Networking
Glossary
Select the first letter of the word from the list above to
jump to appropriate section of the glossary. If the term you are
looking for starts with a digit or symbol, choose the '#' link.
- Access Server
- A device that connects synchronous and asynchronous
devices to a network, providing routing for both types of
communications.
- Account Lockout
- A security measure that prohibits logging on to an NT
server account after a specified number of unsuccessful
attempts.
- Active Hub
- Connects nodes in a star topology, regenerating retiming,
and amplifying the data signal each time it passes
through the hub. Using active hubs more than doubles the
total number of nodes that can be connected to a token
ring network.
- Algorithm
- A block of computer code or logic designed to accomplish
a certain task or to solve problem, such as to control
data communications or to calculate a payroll deduction.
- American National Standards Institute(ANSI)
- An organization that works to set standards for all types
of products, including computer network equipment.
- American Standard Code for Information
Interchange (ASCII)
- A commonly used character set that consists of 96
uppercase and lowercase characters and numbers, plus 32
non-printing characters.
- Analog
- Is a transmission that can vary continuously, such as in
a wave pattern with positive and negative voltage levels.
- AppleTalk
- A peer-to-peer protocol used on networks for
communications between Macintosh computers.
- Asynchronous Communications
- Occur in discrete units in which a start bit at the front
signals the start of a unit and a stop bit at the back
signals the end of the unit.
- Asynchronous Transfer Mode (ATM)
- A transport method that uses multiple channels and
switching to send voice, video, and data transmissions on
the same network. ATM data transfer stresses efficient,
quality of service (QOS), high capacity data transport.
- ATM Switch
- Determines the network channel used to transmit and ATM
cell received from a node, taking into account the type
of information in the cell and the transmission speed
needed.
- Attachment Unit Interface (AUI)
- Connects coax or fiber-optic backbone cable to a network
node, such as a repeater. The interface consists of AUI
standards for connectors, cable, interface circuits, and
electrical characteristics.
- Attenuation
- The amount of signal that is lost as the signal travels
through the communications medium from its source to the
receiving node.
- Backbone
- A high capacity communications medium that joins networks
and central network devices on the same floor in a
building, on different floors, and across long distances.
- Backplane
- The main circuit board in modular equipment, containing
slots as plug-ins for modular cards. The backplane
provides connections between the modular boards, a power
source, and grounding.
- Backup Domain Controller (BDC)
- An NT server that acts as the backup to the primary
domain controller. It has a copy of the security accounts
manager database that contains information about user
accounts and access privileges.
- Basic Rate Interface
- Consists of three channels. Two are 64Kbps channels for
data, voice, and graphics transmissions. The third is a
16 Kbps channel used for communication signaling.
- Baud Rate
- The speed measurement used for early modems, reflecting
that one data bit is sent per each signal oscillation.
For example, an early 300-baud modem could make a maximum
of 300 signal changes per second, thus sending only 300
bits per second.
- Beaconing
- The error condition on a token ring network that
indicates one or more nodes is not functioning.
- Bridge
- Connects different LAN segments using the same access
method, such as one Ethernet LAN to another Ethernet LAN
or a token ring LAN to another token ring LAN.
- Broadband ISDN (B-ISDN)
- Being developed to provide an initial ISDN data transfer
rate of 155 Mbps.The theoretical limit is 622Mbps.
- Broadcast Storm
- Occurs on an Ethernet network when one or more nodes
broadcast continuously, interrupting or delaying
successful network transmissions.
- Bus Topology
- A network configured so that nodes are connected to a
segment of cable in the logical shape of a line, with a
terminator at each end.
- Baseband
- A type of transmission in which the entire channel
capacity of the medium is used by one data signal.
- BNC
- A connector with a bayonet like shell, used for coax
cable.
- Broadband
- A transmission that employs several transmissions
channels on a single communications medium.
- Brouter
- Also called a multiprotocol router, acts like a bridge or
a router, depending on how it is set up to forward a
given protocol.
- Cable Plant
- The total cabling of a network.
- Cable Scanner
- Measures the length of a network cable segment and tests
for electrical opens (breaks) and shorts.
- Call-back Security
- Instructs the RAS server to call back an accessing
workstation to verify that access is requested from an
authorized telephone number.
