Ethernet is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN).
It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3. Ethernet has since been refined to support higher bit rates, a greater number of nodes, and longer link distances, but retains much backward compatibility.
Ethernet was developed at Xerox PARC between 1973 and 1974. It was inspired by ALOHAnet, which Robert Metcalfe had studied as part of his PhD dissertation. The idea was first documented in a memo that Metcalfe wrote on May 22, 1973, where he named it after the luminiferous aether once postulated to exist as an “omnipresent, completely-passive medium for the propagation of electromagnetic waves.
Ethernet was able to adapt to market needs and with 10BASE2, shift to inexpensive thin coaxial cable and from 1990, to the now-ubiquitous twisted pair with 10BASE-T. By the end of the 1980s, Ethernet was clearly the dominant network technology.
By the early 1990s, Ethernet became so prevalent that Ethernet ports began to appear on some PCs and most workstations.
The original 10BASE5 Ethernet uses a thick coaxial cable as a shared medium. This was largely superseded by 10BASE2, which used a thinner and more flexible cable that was both cheaper and easier to use. More modern Ethernet variants use twisted pair and fiber optic links in conjunction with switches. Over the course of its history, Ethernet data transfer rates have been increased from the original.
Systems communicating over Ethernet divide a stream of data into shorter pieces called frames. Each frame contains source and destination addresses, and error-checking data so that damaged frames can be detected and discarded; most often, higher-layer protocols trigger retransmission of lost frames.
Since then, Ethernet technology has evolved to meet new bandwidth and market requirements. In addition to computers, Ethernet is now used to interconnect appliances and other personal devices.As Industrial Ethernet it is used in industrial applications and is quickly replacing legacy data transmission systems in the world’s telecommunications networks.
Ethernet is widely used in homes and industry, and interworks well with wireless Wi-Fi technologies. The Internet Protocol is commonly carried over Ethernet and so it is considered one of the key technologies that make up the Internet.