A

1AESS - Analog switching system found in Central Offices

AAA - Authentication Authroization and Accounting

Access Control Entry (ACE) - Access Control Entry (ACE) An ACE is an entry in an ACL – Access Control List. It defines the protection or auditing to be applied to a file or other object for a specific user or group of users.

Access Control Lists (ACLs) - An access control list (ACL) is a table that tells a computer operating system which access rights each user has to a particular system object, such as a file directory or individual file.

Access Floor Method - A horizontal cabling method that employs cylindrical risers beneath the floor. The cylinders are used to help organize the area beneath the floor into easily manageable cabling zones.

Access Processors - The secondary processors in a centralized network

Access Token - An object that uniquely identifies a user who has logged on and which is attached to all the user processes. An access token contains a private key which is a 64-bit code generated at user logon.

Account matching - The process by which User Authentication searches the domain database or any trusted domain database for a matching user name and password.

ACLs (Access Control Lists) - An access control list (ACL), specifies what operations different users can perform on specific files and directories.

Active Data Objects (ADO) - ADO (ActiveX Data Objects) is an application program interface (API) from Microsoft that lets programmers writing Windows applications get access to relational and nonrelational databases from both Microsoft and other database providers.

Active Directory Services - The Active Directory is Microsoft's implementation of a 'Directory Service' and a directory service is something that stores data in an organized format and has the mechanisms needed to publish and access the data. It is a type of Directory Service that holds information about all resources on the network and clients can query the Active Directory for information about any aspect of the network.

Active Hub - A hub with features that allow a network administrator to monitor traffic and to configure ports.

Active Server Page (ASP) - An Active Server Page (ASP) is an HTML page that includes one or more scripts (small embedded programs) that are processed on a Microsoft Web server before the page is sent to the user.

ActiveX - ActiveX is the name Microsoft has given to a set of "strategic" object-oriented program technologies and tools. ActiveX controls run in Windows 95/98/NT and in Macintosh. Plans to include UNIX.

ADF - Automatic Document Feeder

Administrator - The person responsible for setting up and maintaining domain controllers or local computers and their user/group accounts .. i.e. passwords, permissions, and Networking issues.

Administrators Group - Adding a user to the Administrators group is all that is necessary to make the user an Administrator with nearly complete authority over the domain controllers, workstations, or servers on which the group resides.

ADSL (Asymmetric Digital Subscriber Line) - ADSL allows more bandwidth downstream than upstream. Requires a splitter to separate voice from data.

ADSL Lite (Asymmetric Digital Subscriber Line Lite) - Commonly known as G.Lite, ADSL Lite operates at a lower speed than ADSL but does not need a special splitter, which reduces overall costs.

Advanced Peer To Peer Networking (APPN) - Current form of SNA that allows networking of PCs.

Aerial Method - A campus connection method that uses poles to hold cables up in the air, like telephone lines.

AES - Advanced Encryption Standard

AEP - American Electric Power

AH - Authenication Header

Algorithm - A set formula for solving a problem.

All Rings Broadcast (ABR) - Refers to a packet that will be sent to all nodes in a Token Ring network.

Alpha AXP - The AXP is a new design of the Alpha processor that features quad instruction issue, on-chip secondary cache and the ability to achieve a short latency at a high clock speed. The AXP is manufactured using 0.4-micron process and achieves 300MHz typical operating speed while using between 40 and 50 watts power. The device features a detachable heat sink that can even cool it in PC-type environments.

Alternate drivers - A driver is a piece of software that allows a piece of hardware to communicate with the operating system. In NT the HAL does not permit any software to communicate directly with the hardware as a result alternate drivers must be provided for the hardware to work with Windows NT.

American National Standards Institute (ANSI) - A voluntary organization founded in 1918, now numbering over 1,300 members. ANSI creates standards for the computer industry as well as for other technical areas. Two examples of ANSI standards are the C computer language and FDDI protocols. ANSI also attempts to reach a consensus for standards among other qualified groups, e.g., NFPA and EIA/TIA.

AMI - Alternate Mark Inversion

Amplitude Modulation (AM) - Modulation in which the amplitude wave varies due to some signal in the carrier.

Analog - Continuous signal that "flows," unlike pulse or digital signals.

ANSI - American National Standards Institute. A voluntary organization founded in 1918, now numbering over 1,300 members. ANSI creates standards for the computer industry as well as for other technical areas. Two examples of ANSI standards are the C computer language and FDDI protocols. ANSI also attempts to reach a consensus for standards among other qualified groups, e.g., NFPA and EIA/TIA.

Anycast - Address assigned to more than one interface

Apache - An open source, free Web server available for many different operating systems including Windows NT/2000, UNIX and Linux

APIPA - Automatic Privatre Internet Protocol Addressing

Application layer - OSI layer in charge of program-to-program communication

Application Programming Interfaces (APIs) - An API (application program interface) is the specific method prescribed by a computer operating system or by another application program by which a programmer writing an application program can make requests of the operating system or another application.

Application Server - Database and client interface that reduces the complexity of the client program

Application-Specific Integrated Circuit (ASIC) - Chip that is uniquely designed for an application by connecting circuits in new ways

AppleShare - AppleTalk file and print server

AppleTalk - LAN architecture built into all Apple Macintosh computers

Architecture - In networking terms, an architecture refers to the logical interrelationships between network devices. The term logical architecture (or logical topology) refers to the way that the signals act on a network's physical media or the manner in which data passes through a network from one device to the next. The term architecture may also refer to a reference model (e.g., the OSI reference model) or a model for a specific networking product (e.g., Novel NetWare).

Architectural Models - The OSI reference model sets the standard for the world's networking architectural models. Common networking architectural models that follow the OSI model include AppleTalk, TCP/IP and Novel NetWare. Though rare, networking architectural models also exist that are not based on OSI.

ARCNet - Attached Resource Computer Network. Introduced by Datapoint Corporation in 1968. One of the oldest LANs.

ARIN - American Registry for Internet Numbers

ARP - Windows command that displays or makes changes to tables used by the Address Resolution Protocol to covert IP addresses into physical addresses (MAC addresses).

ARP -A - Windows command that shows the current entries in the table used by ARP.

ARP (Address Resolution Protocol) - TCP/IP protocol used to convert an IP address to a physical address (MAC address). ARP also is a command integrated with Windows operating systems.

ARP -S - Windows command that allows the creation of a permanent record in the table used by ARP. For example, typing ARP -S 10.1.1.252 00-02-2C-C5-B4-7D will associate the IP address 10.1.1.252 with the MAC address 00-02-2C-C5-B4-7D in ARP queries.

ARPANET - Large wide area network created by the U.S. Defense Department’s Advanced Research Project Agency in 1969. ARPANET is the "grandfather" of the Internet.

AS400 systems - The AS/400 (recently renamed the "AS/400e") is a middle-size server designed by IBM for small businesses and departments in large enterprises and now redesigned so that it will work well in distributed networks with Web applications.

ASCII - American Standard Code for Information Interchange. Standard system for changing characters into binary code

ASP - Application Service Provider

Asymmetric Digital Subscriber Line (ADSL) - A new technology allowing more data to be sent over existing copper lines

Asynchronous - Transmission in which data is sent intermittently using a start-and-stop bit, instead of being sent in a steady stream

Asynchronous serial port - Used for serial communication where one bit is sent at a time

Asynchronous Transfer Mode (ATM) - Network technology based on transferring data in packets of a fixed size. Current ATM services support data transfer rates from 25 to 622 Mbps.

ATM (Asynchronous Transfer Mode) - Very fast network technology based on transferring data in packets of a fixed size. The fixed-size packets are called cells.

Attenuation - The opposite of amplification, the normal reduction of signal strength when sent from one point to another. If the signal attenuates too much, you cannot understand it.

AUI (Attachment Unit Interface) - The AUI standard specifies how a cable is connected to a network card in a 10Base5 Ethernet network. Specifically, a coaxial cable is connected to a transceiver, which is connected to a 15-pin socket on an NIC. An AUI connector fits the 15-pin socket.

Authenticode - Encrypted code that helps you safely download software from the Web or another networked computer. Authenticode 2.0 Brings Improvements and Renews Security Features for Internet Explorer Users.

Automatic Route Selection (ARS) - Selection and Routing of outgoing calls electronically or mechanically without human assistance

Autonomous - Independent and self contained

Auxiliary Processor - Backup to the primary processor that keeps track of what is going on with the primary pocessor

Available Bit Rate (ABR) - ATM service guaranteeing a minimum capacity but allowing data to be burst at higher capacities when the network is free

B

10BASE2 - An Ethernet standard that defines transmission speeds of 10Mbps. 10BASE2 uses coaxial cable that is thinner than 10BASE5 (thicknet). It supports network segments of up to 185 meters (202 yards).

10BASE5 - An Ethernet standard that defines transmission speeds of 10Mbps. 10BASE5 uses coaxial cable that is thicker than 10BASE2 (thinnet). It supports network segments of up to 500 meters (547 yards).

10BASE-F - An Ethernet standard that defines transmission speeds of 10Mbps. 10BASE-F uses fiber-optic cabling. It supports network segments of up to 2 kilometers (2000 meters, 1.24 miles), depending on implementation.

10BASE-T - Common Ethernet (IEEE 802.3) standard that uses a twisted-pair cable with a maximum length of 100 meters. Also called Twisted-Pair Ethernet.

100BASE-T - An Ethernet standard that defines transmission speeds of 100Mbps. 100BASE-T uses twisted-pair cabling. It supports network segments of up to 100 meters (109 yards).

10BASE-T Ethernet - Common Ethernet (IEEE 802.3) standard that uses a twisted-pair cable with a maximum length of 100 meters. Also called Twisted-Pair Ethernet.

Backbone - A large transmission line that carries data gathered from smaller lines that interconnect with it.

Backdoor (Slang) - An undocumented means of entering a system, usually placed there by a programmer for testing or future unauthorized use.

Backup Domain Controller (BDC) - A computer running Windows Server in a Windows NT Server Domain. BDCs receive a copy of the domain’s directory database, which contains all account and security policy information for the domain. BDCs also authenticate user logons and can be promoted to function as Primary Domain Controllers as needed.

Bandwidth - The difference between the highest and lowest frequency available for communication system transmission.

Baseband - Refers to communications systems where the medium uses digital data.

Baseline Report - A static picture of a network when everything is working correctly

Baud Rate - Measure of per-second telecommunication signal-state changes; speed at which a modem can transmit data.

Basic Rate Interface (BRI-ISDN) - Speed at which a device can transfer data

Beaconing - Token Ring network signaling process. A device determines the network's condition and the location of the breakdown.

Bellman-Ford algorithm - Used by routers on internetworks to exchange routing information about the status of the network and how to route packets, basically merging routing information into lookup tables

BDF - Building Distribution Frame

BERT - Bit-Error Rate Test

BGP (Border Gateway Protocol) - BGP is a protocol for exchanging routing information between gateway hosts. BGP is often the protocol used between gateway hosts on the Internet. It is a type of EGP (Exterior Gateway Protocol).

Binary Synchronous Communication Protocol (BSC) - Mainframe network protocol requiring sending and receiving device synchronization prior to data transmission

Bits Per Second (BPS) - Speed at which a device can transfer data

BNC - Stands for British Naval Connector or Bayonet Nut Connector, which is a male type connector used with coaxial cable and 10BASE2 Ethernet networks.

Bonding - The degree to which material is secured solidly in a building (e.g., to the walls or ceiling)

Boot - To load an operating system into a computer's main memory. Once the operating system is loaded, it's ready to run applications.

Bootstrap Protocol (BOOTP) - An Internet protocol allowing a workstation to discover its own IP address, the IP address of a BOOTP network server, and a file that boots the machine. BOOTP is defined by RFC 951.

Bottleneck - A stage in a process that causes the entire process to slow down or stop

BPDU - Bridge Protocol Data Unit

BRI - Basic Rate Interface

Bridge - A device that connects two LANs or two segments of the same LAN, even if they are different types of networks or use different protocols. Bridges work at the Data Link Layer of the OSI model and work with MAC addresses.

Bridging - Using a bridge to connect networks or segments, even if they are different types or use different protocols

Broadband-ISDN (B-ISDN) - B-ISDN is a very high-speed version of ISDN. B-ISDN was designed to carry multiple types of signals, such as network data, video signals and telephone conversations. B-ISDN is carried over an ATM network.

Broadcast / Broadcasting - To send the same transmission to everyone on a network

Broadcast Domain - A broadcast domain is a logical area in a computer network where any device connected to the local area can directly transmit to any other device in the area without having to go through a routing device.

Broadcast Infrared Transmissions - Broadcast transmission systems beam light signals in a less concentrated fashion, spreading them throughout a wider area. Broadcast systems often have several receivers, some of which are mobile and frequently moved.

Broadcast Storm - A state of complete network overload caused by and unmanageable amount of data transfer. Also, a packet broadcast on a network that causes most hosts to respond all at once, typically with wrong answers, that start the process over again.

Broadband - Type of data transmission in which the medium carries multiple messages simultaneously. Broadband transmission is often found in WANs.

Broadband Technology - A process in which a single wire can carry several channels at once. Most communication between computer is done over one channel.

Broadband Wireless Access (BWA) - A wireless working group formed in July 1999, in which the focus is a fixed broadband wireless access systems that operate near 30 GHz but will be applicable from 10 to 66 GHz.

Buffer - Using part of the memory to hold data that is waiting to be transferred.

Burrough’s Multipoint Poll Select - One common telecommunication protocol.

Bursts - Refers to a means of data transmission where data is sent faster than normal for a limited time under certain conditions.

Business @ The Speed Of Thought - Bill Gates’ 1999 book comparing digital communication to the human nervous system. Explains how businesses must incorporate Internet technology to keep up with current trends.

Bus Topology - The simplest network topology, where all networked devices are connected to a central cable, called the bus or backbone. Bus networks are relatively inexpensive and easy to install for small networks.

C

C - A unique Unix operating system shell

Cable Modem - A modem that can send and receive data on cable TV cabling.

Cable Organizer - A device used to arrange cables in an organized manner.

Cable Run - A collection of cabling from workstations or network devices to a data closet.

Cabling Scheme - Systematic way of organizing network cable.

Campus Distribution Method - A way for the telecommunication/data cables to get inside a building. The most common methods are direct buried, aerial, conduit and in-tunnel.

Category (CAT) - In networking, CAT typically refers to the quality of twisted-pair cabling (e.g., UTP, STP, ScTP).

CATV - Community Antenna TV is a cable TV system which relies on a single antenna in the community for its signals.

C2 Class - U. S. Department of Defense security classification. Provides "need to know" data protection and subject and action accountability.

CCITT (Consultative Committee for International Telephony and Telegraphy) - The CCITT, now known as the ITU-T (for Telecommunication Standardization Sector of the International Telecommunications Union), is the primary international body for fostering cooperative standards for telecommunications equipment and systems. It is located in Geneva, Switzerland.

CDFS - Compact disc file system. Controls access to the contents of CD-ROM drives.

CD-RW - CD that can be read and written over, erased, and re-used indefinitely.

Cells - Basic unit of data transport in ATM, and is a fixed length data packet.

Centralized Network - Refers to a telecommunications network where the controls and switching center are in a single place.

Centralized WAN - A centralized WAN features a central computer (or group of computers) that serves many other interconnected computers.

Central Office Exchange Service (Centrex) - Similar to PBX, Centrex is a Bell Operating Companies alternative service to PBX. "Centrex ® C.O." indicates that the main equipment will be housed at the central office while "Centrex ® C.U." indicates that the equipment will be housed at the customer’s site.

Channel - Communications path between computers or devices.

Channel Access Administrator - The device that provides a channel for other devices to send data on networks that employ the polling media access method.