- Carrier Sense
- The process of checking a communication medium, such as
cable, for a specific voltage or signal level that
indicates the presence of a data-carrying signal.
- Carrier Sense Multiple Access with Collision
Detection(CSMA/CD)
- A network access control mechanism used with Ethernet
networks. It regulates transmission by sensing the
presence of packet collision.
- Cell
- A unit of data formatted for high-speed transmission over
a network. Typically a cell contains a fixed amount of
data and performs less error checking than a packet to
achieve faster transmission.
- Cell
- A large fixed-length data-carrying unit primarily
consisting of a header with transmission control
information and a large payload section that contains
data.
- Cell Relay
- A communications protocol that uses large fixed-length
cells to transmit voice, video, and data.
- Channel Service Unit (CSU)
- A physical interface between a network device, such as a
router, and a telecommunications line.
- Circuit Switching
- A network communication technique that uses a dedicated
channel to transmit information between two nodes.
- Class A Node
- Dual attached node, on an FDDI ring is a network device,
such as a hub, that is connected to both rings in the
FDDI architecture.
- Class B Node
- Single attached node, in FDDI is a workstation, server,
or host computer that connects to the primary ring only
and connects through a Class A node.
- Client
- A client computer is one that accesses a mainframe, a
minicomputer, or a microcomputer that allows for multiple
users.
- Client/Server Application
- An application in which processing tasks are performed on
the client or on one or more servers to achieve the best
performance and to minimize network load.
- Cluster Remapping
- A fault-tolerance technique used by Windows NT to flag a
damaged cluster and find an undamaged cluster on which to
write data.
- Coaxial Cable
- Consists of a copper core surrounded by insulation. The
insulation is surrounded by another conduction material
such as braided wire, which is covered by an outer
insulating material.
- Collision
- Occurs when two or more packets are detected at the same
time on an Ethernet network.
- Computer Virus
- Software that can spread throughout a computer, damaging
files, file allocation tables, and other software
components.
- Consultative Committee on International
Telegraph and Telephone (CCITT)
- International standards body that develops
telecommunications standards for modems, digital
telephone systems, and e-mail.
- Communications Media
- The cabling or radio waves used to connect one network
computer to another and transport data between them.
- Communications Server
- Connects asynchronous serial devices to a network.
- Compressed Serial Line Internet Protocol
(CSLIP)
- An extension of the SLIP remote communications protocol
that provides faster throughput than SLIP.
- Connection-oriented Services
- Also known as Type 2 operation, occur between the LLC
sub-layer and the network layer and provide several ways
to ensure data is successfully received by the
destination node.
- Connectionless Services
- Also known as Type 1 operation, occur between the LLC
sub-layer and the network layer and provide no checks to
make sure data accurately reaches the receiving node.
- Concentrator
- Also known as a hub or switch.
- Cyclic Redundancy Check (CRC)
- And error detection method that calculates a value for
the total size of the information fields contained in a
frame. The value is inserted at the end of the frame by
the data link layer on the sending node and checked at
the data link layer by the receiving node to determine if
a transmission error has occurred.
- Data Communications Equipment (DCE)
- Consists of network devices that perform packet
switching.
- Datagram
- Does not use a particular communication channel. Data
arrives at the destination node at different times,
because each datagram may follow a different route to the
destination.
- Data Encryption Standard (DES)
- A network encryption standard developed by the National
Institute of Standards and Technology (NIST) and IBM.
- Data Link Control Protocol (DLC)
- A protocol designed for communications with an IBM
mainframe or minicomputer.
- Data Service Unit (DSU)
- Used with a CSU for communications over a
telecommunications line. The DSU converts data to be sent
over the line and converts data received from the line
into a readable digital format.
- Data Terminal Equipment (DTE)
- Consists of terminals, workstations, servers, and host
computers that operate on a packet switching network.
- Defragmentation
- A software process that rearranges data to fill in the
spaces that develop on disks and makes it easier to
obtain.
- Demand Priority
- A data communications technique that transmits a packet
directly from the sending node, through a hub, and to the
receiving node, without making it available to other
network nodes.
