Data Communication Glossary-A
A Data Communication Historical Series
By Bob Pollard
The beginning page of a comprehensive Data Communication glossay  that provides definitions for terms and acronyms
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                                 HOME                                      INDEX

 AAA:

Authentication, Authorization, and Accounting: Pronounced ‘triple a’.

A and B SIGNALING:

Refers to a procedure used in T1 transmission facilities where one bit is removed from each of the 24 sub-channels in every sixth frame and is used for carrying dial and control information.

A and Z DIRECTION:

A term used when describing points on a circuit; on a two-point circuit, one end is A and the other end is Z, and on a multipoint circuit, the master station is A and the remote stations or terminals are Z.

AA:

See Auto Answer

AAL/ AALA:

See Asynchronous Transfer Mode Adaptation Layer

AAL:

ATM Adaptation Layer:  Service-dependent sub-layer of the data link layer. The AAL accepts data from different applications and presents it to the ATM layer in the form of 48-byte ATM payload segments. AAL(s) consist of two sub-layers: CS and SAR. AAL(s) differ on the basis of the source-destination timing used (CBR or VBR) and whether they are used for connection-oriented or connectionless mode data transfer. At present, the four types of AAL recommended by the ITU-T are AAL1, AAL2, AAL3/4, and AAL5.

AAL1:

ATM Adaptation Layer 1: One of four AAL(s) recommended by the ITU-T. AAL1 is used for connection-oriented, delay-sensitive services requiring constant bit rates, such as uncompressed video and other isochronous traffic.

AAL2:

ATM Adaptation Layer 2: One of four AA(Ls) recommended by the ITU-T. AAL2 is used for connection-oriented services that support a variable bit rate, such as some isochronous video and voice traffic.

AAL3/4:

ATM Adaptation Layer ¾: One of four AAL(s) (merged from two initially distinct adaptation layers) recommended by the ITU-T. AAL3/4 supports both connectionless and connection-oriented links but is used primarily for the transmission of SMDS packets over ATM networks.

AAL5:

ATM Adaptation Layer 5: One of four AAL(s) recommended by the ITU-T. AAL5 supports connection-oriented VBR services and is used predominantly for the transfer of classical IP over ATM and LANE traffic. AAL5 uses SEAL and is the least complex of the current AAL recommendations. It offers low bandwidth overhead and simpler processing requirements in exchange for reduced bandwidth capacity and error-recovery capability.

AAMPS:

AUTODIN Automatic Maintenance Programs System: A system of computer hardware maintenance programs used by system troubleshooters to automatically locate and repair hardware faults in computers and peripheral devices. The AAMPS computer programs consisted of a collection of many software routines and modules that exercised the hardware (electronic circuitry) of various devices in the AUTODIN centers. When AAMPS detected a failure (hardware fault) in the device being exercised, it automatically proceeded to diagnose the fault by isolating the failed component down to a specific plug-in (transistorized) circuit card, and often times down to a specific pin number on the failed plug-in card. If the AAMPS diagnostic could not pinpoint the faulty module, the diagnostic routine would provide a list of the most likely plug-in circuit cards, one of which may contain the fault. The troubleshooter would then have to use the ‘process of elimination’ repair method by substituting one plug-in card on the list at a time, then run the particular test that failed again, until the card containing the failed component had been replaced.

AAR:

See Automatic Alternative Routing

AARP

AppleTalk Address Resolution Protocol: A protocol in the AppleTalk protocol stack that maps a data-link address to a network address.

AARP PROBE PACKETS:

Packets transmitted by AARP that determine whether a randomly selected node ID is being used by another node in a non-extended AppleTalk network. If the node ID is not being used, the sending node uses that node ID. If the node ID is being used, the sending node chooses a different ID and sends more AARP probe packets.

A/B SIGNALING:

A function of T1 transmission facilities where one bit, from each of 24 sub channels in every sixth frame, is used for carrying dial and control information.

ABANDONED CALL:

A telephone or requested service call that is attempting to make a connection into a telecommunications network, but is terminated by the originator before it is answered.

ABCD SIGNALING:

A 4-bit telephony line signaling coding in which each letter represents 1 of the 4 bits. This often is associated with CAS or robbed-bit signaling on a T1 or E1 telephony trunk.

ABM:

1) Asynchronous Balanced Mode: A HDLC (and derivative protocol) communication mode supporting peer-oriented, point-to-point communications between two stations, where either station can initiate the transmission.

2)  Accunet Bandwidth Manager.

ABR:

1) Available Bit Rate: A QoS (Quality of Service) class defined by the ATM (Asynchronous Transfer Mode) Forum for ATM networks. ABR is used for connections that do not require timing relationships between source and destination. ABR provides no guarantees in terms of cell loss or delay, providing only best-effort service. Traffic sources adjust their transmission rate in response to information they receive describing the status of the network and its capability to successfully deliver data.

2) See Automatic Baud Rate Detection (Auto-baud)

ABRD:

Automatic Baud Rate Detection

ABS:

Application Bridge Server: A software module that allows the ICM to share the application bridge interface from an Aspect ACD with other applications.

ABSTRACT SYNTAX NOTATION ONE (ASN.1):

OSI language for describing data types independent of particular computer structures and representation techniques; described by ISO International Standard 8824.

AC SIGNALING:

Transmission of information using Alternating Current, tones, sine waves, frequency, carrier signals, Voice, etc.

ACA:

See Automatic Circuit Assurance

ACCELERATOR:

Accelerator technology provides a limited solution to the slow dial-up operation; referred to as ‘high-speed dial-up’. Transmission speeds may be up to five times faster than traditional dial-up service.

High-speed dial-up providers speed up the dial-up transfer rates by loading special software into a server that is referred to as an acceleration server. By sandwiching the acceleration server into the chain between your dial-up connection and the Web, they can speed up the process.

ACCEPTABLE USE POLICY (AUP):

An outline of permitted content and uses on a site or network: Conditions for using that site or network. AUP are often stated for ISPs, networks, organizations, and universities.

ACCEPTANCE MASK:

A term used to identify pre-defined thresholds assigned to circuit performance parameters. When used during circuit testing, it can be determined whether a particular performance parameter has failed.

ACCEPTANCE TESTS:

Trials and operational testing deemed necessary to determine the acceptability of a product or system.

ACCESS – ACCEPT:

Refers to a response packet from the RADIUS server notifying the access server that the user is authentic (valid). This packet contains the user profile, which defines the specific AAA functions assigned to the user.

ACCESS CONTROL:

General term for a group of security techniques such as using passwords or smart cards to limit access to a computer or network only to authorized users.

ACCESS - CHALLENGE:

A Response packet from the RADIUS server requesting that the user supply additional information before being authenticated

ACCESS DEVICE:

The hardware component used in the signaling controller system: An access server or mux.

ACCESS LINE:

Any line, circuit, channel or facility - A communications line interconnecting a frame relay compatible device to a frame relay switch; a telephone circuit that connects a customer location to a network switching center; a connection from a terminal to a switching center.

ACCESS LIST:

A list kept by routers to control access to or from the router for a number of services; for example, to prevent packets with a certain IP address from leaving a particular interface on the router.

ACCESS METHOD:

A terminal (station) polling and on-line access procedure – Example: Local area Networks (LAN) techniques and/or program code that grants access selectively to individual stations; Carrier Sense Multiple Access/Collision Detection (CSMA/CD) and Token Passing.

ACCESS NODE:

A Local Exchange Carrier owned, Broadband, Integrated Service Digital Network (ISDN) remote switch, which performs some processing, concentration and switching.

ACCESS RATE (AR):

Refers to the user’s access channel (line) data rate: The speed of the access channel determines how rapidly (maximum rate) the user may inject data into the network.

ACCESS – REQUEST:

A request packet sent to the RADIUS server by the access server requesting authentication of the user.

ACCESS SERVER:

Communications processor that connects asynchronous devices to a LAN or WAN through network and terminal emulation software; performs both synchronous and asynchronous routing of supported protocols.

ACCESS TIME:

Examples: The time interval between the instant at which an instruction control unit starts a call for data and the instant at which delivery of data is completed. The time interval between the instant data is requested to be stored and the instant storage is begun. The total time required to find, retrieve, and display data after initiation of a retrieval command. The measurement of the longest possible time it takes to get from one section of the medium to another.

ACCESS UNIT:

AU: A device that provides ISDN (Integrated Services Digital Network) access to PSN(s) (Packet Switched Networks)

ACCOUNTING MANAGEMENT:

Refers to one of five categories of network management defined by ISO (International Organization for Standardization) for the management of OSI (Open System Interconnection) networks; accounting management subsystems are responsible for collecting network data relating to resource usage.

ACCUNET:

An AT&T product offering a variety or medium to high-speed digital services including packet switched, T1 and Data-phone Digital Service (DDS). Accunet offerings include:

1) T1.5, terrestrial wideband at 1.544 mbps;

2) Reserved T1.5, satellite -based channels at 1.544 mbps used primarily for video    teleconferencing purposes;

3) Packet Services, packet-switching services;

4) Data-phone Digital Service (DDS), private line digital circuits at 2400, 4800, 9600 and 56 kbps.

ACD:

1) Automatic Call Distributor: A switching system, which automatically distributes all incoming calls in the sequences they are received without human interface. If no receivers (stations) are available the calls will be placed on hold until one becomes free. After the ICM determines the station (target) for a call, the call is sent to the ACD associated with that station (target). The ACD must then complete the routing as determined by the ICM (Intelligent Call Management).

2) Automatic Call Distribution: Device or service that automatically reroutes calls to customers in geographically distributed locations served by the same CO (Central Office).

ACELP:

Algebraic Code Excited Linear Prediction.

ACF:

Advanced Communications Function: A group of SNA (Systems Network Architecture) products that provides distributed processing and resource sharing; see Advanced Communications Function.

ACF/NCP:

Advanced Communications Function/Network Control Program; the primary SNA NCP (Systems Network Architecture / Network Control Program): ACF/NCP resides in the communications controller and interfaces with the SNA access method in the host processor to control network communications. See Advanced Communications Function/ Network Control Program.

ACF/VTAM:

Advanced Communication Function/Virtual Terminal Access Method

ACK / ACKNOWLEDGMENT:

1) Notification sent from one network device to another to acknowledge that some event occurred (for example, the receipt of a message).

