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Ethernet in the first mile (EFM) refers to using one of the Ethernet family of computer network protocols between a telecommunications company and a customer's premises. From the customer's point of view it is their "first" mile, although from the access network's point of view it is known as the "last mile". A working group of the Institute of Electrical and Electronics Engineers (IEEE) produced the standards known as IEEE 802.3ah-2004, which were later included in the overall standard IEEE 802.3-2008. Although it is often used for businesses, it can also be known as Ethernet to the Home (ETTH). One family of standards known as EPON uses a passive optical network. ==History== With wide, metro, and local area networks using various forms of Ethernet, the goal was to eliminate non-native transport such as Ethernet over Asynchronous Transfer Mode (ATM) from access networks. One early effort was the EtherLoop technology invented at Nortel Networks in 1996, and then spun off into the company Elastic Networks in 1998. Its principal inventor was Jack Terry. The hope was to combine the packet-based nature of Ethernet with the ability of Digital Subscriber Line (DSL) technology to work over existing telephone access wires. The name comes from local loop, which traditionally describes the wires from a telephone company office to a subscriber. The protocol was half-duplex with control from the provider side of the loop. It adapted to line conditions with a peak of 10 Mbit/s advertised, but 4-6 Mbit/s more typical, at a distance of about . Symbol rates were 1 megabaud or 1.67 megabaud, with 2, 4, or 6 bits per symbol.〔 The EtherLoop product name was registered as a trademark in the US and Canada. The EtherLoop technology was eventually purchased by Paradyne Networks in 2002, which was in turn purchased by Zhone Technologies in 2005. Another effort was the concept promoted by Michael Silverton of using Ethernet variants that used fiber optic communication to residential as well as business customers. This was an example of what has become known as fiber to the home (FTTH). The Fiberhood Networks company provided this service from 1999 to 2001. Some early products around 2000 were marketed as 10BaseS by Infineon Technologies, although they did not technically use baseband signalling, but rather passband as in very-high-bit-rate digital subscriber line (VDSL) technology. A patent was filed in 1997 by Peleg Shimon, Porat Boaz, Noam Alroy, Rubinstain Avinoam and Sfadya Yackow. Long Reach Ethernet was the product name used by Cisco Systems starting in 2001. It supported modes of 5 Mbit/s, 10 Mbit/s, and 15 Mbit/s depending on distance. In October 2000 Howard Frazier issued a call for interest on "Ethernet in the Last Mile". At the November 2000 meeting, IEEE 802.3 created the "Ethernet in the First Mile" study group, and on July 16, 2001 the 802.3ah working group. In parallel participating vendors formed the Ethernet in the First Mile Alliance (EFMA) in December 2001 to promote Ethernet subscriber access technology and support the IEEE standard efforts. At an early meeting, the EtherLoop technology was called 100BASE-CU and another technology called EoVDSL for Ethernet over VDSL. The working group's EFM standard was approved on June 24, 2004 and published on September 7, 2004 as IEEE 802.3ah-2004. In 2005 it was included into the base IEEE 802.3 standard. In 2005, the EFMA was absorbed by the Metro Ethernet Forum. In early 2006, work began on an even higher-speed 10 gigabit/second Ethernet passive optical network (10G-EPON) standard, ratified in 2009 as IEEE 802.3av. The work on the EPON was continued by the IEEE P802.3bk ''Extended EPON'' Task Force, formed in March 2012. The major goals for this Task Force included adding support for PX30, PX40, PRX40, and PR40 power budget classes to both 1G-EPON and 10G-EPON. The 802.3bk amendment was approved by the IEEE-SA SB in August 2013 and published soon thereafter as the standard IEEE Std 802.3bk-2013. In November 2011, IEEE 802.3 began work on EPON Protocol over Coax (EPoC). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ethernet in the first mile」の詳細全文を読む スポンサード リンク
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