Network Terminology Glossary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A 
Analog A representation that is similar to (or Analogous to) the original. For example, the height of the colored bar on a thermometer is analogous to the amount of heat; the hotter it is, the higher the colored bar.
ANSI American National Standards Institute.
APPC Peer-to-peer networking services in an IBM SNA network.
AppleShare Software by Apple Computer that enables a Macintosh computer to function as file a server.
AppleShare PC Software by Apple Computer that enables MS-DOS based personal computers to access an AppleTalk network.
AppleTalk A local area operating system by Apple Computer. It is built into Macintosh and Apple IIGS computers.
ARCnet A popular local area network that uses token passing passing over a star topology of coaxial cable, twisted pair, or optical fiber.
ASCII American Standard Code for Information Interchange. A common code for representing alphanumeric characters in computers.
B
Backbone The main trunk of a network communication channel.
Band The range of frequencies in which signals are transmitted.
Bandwidth The difference between the highest and lowest frequencies used for a communication channel. Generally, more bandwidth means greater transmission capacity.
Baud rate The maximum number of signal pulses that a communication line can handle per second. Higher baud rates indicate greater transmission capacities.
Baudot code A telecommunication code (representing alphanumeric characters) that predated ASCII. Baudot code was developed for use in telegraphy.
BCDIC Binary Coded Decimal Interchange Code. A code for representing alphanumeric characters in computers.
Bit The smallest unit of data representation in a computer. Can represent 0 or 1.
Bridge An internetworking device that connects two similar networks.
Brouter An internetworking device that functions as a router for protocols that it understands, and as a bridge for those that it does not.
Bus A main communication channel to which devices connect.
Byte Eight bits. A byte can represent whole numbers from 0 to 255. Typically, one byte holds a single character.
Bps Bits per second. A unit of measurement for data transfer rates.
C
CCITT Consultative Committee for International Telephony and Telegraphy. An international standards organization.
Central processing A networking strategy in which processing occurs at a host, not at workstations.
Circuit switching A temporary connection created by connecting two or more communication channels. An example of this is the public switched telephone system.
Client A network node that uses services provided by a server.
Client-server A network in which some nodes provide special services, such as printing and file sharing, for other nodes.
Closed Access is not available. For example a "closed network architecture" is one that does not enable other systems to interconnect.
Cluster controller A device that provides a connection between several devices (such as terminals and printers) and a host.
Coaxial cable A data-transmission medium that contains a single conductor surrounded by a metal shield.
Codec A COde/DECode device that enables analog data to be transmitted over digital lines.
Common carrier A company that provides telecommunications services to the public. Telephone companies are an example.
Communication A process by which information is transferred between at least two parties.
Communication channel The medium through which information is transmitted.
Communications server A specialized network node that provides clients with access to communications capabilities. A typical example is a computer that provides other nodes with access to a shared modem.
Contention A media-access control strategy in which devices attempt to transmit when the channel is not being used by another device. If two devices attempt to transmit at the same time, the contention strategy requires that both devices temporarily stop transmitting until the channel is free again.
Crosstalk Interference caused by "leaks" from a nearby communication channel.
CSMA Carrier Sense Multiple Access. A contention media-access strategy.
D
Data compression A procedure that uses mathematical techniques to encode data so that it uses less space. In most cases, data must be decompressed into its original form to be usable.
Data encryption A security procedure that encodes data so that it cannot easily be understood. To be usable, data must be decrypted into its original form by reversing the procedure that was used to encrypt it.
Database server A network computer that specializes in retrieving and storing data, providing that service to clients.
De facto standard A standard that exists through popular practice.
De jure standard A standard that exists through codes, laws, decrees, or other forms of legislation.
DECnet A network developed by Digital Equipment Corporation that connects DEC computers, PCs, and Macintoshes.
Digital A representation that uses discrete mathematical values to represent an object or amount. For example, a digital thermometer uses numbers to represent the relative amount of heat. (Compare with analog.)
Diskless workstation A networked computer that does not have local storage.
Distributed application An application that runs on two or more networked computers.
Distributed processing A system in which processing of applications stored on the network is done by client computers. "Distributed processing" is also sometimes used to refer to "distributed applications."
DNA Digital Network Architecture. A network architecture developed by Digital Equipment Corporation.
Dumb terminal An entry and display device that has no processing capability. Used in networks based on central processing.
E
EBCDIC Extended Binary Coded Decimal Interchange Code. A common code for representing alphanumeric characters in computers.
Electronic mail Software that enables users to send correspondence through a computer network.
Ethernet A popular local area network that uses a contention media-access method over a bus topology of coaxial cable. Also used to refer to the standard specified by IEEE 802.3.
EWN Enterprise-wide network. A network that serves an entire organization. Implies interoperability of disparate computing platforms, such as MS-DOS, UNIX, OS/2, and Macintosh.
F
FDDI Fiber Distributed Data Interface. Lower layers standard for networks based on optical fiber.
FEP Front-end processor. A device that manages communication between a host and other devices.
File server A node that provides other nodes with the access to shared storage.
G
Gateway A computer that interconnects disparate types of networks, translating protocols as necessary. For example, a gateway might connect personal computers on a LAN to a mainframe computer.
GOSIP Government Open Systems Interconnection Profile. A United States government specification that requires government network purchases to be OSI-compliant.
Groupware Software that enables a group of users to collaborate on a project by means of network communications.
H
HDLC High-Level Data Link Control. A Data Link layer protocol.
Hierarchical networks A network in which a host controls network communications and processing.
Host Computer that controls network communication in a hierarchical network.
I
IEEE Institute of Electrical and Electronics Engineers. A standards organization.
