Business Glossary

a type of local-area network originally developed by Xerox Corporation. Communication takes place by means of radio-frequency signals carried by a coaxial cable. The name "Ethernet" apparently comes from "aether," the 19th-century name for the medium through which light waves were thought to travel.See local-area network (LAN); data communication.

On the physical level, there are four types of Ethernet connections. Thin-wire Ethernet uses RG-58 coaxial cable. Twisted-pair Ethernet is similar but uses a pair of unshielded wires. Conventional baseband Ethernet uses a thicker coaxial cable about 3/8 inch (0.9 cm) in diameter, and broadband Ethernet modulates the whole Ethernet signal on a higher-frequency carrier so that several signals can be carried simultaneously on a single cable, just like cable TV channels.See 10BASE-2; 10BASE-T; 100BASE-T.

The control strategy of Ethernet is called CSMA/CD(Carrier Sense, Multiple Access, Collision Detection). Each computer listens to see if another computer is transmitting. If so, it waits its turn to transmit. If two computers inadvertently transmit at the same time, the collision is detected, and they retransmit one at a time.

Ethernet systems use many software protocols, including TCP/IP, IPX/SPX, and NetBEUI. See TCP/IP; NetBEUI; MAC address; protocol.