2) Acknowledgment control character, ACK1, ACK2: Alternate ASCII control characters sent back to a transmitting device from a receiving device after the receiving device has received an error free data block. (Contrast with NAK)

ACKNOWLEDGMENT CODE:

See ACK

ACM:

Alternate Control Memory: A form of high-speed memory that controls the interpretation of higher-level machine instructions.

ACO:

Alarm Cutoff: A feature that allows the manual silencing of the office audible alarm; subsequent new alarm conditions might reactivate the audible alarm.

ACOM (Allowed Cell Rate):

Term used in G.165 (General Characteristics of International Telephone Connections and International Telephone Circuits): ACOM is the combined loss achieved by the echo canceller, which is the sum of the echo return loss, echo return loss enhancement, and nonlinear processing loss for the call.

ACOUSTIC COUPLER:

A MODEM feature that uses a standard telephone handset to transmit data over the telephone network: Acoustic couplers are normally used for transmitting data at lower speeds (300 Baud) due to the acoustic coupler inability to block out surrounding interference.

ACP 127:

Allied Communications Publication: A message format guide (#127) used by the NATO (North American Treaty Organization) in the AUTODIN system; It appears this would include Communication Instructions, Tape Relay Procedures and Message Relay Procedures.

ACR:

Allowed Cell Rate: A parameter defined by the ATM (Asynchronous Transfer Mode) Forum for ATM traffic management; ACR varies between the MCR (Minimum Cell Rate) and the PCR (Peak Cell Rate), and is controlled dynamically using congestion control mechanisms.

ACRONYM:

1) A word formed from the initials or other parts of several words,

2) Internet slang: Abbreviated Coded Rendition of Name Yielding Meaning

ACS:

1) Asynchronous Communications Server

2) Advanced Communication Service: An AT&T packet switching Service

ACSE:

Association Control Service Element: The OSI (Open System Interconnection) convention used to establish, maintain, or terminate a connection between two applications.

ACTIVE:

Describes the window or icon that you are currently using or that is currently selected. The operating system always applies the next keystroke or command you choose to the active window. Windows or icons on the desktop that are not selected are inactive.

ACTIVE CONTENT:

Dynamic content, such as a stock ticker, a weather map, or news that is usually updated from the World Wide Web or a channel

ACTIVE DIRECTORY:

A directory service that stores information about objects on a network and makes this information available to users and network administrators; Active Directory gives network users access to permitted resources anywhere on the network using a single logon process.

ACTIVE DIRECTORY USERS AND COMPUTERS:

An administrative tool designed to perform day-to-day Active Directory administration tasks. These tasks include creating, deleting, modifying, moving, and setting permission levels on objects stored in the directory. These objects include organizational units, users, contacts, groups, computers, printers, and shared file objects.

ACTIVE DISCOVERY PACKET:

The type of packet used by PPPoE (Point to Point Protocol over Ethernet) during the discovery stage

ACTIVE HUB:

A multi-port device that amplifies LAN (Local Area Network) transmission signals.

ACTIVE MONITOR:

The device responsible for management of a Token Ring: A network node is selected to be the active monitor if it has the highest MAC (Media Access Control) address on the ring. The active monitor is responsible for such management tasks as ensuring that tokens are not lost, or that frames do not circulate indefinitely.

ACTIVE NONVOLATILE MEMORY (ANVM):

Memory that contains the software currently used by the network element

ACTIVE PARTITION:

A partition from which an x86-based computer starts up: The active partition must be a primary partition on a basic disk. If the ‘Windows’ operating system is used exclusively, the active partition can be the same as the system volume.

ACTIVE VOLUME:

The volume from which the computer starts up and the active volume must be a simple volume on a dynamic disk. An existing dynamic volume cannot be marked as the active volume, but it’s possible to upgrade a basic disk containing the active partition to a dynamic disk. Once the disk is upgraded to dynamic, the partition becomes a simple volume that is active.

ACTIVE X:

1) A technology that allows software components to interact with one another in a network environment regardless of the individual component language. They add functionality to software applications by seamlessly incorporating pre-made modules with the basic software package. Modules can be interchanged but still appear as parts of the original software.

2) Microsoft's Windows-specific non-Java technique for writing applets: ActiveX applets take longer to download than the equivalent Java applets; however, they more fully exploit the features of Windows 95. ActiveX sometimes is said to be a superset of Java.

3) On the Internet, ActiveX controls can be linked to Web pages and downloaded by an ActiveX-compliant browser. ActiveX controls turn Web pages into software pages that perform like any other program launched from a server. ActiveX controls can have full system access. In most instances this access is legitimate, but one should be cautious of malicious ActiveX applications.

ACTIVATION:

The process of enabling (activating) a subscriber device for network access and allowing the appropriate privileges for the account

ACU:

See Automatic Calling Unit

ACUTA:

Association of College and University Telecomm Administrators

AD:

Administrative Domain: A group of hosts, routers, and networks operated and managed by a single organization.

A/D:

Analog to Digital conversion

ADA:

A commercial program compiler

ADAPTER:

An intermediate device that electrically accommodates two sets of equipment that cannot be directly interconnected. A computer add-in board. Network adapters connect end-user nodes to the network.

ADAPTIVE DIFFERENTIAL PULSE CODE MODULATION:

See ADPCM

ADAPTIVE EQUALIZATION:

A MODEM function, that continuously compensates for variations in the quality of a channel (line).

ADAPTIVE ROUTING:

A cost-effective routing process: Messages are transmitted through a network via the most efficient path (circuit). Messages are automatically rerouted if a circuit becomes disabled.

ADC:

Analog to Digital Converter

See Analog to Digital Conversion

ADCCP:

Advanced Data Communications Control Protocol: A system handshaking and synchronizing procedure: Examples: A data control media utilized with the experimental AUTODIN ll system; A protocol system that replaced layer 2 in the Open Systems Interconnection (OSI) model found in Packet Switching Networks; A bit-oriented data link protocol, which is basically identical to High-level Data Link Control (HDLC) and a superset of Synchronous Data Link Control (SDLC).

ADCS:

Air Force Data Communications Service (System): A system used to measure the status and performance of the AUTODIN network.

ADD-DROP MULTIPLEXER (ADM):

A Synchronous Optical Network (SONET) multiplexer that can extract or insert lower-rate signals to/from a higher-rate multiplexed signal without completely de-multiplexing the signal.

ADD ON DATA MODULES:

Refers to plug-in circuit boards that allow a Private Branch Exchange (PBX) to receive and transmit digital (data) and analog (voice) signals.

ADD / DROP (ADM):

Digital multiplexing equipment that provides interfaces between different signals (formats) in a network

ADD PATH REQUEST:

A request made by the network to add a path using the Add Path packet, which establishes a multi-hop path between two network nodes. Although the two nodes are usually the source and destination nodes of a VWP, there are cases in which other nodes might want to establish a path between them. Unlike the Restore Path request, the Add Path request is never flooded; it is forwarded using information carried in the path itself (source routing).

ADDRESS:

A location where data or other information is stored in a computer memory or routing information when used as part of a message, sometimes referred to as a ‘Header’.

1) A specific location for data or computer devices where the location is characterized by a unique alphabetic or numeric designation. This type of address will always follow a predefined naming convention.

2) Adding a ‘label’  to provide a destination indicator for a character or block of characters transmitted to a receiving station, i.e. telegraph messages carry an address before their text to indicate the destination of the message.

3) Data structure or logical convention used to identify a unique entity, such as a particular process or a network device

ADDRESS CALL MODE:

A mode that permits control signals and commands to establish and terminate calls in V.25bis.

ADDRESS MAPPING / MASK:

A technique that allows different protocols to inter-operate by translating addresses from one format to another. For example, when routing IP over X.25, the IP addresses must be mapped to the X.25 addresses so that the IP packets can be transmitted by the X.25 network.

ADDRESS RESOLUTION:

In General this term refers to a method for resolving differences between computer addressing schemes. Address resolution usually specifies a method for mapping network layer (Layer 3) addresses to data link layer (Layer 2) addresses.

ADDRESS RESOLUTION PROTOCOL (ARP):

A Transmission Control Protocol/Internet Protocol (TCP/IP) that dynamically binds a high-level IP address to a low-level physical hardware address.

ADDRESS TRANSLATION:

The process of converting internal and/or external addresses into standardized network addresses. All address schemes go through a form of translation (decoding/modifying) in order to cause the proper routing of data (messages).

ADDRESS TRANSLATION GATEWAY (ATG):

Refers to a Cisco DECnet routing software function that allows a router to route to multiple independent DECnet networks; Also, to establish a user-specified address translation for selected nodes between networks.

ADF:

Adapter Description File

ADI:

AUTODIN-to-DISN (Defense Information System Network) Interface

ADJACENT:

Terminals, computers or devices located next to each other or Computer Programs or network devices directly connected by a data link.

ADJACENT CHANNEL:

A channel or frequency that is directly above or below a specific channel or frequency; this may be important information when a channel is divided using frequency division multiplexing.

ADJACENT NODES:

1) In SNA, nodes that are connected to a given node with no intervening nodes.

2. In DECnet and OSI, nodes that share a common network segment (Ethernet, FDDI, or Token Ring networks).

ADJACENY:

A relationship formed between selected neighboring routers and end nodes for the purpose of exchanging routing information. Adjacency is based upon the use of a common media segment.

ADM:

Digital multiplexing equipment that provides interfaces between different signals in a network

See Add-Drop Multiplexer

ADMD:

Administration Management Domain: X.400 Message Handling System public carrier. Together the ADMD(s) in all countries worldwide provide the X.400 backbone.

ADMINISTRATIVE DISTANCE:

A trustworthy rating of a routing information source; Administrative distance often is expressed as a numerical value between 0 and 255; the higher the value, the lower the trustworthiness rating.

ADMINISTRATIVE WEIGHT (AW):

1) The value set by the network administrator to indicate the desirability of a network link; one of four link metrics exchanged by PTSP(s) (Private Network-Network Interface ‘PNNI’ Topology State Packet) to determine the available resources of an ATM network.

