10Base2 - Ethernet specification for thin coaxial cable,
transmits signals at 10 Mbps (megabits per second) with a distance limit of 185 meters per
10Base5 - Ethernet specification for thick coaxial cable,
transmits signals at 10 Mbps (megabits per second) with a distance limit of 500 meters per
10BaseF - Ethernet specification for fiber optic cable, transmits
signals at 10 Mbps (megabits per second) with a distance limit of 1000 meters per segment.
10BaseT - Ethernet specification for unshielded twisted
pair cable (category 3, 4, or 5), transmits signals at 10 Mbps (megabits per second) with
a distance limit of 100 meters per segment.
Access Method - Rules that govern how nodes on a network
access the cable.
AppleTalk - Apple Computer's network protocol originally
designed to run over LocalTalk networks, but can also run on Ethernet and Token Ring.
AUI Connector (Attachment Unit Interface) - A 15 pin connector
found on Ethernet cards that can be used for attaching coaxial, fiber optic, or twisted
Backbone - A cable to which multiple nodes or
workstations are attached.
Bit - Binary digit in the binary numbering system. Its value
can be 0 or 1. In an 8-bit character scheme, it takes 8 bits to make a byte (character) of
BNC Connector (Bayone-Neill-Concelman) - Standard connector
used to connect 10Base2 coaxial cable.
Bridge - Devices that connect and pass packets between two
network segments that use the same communications protocol.
Cable - Transmission medium of copper wire or optical fiber
wrapped in a protective cover.
Client/Server - A networking system in which one or more
file servers (Server) provide services; such as network management, application and
centralized data storage for workstations (Clients).
CSMA/CA - Carrier Sense Multiple Access Collision Avoidance is a
network access method in which each device signals its intent to transmit before it
actually does so. This prevents other devices from sending information, thus preventing
collisions from occurring between signals from two or more devices. This is the access
method used by LocalTalk.
CSMA/CD - Carrier Sense Multiple Access Collision
Detection is a network access method in which devices that are ready to transmit data
first check the channel for a carrier. If no carrier is sensed, a device can transmit. If
two devices transmit at once, a collision occurs and each computer backs off and waits a
random amount of time before attempting to retransmit. This is the access method used by
Coaxial Cable - Cable consisting of a single copper
conductor in the center surrounded by a plastic layer for insulation and a braided metal
Concentrator - A device that provides a central
connection point for cables from workstations, servers, and peripherals. Most
concentrators contain the ability to amplify the electrical signal they receive.
Dumb Terminal - Refers to devices that are designed to
communicate exclusively with a host (main frame) computer. It receives all screen layouts
from the host computer and sends all keyboard entry to the host. It cannot function
without the host computer.
E-Mail - An electronic mail message sent from a host
computer to a remote computer.
End User - Refers to the human executing applications on
Ethernet - A network protocol invented by Xerox
Corporation and developed jointly by Xerox, Intel and Digital Equipment Corporation.
Ethernet networks use CSMA/CD and run over a variety of cable types at 10 Mbps (megabits
Expansion Slot - Area in a computer that accepts
additional input/output boards to increase the capability of the computer.
Fast Ethernet - A new Ethernet standard that supports 100 Mbps using
category 5 twisted pair or fiber optic cable.
Fiber Optic Cable - A cable, consisting of a center glass
core surrounded by layers of plastic, that transmits data using light rather than
electricity. It has the ability to carry more information over much longer distances.
File Server - A computer connected to the network that
contains primary files/applications and shares them as requested with the other computers
on the network. If the file server is dedicated for that purpose only, it is connected to
a client/server network. An example of a client/server network is Novell Netware. All the
computers connected to a peer-to-peer network are capable of being the file server. Two
examples of peer-to-peer networks are LANtastic and Windows for Workgroups.
Gigabyte (GB) - One billion bytes of information. One
Hub - A hardware device that contains multiple independent but
connected modules of network and internetwork equipment. Hubs can be active (where they
repeat signals sent through them) or passive (where they do not repeat but merely split
signals sent through them).
Infrared - Electromagnetic waves whose frequency range is
above that of microwaves, but below that of the visible spectrum.
Internet - A global network of networks used to exchange
information using the TCP/IP protocol. It allows for electronic mail and the accessing and
retrieval of information from remote sources.
LAN (Local Area Network) - A network connecting computers in a
relatively small area such as a building.