- Digital
- Transmission that has distinct levels to represent binary
1s and 0s, such as on and off or +5 volts and 0 volts.
- Discovery
- An information gathering process used by a router, such
as about how many nodes are connected and where they are
located.
- Disk Duplexing
- A fault-tolerance method similar to disk mirroring in
that it prevents data loss by duplicating data from a
main disk to a backup disk. It is different in that it
places the backup disk on a controller or adapter
different from the one used by the main disk.
- Disk Fragmentation
- A normal and gradual process in which files become spread
throughout a disk and empty spaces develop between files.
- Disk Mirroring
- A fault-tolerance method that prevents data loss by
duplicating data from a main disk to a backup disk. Some
operating systems refer to it as disk shadowing.
- Domain Name Service (DNS)
- A TCP/IP application protocol that translates domain
computer names to IP addresses or IP addresses to domain
names.
- Driver
- Software that enables a computer to communicate with
devices like NICs, printers, monitors, and hard disk
drives. Each driver has a specific purpose, such as to
handle Ethernet network communications. The driver is
installed on the computer.
- Domain
- A network of clients and the resources used by the
clients. User workstations and user groups are the
clients; file servers, print servers, and other network
services are the resources.
- Dynamic Addressing
- A method in which an IP address is assigned to a
workstation without the need for the network
administrator to hard-code it in the workstation's
network setup.
- Dynamic Routing
- The router constantly checks the network configuration,
automatically updates routing tables, and makes its own
decisions about how to route frames.
- Dynamic Host configuration Protocol (DHCP)
- Provides a way for a server to automatically assign an IP
address to a workstation on its network.
- E-MAIL
- The use of mail software on the client to compose a
message and send it to mail or post office software on
one or more servers that forward the message to the
intended destination.
- Enterprise Network
- Reaches throughout a large area, such as a college
campus, a city, or across several states, connecting many
kinds of LANs and network resources.
- Enhanced Mode
- When the computer processor is set to indirectly access
computer memory, enabling it to run several programs at
once.
- Encryption
- Involves turning data into an unintelligible sequence of
characters. A key is used to translate the nonsense into
the original information.
- Encryption key
- A digital password known to the sending node and the
receiving node on a network.
- Ethernet
- Transport system that uses the CSMA/CD method for data
transmission on a network. Typically used in a bus or
star topology.
- Extended Binary Coded Decimal Interchange Code
(EBCDIC)
- Used mainly on IBM mainframe computers, consists of a
specially coded 256-character set.
- Fast Ethernet
- Ethernet speeds at up to 100Mbps and is defined under the
IEEE 802.3u standard. Besides the 100Mbps speed, Fast
Ethernet has full duplex capability, which means it can
send and receive packets at the same time.
- Fault Tolerance
- Using hardware and software to ensure against equipment
failures, computer service interruptions, and data loss.
- Fat Pipe
- A fiber optic cable used on a network backbone for
high-speed communications.
- Fiber Distributed Data Interface(FDDI)
- Fiber optic data transport method capable of a 100Mbps
transfer rate using a ring topology.
- Fiber Optic Cable
- Consists of one or more glass or plastic fiber cores
inside a protective classing material and covered by a
PVC outer jacket.
- File Server
- A network computer that makes software applications, data
files, and network utilities available to other
computers.
- File Transfer Protocol (FTP)
- An application protocol within TCP/IP used to transfer
data files from one computer system to another, such as
from a workstation running Microsoft OS to a computer
with a UNIX or IBM MVS OS.
- Firewall
- Software, hardware, or both employed to restrict who has
access to a network, to specific network segments, or to
certain network resources. Secures access to data and
resources from outside intruders. Prevents data from
leaving the network through and inside source.
- Flow Control
- Used to make sure one device does not send information
faster than can be received by another device.
- Frame Relay
- A communications protocol that relies on packet switching
and virtual circuit technology to transmit data packets.
It does not incorporate extensive error checking,
assuming that intermediate nodes will perform that task.
- Frequency Division Multiple Access (FDMA)
- Multiplexing creates separate channels on one
communication medium by establishing different
frequencies for each channel.
- Full Backup
- A backup of an entire system, including all system files,
programs, and data files.