CHAP -- Challenge Handshake Authentication Protocol

CHKDSK - CHKDSK is a DOS command which will verify files, indexes, and security descriptors. Yields report on the number of kilobytes of - total disk storage, user files, indexes, bad sectors, in use by the system, occupied by the log file, and available on disk. Also the bytes on each allocation unit, the number of allocation units, and the number of allocation units available on the disk.

Chooser - On an Apple Macintosh it allows the user to select a printer or other network device.

Chromatic Dispersion - Broadening of the pulse at an optical fiber transmission's receiving end.

CIDR - Classless Interdomain Routing uses special protocols.

Ciphertext - Data coded for security purposes.

CIR - Committed Information Rate is a guaranteed bandwidth that is specified on a Frame Relay service.

Circuit - The communications path between two terminals.

Cladding - The plastic or glass sheath surrounding an optical fiber cable's core

Client - The client in the term client/server network. Typically, a client is an application that runs on a personal computer or workstation and relies on a server to perform certain operations

Client Access Licenses (CAL) - A Client Access License (CAL) provides the legal right for a computer to access a computer running Windows NT Server

Client Computer - Non server computer on a network

Client/Server Network - A server-based network in which client computers request services, and other computers, called servers, respond to these requests. The term client/server describes the relationship between two computer programs in which one program, the client, makes a service request from another program, the server, which fulfills the request.

Clustering - Connecting two or more computers together so that they behave like a single computer

CNAME -- Canonical Name

Coax cable - See Coaxial cable

Coaxial - Well insulated two-conductor cable in wide use today

Coaxial Cable - Well insulated two-conductor data transmission cable in wide use today

CODEC - Coder/Decoder that is a duplex integrated circuit that converts analog signals to digital and converts digital signals to analog

Code Division Multiple Access (CDMA) - Coding scheme where multiple channels are individually coded for transmission over a wideband channel. This allows several transmissions to occur simultaneously within the same bandwidth.

Cold Site - A backup site that is basically an empty office, where services can be moved in the event of a disaster.

Collision - The situation that occurs when two or more devices attempt to send a signal along the same channel at the same time. The result of a collision is generally a garbled message.

Collision Domain - A set of Ethernet segments in which collisions are possible because the segments receive all traffic generated by any node within those segments. Unlike bridges and routers, repeaters and hubs cannot create separate collision domains.

COM - The Component Object Model (COM) is a software architecture that allows applications to be built from binary software components. COM is the core of OLE, and defines how OLE objects and their clients interact within processes or across process boundaries.

COM+ - COM+ is an enhanced version of COM that provides better security and improved performance.

Command Line - Coded message to instruct the computer to perform a specific task

Command Prompt - A point from which the user can issue commands.

Common control switches - More advanced electro-mechanical switch that can switch faster and more efficiently.

Common Gateway Interface (CGI) - The common gateway interface (CGI) is a standard way for a Web server to pass a Web user's request to an application program and to receive data back to forward to the user.

Common Management Information Protocol (CMIP) - Standard OSI protocol used with Common Management Information Services (CMIS), which defines a system of network management services. It improves on earlier security protocols and network reporting services.

Communication - Systems that utilize infrared light as their primary media.

Component Object Model - A software component construction specification that can be inserted into existing programs, or assembled into separate programs, to provide functionality.

Compression - Coding data to take up less storage space by finding repeatable patterns. Text files can usually be reduced by 40%, graphics reduced from 20-90%.

Computer Systems Evaluation Criteria - Originally the US Department of Defense Trusted Computer System Evaluation Criteria, also known as the Orange Book. Originally written for military systems, the security classifications are now broadly used within the computer industry.

Concentrator - Special hub or MAU used in a LAN to combine transmissions from a cluster of nodes.

Conduit - Circular raceway made of metal or plastic that generally comes in sticks of 10 or 20 ft.

Conduit Method - A campus distribution method that uses a circular raceway (conduit) made of metal or plastic.

Constant Bit Rate (CBR) - ATM service specifying a fixed bit rate that sends data in a steady stream.

Connectionless Protocols - Connectionless TCP/IP protocols simply send packets to a receivers address but do not ensure that the receiver is actually listening or that the data is being delivered reliably.

Connection-Oriented Protocols - Connection-oriented TCP/IP protocols establish that the sender and receiver are both ready to communicate and ensure that reliable error-free data transfer occurs.

Constant Bit Rate (CBR) - ATM service specifying a fixed bit rate that sends data in a steady stream.

Contention - A LAN media access method that allows any device to send data to the network at anytime. Carrier Sense, Multiple Access (CSMA) is typically associated with this method.

Continuity - The degree to which transmission pass through a networking medium in an uninterrupted succession or flow.

Control Panel - A collection of computer-accessed tools for managing and configuring hardware and software.

Convergence - A condition that exists in dynamic routing environments when all the routers on the same network have updated their routing tables to reflect the same thing.

Cooperative - A type of multitasking or processing in which one or more background tasks are given processing time during the foreground’s idle time.

Cordboard - A switchboard.

Cost - A variable that is used to determine the most efficient route for data to follow. Cost is determined by the following factors: hop count, ticks and the type of network media that a packet will encounter en route to its destination.

Counter - Windows NT measure any particular process being executed by any particular object by means of counters.

CPU - The Central Processing Unit makes up the “brains” of the computer

CRAM-MD5 -- Challenge-Response Authentication Mechanism - Message Digest 5

CRC (Cyclical Redundancy Check) - CRC is an algorithm used for error detection when transmitting and receiving data. Also referred to as the Frame Check Sequence (FCS)

Crossover Cable - Crossover cables are just like straight-through cables except the pairs of wires are reversed on one end. They are used to directly connect two hubs, two routers, two computers or two other like devices.

Crosstalk - Crosstalk is a disturbance caused by electromagnetic fields where one telecommunication signal affects a signal in an adjacent circuit. See EMI (Electromagnetic Interference).

CSR - Control and status register is a register in most CPUs that stores additional information about the results of machine instructions. It usually consists of several independent flags such as carry, overflow and zero. The CSR is chiefly used to determine the outcome of conditional branch instructions or other forms of conditional execution.

CSMA (Carrier Sense, Multiple Access) - Technology used for contention-based networks that senses traffic on network lines before a packet is sent

CSMA/CA - CSMA/CA is an acronym for Carrier Sense Multiple Access/Collision Avoidance. It is Apple LocalTalk’s collision avoidance protocol and is similar to Ethernet’s CSMA/CD. CSMA/CD

CSMA/CD - Carrier Sense Multiple Access/Collision Detect (CSMA/CD) is the protocol for carrier transmission access in Ethernet networks. CSMA/CD is specified in the IEEE 802.3 standard.

CSU/DSU - Acronym for Channel Service Unit/Digital Service Unit. Bundled together, it is a network interconnectivity device that connects a LAN to a public telephone network. The device is required for T-series connections (e.g., T1 and T3 lines).

Cyber-door (Slang) - A way of accessing a system (through a network, modem, etc.)

Cylinder - A single track location on all the platters that make up a hard disk.

D

Data Closet - The terms equipment room, data closet and telecommunications closet often blend together. In general, telephone and network connections are distributed throughout a building from these areas. In addition, such equipment as routers, switches, CSU/DSUs and patch panels are housed there.

Data Communication Equipment (DCE) - One of two hardware types connected by an RS-232-C serial connection.

Data Encryption Standard (DES) - Commonly used encryption method developed by the U.S. National Security Agency in 1975 and standardized by ANSI in 1981. DES is based on an IBM algorithm and uses a 56-bit key.

Data Frames - Protocol that handles data in special packets.

Datagram - Part of a message transmitted over a packet-switching network in an IP network, also contains the destination address.

Data Link Layer - OSI layer responsible for physically passing data from one node to another.

Data Stream - All the coded information contained in a given packet or set of packets of data going over a network at any given time. Used by Windows NT Network Monitor to diagnose problem areas in sending and receiving data.

Data Lines - Generic term for any line that transports data.

Data link control (DLC) - DLC (Data Link Control) is the service provided by the Data Link Layer of the Open Systems Interconnection (OSI) model for network communication. The Data Link Layer is responsible for providing reliable data transfer across one physical link (or telecommunications path) within the network.

Databases - Electronic filing system.

Database Servers - Server that maintains a database.

Data Terminal Equipment (DTE) - Any device that can transmit information digitally over a cable or communications line in the RS-232-C hardware standard.

dB - decibels

DDCMP - V4.1 describes a data link control procedure that ensures a reliable data communication path between communication devices connected by data links. DDCMP has been designed to operate over full and half-duplex synchronous and asynchronous channels in both point-to-point and multipoint modes.

DDoS -- Distributed Denial of Service

DEC Digital Network ports - The Digital Network Architecture (DNA) is a set of specifications that defines DECnet. DECnet Phase IV uses DDCMP as the basis for its point-to-point links though DDCMP was enhanced to make better use of high-bandwidth and high-latency links such as satellite links.

Decentralized Network - Refers to the network where controls and switching duties are divided up.

DECnet - Network architecture developed by Digital Equipment Corporation that came into prominence in the mid 1980’s.

Decryption - Decoding encrypted data into its original format by using a secret key or password.

Dedicated - Device, program, or procedure that is totally devoted to one function or task.

Dedicated line - Private or leased line that permanently connects two or more locations.

Dedicated Server - Servers are often dedicated, meaning that they perform no other tasks besides their server tasks (e.g., a print server, Web server or file server).

De Facto Standard - When an item becomes the accepted standard because it has become so widespread and popular.

Default Gateway - In IP routing, the term default gateway refers to the IP address of the first router a computer uses to send packets to an outside network.

DEFRAG Program - A disk defragmenter is a utility that rearranges your fragmented files and the free space on your computer so that files are stored in adjacent units and free space is consolidated in one adjoining block. This also improves access time to files that are now contiguous.

De Jure Standard - When an item becomes the accepted standard through a deliberate decision by a legally accepted body.

Demand Paging - In virtual memory systems (Windows NT), demand paging is a type of swapping in which pages of data are not copied from disk to RAM until they are needed.

Demand Priority Access Method - A protocol that deals with devices used for exchanging telecommunications data between systems, including hubs and repeaters.

Demodulation - Method by which a modem converts modulated carrier data to digital form.

Desktop-like workstation - An environment that displays dialogue boxes, icons, and windows on the background screen of your computer.

Device - Any computer subsystem hardware equipment, often requiring its own device driver: printer, disk drive, and serial port.

DHCP (Dynamic Host Configuration Protocol) - DHCP helps network administrators centrally manage and automate the assignment of Internet Protocol (IP) addresses. Without DHCP, IP addresses must be entered manually at each computer.

DHCP Server - The DHCP server leases clients an IP address from a pool [of available addresses] for a specific amount of time. When the lease is up, the client can request to renew its lease or get a new IP address. Fortunately, this exchange occurs automatically and behind the scenes, making the procedure seem non-existent.

Dial-Up Networking (DUN) - Dial-Up Networking (DUN) is the Client side of Remote Access Services (RAS). It is the part that allows NT to dial out to the internet or another computer.

Diaphragm - Sound-wave-sensitive telephone receiver device that compresses and decompresses.

Digital - Describes information sent in binary code

Digital Data Communications Message Protocol (DDCMP) - A Digital DECnet protocol.

Digital Network Architecture (DNA) - DNA is a networking model established by Digital Equipment Corporation that closely follows the OSI model. DECnet conforms to DNA.

Digital Subscriber Line (DSL) - DSL routers are used to connect to the internet over telephone lines. DSL is a high speed technology that provides a dedicated connection between a home and the telephone company's central office.

Digital Switching - Digital signals switched without analog conversion

Dijkstra algorithm - Lets routers find a pathway through a mesh of network connections that will cost the least.

Direct Buried Method - A campus distribution method that calls on the installer to bury cables in trenches beside the buildings they will be serving.

Direct Distance Dialing - Network that includes all the Central Switching Offices in the system. Also called the DDD Network.

Direct Inward Dialing (DID) - Feature that allows internal PBX calls to reach a specific extension without human intervention.

Directional Parabolic Antennas - Satellites designated to send and receive incoming and outgoing microwave transmissions.

Direct Progression control - Early technique for automatically connecting two telephones, with the switch making only one connection at a time.

Direct Sequence - Spread spectrum signaling where data is altered by a bit stream generated by the sender. The bit stream represents each bit in the original data with multiple bits in the stream, which spreads the signal across a wider band.

Directory - A special file that organizes other files into a hierarchical structure.

Directory Database - Managed by "User Manager for Domains." The Directory Database contains all user account name, password, and security policy settings information.

Directory Services (DS) - Network service that identifies all network resources and makes them accessible to users and applications.

Directory Tree - Graphical depiction in tree form of all the directories and subdirectories on a disk.

Direct Progressive Control - Early technique for automatically connecting two telephones, with the switch making only one connection at a time.

Disable the Guest Account - Prevents users from logging on through the Guest Account. First step in establishing security policies. May be re-enabled at any time.

Disk Administrator - Administrative tool used to create, delete and format a computer system’s partitions and disks. Disk Administrator can also mirror, stripe, and reconfigure all hard disk devices.

Distance-vector routing - A type of dynamic routing that finds and updates routes based on the distance and vector (direction) of the destination.

Distributed Component Object Model (DCOM) - DCOM (Distributed Component Object Model) is a set of Microsoft concepts and program interfaces in which client program objects can request services from server program objects on other computers in a network. DCOM is based on the Component Object Model (COM).

Distributed File System (DFS) - Distributed File System (DFS) is a tool for NT server allows Administrators to simulate a single server share environment that actually exists over several servers - a link to a share on another server that looks like a subdirectory of the main server.

Distributed WAN - A distributed WAN, like the Internet, is composed of many computers that, although connected, are situated in various "distributed" locations.

DLC -- Data Link Control

DLC Address (Data Link Control Address) - An error correction protocol responsible for transmitting data between two nodes via a physical link

DLL (Dynamic Link Library) File - A collection of small programs. A DLL file is often a device driver

DMA channels - Direct Memory Access is a capability provided by some computer bus architectures that allows data to be sent directly from an attached device (such as a disk drive) to the memory on the computer's motherboard.

DMZ – Demilitarized Zone - A DMZ is a small network with less restrictive firewall rules than the rest of the network. Usually, servers accessed by outsiders from the Internet are placed in the DMZ to limit potential damage from an attack.

DNS (Domain Name System) - DNS matches Internet computer names with IP addresses

DNS Server - A server dedicated to performing DNS (Domain Name System) functions

DOCSIS -- Data-Over-Cable Service Interface Specification

Domain - A logical computer grouping. Domain computers share common security and user account information. This information is stored in the directory database. A domain is the administrative unit of directory services.

Domain accounts - A collection of user names with passwords within a particular domain. Default accounts on NT Workstation include: Administrators, Backup Operators, Guests, Power Users, Replicators, and Users. Default accounts on NT Server include: Account Operators, Administrators, Backup Operators, Guests, Print Operators, Replicators, Server Operators, and Users.

Domain Admin - A built-in global group within a domain. This group is automatically added to the Administrators local group.

Domain controller - In a domain, one directory database is used to store and control user account and security information for the entire domain. This database is stored on the Primary Domain Controller (PDC) (one only) and shared with all configured Backup Domain Controllers (BDC’s).

Domain Name System (DNS) - The domain name system (DNS) is the way that Internet domain names are located and translated into IP (Internet Protocol) addresses.

Domain Master Browser (DMB) - The Domain Master Browser (DMB) polls each Subnet Master Browser (SMB) and compiles a master browse list of all domain members. The DMB then redistributes this browse list to each SMB.

Domain System Network - Internet service that translates domain names into IP addresses.

DMS 1000 - Nortel manufactured large digital end office Class 5 switch.  This was the first local digital switch used by U.S. telephone companies.

