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Definition: Ethernet


(1) For blockchain contracts, see Ethereum.

(2) Ethernet is the network technology that connects computers via cables to each other and to the Internet. Defined by the IEEE as the 802.3 standard, the Ethernet access method is used worldwide. Companies have hundreds and thousands of PCs wired together via Ethernet, and almost every reference to "local network," "LAN," and "network ready" is Ethernet. All new computers have Ethernet built in, and old machines can be retrofitted (see Ethernet adapter). See LAN and 802.3.

Ethernet Is Wired - Wi-Fi Is Wireless
Wired Ethernet and wireless Wi-Fi exist together in virtually every home and office. Desktop computers may be wired, but phones and tablets use Wi-Fi, and a wireless router provides both. See Wi-Fi and wireless router.

10/100/1000 Gigabit Ethernet
All new routers and Ethernet switches are 10/100/1000 "Gigabit" devices because the top speed is 1000 Mbps (1 Gbps). Older networking hardware maxed out at 10 and 100 Mbps. If device speeds are not equal, Ethernet uses the highest common speed between sending and receiving ports. See Gigabit Ethernet and automotive Ethernet.

Above one gigabit, Ethernets do not mix. There is no such thing as a 10/100/1000/10000 port (see 10 Gigabit Ethernet). See 100 Gigabit Ethernet.

Ethernet and TCP/IP Together
TCP/IP is the protocol that prepares the data that Ethernet transmits. Together, they comprise the global standard for local area networks (LANs). See TCP/IP.

History
Invented by Robert Metcalfe and David Boggs at Xerox PARC in 1973, Ethernet first ran at just under 3 Mbps. Metcalfe joined Digital Equipment Corporation where he facilitated a joint venture with Intel and Xerox to collaborate further, and Ethernet Version 1 was finalized in 1980. In 1983, the IEEE approved the 802.3 standard. See Ethernet adapter, Ethernet switch and automotive Ethernet.

 MAXIMUM CABLE LENGTHS (Device to Switch)

               Speed     Distance
 Version       (Mbps)   Feet/Meters
 TWISTED WIRE PAIR
   10Base-T       10     328/100
  100Base-T      100     328/100
 1000Base-T     1000     328/100

               Speed        Distance
 Version       (Mbps)   Miles/Kilometers
 OPTICAL FIBER
  10Base-FL MM    10       1.2/2
 100Base-FX MM   100       1.2/2
 100Base-FX SM  1000         6/10
  MM=multimode   SM=singlemode




Ethernet Uses a Star Topology
All computers connect to a central switch that lets each sender/receiver pair transmit at full speed (10, 100 or 1000 Mbps). Spare telephone wires are sometimes used, but often at lower speeds. For earlier topologies, see 10Base5 and 10Base2. See Ethernet switch, cable categories and twisted pair.






Ethernet Switch
This earlier Omnitron switch had 16 10/100 ports and, like all Ethernet switches, automatically adjusted to the highest common speed between sender and receiver.






Ethernet Is Everywhere
In the back of a home theater cabinet is a NETGEAR Ethernet switch. It connects the Fire TV, Apple TV and Roku 3 streaming boxes, plus an Oppo Blu-ray player, to the main switch in another part of the house some 60 feet away.