- Gateway
- Enables communications between two different types of
networked systems, such as between complex protocols or
between different e-mail systems.
- Global Group
- Used to make one Microsoft domain accessible to another,
so resources can be shared and managed across two or more
domains.
- Group
- A common entity that contains user accounts and network
resources, such as file and print servers.
- Hertz
- The measurement of the frequency of the alternation of an
electrical current or radio wave.
- Home Directory
- A dedicated location on a file server or a workstation
for a designated account holder to store files.
- Hops
- The number of times a packet travels point to point from
one network to the next.
- Host
- Has an operating system that allows multiple computers to
access it at the same time.
- Hot Fix
- A data-recovery method that automatically stores data
when a damaged area of a disk prevents the data from
being written. The computer operating system finds
another undamaged area on which to write the stored data.
- Hub
- A central device used in the star topology that joins
single cable segments or individual LANs into the
network. Some hubs are called concentrators or access
units.
- Hypertext Markup Language
- A formatting process used to enable documents and graphic
images to be read on the world wide web. HTML also
provides for fast links to other documents, to graphics,
and to web sites.
- Impedance
- The total amount of opposition to the flow of current, in
coaxial cable, a 50-ohm impedance influences how fast a
packet can travel through the conductive material under
optimal conditions.
- Institute of Electrical and Electronics
Engineers (IEEE)
- An organization of scientists, engineers, technicians,
and educators that has influenced in particular standards
for network cabling and data transmissions.
- Integrated Services Digital Network (ISDN)
- A standard for delivering data services over telephone
lines, with a current practical limit of 64Kbps and a
theoretical limit of 622Mbps.
- Intelligent Hub
- One that has network management and performance
monitoring capabilities.
- Internet
- A collection of thousands of smaller networks around the
world linked by a vast array of network equipment and
communications methods.
- Internet Packet Exchange (IPX)
- A protocol developed by Novell for use with its NetWare
file server operating system.
- Intranet
- A private network within an organization. It uses the
same Web-based software as the internet, but access is
highly restricted.
- International Standards Organization (ISO)
- An international body that establishes communications and
networking standards. It is best known for its
contributions to network protocol standards.
- Incremental Backup
- A backup of new or changed files only.
- (empty)
- (empty)
- Leased Telephone Line
- A phone line that is conditioned for high quality
transmissions and is a permanent connection without going
through a telephone switch. There are different levels of
conditioning, depending on the cost and the type of the
line.
- Line of Sight Transmission
- The signal goes from point to point, rather than bouncing
off the atmosphere to skip across the country or across
continents. A limitation is that the transmission are
interrupted by large land masses, such as hills and
mountains.
- Local Area Network (LAN)
- A series of interconnected computers, printers, and other
computer equipment that share hardware and software
resources. This service is usually limited to a given
floor, office, or building.
- Local Bridge
- Connects networks in close proximity and is used to
segment a portion of a network to reduce problems caused
by heavy traffic.
- Local Group
- Consists of accounts, network resources, and global
groups. It is used to manage accounts and resources in a
single domain.
- Locking
- An operating system process that prevents more than one
user from updating a file or a record in a file at the
same time.
- Logical Link Control (LLC)
- A data link sub-layer of the OSI model that initiates the
communication link between nodes and ensures that the
link is not unintentionally broken.
- Local Router
- One that joins networks in the same building or between
buildings in close proximity.
- Mapped Drive
- A disk volume or folder that is shared on the network by
a file server or workstation. It gives designated network
workstations access to the files and data in its shared
volume or folder. The workstation, via
software,determines a drive letter for the shared volume,
which is the workstation's map to the data.
- Media Access Control (MAC)
- A data link sub-layer that examines addressing
information contained in network frames and controls how
devices share communications on the same network.
- Sends data from point to point with each intermediate
node storing the data, waiting for a free transmission
channel, and forwarding the data to the next point until
the destination is reached.
- Metropolitan Area Network (MAN)
- Links multiple LANs within a large city or metropolitan
region.
- Microcom Network Protocol (MNP)
- A set of modem service classes that provide efficient
communications, error correction, data compression, and
high throughput capabilities.
- Mission-Critical
- Software application or hardware service is one that
involves a vital business or support function, such as
college registration, order-entry, or payroll.
