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Ethernet is a frame-based computer networking technology for local area networks (LANs).
It defines wiring and signaling for the physical layer, and frame formats and protocols
for the media access control (MAC)/data link layer of the OSI model. Ethernet is mostly
standardized as IEEE's 802.3. It has become the most widespread LAN technology in use
during the 1990s to the present (2004), and has largely replaced all other LAN standards
such as token ring, FDDI, and
History of Ethernet
Ethernet was originally developed as one of the many pioneering projects at Xerox PARC.
A common story states that Ethernet was invented in 1973, when Robert Metcalfe wrote a
memo to his bosses at PARC about Ethernet's potential. Metcalfe claims Ethernet was actually
invented over a period of several years. In 1976, Metcalfe and David Boggs (Metcalfe's assistant)
published a paper titled, Ethernet: Distributed Packet-Switching For Local Computer Networks.
Metcalfe left Xerox in 1979 to promote the use of personal computers and local area networks (LANs),
forming 3Com. He successfully convinced DEC, Intel, and Xerox to work together to promote Ethernet
as a standard (DIX), which was first published on September 30, 1980. Competing with them at
the time were the two largely proprietary systems, token ring and ARCNET, but both would soon
find themselves buried under a tidal wave of Ethernet products. In the process, 3Com became
a major company.
General description of Ethernet
A typical 1990s Ethernet network card, also called Ethernet adapter, with both BNC (left) and
Twisted pair (right) connectors.Ethernet is based on the idea of peers on the network sending
messages in what was essentially a radio system, captive inside a common wire or channel, sometimes
referred to as the ether. (This is an oblique reference to the luminiferous aether through
which 19th century physicists believed light traveled.) Each peer has a globally unique 48-bit
key known as the MAC address factory-assigned to the network interface card, to ensure that all
systems in an Ethernet have distinct addresses. Due to the ubiquity of Ethernet, many manufacturers
build the functionality of an ethernet card directly into PC motherboards.
It has been observed that Ethernet traffic has self-similar properties, with important consequences
for traffic engineering.
Related Topics
Local area network (LAN)
Wide area network (WAN)
Wireless LAN
Router - History, Functionality and Manufacturers
Integrated Services Digital Network (ISDN) - Consumer, Industry, Services and Configuration
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