches, translating into a longer product life due to reduced heat dissipation.External links
- IEEE P802.3az Energy Efficient Ethernet Task Force Blog for Energy-Efficient Ethernet techniques and news analyses, circa 2009.