2. Administrative Workstation: A personal computer used to monitor the handling of calls in the ICM (Intelligent Call Management) system. The AW also can be used to modify the system configuration or scripts.

ADMINISTRATOR:

1) For Windows XP Professional, a person responsible for setting up and managing domain controllers or local computers and their user and group accounts, assigning passwords and permissions, and helping users with networking problems.

2) For Windows XP Home Edition, a person who can make system-wide changes to the computer, install software, and who has access to all files on the computer. A person with a computer administrator account has full access to other user accounts on the computer.

3) The person who queries the User Registrar to analyze individual subscriber status and problems and to generate aggregate statistics.

ADMSC:

Automatic Digital Message Switching Centers: At the beginning, the CONUS (including Hawaii) sites were called Automatic Electronic Switching Centers (AESC), and the overseas sites were called Automatic Digital Message Switching Centers. Later (about 1969), DCA renamed both under the single term AUTODIN Switching Center (ASC).

ADMISSIONS CONFIRMATION:

An RAS message sent as an admissions confirmation

AND:

Advanced Digital Network: Usually refers to a 56Kbps leased-line.

ADNS:

Automatic Digital Network System

ADP:

1) Automatic Display Processor; 2) Automatic Data Processing; 3) Adaptive Differential Pulse Code Modulation (see ADPCM)

ADPCM:

Adaptive Differential Pulse Code Modulation: A Consultative Committee International Telegraph and Telephone (CCITT) encoding standard for analog voice transmission. The process by which analog voice samples are encoded into high-quality digital signals

ADSL:

Asymmetric Digital Subscriber Line: Like ISDN (Integrated Services Digital Network), ADSL uses standard phone lines to deliver high-speed data communications. But while ISDN transmission speed is limited to 64 kbps, ADSL technology can deliver upstream (from the user) speeds up to 800 kbps and downstream (to the user) speeds 1.5 mbps to 9 mbps. ADSL also uses the portion of a phone line's bandwidth not utilized by voice, allowing for simultaneous voice and data transmission.

ADSL LITE:

A lower data rate speed version of ADSL

ADSP:

See Apple Data-stream Protocol

ADSU:

ATM DSU Terminal adapter used to access an ATM (Asynchronous Transfer Mode) network via an HSSI-compatible device. See Data Service Unit (DSU).

ADTS:

Automated Digital Terminal System

ADU:

See Automatic Dialing Unit or Accumulation and Distribution Unit

ADU:

   Accumulation and Distribution Unit: A hardwired front end computer based on RCA 501 logic that managed the communication lines and processed data to and from the switching center tributaries and the center's Communications Data Processor. The ADU maintains a set of stored memory tallies for managing and control of the incoming and outgoing transmission lines. 

   The ADU was basically the beginning of a ‘Front End’ Computer (circa 1960). The ADU isolated the Data Processor (CDP) from the communication lines. Transistors were used for the primary logic control media. The Data Memory in the ADU was the magnetic core variety. This was before the great silicone wafer chips. 

   The ADU controlled and managed the communication lines and data in and out of the AUTODIN Switching Computer. The control (electronics) was all hard wired and functioned in a cyclic manner. Updating and monitoring control information was stored in the Procedural Memory (PM). This control information was divided into two sets of 96 bit control words called tallies. Two sets of tallies (a tally group) were assigned to each individual duplex (send and receive) communication line for status and monitoring control. The tallies maintained status and housekeeping information, such as, error and rollback counters, block counters, current line status and character code translation. Code translation was necessary because the CDP code set was not compatible with some of the codes sets used by the terminals on the line side. 

   Message data flowing in and out of the ADU were processed in two ways. Asynchronous data (low speed) were processed on a bit by bit basis, accumulated into one eight-bit Fieldata character. Fieldata preceded the ASCII code set. Other message data were processed on a character by character basis. Large chunks of data were accumulated into line blocks. A line block consisted of eighty characters, a header, message content and trailer character, which was equivalent to an IBM eighty-character punched card. The DM storage area channel (line) assignments were configured to store three line blocks of Fieldata characters for low speed lines (300 baud), and seven line blocks for high speed lines (1200 and 2400 baud). Blocking of data occurred in both directions, send and receive, since all lines could operate in a duplex mode. 

   The computer side of each ADU was connected through and input/output transfer channel (port) to the online CDP. Transfer of data to and from the CDP was accomplished through the ADU Data Memory (DM). Partitioned areas of the DM were associated with each specific communication line. Low speed lines were assigned 240 Fieldata character positions in memory and high- speed lines were assigned 560 Fieldata character positions.

ADUA:

Administrative Directory User Agent: A tool used to maintain Directory Service information.

ADU TCCU:

ADU Transfer Channel Control Unit: The ADU front end line communication processor communicates with the online Communication Data Processor (CDP) through a multiple control and data transfer interface. The Transfer Channel is the Input - Output unit that sends data from the ADU to the CDP and from the CDP to the ADU for transmission to and from the connected tributaries.

ADVANCED COMMUNICATION FUNCTION / NETWORK CONTROL PROGRAM (ACF/NCP):

1) IBM Systems Network Architecture (SNA) control software running on a communications controller that supports the operation of the SNA backbone network

2) ACF: A group of SNA products that provides distributed processing and resource sharing.

3) The primary SNA NCP. ACF/NCP resides in the communications controller and interfaces with the SNA access method in the host processor to control network communications.

ADVANCED COMMUNICATIONS FUNCTION/ VIRTUAL TERMINAL ACCESS METHOD (ACF/VTAM):

An IBM System Network Architecture (SNA) network control software or a host computer that allows the host to communicate with network terminals.

ADVANCED COMMUNICATIONS FUNCTION (ACF):

Refers to IBM System Network Architecture (SNA) software and computer inter-communications products

ADVANCED CONFIGURATION and POWER INTERFACE (ACPI):

An industry specification that defines power management on a wide range of mobile, desktop, and server computers and peripherals: ACPI is the foundation for the On-Now industry initiative that allows system manufacturers to deliver computers that will start at the touch of a keyboard. ACPI design is essential to take full advantage of power management and Plug and Play.

ADVANCED CoS MANAGEMENT:

Advanced Class of Service Management: An essential function for delivering the required QoS (Quality of Service) to all applications; Cisco switches contain per-VC queuing, per-VC rate scheduling, multiple CoS (Corporation for Open Systems) queuing, and egress queuing. This enables network managers to refine connections to meet specific application needs.

ADVANCED DATA COMMUNICATIONS CONTROL PROCEDURE / PROTOCOL:

May refer to AppleTalk Echo Protocol that is used to test the connectivity between two AppleTalk nodes; One node sends a packet to another node and receives a duplicate, or echo, of that packet. See ADCCP

ADVANCED INTELLIGENT NETWORK (AIN):

In SS7, an expanded set of network services made available to the user, and under user control, that requires improvement in network switch architecture, signaling capabilities, and peripherals

ADVANCED INTERACTIVE EXECUTIVE (AIX):

Refers to a computer operating system for several Hekimian systems, including REACT 2001, REACT 2000

ADVANCED PEER TO PEER NETWORKING (APPN):

An extension of IBM System Network Architecture (SNA) that routes information around the network without help from the host, allowing systems to adjust dynamically (dynamic routing) making it easier to connect and reconfigure. Nodes can join and leave the network as required, and it also creates a directory of network nodes and other resources.

ADVANCED PEER to PEER COMMUNICATIONS (APPC):

See Advanced Program to Program Communications (APPC)

ADVANCED PEER-TO-PEER NETWORKING (APPN):

Refers to an enhancement to the original IBM SNA architecture; APPN handles session establishment between peer nodes, dynamic transparent route calculation, and traffic prioritization for APPC traffic.

ADVANCED PROGRAM to PROGRAM COMMUNICATIONS (APPC):

A set of IBM System Network Architecture (SNA) protocols that functions within Advanced Peer to Peer Networking (APPN) that supports peer-to-peer communications between workstations attached to Local Area Networks (LAN) and the applications running on those workstations

ADVANCED PROGRAM to PROGRAM COMMUNICATION FILE TRANSFER PROTOCOL (AFTP):

A file transfer protocol used in IBM host systems, the IBM Advanced Program-to-Program Communications; equivalent to the TCP/IP File Transfer Protocol.

ADVANCED VOICE BUSYOUT (AVBO):

The local voice busy-out feature that provides a way to busy out a voice port or a DS0 group (time slot) if a state change is detected in a monitored network interface (interfaces). When a monitored interface changes to a specified state, to out-of-service, or to in-service, the voice port presents a seized/busy-out condition to the attached PBX (Switching Exchange) or other Customer Premises Equipment (CPE). The PBX (Private Branch Exchange) or other CPE (Customer Private Exchange) can then attempt to select an alternate route.

ADVERTISING:

The router process in which routing or service updates are sent at specified intervals so that routers on the network can maintain lists of usable routes

ADWARE:

Any software which causes banner ads or pop-up ads while the computer is in use: It is sometimes installed in freeware or shareware which is downloaded from the internet; and provides one more channel for advertisers to access the computer. Some ‘adware’ will also track files, internet usage, and software activity and report back to advertisers to help them channel relevant ads to the computer in use.

AE:

Application Entity

AEP:

AppleTalk Echo Protocol: Used to test the connectivity between two AppleTalk nodes. One node sends a packet to another node and receives a duplicate, or echo, of that packet.

AERM:

SS7 MTP 2 function that provides monitoring of link alignment errors

AESC:

Automatic Electronic Switching Center: Automatic computer based message switching and processing center that processes and routes messages to and from connected tributaries, trunk lines or another AESC.

A eSATA/USB or USB/eSATA:

combination port is a technology being used in some desktop PCs, and laptop computers. eSATA/USB is a type of serial port in which eSATAp or a USB device can be plugged into the same port. It is an advanced form of an SATA-300 port because it is integrated with the compatibility of USB data protocol and power output

 

eSATA/USB ports are also known by the following names:

eSATAp (Delock, Dynex, Lindy, Addonics)

Power over eSATA (Delock, MSI)

SATA on the go (Asus)

AFB:

Air Force Base: An Air Force military Base that may or may not have an airfield. Some AUTODIN Switching Centers were installed on AFB's while others were installed on Navy, Army and Marine bases.
 