DOS - The first operating system developed and licensed for the IBM compatible computer system

DoS -- Denial of Service

Download - To copy data from a main source to a peripheral device

DSL - Any type of Digital Subscriber Line. The two main ones are ADSL and SDSL. Two other types are HDSL and SDSL.

DSL Forum - Formed in 1994, the DSL Forum and promotes DSL technology, provides support, and does technical work in the following areas: ATM over ADSL (including end-to-end architecture and transport aspects) Voice over DSL (VoDSL), Operations & Network Management, Testing and Interoperability, Symmetrical DSLs, Support to the Emerging DSLs Study Group (incl. VDSL)

DSO - Basic building block in International digital hierarchy--signal format that operates at 64 Kb/sec

DSU -- Data Service Unit

Dual In-Line Package (DIP) - A type of chip within a rectangular casing with two rows of connecting pins on either side

Dual Tone Multi-Frequency (DTMF) - Signaling format that recognizes either pulses or tones.

Dumb Hub - See passive hub

DWDM -- Dense Wavelength Division Multiplexing

Dynamically - Describes an action that takes place as it is needed, not as a planned-ahead provision

Dynamic Link Libraries (DLLs) - API routines that User-mode applications access through ordinary procedure calls. The code for the API routine is not included in the user's executable image. Instead, the operating system automatically points the executable image to the DLL procedures at run time.

Dynamic Host Configuration Protocol (DHCP) - DHCP (Dynamic Host Configuration Protocol) is a protocol that lets network administrators manage centrally and automate the assignment of Internet Protocol (IP) addresses in an organization's network.

Dynamic routing - A type of routing that uses dynamic routing protocols to automatically create and update routing tables.

E

5ESS - Digital Central Office switch that supports small, medium, and large offices. The first U.S. switch that offered Basic Rate Interface ISDN service. Manufactured by Lucent Technologies.

E1 - A leased line used in the European Hierarchy of E-series connections. E1 lines transfer data at speeds up to 2Mbps

E3 - A leased line used in the European Hierarchy of E-series connections. E3 lines transfer data at speeds up to 34Mbps

EAP -- Extensible Authentication Protocol

Eavesdropping - To tap, intercept, or access media without proper authorization or consent.

EBCDIC - Extended Binary Coded Decimal Interchange Code, an IBM code using 8 bits to represent 256 possible characters, mostly in IBM mainframe computers.

EGP (Exterior Gateway Protocol) - EGP is commonly used between hosts on the Internet to exchange routing table information. EGP-2 is the latest version of EGP.

EIA - The Electronics Industries Alliance (EIA) has represented U.S. high technology for over 75 years and has developed over 4,000 standards. EIA began as the Radio Manufacturers Association in 1924. EIA sectioned off its Information and Telecommunications Technology Group to create the Technology Industry Association (TIA).

EIA/TIA - The Electronic Industries Association and Technology Industry Association (EIA and TIA) work together to publish standards that apply to electronic and telecommunications equipment and systems. Among their standards are specific ones that govern telecommunications cabling in buildings, addressing required cable, hardware, design and installation practices.

EIGRP -- Ehanced Interior Gateway Routing Protocol

Electromagnetic Interference (EMI) - Interference caused by electromagnetic signals. EMI can cause reduced data integrity and increased transmission channel error rates

Electronic/Computerized Switching - Modern, fast telephone switch that uses a computer chip

Electrical-Mechanical Switching - Early automatic telephone switch that is determined electronically

Electronics Industries Alliance - Originally created in 1924 as the Radio Manufacturers Association, the EIA is a trade organization for the U.S. high technology community.

Electronics Industry Association (EIA) - EIA has represented U.S. high technology for over 75 years and has developed over 4,000 standards. EIA began as the Radio Manufacturers Association in 1924. EIA sectioned off its Information and Telecommunications Technology Group to create the Technology Industry Association (TIA).

Electronic Industries Association/Technology Industry Association (EIA/TIA) - EIA and TIA work together to publish standards that apply to electronic and telecommunications equipment and systems. Among their standards are specific ones that govern telecommunications cabling in buildings, addressing required cable, hardware, design and installation practices.

Electronic Resources - Data stored electronically in files

EMI (Electromagnetic Interference) - Interference caused by electromagnetic signals. EMI can reduce data integrity and increase error rates on transmission channels

Encryption - Conversion of data into a secret code for transmitting over a public network. Prevents unauthorized users from accessing the data

Entrance Facility - Commonly called the general facilities entrance, the term refers to the manner and area in which telecommunications services enter a building

Environmental Sub-systems - The sub-routines required by Windows NT that allows other operating systems, and third party software to communicate with the NT kernel

ESD -- Electrostatic Discharge

ESP -- Encapsulated Security Packets

ESSID -- Extended Service Set Identifier

Ethernet - Ethernet is the most widely-installed LAN technology. Specified in the IEEE 802.3 standard, Ethernet was developed by Xerox, DEC and Intel

Ethernet, 10BaseT - 10BASET is one of several physical media specified in the IEEE 802.3 standard for Ethernet Local Area Networks. It uses twisted-pair wire. The "10" refers to the transmission speed of 10Mbps. The "BASE" refers to baseband signaling, and the "T" stands for twisted-pair wire.

Ethernet, 100BaseT - 100BASET (or Fast Ethernet) is one of several physical media specified in the IEEE 802.3 standard for Ethernet Local Area Networks. It uses twisted-pair wire. The "100" refers to the transmission speed of 100Mbps. The "BASE" refers to baseband signaling, and the "T" stands for twisted-pair wire.

Ethernet, 1000BaseT - 1000BASET (or Gigabit Ethernet) is one of several physical media specified in the IEEE 802.3 standard for Ethernet Local Area Networks. It uses twisted-pair wire. The "1000" refers to the transmission speed of 1000Mbps. The "BASE" refers to baseband signaling, and the "T" stands for twisted-pair wire.

Ethernet Address - The Media Access Control (MAC) address (or physical address) is a network device's unique hardware number. On an Ethernet LAN, the MAC address is the same as the Ethernet address.

Ethernet LAN - The most common logical architecture for a LAN, Ethernet networks share bandwidth with all devices on the same segment. Ethernet is very flexible, but poorly designed or mismanaged Ethernet LANs can suffer from collision problems.

EtherTalk - Protocols allowing an AppleTalk network to run on an Ethernet cable.

European Telecommunications Standards Institute (ETSI) - Based in France, ETSI is a non-profit organization aims to produce telecommunications standards for use in Europe.

Event Viewer - The Event Viewer enables you to view three logs in which various significant events are recorded. You can select a log to view, set options for what the log records, and save logs to compare them at a later date. The three NT logs include: System log. Records events logged by system components, such as drivers, printers, hardware, and so on. Security log. Records events that are possible breaches in security, such as unsuccessful attempts to log on to the system. The security log can also provide an audit trail when you set up auditing. Application log. Records events logged by software applications, such as file errors, damage to files, and so on.

Exabytes - A unit of computer storage capacity: approximately a billion, billion bytes

Executive Services - The part of the Windows NT operating system which runs in kernel mode, and provides the following services: interprocess communication, interrupt processing, I/O and networking activities, memory management, object management, and thread scheduling.

F

5-4-3 (Five-Four-Three) Rule - As a general rule, to get to its destination, packets should never have to travel between more than five segments, four hubs and/or repeaters, and three populated segments (segments with nodes).

Failover - A fault tolerant mechanism that enables a primary system to automatically switch to a backup system during an unexpected power outage or shutdown.

Fast Ethernet - 100BASET (or Fast Ethernet) is one of several physical media specified in the IEEE 802.3 standard for Ethernet Local Area Networks. It uses twisted-pair wire. The "100" refers to the transmission speed of 100Mbps. The "BASE" refers to baseband signaling, and the "T" stands for twisted-pair wire. 100BaseFX fiber optic Fast Ethernet also is available.

FAT - The table that the operating system uses to find files on a disk. Primarily designed for MS-DOS, FAT is called VFAT in older versions of Windows 95, and FAT32 in newer versions of Windows 95/98.

Fault Tolerance - A system’s ability to recover from a variety of hardware failures including CPU failure, power supply failure and hard drive failure. A properly configured fault-tolerant system will loose no data and suffer minimal down time after a failure. Fault tolerance can also be described as the elimination of a single point of failure.

FCS (Frame Check Sequence) - FCS is an algorithm used for error detection when transmitting and receiving data. Also referred to as the CRC (Cyclical Redundancy Check).

Federal Communications Commission (FCC) - Agency created in 1934 to regulate wire, radio, and other broadcast transmissions in the U.S.

FDD - Short for floppy disk drive (FDD), a disk drive that can read and write to floppy disks

FDDI - FDDI is an abbreviation of Fiber Distributed Data Interface, which is a set of ANSI protocols for sending data over fiber optic cable. FDDI networks are token-passing networks and support data rates of up to 100Mbps. FDDI networks are typically used as backbones and are characterized by their dual rings.

FDM -- Frequency Division Multiplexing

FHSS -- Frequency Hopping Spread Spectrum

Fiber Distributed Data Interface (FDDI) - FDDI is a set of ANSI protocols for sending data over fiber optic cable. FDDI networks are token-passing networks and support data rates of up to 100 Mbps. FDDI networks are typically used as backbones and are characterized by their dual rings.

Fiber Optics - Communications systems that use optical fibers for transmissions.

Fiber Optic Cable - Telecommunications cable that transports light through a specially designed glass or plastic cable.

FIFO - FIFO (first-in, first-out) is an approach to handling program work requests from queues or stacks so that the oldest request is handled next.

File - Basic unit of storage on a computer that distinguishes its data from others.

File Allocation Table (FAT) - A table or listing used by DOS and older Windows operating systems to manage disk space used for file storage. Primarily designed for MS-DOS, FAT is called VFAT in older versions of Windows 95, and FAT32 in newer versions of Windows 95/98.

File and print servers - Network server that provides a centralized area from which to store files and share printers.

File System - A file system is the way in which files are named and where they are placed logically for storage and retrieval.

File Transfer, Access, and Management (FTAM) - Provides file transfer service

Filter - A program or utility that can import or export only certain types of data

Filtering - Process of going through a program or utility that can import or export only certain types of data

Finger - Finger is a program that tells you the name associated with an e-mail address

Firewall - A combination of hardware/software designed to prevent unauthorized access to or from a private network. All messages entering or leaving the intranet pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria.

FireWire - The IEEE 1394 standard for a high-performance serial bus. FireWire provides a single plug-and-socket connection on which up to 63 devices can be attached with data transfer speeds up to 400Mbps.

FixPaks - Updates for OS/2

Flooding - When an LSA is sent to every router on the network

FM -- Frequency Modulation

Foreign Exchange (FX) - Telecommunications network service in which a local user is given a private line to another central office.

FQDN - A Fully Qualified Domain Name (FQDN) consists of a host and domain name(s). For example, www.aries.net is a FQDN. www is the host, aries is the second-level domain and .net is the top-level domain.

Frame Check Sequence (FCS) - FCS is an algorithm used for error detection when transmitting and receiving data. Also referred to as the CRC (Cyclical Redundancy Check).

Frame Format - The format of a data frame depends on the network and protocol. See Frames.

Frame Relay - Packet-switching protocol for connecting nodes on a WAN. U.S. Frame Relay networks support T-1 data transfer rates of 1.544 Mbps and T-3 rates of 45 Mbps. Small information units are relayed over wide area networks, along the best route available between the source and destination. European rates can range from 64 Kbps to 2 Mbps. Frame Relay is very popular currently due to its relatively low cost.

Frames - A frame is data that is transmitted between network points as a unit complete with addressing and necessary protocol control information. The use of frames depends on the network and protocol.

Free Space - Floppy or hard drive area not currently being used or formatted

Frequency Hopping - Spread spectrum signaling where original data is not spread out, but is transmitted over a range of frequencies that change every split second.

Frequency Shift-Key Modulation (FSK) - Output frequency between pre-determined values is shifted by the modulating signal

FTP (File Transfer Protocol) - Used to transfers documents between computers on a TCP/IP network

FTP client - One of the nodes that receives transferred documents between different computers on the TCP/IP network

FTP Packet - Datagram that contains documents between different computers on the TCP/IP network

Full Duplexing - Receiving and transmitting data simultaneously

Fully Qualified domain names (FQDN) - A Fully Qualified Domain Name (FQDN) consists of a host and domain name(s). For example, www.aries.net is a FQDN. www is the host, aries is the second-level domain and .net is the top-level domain.

G

Gateway - Combination of hardware and software that links two types of networks together

GBIC -- Gigabit Interface Converter

Gbps -- Giga bits per second

GDI (Graphic Display Interface) - Graphics Device Interface (GDI) is something that we put between the programs which use a graphic environment and the graphic hardware of the computer. The GDI (graphical device interface) heap is one of the system wide resources in the Windows environment. Its counterpart is the USER heap. Each is limited to 64KB of memory and is shared by all the applications.

.gif - A GIF is one of the two most common file formats for graphic images on the World Wide Web. The other is the JPEG. .gif is the file extension for a GIF file.

Gigabit Ethernet - Gigabit Ethernet provides transmission speeds up to 1000Mbps and is typically used for LAN backbone systems. Standards for 1000BaseT, 1000BaseSX, 1000BaseLX and 1000BaseCX have been defined. A newer standard, 10 Gigabit Ethernet, is also becoming available.

Gigabytes - A unit of computer storage capacity equal to one million bytes. One gigabyte equals 1,024 megabytes or 1,073,741,824 bytes. It is often abbreviated as G or GB.

GigaHertz – GHz - Currently commonly used to measure CPU speed, gigahertz has become the standard for describing the speed of processors, RAM, and cache in computers. 1 gigahertz (GHz) equals 1,000 megahertz (MHz).

Graphical Interface - An interface which uses pictures rather than just words to represent the input and output of a program. A GUI displays icons, buttons, and dialogue boxes for users to access and manipulate the computer’s functions.

Ground / Grounded - A ground is a direct electrical connection to the earth, connection to a particular point in an electronic circuit, or specific type of indirect connection that operates between wireless equipment. A ground drains away unwanted buildup of electrical charge.

GSM - Global System for Mobil Communications, a leading digital cellular system introduced in 1991.

GUI (Graphical User Interface) - A GUI is a graphical user interface to a computer.

H

Half Duplexing - Either receiving data or transmitting data.

HAL (Hardware Abstraction Layer) - A layer of software provided by the hardware manufacturer that hides or abstracts hardware differences from the upper layers of the operating system.

Handset - Portion of the telephone that you normally pick up to use the phone. The handset contains a transmitter and receiver.

Hard Drive Bays - Housing that holds the computer hard drive.

Hardware Abstraction Layer (HAL) - A layer of software provided by the hardware manufacturer that hides or abstracts hardware differences from the upper layers of the operating system.

Hardware Platform - Physical architecture of a computer’s combined hardware components. Some common platforms include Intel x86, MIPS RISC, Digital Alpha AXP RISC, and PowerPC RISC.

HDD - HDD is an abbreviation for "hard disk drive," the mechanism that controls the positioning, reading, and writing of the hard disk

HDLC - Acronym for High-level Data Link Control, which is a data communications transmission protocol that operates at the OSI model\'s Data Link layer

HDSL (High bit-rate Digital Subscriber Line) - HDSL is symmetrical— identical bit rates upstream and downstream. Because of its speed, HDSL can be used as an alternative to T1/E1 lines. HDSL requires two of the four pairs of wires in standard UTP cabling.

Hexadecimal Notation - A hexadecimal number consists of the numbers 0-9 and letters A-F. Every two hexadecimal digits represents a byte (8 binary digits)

High-Level Data Link Control (HDLC) - An X.25 packet switching network protocol that error corrects at the data link layer

High-Performance File System (HPFS) - An OS/2 file system

Hive - Refers to the way Windows NT Registry data is stored in compartmentalized forms. A hive consists of two files: a data file, and a log file.