IEEE 802 Lower-layers standards for LANs set forth by the Institute of Electrical and Electronic Engineers.
Internet A global network that incorporates networks belonging to the United States government, academic institutions, and other organizations.
Interoperability The ability of disparate systems to share network resources.
ISO International Standards Organization.
J
K
Kbps Kilobits per second; how many thousands of bits of data can be transferred in one second.
L
LAN Local area network. A network that is limited to a small geographic area.
Leased line A communication channel provided by a common carrier for a fee.
LocalTalk A lower-layers protocol developed by Apple Computer.
LU 6.2 Another name for APPC (IBM's peer-to-peer networking services provided by SNA networks).
M
MAC Media-Access Control. Portion of the Data Link layer that controls access to the communication channel.
Mainframe computer Large-scale computer, such as those produced by IBM, Burroughs, Univac, NCR, Control Data, and Honeywell. Typically mainframe computers function as hosts in a hierarchical network.
MAN Municipal Area Network or Metropolitan Area Network. A medium-to high-speed network that spans an entire city or municipal area.
Media-access Media-Access Control Portion of the Data Link layer that method controls access to the communication channel.
Mesh Network architecture in which each node has a dedicated connection to all other nodes.
Message A chunk of data that is transmitted over a network.
Message switching A strategy that enables communication channels to be used simultaneously be more than one node. At each transfer point in the connection, incoming data is stored in its entirety, then forwarded to the next point. This process continues until the data reaches its destination.
MHS Message Handling Service. An electronic mail protocol developed by Action Technologies, Inc.
Minicomputer A mid-sized computer that can function as a workstation or a multi-user system.
Modem MOdulate/DEModulate device that enables digital data to be transmitted over analog lines.
N
NETBIOS A network-transport protocol introduced by IBM.
Network A collection of hardware and software that enables a group of computers to communicate and provide users with access to shared resources.
Network adapter A device that enables a computer to attach to a network.
Network architecture A description of how communication occurs within a specific type of network.
Network segment An uninterrupted length of the network communication channel. For example, a single cable between two repeaters, bridges, or routers is a segment.
Network-only application A software program that runs only on, or is useful only on a network.
Node A network-access point. Examples include terminals and computers.
Noise Extrinsic signals that corrupt a data transmission. Noise can come from crosstalk and other forms of electromagnetic interference.
NOS Network Operating System.
O
Open Access is available. For example, an "open network architecture" is one that enables other systems to interconnect.
Optical fiber A glass conduit that transmits data encoded in light signals.
OSI Open Systems Interconnection. A proto-type for network communication that promotes interconnectivity.
P
Packet switching A strategy that enables communication channels to be used simultaneously by more than one node. Before messages are transferred, they are divided into small chunks called packets, that fit easily into memory (unlike message switching, in which entire messages are moved, thus requiring storage for large messages). At the destination, the packets are reassembled into the original message.
Pbx Private branch exchange. A privately owned telephone system typically confined within a single building or campus.
Peer Relationship between network devices that have mutual access to each other's resources.
Peer-to-peer Communication between two network devices that have the same status on the network.
Personal computer (Or microcomputer.) A relatively small single-user computer.
Polling A media-access-control strategy in which a controlling computer mediates access to the communication channel.
POTS Plain Old Telephone Service. The analog voice telephone network provided by common carriers.
Protocol A code or set of rules by which communication is initiated, maintained, and terminated.
Pure network application (Same as network only application.) A software program that runs only on, or is useful only on a network.
Q
R
Real time A transmission or transaction that occurs immediately or in an extremely short period of time. A telephone conversation occurs in real time; correspondence through mail does not.
Receiver The component on the "hearing" end of a transmission.
Repeater A device that connects two network segments to make them work as one. Repeaters can extend the length of a network beyond the physical limitations of a single cable.
Ring A network topology that connects network devices in a continuous loop.
Router A device that connects networks and can determine the best path for data when there are multiple paths.
S
SCSI port Small Computer System Interface port. A high-speed connection that enables devices, such as hard-disk drives and network adapters, to be attached to a computer.
Server A network node that provides services, such as printing or storage, to other nodes.
Shielding A metal foil or mesh surrounding a conductor to reduce electromagnetic interference.
SNA Systems Network Architecture. A network developed by IBM to interconnect IBM's family of computers.
SQL Server Structured Query Language server. A computer that provides client computers with highly efficient access to database files.
Stand-alone application An application that was designed for non-network use.
Stand-alone network application An application that is processed locally by client computers, but stored on the network, typically providing access to network features.
Standards A common set of rules.
Star A network topology in which nodes are connected to a central hub.
Station A computer attached to a network.
T
T-carrier A leased digital line service.
TCP/IP Transport Control Protocol/Internet Protocol. Refers to the Internet Protocols, a set of protocol originally developed for the United States government. Because the Internet Protocols have been implemented on a wide variety of computers, they are often used in networks that interconnect disparate systems.
Token passing A media-access-control strategy in which a sequence of bits known as a "token" is passed from node to node. The node that currently holds the token has control of the communication channel.
Token ring A popular local area network (developed by IBM) that uses a token-passing media access method over a star topology. Also used to refer to the standard specified by IEEE 802.5.
Transceiver A device that can function as a transmitter or receiver.
Transmitter The component on the "speaker" end of a transmission.
Twisted pair Cable consisting of at least two insulated wires that are intertwined to reduce electromagnetic interference.
U
Unguided media Product that transmits data through the air, such as radio or microwave.
V
W
WAN Wide area network. A network of interconnected networks.
X
X.25 A CCITT standard that describes the interface for packet-switched networks.
X.400 A CCITT standard that describes electronic-mail protocols.
Y
Z