- Modem
- A modulator/demodulator that converts a transmitted
digital signal to an analog signal for a telephone line
and converts a received analog signal to a digital signal
for use by a computer.
- Modular Hub
- Also called a chassis hub, is one that contains a
backplane into which different modules, such as retiming,
bridge, routing, and ATM modules, can be inserted.
- Multiplexer
- A switch that divides a communication medium into
multiple channels so several nodes can communicate at the
same time. A signal that is multiplexed must be
demultiplexed at the other end.
- Multiplexing
- A form of circuit switching in which several physical
channels are connected to a switch called a multiplexor.
Multiple computers also are connected to the switch,
transmitting along the channels whose access is
controlled by the switch.
- Multi-Station Access Unit (MAU)
- A central hub that links token ring nodes into a topology
that physically resembles a star, but in which packets
are transferred in a logical ring pattern. Because of the
ring logic, a MAU contains no terminators.
-
- NetBIOS Extended User Interface (NetBEUI)
- A protocol that incorporates NetBIOS for communications
across a network.
- Network
- A system of computers, network devices, printers, and
software linked by communications cabling.
- Network Basic Input/Output System (NetBIOS)
- A combination software interface and network-naming
convention. It is available in Microsoft operating
systems through the file NetBIOS.DLL.
- Network Device Interface Specification (NDIS)
- A set of standards developed by Microsoft for network
drivers that enables communication between a NIC and a
protocol, and that enables for the use of multiple
protocols on the same network.
- Network Interface Card
- An adapter card that enables a workstation, file server,
printer, or other device to connect to a network and
communicate with other network nodes.
- Network File System (NFS)
- A UNIX-based network file transfer protocol that ships
files as streams of records.
- Network Traffic
- The number, size, and frequency of packets transmitted on
the network in a given amount of time.
- Node
- Any device connected to a network, such as microcomputer,
a mainframe, a minicomputer, network equipment, or a
printer.
- NWLink
- A network protocol that simulates the IPX/SPX protocol
for Win95 and NT communications with Novell NetWare file
servers and compatible devices.
- Open Data-Link Interface
- A driver that is used by Novell NetWare networks to
transport multiple protocols on multiple networks.
- Open Systems Interconnect (OSI)
- Developed by the ISO and ANSI, this provides a framework
for network communications based on seven functional
layers. It contains guidelines that can be applied to
hardware and software network communications.
- Packet
- A unit of data formatted or windows transmission over a
network. Normally formatted with control information, a
header that contains information about the packet's
source and destination, the data to be transmitted, and a
footer that contains error-checking information.
- Packet Assembler/Disassembler (PAD)
- A device that converts data from a format used by a DCE
to one that can be place on a X.25 communications network
and translates data received in an X.25 communications
format to a format that can be read by a DCE.
- Packet Switching
- A data transmission technique that establishes a logical
channel between two transmitting nodes, but uses several
different paths of transmission to continually find the
best routes to the destination.
- Partitioned Segment
- One that has been shut down because a portion of the
segment is malfunctioning.
- Passive Hub
- Connects nodes in a star topology, performing no signal
enhancement as the packet moves from one node to the next
through the hub. Each time the signal moves through the
hub, it is weakened slightly because the hub absorbs some
of the signal, reducing the total number of nodes that
can be attached to a token ring network.
- Peer-to-Peer Network
- One in which any computer can communicate with other
networked computers on an equal or peer-like basis
without going through and intermediary, such as a server
or host.
- Peer Protocols
- Enables an OSI layer on a sending node to communicate
with the same layer on the receiving node.
- Permanent Virtual Circuit
- Communication channel stays connected at all times, even
after the communication session is over.
- Permissions
- On a Windows NT Server, these control account or group
access capabilities for reading, viewing, and changing
files or folders.
- Point-to-Point Protocol (PPP)
- A widely used remote communications protocol that
supports IPX/SPX, NetBEUI, and TCP/IP communications
(such as between a remote PC and an NT server on a
network).
- Point to Point Tunneling Protocol (PPTP)
- A remote communications protocol that enables
connectivity to intranets (private virtual network)
through the internet.