Homerun Method - A horizontal cabling method that refers to pulling long cable segments that originate from the data closet to all in-wall feeds that, in turn, connect each workstation. The reason this method is called "homerun" is because it is characterized by exceptionally long cable runs.

Hop Count - The term hop count refers to an intermediate connection linking two network devices. On the Internet, most packets pass through several routers before reaching their destination. Each time the packet is forwarded to the next router, a "hop" occurs. The more hops, the longer it takes for a packet to reach its destination.

Horizontal Cabling - Horizontal cabling gets its name from the usual position that you will find this cable. It generally runs horizontally along the floor and/or ceiling within a building and connects the work area outlets to the telecommunications closet.

Horizontal Raceways Method - A horizontal cabling method that employs cable trays to hold cables that stem from telecommunications closets.

Host / Hosting - In Internet protocol specifications, the term host means any computer that has full two-way access to other computers on the Internet. In this context, a host is a node in a network. A host can also be the company or Web server that provides Web services, which is known as hosting. In other contexts, the term host generally means a device or program that provides services to some less capable device or program.

Host ID - Once a packet has arrived at the proper network, the Host ID allows the packet to be accepted by the proper device.

HOSTS Files - Prior to DNS, HOSTS files were used to translate IP addresses into a host name. A file named HOSTS was created that had a line for each networked device.

Hot Plug (Hot Swap) - A device swapped in for failed equipment without interrupting service. This procedure is called hot swapping.

Hot Site - A site that will continue in event of disaster because it is a fully functional backup location with everything necessary to keep a business going if there is a problem at the main site

Hot Spare - A component (usually a hard drive) that is configured to automatically take over for a defective component at the time that the component fails.

Hot Swappable - A device that can be changed out with functional equipment or components without interrupting service.

HPFS - IBM’s High Performance File System is an optional file system for IBM's OS/2 (FAT is the native file system). HPFS is an installable system that uses caching to provide fast access to large disk volumes. HPFS allows the use of multiple, active file systems on one computer. HPFS also supports extended filenames. HPFS stores files contiguously, so it does not fragment as FAT partitions do. It also requires 500KB of system memory to run. HPFS is supported by OS/2 and Windows NT and is readable by Linux. HPFS systems can read a normal DOS-based FAT partition, but an HPFS partition is not recognized by a booted DOS partition.

HSM (Hierarchical Storage Management) - Hierarchical Storage Management (HSM) is policy-based management of file backup and archiving in a way that uses storage devices economically and without the user needing to be aware of when files are being retrieved from backup storage media.

HSRP - Hot Standby Router Protocol

HTM - HTM is sometimes used as a short form of the file name suffix for an HTML file

HTTP (HyperText Transfer Protocol) - HTTP is widely used to transfer information from Web servers to Web browsers

HTTPS (HyperText Transfer Protocol Secure) - HTTPS is a slightly modified version of HTTP used for advanced Internet security

Hub - A common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets. Hubs operate at the Physical Layer of the OSI Reference Model.

Hybrid Network - A computer network combining server-based and peer-to-peer network features

Hybrid Topology - This term describes a network with the characteristics of more than one network topology. Token Ring, for example, uses a logical ring topology but is physically arranged in a star topology. The Token Ring MAU connects to all networked devices from the center of the network.

Hypertext Markup Language (HTML) - Standardized document format used on the World Wide Web

Hz -- Hertz

I

IANA - Internet Assigned Numbers Authority

IBM (International Business Machines) - International Business Machines is the world’s largest computer company though it began as a punch card tabulating machine company. It began producing personal computers in 1981.

IBM OS/2 - An operating system jointly developed and introduced by Microsoft and IBM in 1987. Intended as a replacement for DOS, Microsoft and IBM followed different development paths after the initial release. IBM retained development rights and have continued development.

IBM RS/6000 - The IBM RS/6000 family combines the benefits of UNIX computing with IBM's leading-edge RISC technology in a broad product line--from powerful desktop workstations ideal for mechanical design up to parallel RS/6000 SP systems that can handle demanding scientific and technical computing, business intelligence and Web serving tasks. AIX 4.3 is an integrated operating environment that supports both 32- and 64-bit RS/6000 systems in their full range of scalability while providing improved software features for both environments.

ICA -- Independent Computer Architecture

ICANN -- Internet Corporation for Assigned Names and Numbers

ICMP (Internet Control Message Protocol) - PING, a command used to test Internet connections, uses ICMP

ICS -- Internet Connection Sharing

IDF -- Intermediate Distribution Frame

IDS -- Intrusion Detection System

IDSL (Integrated Services Digital Subscriber Line) - IDSL is a hybrid of DSL and ISDN. IDSL has a transfer rate of 144kbps, which is the total bandwidth of ISDN's two B channels and one D channel. IDSL has a much greater range than other forms of DSL. IDSL is always connected, whereas, ISDN needs to dial-up a phone number.

IEEE - The Institute of Electrical and Electronics Engineers (IEEE) began in 1884. Best known for developing standards for the computer and electronics industry. IEEE's 802 standards for LANs and MANs are widely used and have help companies to create compatible technologies.

IEEE 802 standard - Institute of Electrical and Electronics Engineers (IEEE) 802 standards were developed simultaneously with the OSI model, and hence, the two standards are compatible. IEEE took the lead in developing standards for OSI layers 1 (Physical) and 2 (Data Link).

IEEE 802.3 Standard - The Institute of Electrical and Electronics Engineers (IEEE) 802.3 standard defines the MAC sublayer for networks that use Carrier Sense Multiple Access with Collision Detection (CSMA/CD), which is the basis for the Ethernet standard.

IETF (Internet Engineering Task Force) - IETF is the main Internet standardizing body. Standards are expressed in the form of Requests for Comments (RFCs). IETF supervises the Internet Research Task Force (IRTF), which researches networking technologies.

IGMP (Internet Group Management Protocol) - IGMP is used to send a single message to multiple recipients

IGP (Interior Gateway Protocol) - IGPs are protocols for exchanging routing information between gateways within an autonomous network (e.g., a system of corporate LANs). Two commonly used IGPs are RIP (Routing Information Protocol) and OSPF (Open Shortest Path First).

IIS -- Internet Information Services

IKE -- Internet Key Exchange

ILD (Injection Laser Diode) - Laser whose active medium is a forward-biased semiconductor junction

IMAP (Internet Mail Access Protocol) - IMAP, like POP3, is used to access e-mail on an e-mail server. IMAP is better suited to users who need to access e-mail from multiple locations

IMAP4 -- Internet Message Access Protocol version 4

Index server - Microsoft Index Server is a full-text indexing and search engine for Internet Information Server and Windows NT Server. It allows any Web browser to search documents for key words, phrases, or properties such as author's name. Index Server is capable of indexing textual information in any document type through content filters. Filters are provided for HTML, text, and Microsoft Office documents.

Infrared Signal - An invisible band of radiation at the lower end of the electromagnetic spectrum.

Infrared Transmission System - Communication system that uses infrared light as its primary media.

Institute of Electrical and Electronics Engineers (IEEE) - IEEE began in 1884. Best known for developing standards for the computer and electronics industry. IEEE's 802 standards for LANs and MANs are widely used and have help companies to create compatible technologies.

Integrated - Refers to programs, components, or activities that can be combined into a functional unit.

Integrated Circuit - Another name for a chip, which is a small device made out of semiconductor material.

Integrated Services Digital Network (ISDN) - International communications standard for sending voice, video, and data over digital telephone lines. ISDN 64 supports Kbps data transfer rates.

Inter-eXchange Carriers (IXC) - Telephone company that provides services between LATAs or between internal exchanges within a LATA. The generally rely on LEC for the local services and traffic termination. The top three IXCs are AT&T, MCI, and Sprint.

International Electrotechnical Commission (IEC) - International standards and conformity assessment body for all technology fields.

Internet Society - The Internet Society is an international non-profit organization for the workings of the Internet. It was founded in 1992 and is based on Reston, Virginia. The Internet Society supports the Internet Architecture Board (IAB), which supervises technical and other issues pertaining to the Internet. The IAB's supervises the well-known Internet Engineering Task Force (IETF).

Internetworking - To switch between one network and another or use a large network made up of smaller networks.

InterNIC Registration Service - A joint project between AT&T and Network Solutions that registers domain names and IP addresses, provides educational services for the Internet community, maintains publicly accessible directory and database services, and has online publications of interest to Internet users.

Interoperability - Ability of devices to function in multiple environments.

Intelligent Hub - Hub that allows an administrator to monitor the traffic passing through and to configure the ports in the hub.

IntelliMirror - Copy files, applications and system configurations, allowing users to install on another PC automatically over a network.

Inter-eXchange Carriers (IXC) - Telephone company that provides services between LATAs or between internal exchanges within a LATA. The generally rely on LEC for the local services and traffic termination. The top three IXCs are AT&T, MCI, and Sprint.

International Organization for Standardization (ISO) - ISO, founded in 1946, developed the OSI reference model (among many other standards) that has allowed companies to create compatible technologies.

International Telecommunications Union (ITU) - Based in Geneva, Switzerland, ITU is a world-wide organization that helps facilitate the standardization, coordination and development of international telecommunications.

Internet Assigned Numbers Authority (IANA) - Both IPv4 and IPv6 addresses are assigned in a delegated manner. Users are assigned IP addresses by Internet service providers (ISPs). ISPs obtain allocations of IP addresses from a local Internet registry (LIR) or national Internet registry (NIR), or from their appropriate Regional Internet Registry (RIR):

The IANA's role is to allocate IP addresses from the pools of unallocated addresses to the RIRs according to their established needs. When an RIR requires more IP addresses for allocation or assignment within its region, the IANA makes an additional allocation to the RIR.

Internet Control Message Protocol (ICMP) - A protocol used to send error and control messages on a TCP/IP network. An example use of ICMP is the PING utility.

Internet Group Management Protocol (IGMP) - Use to inform the local router of a host's intention to join a local multicast group.

Internet Information Server (IIS) - Internet Information Server (IIS) is a World Wide Web server, a Gopher server and an FTP server all in one. IIS means that you can publish WWW pages and extend into the realm of ASP - Active Server Pages allowing JAVA or VBscript (server side scripts) to generate the pages on the fly. IIS has application development environment – FrontPage, integrated full-text searching - Index Server, multimedia streaming - NetShow, and site management extensions.

Internetwork Packet Exchange (IPX) - IPX is a networking protocol from Novell that interconnects networks that use Novell's NetWare clients and servers. IPX is a datagram or packet protocol that works at the network layer of communication protocols and is connectionless. Packet acknowledgment is managed by another Novell protocol, the Sequenced Packet Exchange (SPX).

Internet Protocol (IP) - A connectionless TCP/IP protocol used to route packets across the Internet.The most widely used version of IP today is Internet Protocol Version 4 (IPv4). IP Version 6 (IPv6) is the upcoming version.

Interprocess communication (IPC) - IPC is a set of programming interfaces that allow a programmer to create and manage individual program processes that can run concurrently in an operating system

In-Tunnel Method - A campus distribution method that uses a tunnel to distribute telecommunications/data cables to a building

IP -- Internet Protocol

IP Address - An Internet Protocol address is a 32 bit binary number that identifies a host connected to the Internet for communication purposes.

IPCONFIG - Lists the IP configuration of each of a server’s NICs (IP address, gateway and subnet mask)

IP (Internet Protocol) - A connectionless TCP/IP protocol used to route packets across the Internet. The most widely used version of IP today is Internet Protocol Version 4 (IPv4). IP Version 6 (IPv6) is the upcoming version.

IP Multicast - Internet Protocol multicasting. Extends multicasting technology to a TCP/IP network

IP number - A four-byte number to identify a specific computer location. All IP numbers will be between 0 and 255, and will be separated by periods.

IPC (InterProcess Communication) - Allows one task or process to communicate with another in a multi-tasking operating system. Examples include Named Pipes, Windows' DDE, Novell's SPX and Macintosh's IAC.

IPng - Another name for IPv6, "ng" standing for "next generation".

IPsec (Internet Protocol Security) - IPsec is a set of protocols developed by the Internet Engineering Task Force (IETF) to support the secure exchange of packets. IPsec is widely used for VPNs and supports encryption.

IPv4(Internet Protocol Version 4) - Current version of IP in wide use today.

IPv6(Internet Protocol Version 6) - Internet protocol's "next generation." Backward compatible with and designed to remedy IPv4 shortcomings. IPv6 was originally called IP "Next Generation"—IPng.

IPX - IPX (Internetwork Packet Exchange) is a networking protocol from Novell that interconnects networks that use Novell's NetWare clients and servers. IPX is a datagram or packet protocol that works at the network layer of communication protocols and is connectionless. Packet acknowledgment is managed by another Novell protocol, the Sequenced Packet Exchange (SPX).

IPX/SPX - Primary protocol combination used in Novell NetWare operating systems. While the IPX protocol is similar to IP, SPX is similar to TCP. Thus, NetWare can provide similar services to TCP/IP.

IRQ - Internet ReQuest (IRQ) is hardware line over which device can send interrupt signal to the microprocessor

ISAPI - ISAPI (Internet Server Application Program Interface) is a set of Windows program calls that let you write a Web server application that will run faster than a Common Gateway Interface (CGI) application.

ISDN - International communications standard for sending voice, video, and data over digital telephone lines. ISDN 64 supports Kbps data transfer rates.

IS-IS -- Intermediate System - Intermediate system

ISO - The International Organization for Standardization (ISO), founded in 1946, developed the OSI reference model (among many other standards) that has allowed companies to create compatible technologies

ISP - Acronym for Internet Service Provider. A business that connects users and businesses to the Internet

IT -- Information Technology

IT Policy - Documentation that outlines the rules and procedures pertaining to an organization’s information technology system

ITU - Based in Geneva, Switzerland, the International Telecommunications Union (ITU) is a world-wide organization that helps facilitate the standardization, coordination and development of international telecommunications.

J

Jacks - Switchboard holes that can be connected.

.jpg - The file extension for a JPEG which is a graphic image.

K

Kbps - Kilobits per second

Kerberos - Kerberos is a network authentication protocol. It is designed to provide strong authentication for client/server applications by using secret-key cryptography

Kernel - The part of Windows NT Executive that manages the processor. The kernel’s tasks include: multi-processor synchronization, interrupt and exception handling, and thread scheduling and dispatching.

Kernel mode - The processor mode that allows full, unprotected access to the system. A driver or thread running in kernel mode has access to system memory and hardware.

Korn - A unique Unix operating system shell

L

L2F - Layer Two Forwarding.

L2TP (Layer Two (2) Tunneling Protocol) - L2TP merges the best features of two other tunneling protocols: PPTP from Microsoft and L2F (Layer 2 Forwarding) from Cisco Systems. It is used for virtual private networking.

LACP -- Link Aggregation Control Protocol

LAN - A LAN is a network of interconnected workstations sharing the resources of a single processor or server within a relatively small geographic area.

LAN Emulation (LANE) - Ability to connect Ethernet and Token Ring networks using ATM, allowing common protocols like IP, IPX, DECNet, and Appletalk to travel over the ATM backbone.

LAN Manager - Though superceded now by Windows NT, LAN Manager is a Microsoft network operating system that runs as a server application under OS/2 that supports DOS, Windows and OS/2 clients.

Last Mile - The run of wiring from a home or business to the phone company's central office

Layer 3 switching - Used on switched networks that use ATM backbones or similar environments, these are protocol software techniques for switching packets

Layered - Refers to one or more levels of routines and protocols lying between the application and the computing hardware. Layering makes it easier to adapt programs to different types of equipment.