AFC:

1) An RAS message sent as an admissions confirmation

2)Air Force Communication Center

AFCEA:

Armed Forces Communications and Electronics Association

AFDATACOM:

Air Force Data Communications: An Automated Computer message switching system operated by Air Force military and Government Civil Service personnel; a predecessor, in name, of the AUTODIN System. The AFDATACOM system was re designated (re named) AUTODIN following the initial system implementation.

AFFINITY:

Requirements of an MPLS (Multi-protocol Label Switching) traffic engineered tunnel on the attributes of the links it will cross. The tunnel's affinity bits and affinity mask bits of the tunnel must match the attribute bits of the various links carrying the tunnel.

AFI:

Authority and Format Identifier: The part of an NSAP (Network Service Access Point.) format, ATM (Asynchronous Transfer Mode) address, that identifies the type and the format of the IDI (Initial Domain Identifier) portion of an ATM address.

AFNOR:

Association Francaise de Normalisation

AFP:

AppleTalk Filing Protocol: Presentation-layer protocol that allows users to share data files and application programs that reside on a file server. AFP supports AppleShare and Mac OS File Sharing.

AFSATCOM:

Air Force Satellite Communications

AF/SC:

Deputy Chief of Staff for Command, Control, Communications, and Computers, United States Air Force

AFS:

Andrew File System

AGENT:

1)  Generally, software that processes queries and returns replies on behalf of an application.

2) In NMS(s) (Network Management System), a process that resides in all managed devices and reports the values of specified variables to management stations.

AGGRESSIVE MODE:

The connection mode that eliminates several steps during IKE (Internet Key Exchange) authentication negotiation (phase 1) between two or more IPSec (Internet Protocol Security) peers; Aggressive mode is faster than main mode but not as secure.

AGMS:

AUTODIN Gateway Messaging System

AH:

Authentication Header: A security protocol that provides data authentication and optional anti-replay services. AH is embedded in the data to be protected (a full IP datagram).

AHNENTAFEL:

A Genealogy term: Refers to an information field for exploration on the internet

AHT:

Average Handle Time: The average time it takes for calls to a service or a skill group to be handled. Handle time includes talk time plus after-call work time.

AI:

1) Artificial Intelligence

2) Access Interface

AID:

AUTODIN Interface Device

AIDS:

AUTODIN Interrogating Diagnostic System: An integrated maintenance software system combining the functions of AAMPS, AUTOLEX & CABA; provides information for maintenance analysis, resolution and repair.

AIFF:

Audio Interchange File Format: A common audio file format originally for Macs, but also used with other systems.

AIM:

Asynchronous Interface Module

AIN:

Advanced Intelligent Network: In SS7, an expanded set of network services made available to the user, and under user control, that requires improvement in network switch architecture, signaling capabilities, and peripherals. See also SS7.

AIO:

Asynchronous input/output.

AIOD:

See Automatic Identification of Outward Dialing

AIP:

ATM Interface Processor: ATM (Asynchronous Transfer Mode) network interface for Cisco 7000 series routers designed to minimize performance bottlenecks at the UNI (User-Network interface). The AIP supports AAL3/4 and AAL5.

AIRLINE CONTROL PROTOCOL:

Data link layer polled protocol that runs in full-duplex mode over synchronous serial (V.24) lines and uses the binary-coded decimal (BCD) character set.

AIRLINE PRODUCT SET:

A tunneling mechanism that transports airline protocol data across a Cisco router-based TCP/IP network to an X.25-attached mainframe; This feature provides connectivity between an Agent Set Control Units {ASCU(s)} and a mainframe host that runs the airline reservation system database.

AIRLINE PROTOCOL:

Generic term that refers to the airline reservation system data and the protocols, such as P1024B (ALC), P1024C (UTS) and MATIP that transport the data between the mainframe and the ASCU(s)

AIRLINE X.25:

X.25 implementation based on a CCITT 1984 recommendation using Permanent Virtual Circuits (PVC) only. There is one nonstandard aspect of this protocol: Packets can be sent with the m-bit set, but the size of the packet is less than the maximum packet size for the virtual circuit.

AIS:

1) Alarm Indication Signal: An unframed one bits signal that replaces the normal data signal when a maintenance alarm has been activated, also called a blue alarm. In a T1 transmission, an all-ones signal transmitted in lieu of the normal signal to maintain transmission continuity and to indicate to the receiving terminal that there is a transmission fault that is located either at, or upstream from, the transmitting terminal.

2) Automatic Intercept System

3) DoD (Department of Defense) acronym for ‘Automated Information System’.

AIT:

AUTODIN Interface Terminal

AIX:

See Advanced Interactive Executive

AJAX:

Asynchronous JavaScript and XML: A method of including additional content in a web page; java-script code in the web page fetches some data from a server and displays it without re-fetching the entire surrounding page at the same time (hence 'Asynchronous')
It is common for Ajax applications to update the Ajax content multiple times without the surrounding page needing to be updated,

AL:

See Access Line

ALAP:

See AppleTalk Link Access Protocol

ALARM:

Notification that the traffic signal has degraded or failed or equipment is malfunctioning; An SNMP message notifying an operator or an administrator of a network problem.

A-LAW:

ITU-T companding (compression and/or expansion) standard used in the conversion between analog and digital signals in PCM systems; A-law is used primarily in European telephone networks and is similar to the North American mu-law standard.

ALBO:

See Automatic Line Build Out

ALGORITHM:

1) In communications this would refer to a set of instructions or mathematical formulas used to solve a given communications problem.

2) A sequence of steps needed to solve logical or mathematical problems.

Certain cryptographic algorithms are used to encrypt or decrypt data files and messages and to sign documents digitally.

ALIAS / ENTITY:

Generally, an individual, manageable network device

ALIASING:

A term that refers to a condition where a transmission error fragments a message and the fragments appear to be a good message or picture at the receiver. Protocols have been developed to help prevent this problem, such as High Level Data Link Control (HDLC).

ALIEN PORT ADAPTER:

A dual-wide port adapter for the Cisco 7200 router: The Alien Port Adapter is ABR (Available Bit Rate) ready and supports traffic shaping.

ALIGNMENT ERROR:

In IEEE 802.3 networks, an error that occurs when the total number of bits of a received frame is not divisible by eight; Alignment errors usually are caused by frame damage due to collisions.

ALIGNMENT ERROR RATE MONITOR (ALERM):

SS7 MTP 2 function that provides monitoring of link alignment errors

A-LINK:

SS7 Access Link: A dedicated SS7 signaling link not physically associated with any particular link carrying traffic.

ALL ONES CODE:

This term refers to a condition when a device loses synchronization all ones code is transmitted to keep the network up and to indicate there is a transmission problem.

ALL RINGS EXPLORER PACKET:

The terms ‘All Routes Explorer Packet”, ‘Explorer Packet’, ‘Spanning Explorer Packet’, or ‘Local Explorer Packet’ may also be used:  Packet generated by an end system in an SRB (Source-Route Bridging) network to find a host connected to the local ring. If the local explorer packet fails to find a local host, the end system produces either a spanning explorer packet or an all-routes explorer packet.

ALL ROUTES EXPLORER PACKET:

An explorer packet that traverses an entire SRB (Source-Route Bridging) network following all possible paths to a specific destination; See All-Rings Explorer Packet

ALLOCATION:

The allotment or apportionment of available memory and file storage in order to accommodate the necessary programs, files and data

ALLOCATION UNIT:

The smallest amount of disk space that can be allocated to hold a file: All file systems used by Windows organize hard disks based on allocation units. The smaller the allocation unit size, the more efficiently a disk stores information. If you do not specify an allocation unit size when formatting the disk, Windows picks default sizes based on the size of the volume. These default sizes are selected to reduce the amount of space that is lost and the amount of fragmentation on the volume. An allocation unit is also called a ‘cluster’.

ALO TRANSACTION:

An ATP (ALPS Tunneling Protocol) transaction in which a request is repeated until response(s) is received from the receiving party or until a maximum retry count is reached. This recovery mechanism ensures that the transaction request is executed at least once.

ALPHANUMERIC:

A character (code) set consisting of or containing alphabet characters and numbers. A contraction of alphabet-number

ALPS:

Airline Product Set: A tunneling mechanism that transports airline protocol data across a Cisco router-based TCP/IP (Transmission Control Protocol / Internet Protocol) network to an X.25-attached mainframe. This feature provides connectivity between Agent Set Control Units (ASCU) and a mainframe host that runs the airline reservation system database.

ALPS CIRCUIT:

Refers to a communication path across a TCP (Transmission Control Protocol) connection between a host reservation system and an ASCU (Agent Set Control Unit); When MATIP (Mapping of Airline Traffic over Internet Protocol) encapsulation is used on an ALPS circuit, it is equivalent to a MATIP session.

ALPS TUNNELING PROTOCOL:

Airline Product Set Tunneling Protocol. See ATP

ALS:

Active Line State

ALT:

Assembly Library Tape: A magnetic tape containing historical or backup data or programming information

ALTAIR:

A Motorola wireless low power microwave transfer Local Area Network (LAN) product, which is compatible with Novell NetWare.

ALTERNATE CONTROL MEMORY:

See ACM

ALTERNATE DELIVERY:

Alternate Delivery: A process where messages sent to a particular device/display or terminal would be re-routed via an alternate path due to an out of service or busy condition. Refer to alternate routing.

ALTERNATE FREQUENCY:

Frequency assigned for use only at certain times or for a specific purpose and may supplement or replace the frequency normally used.

ALTERNATE MARK INVERSION (AMI);

Transmitted binary digits in which successive mark bits are normally positive or negative but equal in amplitude and the space bit is zero amplitude.

ALTERNATE ROUTE:

A secondary communication path used to reach a destination if the primary path is unavailable. This could be accomplished through a program feature or by a manual patching procedure in Technical Control.

ALTERNATE USE:

The ability to use communications transmission facilities for multiple applications, such as voice or data

ALTERNATE VOICE DATA (AVD):

A transmission (circuit) facility that can be used for either voice or data

ALU:

Arithmetic and Logic Unit: Contained within the Communications Data Processor and the Tape Search Unit computer. The ALU is where arithmetic and logical functions are performed on data operands.