- Power Budget
- Optical fiber cable communications is the difference
between the transmitted power and receiver sensitivity,
measured in decibels.
- Power Supply
- The component in a n electrical device that converts
power from the wall outlet to the type and level of power
required by the electrical device.
- Promiscuous Mode
- It reads frame destination address information before
sending a packet onto other connected segments of the
network.
- Primary Domain controller (PDC)
- An NT server that acts as the master server when there
are two or more NT servers on a network. It holds the
master database of user accounts and access privileges.
- Primary Rate Interface (PRI)
- Consists of switched communications in multiples of 1536
Kbps.
- Primitive
- A command used to transfer information from one layer in
an OSI stack to another layer.
- Privileged Mode
- A protected area from which the operating system runs.
Direct access to the computer's memory or hardware is
allowed only from this mode. Applications programs that
need to access memory and hardware issue requests to an
operating system service rather than issuing direct
memory or hardware instructions.
- Protocol
- An established guideline that specifies how networked
data is formatted into a packet, how the packet is
interpreted at the receiving end.
- Protocol Data Unit (PDU)
- The information transferred between layers in the same
OSI stack.
- Public Dial-Up Line
- An ordinary telephone connection that is temporarily
switched for the duration of the network communication
session, with the connection dropped as soon as you hang
up.
- (empty)
- Real Mode
- When a computer processor is set to run programs so the
programs have direct access to memory locations t 1024K
or below and only one program can be run at a time. This
is used in older MS-DOS and 16-bit Windows programs.
- Real Time Application
- One that involves immediate processing results, such as
entering a new employee into a hum resource database
through an application that immediately updates the
database as you are working.
- Redirector
- A service used via the application lay to recognize and
access other computers with operating such as Win 3.11,
Win 95, Win NT, LAN Manager, or LAN Server.
- Redundant Array of Inexpensive Disks (RAID)
- A set of standards to extend the life of hard disk drives
and to prevent data loss from a hard disk failure.
- Registry
- A database used to store information about the
configuration, program setup, devices, drivers, and other
data important to the setup of a computer running windows
NT or Win95.
- Remote Access Services (RAS)
- Software services that enable off-site workstations to
access an NT server through modems and analog telephone
or digital ISDN telecommunication lines.
- Remote Bridge
- Joins networks across the same city, between cities, and
between states to create one network.
- Remote Router
- Joins networks across large geographic areas.
- Repeater
- Amplifies and retimes a packet-carrying signal so it can
be sent along all cable segments.
- Request for Information (RFI)
- A general planning document sent to vendors to obtain
information about what services and products each vendor
can offer.
- Request for Proposal
- A detailed planning document, often written from
information received in RFIs, that is sent to vendors
with exact specifications for services and products an
organization intends to purchase.
- Resource
- The physical components on a workstation, or the physical
components on a network.
- Rights
- In Windows NT Server are high level access privileges for
activities such as to log on to a server, to shut down a
server, and to create user accounts.
- Ring Topology
- A network in the shape of a ring or circle, with nodes
connected around the ring.
- Router
- An intelligent network device that can learn different
network paths, forward data along certain paths for best
network performance, and read data frames received in
different formats. A router constantly gathers
information about the network, such as about how many
nodes are connected and where they are located. This
information is stored on the routing data table.
- Sector Sparing
- Available in windows NT server and NT workstation for
SCSI drives, certain hard disk sectors are reserved so
they can e used when a bad sector is discovered.
- Security Accounts Manager (SAM) Database
- Also called the directory services database, stored
information about user accounts, groups, and access
privileges on a MS WinNT Server.
- Segments
- A Segment of cable is one cable run within the IEEE
specifications, such as one run of 10BASE2 cable that is
185 meters long and has only 30 nodes or less.
- Segmenting
- Isolating and directing network traffic to reduce
bottlenecks and to reduce the impact of a network
malfunction on other portions of the network.
- Service Data Unit
- The PDU minus control and transfer information used to
transfer the data from the previous layer in the OSI
stack.
- Serial Communications
- Data transmissions that use one channel to send data bits
one at a time. Terminals and modems use serial
communications. The serial communications port on a PC
conforms to the EIA/TIA-23(formerly the RS-232) standard
for communications up to 64 Kbps.