LC -- Local Connector

LDAP -- Lightweight Directory Access Protocol

Leased line - A leased line is a dedicated line that is rented from a telephone company. It is a dedicated connection, which is continuously in place (e.g., T1 line).

Leases - In this case, grants temporary ownership to grant access

Least Cost Routing (LCR) - Configuration that automatically sends data communications across the path that will be most economical

LEC -- Local Exchange Carrier

LED (Light emitting diode) - Display technology that emits light via a semiconductor diode when charged

Length Field - One of the six basic sections pf an Ethernet data frame. It specifies how much data is entered into the frame from an Ethernet packet. Packets are broken down into frames.

Light directory access protocol (LDAP) - LDAP (Lightweight Directory Access Protocol) is a software protocol for enabling anyone to locate organizations, individuals, and other resources such as files and devices in a network, whether on the Internet or on a corporate Intranet.

Lightweight Directory Access Protocol (LDAP) - Set of protocols to access information directories. Also called X.500-lite.

Line Conditioner - A device that helps regulate and condition electricity to protect equipment.

Link-State Advertisements - Broadcasts that advertise updates to routers about how a network has changed.

Link-State Routing - The next generation of dynamic routing that evaluates routes based on ticks, hops and network media.

Linux - Linux is an operating system based on the UNIX operating system. LINUX is designed for IBM compatible PCs and is available for free from the Internet.

Load Balancing - Organizing tasks between networked computers, so that none are overworked.

Local Access Transport Areas (LATA) - Geographical area where a Bell Telephone Company can offer telecommunications services. Under the Divestiture decision the "Baby Bells" usually can not provide services that begin in one LATA and terminate in another LATA.

Local Computers - Computers on a LAN

Local Exchange Carriers (LEC) - Local telephone company that supplies regular telecommunications services within a specified area

LocalTalk - Cabling schematic supported by AppleTalk

Logical Link Control (LLC) - Data Link sublayer for error correction and flow control

Logical Security - Logical security protects or safeguards something non-physical, such as data or intellectual property

Logical Topology / Logical Architecture - The term logical topology (or logical architecture) refers to the way that the signals act on a network's physical media or the manner in which data passes through a network from one device to the next.

Loopback Address - The loopback IP address is 127.0.0.1. It always equals the current network connection. It can be used to test the network connection of a TCP/IP network computer

LPR -- Line Printer Request

LSL (Link Support Layer) - Network driver interface operating at the OSI model's Data Link layer. LSL provides a common language between the transport and data link layers.

M

MAC Address - The Media Access Control (MAC) address (or physical address) is a network device's unique hardware number. On an Ethernet LAN, it's the same as the Ethernet address. In contrast, an IP address is referred to as a logical address.

Macintosh - Referring to the operating system developed by Apple computers.

Mac OS - The Mac OS is the operating system designed by Apple to run on its Macintosh computers.

Mac’s - The Apple Macintosh uses Motorola microprocessor architecture and a proprietary operating system.

Mail server - A computer than controls mail access and resources on a local area network (LAN).

Mainframe - Large and costly high-level computer designed for intensive tasks and can support hundreds of users simultaneously.

MAN - Metropolitan Area Network. Uses WAN technology to interconnect LANs within a geographical region, generally a city.

Manageable hub - See Intelligent Hub

Manage Documents - In the Printers folder window selecting File, Document Defaults opens the Default Document Properties dialog box, which holds page setup and document settings for a given printer.

Manual Switching - Early method of telephone switching through a cordboard (switchboard)

MATV - Master Antenna Television System contains a combination of components that provide multiple television receiver operations from either one antenna or a group of antennas

Mbps -- Megabits per second

MBps -- Megabytes per second

Mbone (Multicast Backbone) - Multicast Backbone is an extension on the Internet that supports IP multicasting in which data can transmit between multiple sites

MDF -- Main Distribution Frame

MDI -- Media Dependent Interface

MDIX -- Media Dependent Interface Crossover

Measured lines - Refers to telecommunications lines that record how a device is used in order to assign charges for it

Media - In networking, the term media typically refers to the type of cabling used to transport data. The term media may also refer to a wireless technology (e.g., radio wave).

Media Access Control (MAC) - One of the Data Link Layer's sublayers. The other one is LLC, Logical Link Control.

Media Access Method - Media access refers to the method in which a computer communicates with a network. A network’s media access method is a set of rules used by servers and workstations to put data onto a network. The two most common media access methods are token passing and contention.

Mesh Topology - In a mesh topology, each device is connected through multiple paths to other devices on the network, resulting in an extremely fault tolerant system. For this reason, mesh topologies are often used in conjunction with mission critical networks. They are also the most expensive to install and maintain.

Message Handling Systems (MHS) - Provides transport for electronic messaging applications. (Not to be confused with NetWare MHS).

Message Queuing - In programming, message queuing is a method by which processes (or program instances) can exchange or pass data using an interface to a system-managed queue of messages.

Metropolitan Area Network (MAN) - Interconnects LANs within a geographical region, generally a city

MIB -- Management Information Base

Microkernal - The name given to the core portion of a modular operating system

Microsoft - Most influential company in the personal computer industry, a software company founded by Bill Gates and Paul Allen in 1975.

Microsoft Management Console (MMC) - The MMC console is a Windows-based multiple documents interface (MDI) application that heavily leverages Internet technologies. Both Microsoft and Third party vendors extend the console by writing MMC Snap-Ins, which are responsible for actually performing management tasks.

Microsoft Message Queue Server 1.0 (MSMQ) - The Microsoft Message Queue Server is a Message Oriented Middleware that was designed for - fast, reliable asynchronous electronic communication. It also ensures guaranteed message delivery, receipt notification and transaction control.

Microsoft NetShow Theater Server - Microsoft NetShow Theater Server delivers, broadcast-quality multimedia to hundreds of client workstations anytime, anywhere your network reaches. Applications range from video-on-demand, corporate communications, interactive training, news delivery, and movie services for hotels and airlines, to more specialized applications such as advertising, kiosks for sales and marketing automation, and medical imaging.

Microsoft Proxy Server - Microsoft Proxy Server 2.0 is an extensible firewall and Web cache server that provides Internet security while improving network response time and efficiency.

Microsoft Transaction Server (MTS) - The Microsoft Transaction Server (MTS) is a program that runs on an Internet or other network server with a Windows NT system and manages application and database transaction requests on behalf of a client computer user. The Transaction Server screens the user and client computer from having to formulate requests for unfamiliar databases and, if necessary, forwards the requests to database servers. It also manages security, connection to other servers, and transaction integrity.

Microwave - An electromagnetic wave that vibrates at 1GHz and above. Used in communications satellites as well as in line-of-sight systems on earth.

MIPS - Millions of instructions per second. A common measure of processor speed.

MIPS R4000 - Acronym for million instructions per second. The R4000, which is expanded to 64 bits and is superpipelined (twice as many pipeline stages do less work at each stage, allowing a higher clock rate and twice as many instructions in the pipeline at once.

MIPS Rx400 - The Rx400 generation of the MIPS processor. the MIPS32 4K core family is an ideal entry-level, low power solution. The Rx400 core adds single cycle multiply/accumulate instructions and the 4K core is optimized for Windows CE and other real time operating systems.

MLID (Multiple Link Interface Driver) - Also called the LAN driver, operates at the Data Link layer of the OSI model communicating with the Network Interface Card.

MMF -- Multimode Fiber

Modem (Modulator/Demodulator) - A telecommunication device that "modulates" a sending computer's digital data into analog signals to be transmitted over phone lines and then "demodulates" those analog signals back into digital signals to be read by the receiving computer.

Modulation - Blending data into carrier signals (examples: AM and FM radio and telephone signals) that replicate sound waves

MPLS -- Multi-Protocol Label Switching

Mrouter - A router that supports multicasting

MSAU - Multiple Station Access Unit. A Token Ring network device that physically connects network computers in a star topology while retaining the logical ring structure. One of the problems with the Token Ring topology is that a single non-operating node can break the ring. The MAU solves this problem because it has the ability to short out non-operating nodes and maintain the ring structure.

MS-CHAP -- Microsoft Challenge Handshake Authentication Protocol

MS-DOS (Microsoft Disk Operating System) - MS-DOS was the Microsoft-marketed version of the first installed operating system in personal computers

MT-RJ -- Mechanical Transfer-Registered Jack

Multicast / Multicasting - Transmission of a message to a select group via email, teleconferencing or videoconferencing. In networking, a distinction is made between broadcasting and multicasting. Broadcasting sends a message to everyone on the network whereas multicasting sends a message to a select list of recipients.

Multiple Document Interface (MDI) - An interface that supports multiple simultaneous views, or windows

Multiplexing - Process of combining multiple signals to transmit communications data over a single medium

Multiplexor - Networking device that combines multiple signals to transmit communications data over a single medium

Multipurpose Internet Mail Extension (MIME) - Originally designed for ASCII text, MIME is a common method for transmitting non-text files via e-mail

Multistation Access Unit (MAU) / Multiple Station Access Unit (MSAU) - A Token Ring network device that physically connects network computers in a star topology while retaining the logical ring structure. One of the problems with the Token Ring topology is that a single non-operating node can break the ring. The MAU solves this problem because it has the ability to short out non-operating nodes and maintain the ring structure.

Multitasking - The CPU performing a bit of task A, a bit of task B, a bit of task C, giving the illusion that more than one application is running at a single time. True multitasking requires two or more processors.

MX -- Mall Exchanger

N

NAC - Network Access Control

NADN - Nearest Active Downstream Neighbor. In Token Rings, refers to the next active computer that will receive data

Named pipes - An interprocess control (IPC) protocol for exchanging information between two applications, possibly running on different computers in a network. Named Pipes are supported by a number of network operating systems (NOSs), including NetWare and LAN Manager. IPC enables one application to control another application, and for several applications to share the same data without interfering with one another. IPC is required in all multiprocessing systems such as Windows NT, but it is not generally supported by single-process operating systems such as DOS.

Narrowband Radio - Bandwidth set by the FCC for mobile or portable radio services like paging systems. Refers to a bandwidth from 50 to 150 bps.

NAT -- Network Address Translation

NAUN - Nearest Active Upstream Neighbor. In Token Rings, refers to the active computer that should be sending data to your machine.

NBTSTAT - Windows command used to display information about network devices that use NetBIOS over TCP/IP, which is common in Windows networks.

NBTSTAT -s - Windows command used to show current NetBIOS sessions. The remote host of the connection is displayed with its NetBIOS name.

NCP (NetWare Core Protocols) - Novell NetWare Core Protocol, manages access to the primary NetWare server resources.

NDIS (Network Driver Interface Specification) - NDIS is a Windows specification for how communication protocol programs (e.g., TCP/IP) and network device drivers should communicate. It is similar to ODI (Open Data-Link Interface).

NDS (Novell Directory Services) - NDS (Novell Directory Services) is a popular software product for managing access to computer resources and keeping track of the users of a network, such as a company's intranet, from a single point of administration.

NetBEUI (NetBIOS Enhanced User Interface) - Enhanced version of the NetBIOS protocol used by various network operating systems. Originally developed by IBM, NetBEUI has been adopted and extended by Microsoft and Novell.

NetBIOS name - Unique name given to each computer on a LAN segment.

NetBIOS (Network Basic Input/Output System) - Networking protocol in DOS and Windows networks that acts as a programming interface for applications at the Session layer.

NetBIOS-over-TCP/IP (NBT) - The capability that is enabled automatically when TCP/IP is installed on a Microsoft networking client. NBT enables applications written to the NetBIOS API to run over a TCP/IP protocol stack.

NET ID Subfield - The network number field, also called the "network prefix."

NETSTAT - A Windows command that provides current information about TCP/IP connections, such as, the IP address of the remote connection and the port to which it is connected.

NETSTAT -S - A Windows command that provides detailed TCP/IP statistics, such as, packets received and errors that occurred.

NetWare - NetWare, made by Novell, is the most widely installed network server operating system. The latest version of NetWare, NetWare 5, comes with support for both Novell's own IPX network protocol and for the Internet's IP protocol as well as application-level support for a Web server. NetWare has integrated its own Novell Directory Services (NDS) with the industry standard Domain Name System (DNS) and the Dynamic Host Configuration Protocol (DHCP).

NetWare supports Java applications and the Common Object Request Broker Architecture (CORBA) Object Request Broker (ORB). Its kernel supports multiprocessing. Additional features include what it calls "next generation" file system and printing services and advanced security (public-key cryptography and Secure Authentication Services-SAS).

Network - Group of computers and devices that are connected by communications facilities.

Network Address Translation (NAT) - Specified in RFC 1631, NAT lets a LAN use one set of IP addresses for internal traffic and another set of addresses for external traffic.

Network Administrator - The person responsible for designing, planning, configuring, and managing the daily operations of a system network.

Network Broadcast - System of communication on a network where a datagram goes out to all clients.

Network Device Interface Specification (NDIS) - NDIS (Network Driver Interface Specification) is a Windows specification for how communication protocol programs and network device drivers should communicate with each other.

Network Hierarchy - Refers to how a network is organized.

Network ID - Network IDs specify the network on which a networked device is located.

Network Intelligence - Refers to network organization, protocols, and procedures the network will follow.

Network Interface Cards - An expansion board that allows a computer to be connected to a network

Network Layer - OSI's third layer, routing data from node to node

Network Operating System (NOS) - NOSs are operating system that are designed to support workstations on a LAN

Network Printer Server - Any computer on a network with a shared printing device physically attached to it

New Technology File System (NTSF) - Advanced Windows operating system that supports long filenames and has features to improve reliability, such as transaction logs and file system recovery. NTFS also has a number of security features.

NDIS (Network Driver Interface Specification) - NDIS (Network Driver Interface Specification) is a Windows specification for how communication protocol programs (such as TCP/IP) and network device drivers should communicate with each other.

NIC - Network Interface Card. An expansion board that allows a computer to be connected to a network

NLSP ( Network Link Services Protocol) - A routing protocol operating at the Network Layer of the OSI model

nm -- Nanometer

NNTP -- Network News Transport Protocol

Node - Any network-connected device that can communicate with other network devices

North American Numbering Plan (NANP) - Originally designed by AT&T in 1947, this is the system for establishing area codes, telephone numbers, and other network codes in the U.S. and 17 other countries. Currently administered by Lockheed Martin IMS.

Novell NetWare - Novell's proprietary LAN operating system

NSLOOKUP - A Windows command used to access a DNS server to query its IP-address-to-FQDN database

NTFS - New Technology File System. An advanced operating file system supporting file system recovery, large storage media, long file names, and some POSIX subsystem features. By treating all files as objects New Technology File System supports object-oriented programs.

NTP (Network Time Protocol) - NTP allows clients to have their time clocks synchronized to a server

Numbering Plan Area (NPA) - In telephone communications, often referred to as the Area Code system, the NPA represents U.S. geographical areas and their divisions.

NWLink - NWLink is a streams-based transport (similar to TCP/IP and NDIS compatible). NWLink supports the Novell NetBIOS protocol. The goal of NWLink is to supply added value for accounts who would like to use Windows NT as an application server with current MS-DOS, Windows, or OS/2 NetWare clients.

O

Object - The focus of a Performance Monitor tracking. May include anything from NT’s browser to memory, protocol, or thread.

Object Linking and Embedding - An Application Programming Interface that allows for information transferring and sharing among applications

Octet - An octet (from the Latin octo or "eight") is a sequence of eight bits

OCx -- Optical Carrier

ODBC Drivers and Administration - Open Database Connectivity (ODBC) is an API from Microsoft, derived from the call level interface (CLI) published by the SQL Access Group and X/Open in 1992. ODBC is the standard for client/server data access. Drivers and Administration tools are provided by many third party vendors including Lotus, Unix, Sybase, Informix, Btrieve, and Filemaker .. to mention a few.