AM:

Amplitude Modulation: A modulation technique where information is transmitted through the changing amplitude of the carrier signal.

AMA:

Automatic Message Accounting: Refers to equipment that automatically records all data concerning dialed long distance calls. This information is normally used for billing purposes.

AMADNS:

Automatic Message Accounting Data Networking System: In OSS (Operations Support System), the collection and the transport of AMA (Automatic Message Accounting) data from central office switches to a billing system.

AMATPS:

Automatic Message Accounting Teleprocessing System: In OSS, the Bellcore legacy system for collecting and transporting AMA data from central office switches to a billing system. The AMATPS consists of an AMA transmitter and a collector.

AMBIENT NOISE:

Any form of telecommunications interference continuously present in a communications line (circuit).

AMERICAN NATIONAL STANDARDS INSTITUTE:

See ANSI

AMERICAN TELEPHONE AND TELEGRAPH COMPANY: (AT&T):

Long distance (inter-exchange) US carrier

AMERICAN WIRE GAUGE:

See AWG

AMHS:

Automated Message Handling System

AMI:

See Alternate Mark Inversion

AMPLIFIER:

A unidirectional electronic device that is used to boost (amplify) signals, and the input or output level is usually measured in decibels.

AMPLITUDE:

The size or magnitude of a voltage or current wave form

AMPLITUDE DISTORTION:

Refers to the amplitude distortion of analog waves (sine waves) usually caused by attenuation.

AMPLITUDE MODULATION (AM):

A modulation process where the amplitude of analog sine waves is varied; a method of modulating carrier waves to cause them to vary in amplitude corresponding to the amplitude of the introduced signal.

AMPS (Advanced Mobile Phone System):

In 1983, the analog cell phone standard called AMPS was approved by the FCC (Federal Communications Commission) and first used in Chicago. The AMPS use a range of frequencies between 824 megahertz (MHz) and 894 MHz for analog cell phones. In order to encourage competition and keep prices low, the U. S. government required the presence of two carriers in every market, known as A and B carriers. One of the carriers was normally the Local Exchange Carrier (LEC), the local phone company.

AMRL:

Adjusted Main Ring Length

AMS:

AUTODIN Mail Server

AN:

See Access Node or Enunciator

ANALEX:

High Speed Printer: The HSP prints a complete line of text as the platen (cylinder) spins a single 360 degrees. The platen had the entire alphabet and numbers, including punctuation characters, on the platen. I.E. a row of A's, B's 1's, etc. Each character individually (alphanumeric) was printed across the page as the platen rotated, and in one rotation of the platen a line across the page was printed. This line of data would contain all the necessary characters to form the words.

ANALOG, ANALOG DATA:

Refers to any data in the form of continuously variable physical qualities (analog wave / wave form), which are ‘analogous’ to the data source; a continuously variable signal as opposed to discretely variable signal.

ANALOG COMPUTER:

1) A computer designed and used for measured angles or analog signals.

2) A device that measures voltages, linear lengths, resistance, and light intensities. It can be manipulated by the computer and can also solve problems by setting up equivalent electrical circuits. Analogue computers have limited capability to reduce approximate solutions, whereas digital computers give exact solutions.

ANALOG INTEGRATED CIRCUIT:

A type of linear integrated circuit providing an output that is a continuous mathematical function of the input. Example: an operational amplifier.

ANALOG LOOP BACK:

Refers to a maintenance diagnostic test, where a loop is placed at the MODEM on the line interface side in order to test the analog signals. The analog input side is strapped to the output side.

ANALOG SIGNAL:

Everything that we see and hear reaches us through analog waves (frequency in Hz 'cycles'). When we speak, we produce analog waves (signals). When we hear a sound, we receive and process analog signals.

ANALOG TO DIGITAL CONVERSION:

Refers to a process where analog signals are converted to digital signals. This usually accomplished through a device, such as a MODEM.

ANALOG TRANSMISSION (AC):

Communications by transmission of continuously varying representations (frequencies) of the input signal, as compared to coded words in digital transmission.

ANCILLARY EQUIPMENT:

Equipment not directly controlled by the processing unit, but available as needed (auxiliary/back-up).

&NBSP:

HTML coding for a non-breaking space: It is used in HTML between consecutive words on a web page to prevent those two words from being broken apart at the end of a line.

ANI:

Automatic Number Identification: SS7 (Signaling System 7) feature in which a series of digits, either analog or digital, are included in the call, identifying the telephone number of the calling device. ANI identifies the number of the calling party.

ANIMATED GIF:

A GIF (Graphic Interchange Format) graphic file, which consists of two or more images shown in a timed sequence to give the effect of motion.

ANNEX D:

Refers to a synchronous polling feature used for the link management of a frame relay channel where the user polls the network to obtain status information on the configured Permanent Virtual Circuits (PVC).

ANNUNCIATOR (AN):

An intercept device that provides an audible signal indicating the condition or restrictions associated with circuits or procedures.

ANONYMOUS - FTP:

Anonymous File Transfer Protocol: Allows a user to retrieve documents, files, programs, and other archived data from anywhere on the Internet without having to establish a user ID and password. By using the special user ID of anonymous, the network user bypasses local security checks and can access publicly accessible files on the remote system. See also FTP.

ANP:

Automatic Numbering Plan

ANSCII:

American National Standard Code for Information Interchange: A later version of the ASCII Code. See ASCII for details.

ANSI:

American National Standard Institute: A voluntary organization that represents the USA in the ISO (International Standards Organization) and is responsible for defining ASCII. Members include manufacturers, common carriers, and other standards organizations such as the IEEE. See ASCII.

ANSI EMULATION: Refers to the ability to send, receive, and display ANSI graphics.

ANSWER BACK:

Could be a polling response back from polled device indicating a ready to receive status or a response from a receiving device (terminal) acknowledging a message was satisfactorily received.

ANSWER MODE:

1) Refers to an on line status where a MODEM ready to pick up the phone (answer) when it rings and then the MODEM will complete the connection with the called device

2) Specifies that the router should not attempt to initiate a trunk connection, but should wait for an incoming call before establishing the trunk connection

ANSWER SUPERVISION TEMPLATE:

The sequence of autonomous responses to the detection of specific signaling events for outbound calls from the Cisco VCO/4K switch.

ANTENNA:

A device for transmitting or receiving a radio frequency (RF): Antennas can be designed for specific and relatively tightly defined frequencies. An antenna for a 2.5 GHz (MMDS) system probably would not work for a 28 GHz (LMDS) designed system. Also antennas can be designed to operate using a multiple of frequencies, i.e. television antennas.

ANTI-REPLAY:

A security service where the receiver can reject old or duplicate packets in order to protect itself against replay attacks; IPSec (Internet Protocol Security) provides this optional service through the use of a sequence number combined with the use of data authentication

ANTI-VIRUS SOFTWARE:

Anti-virus software (Anti-virus Scanner) scans a computers memory and disk drives for viruses. If it finds a virus, the application informs the user and may clean, delete or quarantine any files, directories or disks affected by the malicious code.

ANTI-VIRUS VIRUS:

Anti-antivirus (Retrovirus) viruses attack; disable or infect specific anti-virus software.

ANVM:

Active Nonvolatile Memory: Memory that contains the software currently used by the network element.

ANW:

Advanced Netware

ANYCAST:

In ATM (Asynchronous Transfer Mode) an address that can be shared by multiple end systems. The Any-Cast address can be used to route a request to a node that provides a particular service.

AOW:

Asia and Oceania Workshop

AP:

Access Point; Application Process; Application Processor:

1) A hardware device, or software used in conjunction with a computer, that serves as a communications ‘hub’ for wireless clients and provides a connection to a wired LAN (Local Area Network). An AP can double the range of wireless clients and provide enhanced security.

2) A base station in a wireless LAN. Access points are typically stand-alone devices that plug into an Ethernet hub or server. Like a cellular phone system, users can roam around with their mobile devices and be handed off from one access point to the other.

APA:

All Points Addressable

APACHE:

A common web server (or HTTP server) software on the Internet: Apache is an open-source application originally created from a series of changes ("patches") made to a web server written at the National Center for Supercomputing Applications, the same place the Mosaic web browser was created. 
Apache is designed as a set of modules, enabling administrators to choose which features they wish to use and making it easy to add features to meet specific needs, including handling protocols other than the web-standard HTTP.

APAD:

Asynchronous Packet Assembler-Dissembler

APaRT:

Automated Packet Recognition / Translation: Technology that allows a server to be attached to CDDI or FDDI without requiring the reconfiguration of applications or network protocols. APaRT recognizes specific data link layer encapsulation packet types and, when these packet types are transferred from one medium to another, translates them into the native format of the destination device.

APC:

1) Adaptive Power Control: A feature of wireless handsets that helps reduce power consumption to increase battery life

2) Adjacent Point Code: The point code of the next hop in the system for the bearer channels; usually it is the STP (Signal Transfer Point)

APDU:

Application Protocol Data Unit

API:

Application Program Interface: The means by which an application program talks to communications software. Standardized API(s) allow application programs to be developed independently of the underlying method of communication. A set of standard software interrupts, calls, and data formats that computer application programs use to initiate contact with other devices, for example, network services, mainframe communications programs, or other program-to-program communications. Typically, APIs make it easier for software developers to create the links that an application needs to communicate with the operating system or with the network.

APN:

Access Point Name: Identifies a PDN (Public Data Network) that is configured on and accessible from a GGSN (Gateway GPRS Support Node) in a GPRS (General Packet radio Service) network.

APNIC:

Asia Pacific Network Information Center: Nonprofit Internet registry organization for the Asia-Pacific region. The other Internet registries are currently IANA, RIPE NCC, and Inter-NIC.

APOLLO DOMAIN:

Proprietary network protocol suite developed by Apollo Computer for communication on proprietary Apollo networks.

APPC:

See Advanced Program to Program Communications

APPC/PC:

A version of Advanced Program to Program Communications (APPC) developed by IBM to run on Personal Computer (PC) based Token Ring networks.

