Ethernet Glossary

After you've finished, you can test your knowledge with Quiz #28: Ethernet.

AUI (attachment unit interface) - the 15-pin physical connector interface between a computer's network interface card (NIC) and an Ethernet cable. On 10BASE-5 ("Thicknet") Ethernet, a short cable is used to connect the AUI on the computer with a transceiver on the main cable. In 10BASE-2 or "Thinnet" Ethernet networks, the NIC connects directly to the Ethernet coaxial cable at the back of the computer.

BNC - a type of connector used to connect a computer to a coaxial cable in a 10BASE-2 Ethernet network.

bridge - a device that connects one local area network (LAN) to another local area network.

Carrier Sense Multiple Access/Collision Detect (CSMA/CD) - the protocol for carrier transmission access in Ethernet networks. CSMA is the ability to detect whether the medium is in use; CD is the ability to detect a collision and retry after some length of time.

coaxial cable - the kind of copper cable used by cable TV companies between the community antenna and user homes and businesses. It is also widely installed for use in business and corporation Ethernet and other types of local area network.

collision - the result of two devices on the same Ethernet network attempting to transmit data at exactly the same time.

Ethernet - the most widely-installed local area network (LAN) technology. Specified in a standard, IEEE 802.3, Ethernet was originally developed by Xerox and then developed further by Xerox, DEC, and Intel.

Ethernet/IP (Ethernet Industrial Protocol) - a network communication standard capable of handling large amounts of data at speeds of 10 Mbps or 100 Mbps, and at up to 1500 bytes per packet. The specification uses an open protocol at the Application layer and is especially popular for control applications.

Fast Ethernet - a local area network (LAN) transmission standard that provides a data rate of 100 megabits per second (referred to as "100BASE-T").

frame - the unit of data that is transmitted between network points on an Ethernet network. It has explicit minimum and maximum lengths and a set of required pieces of information that must appear within it.

Gigabit Ethernet - a transmission technology based on the Ethernet frame format and protocol used in local area networks (LANs), provides a data rate of 1 billion bits per second (one gigabit). Gigabit Ethernet is defined in the IEEE 802.3 standard and is currently being used as the backbone in many enterprise networks.

header - the beginning part of a data packet or frame that identifies the information unit's source, its destination, and its size.

Jabber - a device that is handling electrical signals improperly. In an Ethernet network, a jabber can look like a device that is always sending, effectively bringing the network to a halt. A jabber is usually the result of a bad network interface card (NIC).

MAU (medium attachment unit) - a device that interconnects the attachment unit interface (AUI) port on an attached host computer to the Ethernet network medium (such as unshielded twisted pair or coaxial cable). The MAU provides the services that correspond to the physical layer of the Open Systems Interconnection (OSI) reference model.

network interface card (NIC) - a computer circuit board or card that is installed in a computer so that it can be connected to a network.

100BASE-T - one of three types of physical wiring used in Fast Ethernet (100 Mbps Ethernet) that can carry signals: 100BASE-T4 (four pairs of telephone twisted pair wire); 100BASE-TX (two pairs of data grade twisted-pair wire); and100BASE-FX (a two-strand optical fiber cable).

Power over Ethernet (PoE) - a technology for wired Ethernet LANs (local area networks) that allows the electrical current necessary for the operation of each device to be carried by the data cables rather than by power cords.

10BASE-2 - consists of Thinwire coaxial cable with a maximum segment length of 185 meters. Like other specified media, 10BASE-2 supports Ethernet's 10 Mbps data rate.

10BASE-5 - consists of Thickwire coaxial cable with a maximum segment length of 500 meters. Like other specified media, 10BASE-2 supports Ethernet's 10 Mbps data rate.

10BASE-T - ordinary telephone twisted pair wire; one of several physical media specified in the IEEE 802.3 standard for Ethernet local area networks (LANs).

10-Gigabit Ethernet - a developing telecommunication technology, being standardized in IEEE 802.3a, that offers data speeds up to 10 billion bits per second.

Thicknet and Thinnet - commonly used terms for the larger and smaller size of coaxial cable used in Ethernet local area networks.

vampire tap - used to connect each device to Thicknet coaxial cable in the bus topology of an Ethernet 10BASE-T local area network.

This was last updated in April 2008

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