ODBC (Open Database Connectivity) - ODBC is a Microsoft-developed interface that allows any program compliant with the ODBC standard the permission to access any other database compliant with the ODBC standard.

ODI (Open Data-Link Interface) - ODI allows networks cards used in Novell Netware to support more than one protocol at a time, such as TCP/IP and IPX/SPX. It is similar to NDIS (Network Driver Interface Specification).

OEMs - An OEM (original equipment manufacturer) is a company that uses product components from one or more other companies to build a product that it sells under its own company name and brand.

Offline - Unconnected to the network.

OLE - Object Linking and Embedding An Application Programming Interface that allows for information transferring and sharing among applications.

Open Network Architecture - Publicly available network specifications.

The Open Data-Link Interface (ODI) - ODI (Open Data-Link Interface) is a software interface that allows different Data-Link Layer protocols to share the same driver or adapter in a computer.

Open Shortest Path First (OSPF) -Routing protocol based on the shortest path in the Link-state routing algorithm that was developed by Proteon.

Open Systems Interconnection (OSI) - An ISO standard for international computer communications. Sets up a structured framework of protocols in seven layers.

OpenVMS - OpenVMS is an operating system from the Digital Equipment Corporation (DEC) that runs in both its VAX and Alpha computers. OpenVMS is a multitasking and multiprocessing operating system based on VMS; it was renamed OpenVMS when it was redeveloped for the Alpha processor.

Operating System - Software that gives the computer its basic capability to communicate, store and retrieve data, and to run a wide variety of programs.

Optical Fiber - Technology that transfers data via glass or plastic threads that utilize light waves to transport the data.

Orange Book - The specification covering writable CDs, including Compact Disk-Recordable drives.

OS/2 - An operating system jointly developed and introduced by Microsoft and IBM in 1987. Intended as a replacement for DOS, Microsoft and IBM followed different development paths after the initial release. IBM retained development rights and have continued development.

OS/2 Warp Server - IBM's server version of OS/2 that combines LAN Server with OS/2.

OSI Model (Open System Interconnection Model) - International Standards Organization criterion for computer communications that sets up a structured seven-layer protocol framework.

OSI Reference Model - Open Systems Interconnection model. A layered architecture that standardizes service levels and interaction types for computer data exchanges.

OSPF (Open Shortest Path First) - OSPF is a protocol designed to replace RIP (Routing Information Protocol) for determining routes. It provides a way for routers to communicate to find the best path. OSPF is a type of IGP (Interior Gateway Protocol).

OTDR -- Optical Time Domain Reflectometer

P

Packets - A packet is data that is transmitted between network points as a unit complete with addressing and necessary protocol control information. The use of packets depends on the network and protocol.

Paging - A technique, used by Windows NT, to help ensure that the data required is available as soon as possible. The operating system copies a certain number of pages from the hard drive to main memory. When a program needs a page that is not in main memory, the operating system copies the required page into memory and copies another page back to the disk.

Each time a page is required that is not currently in memory, a page fault occurs. An invalid page fault occurs when the address of the page being requested is invalid. In this case, the application is usually terminated.

Paging Service - Often a one-way service broadcast through an antenna that provides a limited "incoming call screening"; service

PAP -- Password Authentication Protocol

Parallel - In data communications, describes information sent in groups over multiple wires

Partition - Physical disk or storage device part that functions as though it were a separate physical device

Passive Hub - A simple device that simply sends data from one network device or segment to another

Password protection - Coded protection of a system, object, or other resources through the use of a password

PAT -- Port Address Translation

Patch Cable - In networking, a patch cable is used to connect to a patch panel. Other than that, patch cables are typically the exact same as a straight-through cable.

Patch Panel - A rack-mounted hardware unit found in data closets that contains an assembly of port locations. In a network, a patch panel serves as a switchboard, interconnecting cables from computers within a LAN. Also called a punch block.

Path - In Windows NT a path is a list of directories and subdirectories where the operating system looks for executable files

Pathworks - PATHWORKS provides open PC networking and multivendor network operating system (NOS) integration in local and wide area networks--and it integrates the broadest set of PCs, servers, NOSs, and network protocols right ‘out of the box,’ eliminating the need for costly custom system setup and integration.

PC - The "IBM-compatible" PC is one with an Intel microprocessor architecture and an operating system such as DOS or Windows that is written to use the Intel microprocessor

PC-DOS (Personal Computer – Disk Operating System) - PC-DOS (Personal Computer - Disk Operating System) was the first operating system installed in personal computers. Microsoft developed PC-DOS for IBM. PC-DOS and MS-DOS are a non-graphical line-oriented command-driven operating system, with a simple interface.

PCI (Peripheral Component Interconnect) - An interconnection system designed by Intel for connecting a microprocessor and attached devices. PCI transmits 32 bits at a time in a 124-pin connection and 64 bits in a 188-pin connection.

PDC - Primary Domain Controller. The computer running Windows NT Server in a Windows NT Server Domain. Primary Domain Controller authenticates domain logons and maintains the directory database for a domain. The PDC tracks changes made to accounts of all computers on a domain.

Peer-to-Peer network - A network in which each connected computer can operate as a client or server to other computers on the same network

Performance tab displays a dynamic overview of your computer’s performance including Graphs for CPU and memory usage, the number of items running (including handles, threads, and processes), and information about physical, kernel, and commit memory.

Peripheral - A device connected to a computer and controlled by the CPU. Examples: disk drive, printer, modem, or game playing devices.

Permissions - A shared resource’s settings that determine whether and to what extent a user may access that resource

Phase Modulation (Phase Shift Modulation) - Method of shifting information onto a waveform signal by changing the wave phase to represent information, like binary digits.

Photodiodes - An electronic component that receives and interprets binary code-embedded, infrared light signals

Photons - A unit of energy made up of elementary particles of electromagnetic radiation.

Physical Layer - OSI's first layer, managing data entry and exit from the network media.

Physical Security - Physical security prevents or limits the movement of people into or out of a specific area. Physical security also prevents the removal of or access to equipment.

PING - A command used to verifie a connection between two nodes

PKI -- Public Key Information

Plaintext - Normal, readable text

Plenum - In building construction, a plenum is an area provided for air circulation in the space between the structural ceiling and a drop-down ceiling. In buildings with computer installations, the plenum space is often used to house communication cables. Because ordinary cable produces toxic gas when burned, special plenum cabling is required in plenum areas.

Plug and Play - Enables operating systems to detect installed hardware, and to automatically set parameters such as interrupts, DMA channels, and address, without the need for manual configuration

PNNI (Private Network-Network Interface) - PNNI is a dynamic routing protocol for ATM internetworks that provides routing between ATM switches and groups of switches

PoE -- Power over Ethernet

Point of Presence (POP) - A physical place within a LATA where IXC establishes itself to gain LATA access and where the LEC provides services

Point-To-Point - Single-line communications path: from one point to another point. Different from multipoint communications that provide a path from one point to several points.

Point-to-Point Infrared Transmissions - Infrared signals are electromagnetic waves or photons. To work properly, infrared signals require a line-of-sight (point-to-point) broadcast or an omni-directional broadcast (light is redirected off objects to reach its destination). Point-to-point broadcast features superior data rates, while omni-directional broadcasts allow for greater flexibility in positioning the transmitter and receiver.

Point-to-Point Protocol (PPP) - A method, more common than SLIP, for connecting a computer to the Internet. PPP error checks and is more stable than SLIP.

Poke-Through Method - A horizontal cabling method where cables are run beneath the floor and poked through holes to reach workstations.

Polling - A LAN media access method characterized by a channel access administrator asking each device on the LAN if it has data to send.

POP3 (Post Office Protocol 3) - POP3 provides the login name and password needed to access an e-mail account and issues commands to an e-mail server to retrieve and delete e-mail.

Populated Segment - A network segment that has one or more nodes directly attached to it. See segment.

Port - Computer interface point where you can connect a device.

Port Address Translation (PAT) - Network Address Translation enhancement allowing multiple hosts to share a single IP address by using different port numbers.

Port Number 21 - The usual port used by FTP servers for data exchange.

Port - An opening that allows network data to pass through. Physical ports or those physically connected to a device with a cable or some other type of hardware. Logical ports are electronic ports used by devices to transmit or receive data (e.g., default port 80 used for the transmission of Web data).

Portable Operating System Interface - An IEEE (Institute of Electrical and Electronics Engineers) standard that defines a set of operating system services. Programs that adhere to the POSIX standard can be easily ported from one system to another.

Ports Settings tab - Under modem properties/connection, the port settings tab shows advanced port settings and allows for the selection of lower settings to correct connection problems, or higher settings for faster performance. Also the location to enable FIFO buffers.

POSIX - Portable Operating System Interface. An IEEE (Institute of Electrical and Electronics Engineers) standard that defines a set of operating system services. Programs that adhere to the POSIX standard can be easily ported from one system to another.

POSIX and OS/2 sub-systems - Portable Operating System Interface and IBM OS/2 Warp 4.0 are inexpensive, full-featured, operating systems for PCs using the Intel 486 and compatible (or better) CPU's. In addition to running native OS/2 applications (both 16 and 32 bit), OS/2 4.0 can run 16 bit DOS and Windows 3.1 applications. Windows NT is designed to communicate with POSIX and OS/2 sub-systems through its Win32 subsystem.

POST (Power On Self Test) - The diagnostic testing sequence that a computer's basic input/output system runs at startup to determine if the keyboard, random access memory, disk drives, and other basic hardware are working correctly.

POTS - Plain old telephone service

Power Distribution System - Power Supply system component

PowerPC - PowerPC microprocessor architecture is designed to expand the use of the processor in embedded applications, such as networking infrastructure and telecommunications solutions. PowerPC's new Book E architecture makes a number of enhancements that will substantially improve the suitability of PowerPC processors for embedded applications.

Since 1991, IBM and Motorola have collaborated on the PowerPC architecture for personal computers, workstations, servers and embedded processor product lines.

Power Supplies - Box inside the computers system unit that converts AC electricity from a power outlet to the DC electricity used by the computer. The power supply box always has a fan that keeps the box and the other components from over-heating. The device at the rear of the monitor case which plugs into a 110v wall socket to supply the power to the monitor. The average monitor power supply outputs about 100 watts.

PPP (Point-to-Point Protocol) - Personal computer users usually get to the Internet through the Serial Line Internet Protocol (SLIP) or the Point-to-Point Protocol (PPP). These protocols encapsulate IP packets so that they can be sent over a dial-up phone connection. As PPP has gained in popularity, SLIP has become outdated.

PPPoE -- Point-to-Point Protocol over Ethernet

PPTP (Point-to-Point Tunneling Protocol) - PPTP is a protocol that allows corporations to extend their own corporate network through private "tunnels" over the public Internet.

Preamble - The preamble is put on the front of the frame by the NIC just before the frame is put on the medium in use. In between the preamble and the MAC address header is a one-byte delimiter to indicate the start of the frame. The preamble is 7 bytes long and the delimiter is 1 byte.

Preemptive - Describes a preferred function performed before another, less preferred or unwanted, function can occur.

Presentation layer - OSI's sixth layer, managing data representation conversions

PRI -- Primary Rate Interface

Primary Domain Controller (PDC) - The computer running Windows NT Server in a Windows NT Server Domain. Primary Domain Controller authenticates domain logons and maintains the directory database for a domain. The PDC tracks changes made to accounts of all computers on a domain.

Primary Partition - The designated portion of a hard drive, functioning as a separate unit, which can be marked for use by an operating system. A primary partition cannot be sub-partitioned. There can be up to four primary partitions per physical hard drive (three with one extended partition). Any primary partition can be configured to enable an operating system to boot in that partition.

Primary Processor - The main processor on a motherboard.

Primary Rate Interface (PRI-ISDN) - In North America, PRI supports up to twenty-three 64Kbps B channels, as needed, and one 64Kbps D channel (up to 1.472Mbps). In Europe, thirty B channels are used (up to 1.92Mbps).

Printer Management - Printer Management commands provide the Windows NT administrator with the ability to add, maintain and delete printer queues and the various print jobs enqueued on those printers.

*Note: Windows NT does require special rights in order to manipulate or otherwise maintain printer queues.

Printer pooling - This function enables redirection to a printer not in use–only applies if you have two or more similar printers connected.

Print Server Management - Any user with the authority (Administrator, Print Operator) to manage an attached printing device either locally or over a network connection.

Private Branch Exchange (PBX) - Automatic telephone switching system that allows organizational users to place calls to each other without using the telephone network.

Process Tracking - A function in which an object-type which consists of an executable program, virtual memory address(es), and one or more threads is monitored.

Promote Back-Up Domain Controller (BDC) - The process of promoting the Back-up Domain Controller to Primary Domain Controller. Used when the Primary Domain Controller needs to be worked on or rebooted.

Propagation Delays - The time it takes to transmit a signal from one place to another.

Protocols - Agreed upon procedures and formats for transmitting data between devices.

Protocol Stack - A set of protocol layers that work together on different levels to enable data communication.

Protocol Suite - A collection of protocols that work together to accomplish a variety of network functions. TCP/IP, Novel NetWare and AppleTalk are examples of protocol suites.

Proxy Server - In an enterprise that uses the Internet, a proxy server is a server that acts as an intermediary between a workstation user and the Internet so that the enterprise can ensure security, administrative control, and caching service.

PSE - Packet Switch Exchange.

PSTN (Public Switched Telephone Network) - The world's collection of interconnected voice-oriented public telephone networks, both commercial and government-owned. Also referred to as the Plain Old Telephone Service (POTS).

Public Data Network (PDN) - Telecommunications network that provides data transmission services for the public

Public Key - Encryption tool used to pass secure data

Public Key Infrastructure (PKI) - A PKI (public key infrastructure) enables users of a basically unsecured public network such as the Internet to securely and privately exchange data and money through the use of a public and a private cryptographic key pair that is obtained and shared through a trusted authority. The public key infrastructure provides for digital certificates that can identify individuals or organizations and directory services that can store and revoke them.

Public-Switched Telephone Network (PSTN) - A common carrier network that uses circuit switching with its public users

Punch Block - A rack-mounted hardware unit found in data closets that contains an assembly of port locations. In a network, a patch panel serves as a switchboard, interconnecting cables from computers within a LAN. Also called a patch panel.

PVC -- Permanent Virtual Circuit

Q

Quadrature Amplitude Modulation (QAM) - Encoding method that combines amplitude and phase modulation.

Quality of Service (QoS) - Criteria defining a communications system performance level.

R

RADSL (Rate Adaptive Digital Subscriber Line) - RADSL works very much like ADSL except that it adjusts dynamically to the quality of the UTP cabling.

RAID (Redundant Array of Inexpendent Disks) - RAID arrays (with the "I" standing for Inexpensive) are used to store the same data in different places on multiple hard disks. Placing data on multiple disks improves performance and increases fault tolerance.

RAID 0 - RAID level 0 uses striping to optimize read/write performance. It requires at least two hard drives, but does not provide fault tolerance because there is no parity or redundancy of data. If one drive in a RAID 0 cluster fails, all stored data will be permanently lost.

RAID 1 - RAID level 1 uses mirroring, a type of fault tolerance that safeguards against lost data. Mirroring does just what its name implies: it creates a mirrored image of all data on partnered disk drives.

RAID 2 - Where RAID 0 and RAID 5 work with blocks of data, RAID 2 works with individual bits. Data is written bit-by-bit across multiple hard drives, while other hard drives are used only for storing Hamming Code ECC (Error Correction Code) information.

RAID 3 - RAID 3 combines two separate features to provide faster reading and simultaneous fault tolerance. Like RAID 0, RAID 3 provides striping to speed up data transfer, but it also includes an extra disk to store parity information. Implementing RAID 3 requires at least three drives—two for striping and one for parity.