APPLE DATASTREAM PROTOCOL (ADSP):

A transport mechanism for inter-communications between Apple Macintosh and DEC (Digital Corp), Vax minicomputers

APPLE TALK:

An Apple Computer proprietary Local Area Network (LAN) protocol for linking Macintosh Computers and peripheral devices: AppleTalk is a 115 Kbps Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) network that allow connecting up to 32 devices.

APPLE-TALK FILING PROTOCOL (AFP):

Apple Computer services that handle remote file access across a Local Area Network (LAN): AFP is a presentation layer service within the Open System Interconnection (OSI) model.

APPLET:

An Applet is a program written in the JavaTM programming language that can be included in an HTML (Hypertext Markup Language) page, much in the same way an image is included. Java technology enables a browser to view a page that contains an Applet. The Applet's code is transferred to the users system and executed by the browsers Java Virtual Machine (JVM).

Authors often embed applets within the HTML page as a foreign program type.

Java applets are usually only allowed to access certain areas of the user's system. Computer programmers often refer to this area as the sandbox.

APPLICATION LAYER:
Refers to the Open Systems Interconnection (OSI) Model concerning the top or seventh layer, which contains the user or application programs.

APPLE TALK LINK ACCESS PROTOCOL (ALAP):

Apple Computer services that govern packet transmission across an AppleTalk network: ALAP operates at the Open System Interconnection (OSI) data-link layer.

APPLICATION PROGRAM:

A program written for or by a user that applies to his work or for processing one function. In data communications, a program that usually resides in Data Communication Equipment (DCE) that communicates with Data Terminal Equipment (DTE) and performs a set of specified functions for terminal users.

APPLICATION SERVER:

A server in a client server network running applications, which can be shared by client stations and also shares the data processing burden with client stations. In many circumstances, the application server model allows for faster data processing, faster throughput, greater data reliability, and increased data security.

APPLICATION SPECIFIC INTEGRATED CIRCUIT (ASIC):

Very Large Scale Integrated Circuit custom-designed to perform particular (specific) functions: Advantages include fewer discrete components, lower power consumption and increased reliability. See ASIC

APPN:

Advanced Peer-to-Peer Net-working an enhancement to the original IBM SNA architecture: APPN handles session establishment between peer nodes, dynamic transparent route calculation, and traffic prioritization for APPC traffic.

See Advanced Peer to Peer Networking

APPN+:

Next-generation ‘Advanced Peer-to-Peer Net-working’ that replaces the label-swapping routing algorithm with source routing.

APS:

Automatic Protection Switching: A method that allows transmission equipment to recover automatically from failures, such as a cut cable.

APSB:

Automatic Protection Switching Byte: A failure-condition code

AR:

Access Registrar: Provides RADIUS services to DOCSIS cable modems for the deployment of high-speed data services in a one-way cable plant requiring Telephone Company-return for upstream data.

ARA:

AppleTalk Remote Access: A protocol that provides Macintosh users direct access to information and resources at a remote AppleTalk site.

ARC:

ATM (Asynchronous Transfer Mode) Research Consortium

ARCHITECTURE:

It is the structure given to information, applications, organizational and technological components, the grouping of components, interrelationships, the principles and guidelines governing designs and their evolution over time.

ARCHIE:

A software tool using known file names or sub-strings to find files stored at anonymous FTP (File Transfer Protocol) sites. An early search Engine

ARCnet:

See Attached Resource Computer Network

ARCnet-Plus:

See Attached Resource Computer Network Plus

AREA:

Refers to a logical set of network segments (CLNS, DECnet, or OSPF) and their attached devices; Areas usually are connected to other areas via routers, making up a single autonomous system.

ARIN:

American Registry for Internet Numbers: A nonprofit organization established for the purpose of administrating and registering IP (Internet Protocol) numbers to the geographical areas currently managed by Network Solutions (Inter-NIC). Those areas include, but are not limited to,North America, South America, South Africa, and the Caribbean.

ARITHMETIC/LOGIC UNIT:

A section of the computer that performs the various arithmetic operations, using registers, software routines and memory.

ARL:

Adjusted Ring Length

ARMORED VIRUS:

An armored virus tries to prevent analysts from examining its code. The virus may use various methods to make tracing, disassembling and reverse engineering its code more difficult.

ARP/RARP:

Address Resolution Protocol/Reverse Address Resolution Protocol: The Internet commands to resolve Internet Protocol (IP) addresses on a name server. RARP (protocol) when sent to a name server with an IP argument the server returns the logical address (domain). The ARP command is just the opposite, when the logical address argument is sent to the name server, the numerical IP address is returned by the server.

ARPA:

Advanced Research Projects Agency: Directly involved in the design of ARPANET, the first widely used packet switching network.

ARPANET:

Advanced Research Project Agency: Network: The precursor to the Internet, ARPANET was a large wide-area network created by the United States Defense Advanced Research Project Agency (ARPA). Established in 1969, ARPANET served as a test bed for new networking technologies, linking many universities and research centers. The first two nodes that formed the ARPANET were at UCLA and the Stanford Research Institute, followed shortly thereafter by the University of Utah.
ARP:

See Address Resolution Protocol

ARQ:

A communication technique in which the receiving device detects errors and requests retransmissions; See Automatic Repeat Request

ARTIFACT:

Identifies imperfections (distortion) introduced into a signal as a result of digital signal processing.

ARU:

Alarm Relay Unit

AS:

A collection of networks under a common administration sharing a common routing strategy: Autonomous systems are subdivided by areas. An autonomous system must be assigned a unique 16-bit number by the IANA, which may be abbreviated AS.

ASA:

Average Speed of Answer: Average answer / wait time for calls to a service or a route.

ASAM:

ATM (Asynchronous Transfer Mode) Subscriber Access Multiplexer: A telephone central office multiplexer that supports SDL ports over a wide range of network interfaces. An ASAM sends and receives subscriber data (often Internet services) over existing copper telephone lines, concentrating all traffic onto a single high-speed trunk for transport to the Internet or the enterprise intranet. This device is similar to a DSLAM.

ASBR:

Autonomous System Boundary Router: ABR located between an OSPF autonomous system and a non-OSPF network. ASBR(s) run both OSPF and another routing protocol, such as RIP.

ASC:

1) AUTODIN Switching Center (Automatic Switching Center)

2) American Satellite Corporation (ASC)

3) The original AESC was later renamed ASC

4) ASC purchased AUTODIN from Western Union and the CONTEL Corporation (Continental Telephone) later acquired ASC.

5) Government ASC designations: Air Systems Command; assign switch class mark; Acting Service Chief

ASCII:

American Standard Code for Information Interchange:  A combination of 8 BITS (Binary Digits) that can be permutated into 236 distinct codes, for transmitting and receiving 26 uppercase, 26 lower case, 0-9 numeric digits, punctuation marks and 32 transmission control characters; Adopted by the IEEE (Institute of Electrical and Electronic Engineers) as a standard encoding sequence for sending intelligence by electrical signals. A later version is ANSCII

ASCII FILES:

ASCII files are usually text files consisting of only ASCII characters. With effort, it is possible to write program files consisting only of printable characters, such as EICAR Standard Anti-virus Test File. Windows Batch (BAT) files and Visual Basic Script (VBS) files are also typically pure text, and program files.

Because of the danger macro viruses can pose, using ASCII files in e-mail communications may by less risky. While it is possible for ASCII files to contain program code, and thus to contain viruses, ASCII files let the user control both content and layout, ensuring the e-mail is legible by most e-mail programs.

ASCII TERMINAL:

Generally applies to a terminal using the American Standard Code for Information Interchange (ASCII) code set, which could operate in an asynchronous (start, stop bits) or synchronous (no start, stop bits), bit stream, mode.

ASCU:

Agent-Set Control Unit

ASD:

Automated Software Distribution

ASE:

1) Amplified Spontaneous Emissions: Noise that is added to an optical signal when it is amplified. This noise (ASE) accumulates and builds in optical spans that have multiple optical amplifiers between regenerators.

2) Application Service Element

ASI:

ATM (Automatic Transfer Mode) Service Interface

ASIC:

Application Specific Integrated Circuit (chip): VLSI Very Large Scale Integrated Circuits designed for specific functional applications.

ASIST:

Application Software Integration Support Tools: A set of C-language application development tools designed to facilitate the creation of host-controlled applications by Cisco VCO/4K customers.

ASM:

Automatic Switch Monitor

ASN:

Auxiliary Signal Network

ASN.1:

Abstract Syntax Notation One: OSI language that describes data types independent of particular computer structures and representation techniques; Described by ISO International Standard 8824.

ASP:

1) AppleTalk Session Protocol: A protocol that uses ATP to provide session establishment, maintenance, and teardown, as well as request sequencing.

2) Auxiliary Signal Path: Telecommunications link between Trans-Paths that allow them to exchange signaling information that is incompatible with the PSTN backbone network; provides feature transparency.

3) Application Service Provider: An organization, such as a business, that runs one or more applications on their own servers and provides access to others. Common examples of services provided this way include web-based software such as Calendar systems, Human Resources tools (timesheets, benefits, etc.), and various applications to help groups collaborate on projects.

4) Active Server Pages

ASSEMBLE:

1) To convert a program written in non-machine (computer) language into actual machine instructions and to assign memory storage for those instructions.

2) To accumulate in main or auxiliary (secondary) memory portions of an incoming long message.

ASSIGNED NUMBERS:

RFC [STD2] documents the currently assigned values from several series of numbers used in network protocol implementations. This RFC (Request for Comments) is updated periodically, and current information can be obtained from the IANA. (Internet Assigned Numbers Authority). When developing a protocol or an application that requires the use of a link, socket, port, protocol, and so on, contact the IANA to receive a number assignment.

ASR:

‘Automatic Send and Receive’ Teletype terminal: I.E. ASR-33/28 Teletype Automatic Send and Receive Terminal consisting of a terminal printer, paper tape punch, transmitter and reader.

AST:

Automatic Spanning Tree: A function that supports the automatic resolution of spanning trees in SRB networks, providing a single path for spanning explorer frames to traverse from a given node in the network to another node. AST is based on the IEEE 802.1 standard.

ASTA:

Advanced Software Technology and Algorithms: Component of the HPCC (High-Performance Computing and Communications) program used to develop software and algorithms for implementation on high-performance computer and communications systems.