- Serial Line Internet Protocol (SLIP)
- An older remote communications protocol used by UNIX
computers.
- Sequence Packet Exchange (SPX)
- A Novell protocol used for network transport when there
is a particular need for data reliability.
- Shielded Twisted-Pair
- A cable that contains pairs of insulated wires that are
twisted together, surrounded by a shielding material for
added EMI and RFI protection, all inside a protective
jacket.
- Simple Mail Transfer Protocol (SMTP)
- An e-mail protocol used by systems having TCP/IP network
communications.
- Small Computer System Interface (SCSI) Adapter
- A 32- or 64-bit computer adapter that transports data
between the computer and one or more attached devices,
such as hard disks.
- SONET (Synchronous Optical Network)
- Fiber-optic technology allows for high-speed data
transmission. Networks based on SONET can deliver voice,
data, and video.
- Spread Spectrum Technology
- Used by wireless networks in place of cable for
communications between network nodes. Network data is
transmitted by means of reliable high-frequency radio
signals.
- Standalone Server
- An NT server that is used as a special-purpose server,
such as to store databases. It does no account logon
verification.
- Static Addressing
- Is an IP (internet Protocol) addressing method that
requires the network administrator to assign and set up
manually a unique network address on each workstation
connected to a network.
- Static Routing
- Involves control of routing decisions by the network
administrator through preset routing instructions.
- Star Topology
- A network configured with a central hub and individual
cable segments connected to the hub, resembling the star
shape.
- Statistical Multiple Access
- Multiplexing allocates the communication resources
according to what is needed for the task, such as
providing more bandwidth for a video file and less for a
small spreadsheet file.
- Striping
- A data storage method that breaks up data files across
all volumes of a disk set to minimize wear on a single
volume.
- Switched Megabit Data Service (SMDS)
- Developed by regional telephone companies to provide
cell-based, high-speed communications between MANs.
- Switched Virtual Circuit
- A communication channel that is established for only as
long as the communication session lasts.
- Synchronous communications
- Continuous bursts of data controlled by a clock signal
that starts each burst.
- Systems Network Architecture (SNA)
- A layered communications protocol used by IBM for
communications between IBM mainframe computers and
terminals. SNA employs seven-layered communications that
are similar to the OSI modes, but there are differences
in the way the services are grouped within the layers.
- T-Carrier
- A dedicated telephone line for data communications.
- Telnet
- A TCP/IP application protocol that provides
terminal-emulation services.
- Terminal
- A device consisting of a monitor and a keyboard to
communicate with a host computer that runs the programs.
The terminal does not have a processor to use for running
programs locally.
- Terminal Adapter (TA)
- Popularly called a digital modem, connects a computer or
fax machine to an ISDN line. A digital modem does not
truly convert a signal between digital and analog
circuits(modulate and demodulate). It simply converts a
digital signal to a protocol that can be sent over a
digital telephone line.
- Time Division Multiple Access (TDMA)
- Multiplexing enables multiple devices to communicate over
the same communications medium by creating time slots in
which each device transmits.
- Token Ring
- Network transport method that uses a ring topology to
pass a token from node to node. The token is used to
coordinate transmission of data, because only the node
processing the token can send data.
- Topology
- Has two components: the physical layout of the cable and
the logical path followed by network packets sent on the
cable.
- Transaction Tracking
- Also called transaction logging or journaling, is a fault
tolerance method in which a log is kept of all recent
transactions until they are written to disk. If a hard
disk or system failure occurs, unwritten transactions are
recovered from the log.
- Transmission Control Protocol/Internet
Protocol
- A protocol particularly well suited for medium and large
networks. The TCP portion was originally developed to
ensure reliable connections on government, military, and
educational networks. It performs extensive error
checking to ensure that data is delivered successfully.
The IP portion consists of rules for packaging data and
for ensuring that it reaches the correct destination
address.
- Twisted-Pair
- A flexible communications cable that contains pairs of
insulated copper wires twisted together and covered with
an outer insulating jacket.
- Uninterruptible Power Supply (UPS)
- A device built into electrical equipment or a separate
device that provides immediate battery power to equipment
during a power failure or brownout.
- Unshielded Twisted-