RAID 4 - RAID 4 is almost the same as RAID 3, with one exception; it uses larger blocks of data instead of byte-level striping. Like RAID 3, RAID 4 also requires at least three disks.

RAID 5 - RAID 5 allows striping with parity and is the most common RAID scheme. RAID 5 stores data across multiple hard drives in blocks and distributes parity information across the hard drives. RAID 5 allows one hard drive to fail without data loss. RAID 5 requires a minimum of three hard drives.

RAID 6 - RAID 6 is a slight variation on RAID 5 that offers a second level of fault tolerance by writing two sets of parity information. This advantage, however, is offset by a higher price tag. RAID 6 requires at least four hard drives.

RAID 10 - RAID 10 is a hybrid of RAID 1 and RAID 0

RAID 30 - RAID 30 is a hybrid of RAID 3 and RAID 0

RAID 50 - RAID 50 is a complex hybrid of RAID 5 and RAID 0

RAIDIUS -- Remote Authentication Dial-In User Service

Raised-Floor Method - A horizontal cabling method where floor access panels are used to conceal cables underneath work areas

RAM - Short for Random Access Memory that refers to volatile memory that can be read or written to

RARP (Reverse Address Resolution Protocol) - The opposite of ARP (Address Resolution Protocol) is RARP. RARP converts physical addresses (MAC addresses) into IP addresses.

RAS (Remote Access Server) (Remote Access Service) - A Remote Access Server (RAS) is connected to both a LAN and the Public Switched Telephone Network (PSTN). The servers are used to connect a remote access client to a LAN. The term Remote Access Service (RAS), in general, refers to a dial-up networking feature found in Microsoft Windows NT/2000/XP operating systems.

RDP -- Remote Desktop Protocol

Real Time - Operation in which the computer's activities match simultaneous human activities.

Receiver - Part of the telephone headset that receives input signals.

Reduced Instruction Set Computing - A microprocessor design that operates faster and more efficiently on a smaller, limited number of instructions.

Redundancy - The ability of a network to continue working after a vital service malfunctions or fails.

Redundant Arrays of Inexpensive Disks (RAID) - Technology for improving hard drive performance and fault tolerance.

Reflection - The act of reflecting, or turning or sending back.

Refraction - The turning or bending of any wave, such as a light or sound, when it passes from one medium into another of different optical density.

Refresh - Update displayed information, providing most current data

Registry - A CPU primary memory slot that acts as a temporary storage unit for data actually being used. The Registry is a hierarchical database containing information about a computer’s hardware and user information configurations.

Remote Access Services (RAS) - A feature built into Windows NT that enables users to log into an NT-based LAN using a modem, X.25 connection or WAN link. RAS works with several major network protocols, including TCP/IP, IPX, and Netbeui.

Repeater - Device that duplicates or regenerates a signal to prevent transmission loss over a network

Repeater hub - Device that duplicates or regenerates a signal to prevent transmission loss over a network

Reverse ARP (RARP) - Protocol that a host can use to discover its IP address

RFC (Request for Comments) - An Internet Engineering Task Force (IETF) document describing a technology's requirements. Go to www.ietf.org/rfc to see the IETF's more than 2500 RFCs.

RFI -- Radio Frequency Interface

RG -- Radio Guide

Ring Topology - A topology where all devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices one on both sides

Ringing - Back-and-forth travel of un-terminated bus network signals

RIP (Routing Information Protocol) - RIP is a protocol used by routers to determine the best route to send data. RIP determines the best route by finding out how many hops are needed to reach the intended destination and choosing the shortest path. It is a type of IGP (Interior Gateway Protocol).

RISC - Reduced Instruction Set Computing. A CPU primary memory slot that acts as a temporary storage unit for data actually being used. The Registry is a hierarchical database containing information about a computer’s hardware and user information configurations.

RJ -- Registered Jack

Root Directory - The top directory in a hierarchically arranged file system. It is sometimes referred to simply as the root

Routable Protocol - A protocol that can be used to transfer data between separate networks or separate subnets

Router - Device that connects LANs and determines where packets go. Functions at the Network Layer of the OSI model and works with IP addresses.

Router Server - A server that uses software to act as a router

Routing - Directing packets from a local network to their proper destination on an external network. Routing occurs at the Network Layer of the OSI model and uses IP addresses.

Routing Information Field (RIF) - Portion of the header in a data packet that gives information about its destination

Routing Switch - New class of router that uses integrated circuits designed for specific applications that perform at multigigabit speeds

Routing Table - A table used by routers that shows existing routes for data to travel

RPC - RPC (Remote Procedure Call) is a protocol that one program can use to request a service from a program located in another computer in a network without having to understand network details.

RS-232-C Interface - Industry standard for serial communications connections, adopted by the EIA

RSH -- Remote Shell

RTP -- Real Time Protocol

S

SAN (Storage Area Network) - The concept of a SAN is to create a separate, behind-the-scenes network for storage devices. Storage devices are nothing more than computers dedicated to storing data. They usually have less RAM and are less powerful CPUs, but they are tailored to creating high-speed data transfers.

SAP( Service Advertising Protocol) - Novell's Service Advertising Protocol, provides information about what servers are available on the network.

Satellite Microwave Transmission Systems - A microwave communication system that employs satellites and is capable of worldwide transmissions

SC -- Standard Connector

Scalability - Term referring to how well a hardware or software system can adapt to increased demands

SCANDISK - ScanDisk is a Windows DOS utility used to check your hard disk for errors and to correct problems that are found. Because scandisk needs to access the hard drive directly, it will not run in Windows NT. In later versions of Windows 95 and Windows 98, scandisk is initiated for you automatically following system restarts in which shutdown was not complete.

Scheduling Tab – Printer properties - Used for managing time sensitive documents. Also "available" for scheduling big documents to print during off-peak times and giving groups printer priority

SCP -- Secure Copy Protocol

Script - A script is a series of commands, like a batch file, used to automate repetitive tasks that you do often

ScTP (Screened Twisted-Pair) Cable - A type of shielded cabling with shielding around the entire cable bundle but not on each wire. Also called Foil Twisted Pair (FTP)

SDH (Synchronous Digital Hierarchy) - SDH is a European fiber optic standard that has a minimum transmission rate of 155.52Mbps. The North American equivalent is called SONET.

SDN - Software Defined Network, which is AT&T's Virtual Private Network method.

SDSL (Symmetric Digital Subscriber Line) - SDSL is symmetrical—identical bit rates upstream and downstream.

Secondary - For any HDLC communications session, one station is designated primary and the other secondary

Sectors - The smallest unit of physical storage on a disk. Sectors have a fixed size

Secure HTTP (S-HTTP) - The most popular security protocol used on the World Wide Web

Secure Multipurpose Internet Mail Extensions (S/MIME) - S/MIME (Secure Multi-Purpose Internet Mail Extensions) is a secure method of sending e-mail that uses the RSA encryption system.

Secure Sockets Layer (SSL) - SSL (Secure Sockets Layer) is a program layer created by Netscape for managing the security of message transmissions in a network.

Security ID - A unique name identifying a user or group of users to the security system.

Security Patch - An update applied to an operating system to correct security flaws.

Security Policy - Protocol to ensure that computer stored data cannot be read or compromised.

Security to Network Folders - A unique name identifying a user or group of users to the security system to access system folders. Different levels of permissions can be granted users and groups.

Segment - Subsection of a network that is divided off by bridges, routers, switches or hubs.

Sequenced Packet Exchange (SPX) - SPX is the protocol for handling packet sequencing in a Novell NetWare network. SPX prepares the sequence of packets that a message is divided into and manages the reassembly of received packets, confirming that all have been received and requesting retransmission when they haven't.

Serial - One by one. In telecommunications, sending information one bit at a time

Serial Line Internet Protocol (SLIP) - A data link protocol for dial-up access to TCP/IP networks, commonly used to gain access to the Internet as well as to provide dial-up access between two LANs.

Server - A computer or device on a network that manages network resources. For example, a print server is a computer that manages one or more printers, and a network server is a computer that manages network traffic.

Server-Based Network - Microsoft’s preferred terminology for client/server network. See Client/server network

Services - Conveniences and special features

Service Packs - Provide updates and bug fixes for the Windows NT and Windows 2000 operating systems. Service Packs are provided free of charge.

Service access points (SAPs) - An access point in each of the OSI layers that is used for communication between layers. Multiple SAPs can be active in any of the protocol layers.

Session Layer - OSI's fifth layer, establishing and maintaining communications channels

SFTP -- Secure File Transfer Protocol

Shared Network - Typical network that is connected through regular routers, hubs, and bridges

Shells - A shell is the interface used to communicate with the Unix operating system

Short Circuit - An accidental bridging of circuits causing a massive unintended flood of electricity, usually at a detriment to a system

SID - Security ID. A unique name identifying a user or group of users to the security system

SIP -- Sessioin Initiation Protocol

Sidetone - The telephone user's voice and background noise heard in the speaker's receiver

SLIP (Serial Line Internet Protocol) - Personal computer users usually get to the Internet through the Serial Line Internet Protocol (SLIP) or the Point-to-Point Protocol (PPP). These protocols encapsulate IP packets so that they can be sent over a dial-up phone connection. As PPP has gained in popularity, SLIP has become outdated.

Small Computer System Interface (SCSI) - An industry standard high-speed parallel interface used for connecting microcomputers to peripheral devices and other computers.

Smart Hub - See intelligent hub

SMF -- Single Mode Fiber

SMTP (Simple Mail Transfer Protocol) - SMTP is a TCP/IP protocol used in sending and receiving e-mail. However, since it's limited in its ability to queue messages at the receiving end, it's usually used with one of two other protocols, POP3 or IMAP, that let the user save messages in a server mailbox and download them periodically from the server.

SNA (Systems Network Architecture) - SNA is a proprietary IBM architecture for network computing

SNAT -- Static Network Address Translation

SNMP (Simple Network Management Protocol) - SNMP is the protocol governing network management and the monitoring of network devices and their functions

SOA -- Start of Authority

SOHO -- Small Office / Home Office

SONET (Synchronous Optical Network) - SONET is a North American and ANSI standard that has a minimum transmission rate of 51.84Mbps. It is a digital transmission standard for fiber optic cable designed to accommodate ATM. The European equivalent is called SDH.

Sound Waves - Acoustic waves---longitudinal waves made up of pressure pulses or displacementsl---that can be heard by the human ear

Source-Route Bridging (SRB) - Token Ring protocol specified in IEEE 802.5 that allows a bridge to read and direct a data packet towards its proper destination.

Spread Spectrum Radio - A technique for radio communication that is also used in digital cellular communication. The original signal is spread out to a very large bandwidth often 200+ times the original.

SPS -- Standby Power Supply

SPX (Sequenced Packet Exchange) - SPX is the protocol for handling packet sequencing in a Novell NetWare network. SPX prepares the sequence of packets that a message is divided into and manages the reassembly of received packets, confirming that all have been received and requesting retransmission when they haven't.

SQL Server - SQL (Structured Query Language) is a standard interactive and programming language for getting information from and updating a database. An SQL Server is the computer running the SQL Server software that maintains the master SQL database info.

SSH -- Secure Shell

SSID -- Service Set Identifier

SSL (Secure Sockets Layer) - SSL is a security protocol commonly used on Internet commerce sites, such as stores and banks. SSL is included as part of both the Microsoft and Netscape browsers and most Web server products. HTTPS is based on SSL.

ST -- Straight Tip

Stand Alone Server - A computer than controls access and resources on a local area network (LAN). Also used to refer to a computer used on the Internet to respond to client requests, and store information for later retrieval. A provider of resources to clients.

Standalone Hub - See passive hub.

Standard X.509 certificates - The most widely used standard for defining digital certificates. A digital certificate is an attachment to an electronic message used for security purposes. Both Netscape and Microsoft use X.509 certificates to implement SSL in their Web servers and browsers.

Star Topology - A topology where all devices connect to a central hub. Star networks are relatively easy to install and manage, but bottlenecks can occur because all data must pass through the hub.

Static Routing - A type of routing that requires a user to manually input and update the routing table data.

Station Message Detail Recording (SMDR) - Record of all calls received and generated from a switching system.

Straight-Through Cable - In general, the term straight-through cable refers to the twisted-pair cable used in an Ethernet network to connect hubs, switches, etc. to workstations. The opposite of a straight-through cable is a crossover cable.

STP (Shielded Twisted-pair) - Twisted-pair cabling with metal sheathing around each pair of wires to protect them from electromagnetic interference.

STS - Synchronous Transport Signal is the electrical signal interface and structure for SONET.

Switched Multi-Megabit Data Service (SMDS) - High speed switched data communications service offered by telephone companies that allows organizations to connect remote LANs into a sing WAN.

Streettalk - Highly regarded directory service used in the Banyan Systems VINES network operating system. Streettalk Desktop is a 32-bit Windows program that allows clients to create folders and track shared documents.

Stripe Set - The saving of data across similarly sized partitions on different physical drives.

Sub Directory - A directory that is contained under any other directory.

Subnet Mask - The number used by TCP/IP network devices to identify the Network ID and Host ID portions of an IP address.

Subnet Master Browser - The Subnet Master Browser (SMB) maintains the browse list for the entire subnet. The browse list is what is seen in the network neighborhood of all the other machines on the subnet. Each time a machine is powered on it registers itself with the subnet master browser for the subnet on which it resides.

Subnetting / Subnetworking - Dividing a network into smaller components that share a common IP address.

Subnetwork (Subnet) - A subnetwork is a separately identifiable portion of a larger network.

Surge Protector - A surge suppressor or surge protector is a device that prevents damage to electronic equipment from high voltage.

Switch - A device that filters and forwards packets between LAN segments. Switches operate at the Data Link Layer (Layer 2) of the OSI Reference Model. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs.

Switch based network - A network that operates faster by using switches.

Switched Ethernet - Also called full-duplex Ethernet, switched Ethernet can be configured to use different pairs of wires in a twisted-pair cable to allow devices to send and receive at the same time. Switched Ethernet eliminates collisions because each device is on its own switched port (i.e., own collision domain).

Switching Hub - Hub that reads the destination address of a packet and sends it to the right place.

Symmetric Multi-Processing (SMP) - SMP is a load-balancing strategy that designates specific functions for each processor.

Synchronous - Refers to data transmission in which data is transferred in blocks of bits.

Systems Network Architecture (SNA) - Network protocols developed by IBM originally for mainframes, but now supports workstations in peer-to-peer networks.

T

T1 - A point-to-point connection (leased line) of the North American Digital Hierarchy with a speed of 1.544Mbps.

T3 - A fast point- to- point connection (leased line) of the North American Digital Hierarchy with a speed of 44.736Mbps

TA -- Terminal Adapter

TACACS+ -- Terminal Access Control Access Control System +

Taskbar - The Taskbar contains the Start button and an area that displays buttons for each window or program you have open.

Task Manager - Task Manager enables you to monitor and control your computer and what’s running on it. The Applications tab shows the status of the programs (also known as tasks) that are currently running on your computer. From this window, you can end, switch to, or start a program. The Processes tab shows information about the processes that are currently running on your computer. From this window, you can end a process. To view other information about a process, Lclick View, and then Lclick Select Columns.

TCO - The Total Cost of Ownership (TCO) includes the original cost of the computer and software; hardware and software upgrades; maintenance; technical support; and training. LANs offer businesses a lower TCO by allowing many users to share expensive resources.

TCP (Transmission Control Protocol) - TCP transfers information between two devices on a TCP/IP network. TCP also monitors information transmission. It is a connection-oriented protocol.

TCP/IP - Transmission Control Protocol/Internet Protocol is a suite of protocols, widely available and implemented across a huge range of systems, which allows information to be transmitted across a network. TCP/IP is the protocol used by the Internet, and it is used over a SLIP connection in OS/2 Warp's built-in Internet Connection.