ASYMMETRICAL:

Refers to different data rates in the upstream and downstream directions, where upstream is the direction from the user to the network, and downstream is the direction from the network to the user.

ASYMMETRICAL MODULATION:

A technique in which a high speed MODEM divides a channel and simulates full duplex transmission by using the majority of the bandwidth for transmission in one direction, while using a smaller bandwidth portion for information flowing in the opposite direction.

ASYNCHRONOUS / ASYNCHRONOUS TRANSMISSION:

1) Data flow containing start & stop bits - During the transmission of data each character (7/8 bit ASCII character) is preceded a by a Start bit (spacing pulse, no current) followed by a Stop bit (marking pulse, current). These leading and lagging bits are referred to as framing bits, and allow the random transmission of individual characters. Contrast this concept with synchronous.

2) A term describing digital signals that are transmitted without precise clocking: Such signals generally have different frequencies and phase relationships

ASYNCHRONOUS TRANSFER MODE (ATM):

International Integrated Services Digital Network (ISDN) high-speed, high-volume, packet switching transmission protocol standard: ATM uses short, uniform, 53-byte cells to divide data into efficient, manageable packets for ultra-fast switching through the communications network. The 53-byte cells contain a 5-byte destination address header and 48 data bytes. ATM supports integrated voice, video, and data communications applications. ATM currently accommodates transmission speeds from 64 Kbps to 622 Mbps.

ASYNCHRONOUS TRANSFER MODE ADAPTATION LAYER (AAL and AALA):

A series of protocols, which enables the Asynchronous Transfer Mode (ATM) to be compatible with virtually all of the commonly used standards for voice, data, image, and video.

AT:

Advanced Technology

AT&T:

See American Telephone and Telegraph Company

AT&T INFORMATION SYSTEMS:

See ATTIS

ATB:

All Trunks Busy: The state of a trunk group when all trunks are in use. The trunk group cannot accept any new inbound or outbound calls in this state. The ICM (Intelligent Call Management) tracks the amount of time during which all trunks in a trunk group are busy.

ATCP:

AppleTalk Control Protocol: The protocol that establishes and configures AppleTalk over PPP (Point-to-Point Protocol), as defined in RFC 1378.

ATDM:

Asynchronous Time-Division Multiplexing: A method of sending information that resembles normal TDM (Time-Division Multiplexing), except time slots are allocated as needed rather than pre-assigned to specific transmitters.

ATC:

AUTODIN Terminal Controller: Capacity of 1287 channels each; three on-line, one on stand-by; replaced the ADU, BCU and BBU.

ATCSW:

AUTODIN Terminal Controller-Line Switching Interfaces: Provided the on-line or off-line switching capability for ATC.

ATG:

Address Translation Gateway: Cisco DECnet routing software function that allows a router to route multiple signals to independent DECnet networks and to establish a user-specified address translation for selected nodes between networks.

ATH:

Attention Hang-up.

ATM:

Asynchronous Transfer Mode: The international standard for cell relay in which multiple service types (such as, voice, video or data) are conveyed in fixed-length (53-byte) cells. Fixed-length cells allow cell processing to occur in hardware, thereby reducing transit delays. ATM is designed to take advantage of high-speed transmission media, such as E3, SONET, and T3.

See Asynchronous Transfer Mode

ATM ARP SERVER:

Asynchronous Transfer Mode /Address Resolution Protocol: A device that provides address-resolution services to LIS(s) (Logical IP Subnet) when running classical IP (Internet Protocol) over ATM.

ATM edge LSR:

Asynchronous Transfer Mode edge Label Switch Router: A router that is connected to the ATM-LSR cloud through LSC-ATM (Label Switch Controller-ATM) interfaces. The ATM edge LSR adds labels to unlabeled packets and strips labels from labeled packets.

ATM ENDPOINT:

Asynchronous Transfer Mode Endpoint: The point in an ATM network where an ATM connection is initiated or terminated. ATM endpoints include ATM-attached workstations, ATM-attached servers, ATM-to-LAN (Local Area Network) switches, and ATM routers

ATM FORUM:

Asynchronous Transfer Mode International organization jointly founded in 1991 by Cisco Systems, NET/ADAPTIVE, Northern Telecom, and Sprint that develops and promotes standards-based implementation agreements for ATM technology. The ATM Forum expands on official standards developed by ANSI and ITU-T, and develops implementation agreements in advance of official standards.

ATM LAYER:

Asynchronous Transfer Mode Service-independent Sub-layer of the data link layer in an ATM network. The ATM layer receives the 48-byte payload segments from the AAL (ATM Adaptation Layer) and attaches a 5-byte header to each, producing standard 53-byte ATM cells. These cells are passed to the physical layer for transmission across the physical medium.

ATM LITE:

Asynchronous Transfer Mode Entry-level Port adapter for Cisco 7500 and 7200 routers: The Cisco ATM Lite port adapter does not support traffic shaping or ABR (Available Bit Rate).

ATM-LSR:

Asynchronous Transfer ModeA’ Label Switch Router with several LSC-ATM (Label Switch Controller-ATM) interfaces. The router forwards the cells among these interfaces using labels carried in the VPI/VCI (Virtual Path Identifier / Virtual Channel Identifier) field of the cells.

ATM NETWORK:

Asynchronous Transfer Mode Network: Traditional Cisco ATM network built around BPX switches.

ATM NIC:

Asynchronous Transfer Mode Network Interface Card

ATM USER-USER CONNECTION:

A connection created by the ATM (Asynchronous Transfer Mode) layer to provide communication between two or more ATM service users, such as ATMM processes. Such communication can be unidirectional, using one VCC (virtual channel connection), or bidirectional, using two VCC(s).

ATMM:

Asynchronous Transfer Mode management: A process that runs on an ATM switch that controls VCI (Virtual Channel Identifier) translation and rate enforcement.

ATOM:

An evolving protocol for syndication and sharing of content: Atom is being developed as a successor to and improvement over RSS (Rich Site Summary) and is more complex than RSS while offering support for additional features such digital signatures, geographic location of author, possibly security/encryption, licensing, etc.
Like RSS (Rich Site Summary), Atom is an XML (Extensible Markup Language) based specification.

ATP:

1) ALPS Tunneling Protocol. A protocol used to transport ALPS (Airline Product Set) data across a TCP/IP network between an ALC/UTS router and an AX.25/EMTOX router. It consists of a set of messages (or primitives) to activate and deactivate ALPS ATP circuits and to pass data.

2) AppleTalk Transaction Protocol: A transport-level protocol that provides a loss-free transaction service between sockets. The service allows exchanges between two socket clients in which one client requests the other to perform a particular task and to report the results. ATP binds the request and the response together to ensure the reliable exchange of request-response pairs.

ATTACHED RESOURCE COMPUTER NETWORK (ARC-net):

Refers to Data-point Corporation's 2.5 Mbps base-band, token-passing, media-access protocol

ATTACHED RESOURCE COMPUTER NETWORK PLUS (ARC-net-Plus):

Refers to Data-point Corporation's 20 Mbps base band, token passing and media access protocol

ATTACHMENT UNIT INTERFACE (AUI):

The Institute of Electrical and Electronic Engineers (IEEE) 802.3 cable and connector specifications for connecting devices to a Media Access Unit (MAU)

ATTACK:

An attempt to subvert or bypass a system's security; Attacks may be passive or active. Active attacks attempt to alter or destroy data. Passive attacks try to intercept or read data without changing it.

ATTENUATE / ATTENUATION:

A general term used to denote deterioration or decrease in signal magnitude or quality. It may be expressed as a ratio, or by extension of the term, in decibels. Contrast this with gain.

ATTIS:

AT&T Information Systems: A division of AT&T that manufactures and supplies Customer Premises Equipment (CPE).

ATTRIBUTE:

For files: information that indicates whether a file is read-only, hidden, ready for archiving (backing up), compressed, or encrypted, and whether the file contents should be indexed for fast file searching.

ATU-C:

Termination Unit - Central Office: The device located at the end of an ADSL line that is connected between the line and the first item of equipment in the telephone switch. It can be integrated within an access node.
ATU-R:

Termination Unit – Remote: The device located at the end of an ADSL line that is connected between the line and the first item of equipment in the subscriber's premises. It may be integrated within an access node.

ATX:

Advanced Technology Extended: A power supply specification; specific to a motherboard type

AU:

Access Unit: A device that provides ISDN (Integrated Services Digital Network) access to PSN(s) (Packet-Switched Network)

AUDIO FREQUENCIES:

Frequencies that can be received (heard) by the human ear, usually in the range of 30 to 20,000 Hz

AUDIO INPUT DEVICE:

An audio input device records music and voice input into your computer. Examples of audio input devices are CD-ROM and microphones.

AUDIO RESPONSE UNIT:

A ‘Voice Answer Back device’, digitally controlled, that gives word responses to persons entering data, usually from a keyboard.

AUI:

Attachment Unit Interface: An IEEE 802.3 interface between a MAU (Media Attachment Unit) and a NIC (Next Hop Server). The term AUI also can refer to the rear panel port to which an AUI cable might attach; also called transceiver cable.

See Attachment Unit Interface

AUP:

Acceptable Use Policy: Many transit networks have policies that restrict the usage on a network; the enforcement of AUP(s) varies with the network.

AURP:

AppleTalk Update-Based Routing Protocol: A method of encapsulating AppleTalk traffic in the header of a foreign protocol, allowing the connection of two or more non-contiguous AppleTalk inter-networks through a foreign network to form an AppleTalk WAN (Wide Area Network). This connection is called an AURP tunnel. In addition to its encapsulation function, AURP maintains routing tables for the entire AppleTalk WAN by exchanging routing information between exterior routers.

AURP TUNNEL:

AppleTalk Update-Based Routing Protocol Tunnel: A connection created in an AURP WAN (Wide Area Network) that functions as a single, virtual data link between AppleTalk inter-networks physically separated by a foreign network.

AUSM:

ATM User Service Module

AUTHENTICATION:

The process for verifying an entity or object: Examples include confirming the source and integrity of information, such as verifying a digital signature or verifying the identity of a user or computer.

AUTHORITY ZONE:

Associated with DNS (Domain Name System); an authority zone is a section of the domain-name tree for which one name server is the authority.

