In 1985, the U.S. Institute of Electrical and Electronic Engineers (IEEE) developed standards for Local Area Networks (LANs) called the IEEE 802 standards. These standards presently form the basis of most networks.

One of the IEEE 802 standards—the IEEE 802.3—is known as “Ethernet,” the most prevalently used LAN technology around the globe. Ethernet was designed by the Xerox Corporation in 1972, and in its simplest form it used a passive bus operated at 10 Mbps. A 50-Ohm coaxial cable connected the computers in the network.

Though a single LAN can have as many as 1,024 attached computer systems, in practice most LANs have far fewer than this. Typically, one or several coaxial cable pieces are joined end-to-end to form the bus, also known as an “Ethernet cable segment.” Each Ethernet cable segment is terminated at both ends by 50-Ohm resistors and is usually grounded at one end for safety reasons. Thus, computers attach to the cable using network interface cards and/or transceivers.

Since its birth, Ethernet has grown to much higher speeds. For example, at the start of 2004, 10 GBit/s (standardized as 802.3ae) network adapters were introduced. Furthermore, the once error-prone, single-cable bus architecture has evolved into a notable error-reduced star topology using hubs and switches.

See Also: Local Area Networks (LAN).