TCP/IP Network - A network that uses the former UNIX standard, TCP/IP. In recent years, TCP/IC has become the protocol of the Internet in addition to a global standard for computer-based communications

tcsh -- Turbo C shell

TDM (Time Division Multiplexing) - Technology sending multiple signals at once over a single transmission path, assigning data streams a different time slot

TDR -- Time Domain Reflectometer

Technology Industry Association (TIA) - TIA creates performance standards for telecommunications equipment and systems. TIA was formed in 1988 after the United States Telecommunications Suppliers Association (USTSA) merged with the Information and Telecommunications Technologies Group of the Electronics Industries Alliance (EIA).

Technology Industry Association/Electronic Industries Association (TIA/EIA) - TIA and EIA work together to publish standards that apply to electronic and telecommunications equipment and systems. Among their standards are specific ones that govern telecommunications cabling in buildings, addressing required cable, hardware, design and installation practices.

Telco -- Telephone company

Teleconferencing - Communications system that allows people from different parts of the world to participate in a meeting or discussion via audio, video, or computer equipment

Telenet - Owned by U.S. Sprint Communications System, one of the largest public data networks that serves as a communications backbone for many online services

Telephony - Science of transmitting voice, data, video, or images over a relatively long distance

Telephony API (TAPI) - An Application Programming Interface used by programs that provide a range of digital/analog conversion routines necessary for computer telecommunication

Telnet - Telnet is a user command and an underlying TCP/IP protocol for accessing remote computers.

Terahertz - A unit of frequency measuring 1000 GHz.

Terminal - In data communications, a terminal is any device that terminates one end (sender or receiver) of a communicated signal.

Terminal adapter - Device that connects a computer to a digital communications line.

Terminating Resistor - A device that absorbs excess electrical signals off of a wire.

Terminator - A cable-end device preventing a signal that has reached the cable's end from returning through the cable.

Terrestrial Microwave Transmission Systems - Localized, line-of-sight communication systems that use microwaves.

TFTP (Trivial File Transfer Protocol) - TFTP is a simple, less powerful version of FTP. TFTP uses UDP instead of TCP and does not support security authentication (e.g., a password).

Thicknet - A thick coaxial cable used for 10Base5 Ethernet.

Thinnet - A thin coaxial cable used for 10Base2 Ethernet.

Thread - A discrete unit of execution handled independently by the CPU. Threads allow concurrent operations within a process, enabling one process to run different parts of its program on different processors simultaneously.

TIA - The Technology Industry Association (TIA) creates performance standards for telecommunications equipment and systems. TIA was formed in 1988 after the United States Telecommunications Suppliers Association (USTSA) merged with the Information and Telecommunications Technologies Group of the Electronics Industries Alliance (EIA).

TIA/EIA - The Technology Industry Association and Electronic Industries Association (TIA and EIA) work together to publish standards that apply to electronic and telecommunications equipment and systems. Among their standards are specific ones that govern telecommunications cabling in buildings, addressing required cable, hardware, design and installation practices.

Ticks - A metric that keep track of the time it takes a packet to reach its destination, each tick is equal to 1/18th of a second

Tie Lines - Private line leased from a telecommunications carrier that often links two or more points in an organization

Time Division Multiple Access (TDMA) - Used often in satellite systems, security systems, and LANs, this is a communications technique that allocates time slots to multiple users so that they can use the same communications channel.

Time To Live (TTL) - The time to live is a value in an TCP/IP packet that tells a network router whether or not the packet has been in the network too long and should be discarded. A combination of incorrect routing tables could cause a packet to loop endlessly on the Internet. To avoid this scenario, packets are discarded after a certain amount of time.

TKIP -- Temporal Key Integrity Protocol

TLS -- Transport Layer Security

Token - A token is a special series of bits that travels around networks that use a token passing media access method (e.g., Token Ring). As the token circulates, computers attached to the network can capture it. The token acts like a ticket, enabling its owner to send a message across the network. There is only one token for each network, so there is no possibility that two computers will attempt to transmit messages at the same time.

Token Bus - Defined by IEEE 802.4, token bus networks are physically a bus topology but logically a Token Ring architecture.

Token Passing - A LAN media access method characterized by a data frame (called a token) that is passed, in order, from device to device, that allows data to be attached to it for routing to another device.

Token Ring Network - When capitalized, Token Ring refers to the network architecture developed by IBM. The IBM Token Ring specification has been standardized by the IEEE 802.5 standard. These networks use a token passing media access method.

TokenTalk - Protocols that allow AppleTalk to connect to Token Ring.

Topology - In the context of communication networks, a topology describes (pictorially) the configuration or arrangement of a network, including its nodes and connecting lines. Topologies, in general, refer to a physical layout, but the term logical topology also is used.

Total Cost of Ownership (TC0) - The TCO includes the original cost of the computer and software; hardware and software upgrades; maintenance; technical support; and training. LANs offer businesses a lower TCO by allowing many users to share expensive resources.

TRACERT - A Windows command used to trace the route of a data packet from one IP address to another.

Tracks - Term for the rings on a floppy or hard disk that contain several sectors. The operating system and disk drive keep tabs on where information is stored on the disk by noting its track and sector number.

Transceiver - A combination of a transmitter and receiver in a single device. A LAN device that transmits and receives either analog or digital signals.

Transmitter - Changes sound waves into electrical impulses.

Transmission Control Protocol (TCP) - Transfers information between two devices on a TCP/IP network. Unlike IP, TCP is a connection-oriented protocol.

Transport Driver Interface (TDI) - TDI is the common interface for Network components that communicate at the Session layer.

Transport Layer - OSI's fourth layer, responsible for data transmission integrity.

Tree-Structured Database - A hierarchical organization of information/data allowing a program quick and easy access to data. Top of the Tree is a Directory, followed by sub-directories and then files which contain the related data.

Trojan Horse - A program (usually a destructive virus) which resides inside another ‘user friendly’ program, automatically initiated when the user runs the seemingly common executable. Without a current virus protection program, a Trojan Horse can run in the background (unknown to the user) and completely destroy directories or files causing a system crash and an irretrievable loss of data.

Trunk - A high-speed line that carries multiple voice or data channels, often between two central communications offices. In digital communications, a trunk is often a line in an E-series system (e.g., E1 or E3 line) or a T-series system (e.g., T1 or T3 line).

Trust Relationship - A pass-through authentication link between domains. Trust relationships allow for and combine two domains into one administrative unit. The single administrative unit can authorize access to resources on both domains. Trust relationships are either one-way or two-way (full).

TTL -- Time to Live

Twisted-Pair Cable - A cable with two insulated wires twisted around each other, one wire carrying the signal, the other wire acting as a ground.

Two factor authentication - Two factor authentication is 'something you know' (password) and 'something you possess' (access token)

.txt - The file extension for a text file

U

UDP (User Datagram Protocol) - UDP does not route data to a specific host; it simply broadcasts data. It is a connectionless TCP/IP suite protocol.

UNC -- Universal Naming Convention

Uniform Resource Locator (URL) - A URL (Uniform Resource Locator) is the address of a file (resource) accessible on the Internet. The URL contains the name of the protocol required to access the resource, a domain name that identifies a specific computer on the Internet, and a hierarchical description of a file location on that computer.

Updates and Patches - An operating system update to fix a possible security problem or update problematic system programming

Upload - To copy a file from your own computer to another computer (opposite from download)

UPS (Uninterrupted Power Supply) - A UPS is a power supply that includes a battery to maintain power in the event of a power outage. Typically, they also protect devices from power surges.

URL -- Uniform Resource Locator. Most common examples are the addresses of web pages on the World Wide Web.

USB -- Universal Serial Bus that commonly connects computer peripherals such as mice keyboards, printers, media players, flash drives, and external hard drives.

User and Group Rights - User and Group rights are the actions that users or groups are permitted to perform by an operating system. For example, shutting down the system is considered a user right.

User authentication - You can control access to a particular directory on your servers by using a concept commonly termed "user authentication". The "Basic" user-authentication allows you to restrict access to users who can provide a valid username/password pair.

User Logon - Individual method to open an operating system that has been running on a network.

User Mode - The non-privileged processor mode in which an application thread may only access system resources through system services.

Username - A unique name assigned to a person for identification purposes and access to resources. The username usually is accompanied by a password.

User Rights - Access permissions and actions a user may perform on a local computer or domain.

Uniform Resource Locator (URL) - Uniform Resource Locators (URLs) are the addresses of resources (files) available on the World Wide Web. URLs contain information about the protocol required to access a resource (e.g., http) and a domain name that identifies a specific computer (or server) on the Internet (e.g., www.aries.net).

UNIX - UNIX is a very powerful operating system usually used on servers. Although UNIX is very stable, secure, and efficient, it is very difficult to use.

Unspecified Bit Rate(UBR) - ATM service used most often for file transfers and other services that can tolerate delays since throughput levels are not guaranteed.

UTP - Acronym for Unshielded Twisted Pair cabling. Used most often in LANs and telephone networks. UTP lacks the protective coating of Shielded Twisted-Pair (STP) cables.

V

VDSL (Very high bit-rate Digital Subscriber Line) – VDSL is the speediest digital technology and less expensive than fiber optics. VDSL can be used to provided Internet, telephone and TV service.

Value Added Network (VAN) – Communications network that offers special services like resource management and message routing.

Vampire Tap – A connection to a coaxial cable in which a hole is punched through the outer shield of the cable so that a clamp can be connected to the inner conductor of the cable. They are used for 10Base5 (thicknet) Ethernet cable connections.

Variable Bit Rate (VBR) – ATM service that provides a specified connection capacity but sends data unevenly. A popular choice for voice and videoconferencing data.

VAX – Digital Equipment Corporation’s successor to its PDP-11 computer that features an operating system that supports virtual memory. The name is short for Virtual Address Extension. VAX computers reached their peak in the mid 1980’s but may still be used as servers today.

VLAN – Virtual network of computers that act like they are connected to the same wire despite the fact that they are physically located on different segments

Videoconferencing – Teleconferencing in which video images play an integral part

Virtual Memory – Hard disk space appearing to be larger and more uniform than actual physical RAM. Virtual memory allows more applications to run than physical memory would normally allow using a process called paging (or swapping).

Virtual Private Networks (VPN) – A VPN is a private data network that makes use of the public telecommunication infrastructure, maintaining privacy through the use of a tunneling protocol and security procedure.

Virtual Terminal Protocol (VTP) – Allows users to run remote jobs on mainframes

VMS – Virtual Memory System runs on DEC’s VAX computers and its Alpha lines of computers and workstations. Introduced in 1979, it has undergone a number of changes over the years and is more likely to be called Open VMS currently. It operates with a virtual memory and can do multi-tasking.

VNC -- Virtual Network Connection

Voice and Data Networks – A network that primary function is to support the data and voice transmissions

Voice Over IP (VoIP) – The term VoIP is derived from the VoIP Forum, an effort by major equipment providers, including Cisco, VocalTec, 3Com, and Netspeak, to promote a standard for sending voice and video using the public Internet and within an intranet.

Volume – A partition or collection of partitions formatted as one partition for use by a file system

Volume Set – Several (at least 2) "free space" segments combined from 1 to 32 disk drives

VPN (Virtual Private Networks) – A VPN is a private data network that makes use of the public telecommunication infrastructure, maintaining privacy through the use of a tunneling protocol and security procedure.

VTAM (Virtual Telecommunications Access Method) – Software controlling communications in SNA networks

VTP -- Virtual Trunk Protocol

W

WAN – Wide Area Network. A collection of interconnected networks using a third-party communications carrier to link the networks

WAP -- Wireless Applicatoin Protocol / Wireless Access Point

Web-based Enterprise Management (WBEM) – Technology that provides a mechanism to specify information exchange between management applications and managed components

Web Browser – Client application that allows a user to view documents on the Internet. Mosaic was the first browser; Microsoft Explorer and Netscape are the main browsers in use today.

Web pages – Document on the World Wide Web, located with a specific url address

Web server – A computer that delivers web pages

WEP -- Wired Equivalent Privacy

Wide Area Telephone Service (WATS) – Toll service between a user and a central office in which certain fixed rates can be established.

Wideband – Transmission often found in WANs in which the medium can carry multiple messages at a time. Often called broadband.

WINIPCFG – A graphical version of IPCONFIG. WINIPCFG only comes installed on Windows 9x operating systems.

WINS -- Window Internet Name Service

Wireless Topology / Wireless LAN – Wireless topologies connect network devices without cables. Instead, radio, microwave and infrared frequencies are used.

Wireless Media – Components in communication systems designated to hold data, or allow data to travel from one location to another without cables or wires.

Wireless Personal Area Networks (WPAN)s – Networks made up of wireless PCs, Personal Digital Assistants, cell phones, pagers, and other consumer electronics.

Windows 9x – A term that refers to all editions of the following Windows operating systems: 95, 98 and Me.

Windows 2000 active directory – Current Windows 2000 file configuration.

Windows Internet Naming Service (WINS) – WINS (Windows Internet Name Service) is a NetBIOS Name Server that registers your NetBIOS names and resolves them into IP addresses.

Windows Management Instructions (WMI) – Windows Management Instrumentation. Extensions to WDM developed for Windows 2000 and Windows 98 to provide an operating system interface through which instrumented components can provide information and notifications.

Windows NT – 32-bit network operating system developed by Microsoft.

Windows NT Diagnostics – The Windows NT diagnostics tool (Administrative Tools (Common)) contains a wealth of information about the hardware, the operating system, and the software of the system. All this information is accessible from one source in an easy-to-read format. Although it is a read only utility, Windows NT diagnostics tool will be your troubleshooting companion.

Windows NT File System (NTFS) – NTFS (NT file system) is the system that the Windows NT operating system uses for storing and retrieving files on a hard disk. NTFS is the Windows NT equivalent of the Windows 95 FAT (file allocation table) and the OS/2 HPFS (high performance file system).

Windows NT Registry – The Windows NT Registry is the repository for all hardware, software, and application configuration settings.

Windows NT Workstation – Designed to serve as a network client and desktop operating system, NT Workstation is a secure, portable, 32-bit, preemptive multi-tasking operating system, developed by Microsoft.

WINS (Windows Internet Name Service) – Used to translate NetBIOS names into numeric IP addresses.

WINS Server – WINS servers are a lot like DNS Servers, although rather than translating FQDNs into IP addresses, WINS servers translate NetBIOS names into numeric IP addresses.

Winsock – Winsock is a programming interface and the supporting program that handles input/output requests for Internet applications in a Windows operating system.

Workgroup – A collection of computers grouped together for viewing

WPA -- Wi-Fi Protected Access

www -- World Wide Web

X

X.25 – Popular standard for connecting a terminal and a packet-switching network that was approved by the ITU (formerly CCITT) in 1976. It specifies a synchronous connection that defines layers 1, 2, and 3 in the OSI reference model.

xDSL – Any type of Digital Subscriber Line. The two main ones are ADSL and SDSL while two other types are HDSL and SDSL.

XML – XML (Extensible Markup Language) is a flexible way to create common information formats and share both the format and the data on the World Wide Web, intranets, and elsewhere.

x TU-C – DSL transceiver unit located at the Central Office.

x TU-R – DSL transceiver unit located at a remote location (often at the user’s home).

X Window System – X Windows System is a windowing system designed to run beneath UNIX and other major operating systems. X Windows allows users to run applications on remote computers on the network, while viewing output on their own screen.

Y

Z

Zero Administration Kit (ZAK) – The Zero Administration Kit is a set of tools, methodologies, and guidelines for IT Managers and OEMs that incorporates and supplements existing Windows technologies to allow for simplified implementation of a secure, policy-based management.

Zeroconf -- Zero Configuration