AUTHORIZATION:

1) The process that determines what a user is permitted to do on a computer system or network.

2) The method for remote access control, including one-time authorization or authorization for each service, per-user account list and profile, user group support, and support of IP (Internet Protocol), IPX (Inter-network Packet Exchange), ARA (AppleTalk Remote Access), and Telnet.

AUTO ANSWER:

Refers to a MODEM that automatically sends an answering tone in response to an incoming call

AUTO DIAL (Dialer):

Refers to a MODEM that automatically originates a call by dialing the requested number

AUTO PARTITION:

A 10 Base T feature: When a port in a hub or concentrator senses 32 consecutive workstation or network segment collisions, or when a received packet far exceeds the maximum allowable length, the port stops forwarding packets. The port continues to monitor traffic and will automatically begin normal packet forwarding when the first correct packet is received

AUTO RESTART (AUTOMATIC - RESTART):

The capability of a computer to perform automatically the initialization functions necessary to resume operations following an equipment or power failure.

AUTOBAUD or AUTOMATIC BAUD RATE DETECTION (ABR):

A receiving device that can accept data from a variety of devices, operating at different speeds and code levels (minus or plus start/stop bits). ABR usually relies on a sign on character (flag) to provide the information needed to make the necessary adjustments.

AUTODIN:

   Automatic Digital Network (other options: Automatic Digital Information Network or AUTOmated Distributive Intelligence Network) - A closed network of computer based Message Switching Centers installed in the Continental United States (CONUS) and overseas, for the Department of Defense (DoD) and Defense Communications Agency (DCA). Norton AFB in San Bernardino, California was the first AUTODIN site to go on line in November of 1962. There were originally nine CONUS (Continental United States) AUTODIN Centers and fifteen overseas sites, although not all the overseas sites were active at the same time. All the centers, except three, have been closed as of January 2001.

   The AUTODIN system (ASC) is a computer controlled store-and-forward message switching communications system. The ASC is capable of transmitting and receiving message traffic, to and from another ASC or Terminals at transmission rates of 45.5 to 4800 baud. A wide variety of terminal devices are used, which included: Teletypewriters, Punched Card machines, Cathode Ray Tube Terminals, Magnetic Tape Terminals, and other computers. Several code sets are used, such as, ITA2 (Baudot), ASCII and Hollerith (modified). Code translation is performed in order to accommodate the variety of terminals.

AUTOFAC:

AUTODIN Facility: The name given by the Army to the test bed located in Bldg 1671, at the 1110th Signal Battalion, Ft. Detrick, MD.

AUTOLEX:

AUTODIN Online Exerciser (replaced OLEX): Each time the CDP processing cycle reach the end of a current cycle and was waiting for I/O (Input/Output) device terminations, this maintenance exerciser program would be called into the processor. One of the OLEX main tests was to ripple core memory looking for BTPE (Bus Transmission Parity Errors). OLEX was gradually expanded over time to test other areas of the CDP logic.

AUTOMATED PACKET RECOGNITIION TRANSLATION (APaRT):

Technology that allows a server to be attached to CDDI (Copper Distributed Data Interface) or FDDI (Fiber Distributed Data Interface) without requiring the reconfiguration of applications or network protocols: APaRT recognizes specific data link layer encapsulation packet types and, when these packet types are transferred from one medium to another; translates them into the native format of the destination device.

AUTOMATIC ALTERNATIVE ROUTING (AAR):

A system, which provides continued telecommunications service in the event that a primary transmission route has a catastrophic failure.

AUTOMATIC BAUD RATE DETECTION (AUTOBAUD):

A function of a data TDM (Time Division Multiplex) that cause data rate speed self-adjustment to match the received data rate at the TDM ports. Typically used when connecting a dial-up modem to a port of a remote TDM.

AUTOMATIC CALL DISTRIBUTOR:

See ACD

AUTOMATIC CALL RECONNECT:

A feature that permits automatic call rerouting around a failed trunk line

AUTOMATIC CALLING UNIT (ACU):

A device designed to place a telephone call automatically upon receipt of information from some form of Data Terminal Equipment (DTE).

AUTOMATIC CIRCUIT ASSURANCE: (ACA)

A Private Branch Exchange (PBX) feature that traces and identifies malfunctioning trunk lines.

AUTOMATIC CONFIGURATION:

Automatic configuration provides the features that allow networks to readjust in the event of a link or device failure, which enables the network to continue operation.

AUTOMATIC DIALING UNIT (ADU):

Automatic Calling Unit/Automatic Dialer - A device that is programmed with frequently called numbers, which allows the caller to dial one to three digits and the preprogrammed number is automatically dialed.

AUTOMATIC DISPLAY PROCESSOR (ADP):

   The Automatic Display Processor was interchangeably called "AUTODIN Display Processor" by some including the manufacturer. However it has been determined the correct definition of the ADP was "Automatic Display Processor” as indicated in the official AUTODIN documentation.

   The ADP continuously polled each piece of equipment (peripheral Devices) within the ASC (Automatic Switching Center) to determine the equipment's runtime status. When a peripheral device was inoperative (failed state), the ADP issued the appropriate printout to the SCMP (Systems Console Monitor Printer) to advise the SC operator. The actual removal of a device was performed by the CDP (Communications Data Processor) per instruction input from the SC operator.

AUTOMATIC ERROR CORRECTION:

An error detection and correction technique: Requires special codes, bit patterns (additional added bits) or automatic retransmission. The receiving device may correct the error if sufficient information is included or appended to the transmitted data; a Forward Error Correction function.

AUTOMATIC IDENTIFICATION OF OUTWARD DIALING (AIOD):

A PBX service feature that identifies the calling extension, permitting cost allocation

AUTOMATIC LINE BUILD OUT (ALBO):

A function of allowing the Data Service Unit (DSU) and Channel Service Unit (CSU) to automatically adjust signal output based on the line distance.

AUTOMATIC MESSAGE ACCOUNTING:

See AMA

AUTOMATIC RECOVERY:

Refers to a system recovery function: A device or system feature that initiates a restart of the switched message flow after a fatal system failure: The recovery process could be automatic or started by an operator response through the use of stored processing and communications records.

AUTOMATIC REPEAT REQUEST (ARQ):

A software or hardware feature that automatically initiates a request for retransmission when a data transmission error is detected; Or a control character (NAK) or sequence sent to a transmitting location for automatic retransmission of the previous data set.

AUTOMATIC ROUTE SELECTION:

A Private Branch Exchange (PBX) feature: Automatically selects the lowest cost network routing for a connection call request.

AUTOMATIC ROUTING MANAGEMENT (AutoRoute):

The connection-oriented mechanism used in Cisco WAN (Wide Area Network) switches to provide connectivity across the network. These switches perform a Connection Admission Control (CAC) function on all types of connections in the network. Distributed network intelligence enables the CAC function to route and reroute connections automatically over optimal paths while guaranteeing the required QoS (Quality of Service).

AUTOPOLLING:

A function of automatically polling terminals (stations) for input or receive status, usually in a sequential order. The host computer, communication computers (front end), multiplexers, concentrators, etc. may perform this action.

AUTONOMOUS CONFEDERATION:

A group of autonomous systems that rely on their own network availability and routing information more than they rely on that received from other autonomous systems or confederations.

AUTOMOMOUS SWITCHING:

A feature on Cisco routers that provides faster packet processing by allowing the Cisco-Bus to switch packets independently without interrupting the system processor

AUTOMONITOR:

Refers to a procedure where a computer produces a record of its data processing operations for study and analysis purposes.

AUTO-RCONFIGURATION:

The process performed by nodes within the failure domain of a Token Ring network. Nodes automatically perform diagnostics in an attempt to reconfigure the network around the failed areas.

AUTOSEVOCOM:

Automatic Secure Voice Communications Network

AUTOVON:

4-wire dial-up circuits used for connecting communications lines and equipment

AUXILIARY EQUIPMENT:

See Ancillary Equipment

AUXILIARY STORAGE (SECONDARY):

A device or media, which is normally capable of holding a larger amount of information than the main memory of the computer, usually with slower access, time. See Secondary storage.

AVAILABILITY:

A percentage measurement: A measurement of the time when computer equipment, system, or network data communication service is available. The percentage is generally expressed as the ratio of satisfactory operating time versus down time.

AVBO:

Advanced Voice Busy-out: The local voice busy-out feature that provides a way to busy out a voice port or a DS0 group (time slot) if a state change is detected in a monitored network interface(s). When a monitored interface changes to a specified state, out-of-service, or in-service, the voice port presents a seized/busy-out condition to the attached PBX (Private Branch Exchange) or other Customer Premises Equipment (CPE). The PBX or other CPE can then attempt to select an alternate route. AVBO adds the following functionality to the local voice busy-out feature:

·         For Voice over IP (VoIP): Monitors links to remote, IP-addressable interfaces through the use of a Real Time Reporter (RTR).

·         Configuration by voice class to simplify and speed up the configuration of voice busy-out on multiple voice ports.

·         Local voice busy-out is supported on analog and digital voice ports using Channel-Associated Signaling (CAS).

AVD:

See Alternate Voice Data

AVERAGE RATE:

An average rate, in kilobits per second (kbps), at which a given virtual circuit can transmit

AVI:

Audio Video Interleaved: A Microsoft video format where audio and video coding appears in alternate segments. AVI files will end with an .avi extension.

AVM:

ATM (Asynchronous Transfer Mode) Voice Multiplexer

AW:

1) Administrative Weight: The value set by the network administrator to indicate the desirability of a network link: One of four link metrics exchanged by PTSP(s) (PNNI Topology State Packet) to determine the available resources of an ATM (Asynchronous Transfer Mode) network.

2) Administrative Workstation: A personal computer used to monitor the handling of calls in the ICM (Intelligent Call Management) system. The AW also can be used to modify the system configuration or scripts.

See Administrative Weight

AWG:

American Wire Gauge: The standard used to define wire size in communication lines or other media; the smaller the number the larger the wire.

AX.25:

X.25 implementation based on a CCITT 1984 recommendation using Permanent Virtual Circuits (PVC(s)) only. There is one nonstandard aspect of this protocol: packets can be sent with the m-bit set, which means the size of the packet is less than the maximum packet size for the virtual circuit.