Linear Bus - A network topology in which each node
attaches directly to a common cable.
LocalTalk - Apple Corporation proprietary protocol that
uses CSMA/CA media access scheme and supports transmissions at speeds of 230 Kbps
(Kilobits per second).
MAN (Metropolitan Area Network) - A network connecting computers
over a large geographical area, such as a city or school district.
MAU (Multistation Access Unit) - A Token Ring wiring hub.
Modem (Modulator/Demodulator) - Devices that convert digital
and analog signals. Modems allow computer data (digital) to be transmitted over
voice-grade telephone lines (analog).
Multiplexer - A device that allows multiple logical
signals to be transmitted simultaneously across a single physical channel.
Network Modem - A modem connected to a Local Area Network
(LAN) that is accessible from any workstation on the network.
Network Interface Card (NIC) - A board that provides network
communication capabilities to and from a computer.
Network Operating System (NOS) - Operating system designed to
pass information and communicate between more than one computer. Examples include
AppleShare, Novell NetWare, and Windows NT Server.
Node - End point of a network connection. Nodes include any
device attached to a network such as file servers, printers, or workstations.
Node Devices - Any computer or peripheral that is
connected to the network.
PCMCIA - An expansion slot found in many laptop computers.
Peer-to-Peer Network - A network in which resources and files
are shared without a centralized management source.
Physical Topology - The physical layout of the
network; how the cables are arranged; and how the computers are connected.
Point-to-Point - A direct link between two objects
in a network.
Ports - A connection point for a cable.
Protocol -A formal description of a set of rules and
conventions that govern how devices on a network exchange information.
RAID (Redundant Array of Inexpensive Disks) - A configuration
of multiple disks designed to preserve data after a disk casualty.
RAM (Random Access Memory) - The working memory of a computer
where data and programs are temporarily stored. RAM only holds information when the
computer is on.
Repeater - A device used in a network to strengthen a
signal as it is passed along the network cable.
RJ-45 - Standard connectors used for unshielded twisted-pair
Router -A device that routes information between
interconnected networks. It can select the best path to route a message, as well as
translate information from one network to another. It is similar to a superintelligent
Segment - Refers to a section of cable on a network. In
Ethernet networks, two types of segments are defined. A populated or trunk segment is a
network cable that has one or more nodes attached to it. A link segment is a cable that
connects a computer to an interconnecting device, such as a repeater or concentrator, or
connects a interconnecting device to another interconnecting device.
Sneaker-Net - Refers to a manual method of sharing
files in which a file is copied from a computer to a floppy disk, transported to a second
computer by a person physically walking (apparently wearing sneakers) to the second
computer, and manually transferring the file from floppy disk to the second computer.
Speed of Data Transfer - The rate at which
information travels through a network, usually measured in megabits per second.
Star Topology - LAN topology in which each node on a network
is connected directly to a central network hub or concentrator.
Star-Wired Ring - Network topology that connects
network devices (such as computers and printers) in a complete circle.
Tape Back-Up - Copying all the data and programs of a
computer system on magnetic tape. On tape, data is stored sequentially. When retrieving
data, the tape is searched from the beginning of tape until the data is found.
Terminator - A device that provides electrical
resistance at the end of a transmission line. Its function is to absorb signals on the
line, thereby keeping them from bouncing back and being received again by the network.
Token - A special packet that contains data and acts as a
messenger or carrier between each computer and device on a ring topology. Each computer
must wait for the messenger to stop at its node before it can send data over the network.
Token Ring - A network protocol developed by IBM in
which computers access the network through token-passing. Usually uses a star-wired ring
Transceiver (Transmitter/Receiver) - A Device that
receives and sends signals over a medium. In networks, it is generally used to allow for
the connection between two different types of cable connectors, such as AUI and RJ-45.
Tree Topology - LAN topology similar to linear bus
topology, except that tree networks can contain branches with multiple nodes.
Twisted Pair - Network cabling that consists of four pairs
of wires that are manufactured with the wires twisted to certain specifications. Available
in shielded and unshielded versions.
WAN (Wide Area Network) - A network connecting computers within very
large areas, such as states, countries, and the world.
Workgroup - A collection of workstations and servers on
a LAN that are designated to communicate and exchange data with one another.
Workstation - A computer connected to a network at
which users interact with software stored on the network.
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