Glossary-C
A Data Communication Historical Series
By Bob Pollard

HOME                       INDEX

C BAND:

The portion of the electromagnetic spectrum used for satellite and microwave transmission with frequencies of approximately 6/4 GHz (giga hertz).

C CONDITIONING:

A type of line conditioning that controls attenuation, distortion, and delay distortion so they are maintained within specific limits.

C CONNECTOR:

A coaxial cable connector that uses a bayonet lock

CA:

1) Certification Authority: Entity that issues digital certificates (especially X.509 certificates) and vouches for the binding between the data items in a certificate.

2) Telecommunications: Call Appearance

CA CERTIFICATE:

Digital certificate for one CA (Certification Authority) issued by another CA

CABA:

Computerized Automatic Board Analyzer - An automatic Circuit Card (Board) analyzer and repair device utilized for the testing, analysis and repair of circuit cards.

CABINET:

A physical stand or enclosure designed to rack-mount data equipment and provide easy access to both front and rear panels.

CABLE:

An assembly of one or more wires (conductors) enclosed by a protective covering and constructed to permit the use of the wires separately, in pairs or in a group. In some cases the cable may have a metallic grounded housing in order to eliminate outside interference

(1) A stranded conductor with or without insulation or cover.

(2) Conductors insulated from one another as a multi-conductor cable.

(3) In fiber optics, a single or jacketed bundle of fiber(s) in a form that can be terminated.

CABLE BASED LAN:

A local area network (LAN) that uses a coaxial or twisted pair cable as its transmission medium

CABLE LOADING:

A process where electrical coils are added at specific intervals along a communications cable in order to improve transmission quality

CABLE MODEM:

A device (MODEM): Connected between a Personal Computer and an analog cable TV distribution facility. It allows cable TV companies to provide data transmission capabilities to customers over the existing infrastructure. Access speeds vary greatly, with a maximum throughput of 10 megabits per second (mbps).

CABLE PLANT:

A central location where cabling, connectors, circuit splices, patch panels and equipment is installed

CACHE / CACHE MEMORY:

A section of computer memory, previously loaded with (contains) the next most likely instruction or sequence of instructions to be executed following the completion of the present instruction(s) (operation).

CABLE RANGE:

Range of network numbers that is valid for use by nodes on an extended AppleTalk network: The cable range value can be a single network number or a contiguous sequence of several network numbers. Node addresses are assigned based on the cable range values.

CABLE ROUTER:

Modular chassis-based router optimized for data-over-CATV Hybrid Fiber-Coaxial (HFC) applications

CAC:

Connection Admission Control: Set of actions taken by each ATM (Asynchronous Transfer Mode) switch during connection setup to determine whether a connection's requested QoS (Quality of Service) will violate the QoS guarantees for established connections. CAC also is used when routing a connection request through an ATM network.

CACHING:

 A method of temporarily storing frequently accessed data in RAM or a special area of a hard disk drive, which allows higher speed processing. With sufficient storage, processor and backup memory, a storage system also supports write caching temporary storage where data is held for a short time before being written on disk for permanent storage.

CADP:

Computer Analysis and Diagnostic Programming: A Western Union/TII programming group that was located in Mahwah, New Jersey.

CAF:

Controllable ATM (Asynchronous Transfer Mode) Fabric

CALCULATED PLANNING IMPAIRMENT FACTOR (ICPIF):

Loss/delay busy-out threshold: The ICPIF numbers represent predefined combinations of loss and delay. Packet loss and delay determine the threshold for initiating the busy-out state.

CALIFORNIA EDUCATION AND RESEARCH FEDERATION NETWORK (CERFnet):

TCP/IP (Transmission Control Protocol / Internet Protocol) network, based in Southern California that connects hundreds of higher-education centers inter-nationally while also providing Internet access to subscribers

CALL (Polling):

Refers to a request to connect or be connected for either voice or data transmission.

CALL ACCOUNTING:

The recording of data pertaining to start/end times, number of segments, NUI, NTN etc., in packet-switched networks.

CALL ADMISSION PREFERENCE:

An MPLS (Multi-protocol Label Switching) traffic engineering tunnel with a higher priority will, if necessary, preempt an MPLS traffic engineering tunnel with a lower priority. Tunnels that are harder to route are expected to have a higher priority and may preempt tunnels that are easier to route. The assumption is that a lower-priority tunnel can find another path.

CALL AGENT:

An intelligent entity in an IP (Internet Protocol) telephony network that handles call control in an MGCP (Media Gateway Control Protocol) Voice over IP (VoIP) network Also known as a Media Gateway Controller (MGC).

CALL DETAIL RECORDING (CDR):

1) A PBX (Private Branch Exchange) feature where each phone call is logged by time and charges recorded.

2) A record written to a database for use in post-processing activities. CDR files consist of several CDB(s) (Call Detail Block). These activities include many functions, but primarily are billing and network analysis. Cisco Call-Manager writes CDR records to the SQL (Structured Query Language) database as calls are made; this happens in a manner consistent with the configuration of each individual Cisco Call-Manager.

3) Used in the original telephony networks, now extended to mobile wireless network calls, the CDR contains billing information for charging purposes. In a GPRS (General Packet Radio Service) network, the charging gateway sends the billing information within a CDR to the network service provider for each appropriate subscriber.

4) VNS (Virtual Networking Services) record of voice or data SVC(s) (Switched Virtual Circuit), which includes calling and called numbers, local and remote node names, data and time stamp, elapsed time, and Call Failure Class fields.

5) Wireless: Used in the original telephony networks and now extended to mobile wireless network calls. The CDR contains billing information for charging purposes. In a GPRS (General Packet Radio Service) network, the charging gateway sends the billing information within a CDR to the network service provider for each subscriber.

CALL FORWARDING:

A telephone service: Can be programmed to automatically forward incoming calls to another number.

CALL LEG:

Discrete segment of a call connection: A call leg is a logical connection between the router and either a telephony endpoint over a bearer channel, or another endpoint using a session protocol.

CALL PRIORITY:

Priority assigned to each origination port in circuit-switched systems. This priority defines the order in which calls are reconnected. Call priority also defines which calls can or cannot be placed during a bandwidth reservation.

CALL SETUP TIME:

In data communications this term would normally refer to the length of time it takes to establish a switched call between two devices/terminals.

CALL WAITING or CAMP-ON:

Refers to a telephone service, which places a hold on a call to a busy telephone and a tone notifies the busy telephone that a call is waiting. Or a Local Area Network (LAN) feature that allows a user to wait in a queue if the requested resource is busy. Once the resource becomes available connections are accomplished on a first come first serve basis.

CALLED CHANNEL:

A channel that can receive a call, but cannot originate a call; a calling channel can call, but not receive calls, while a called/calling channel can both originate and receive calls. These examples are found in both LAN and packet-switched networks.

CALLED STATION:

A polled or selected station (terminal) to which a message or a data transmission is routed.

CALLED SUBSCRIBER ID (CSID) String:

An ID string that identifies the Called Subscriber; an ID transmitted by the receiving fax machine when receiving an inbound fax. This string is usually a combination of the fax or telephone number and the name of the business. It is often the same as the transmitter subscriber ID.

CALLING DEVICE:

A device that automatically generates the necessary dialing pulses for establishing a connection in an automatic telephone switching system.

CALLING RATE:

The average number of calls per telephone; determined by dividing the number of busy-hour calls by the number of telephones.

CALLING STATION:

A station (terminal) that initiates a telephone call or a connection for message or data transmission.

CAM:

1) Content-Addressable Memory (Associative Memory): Memory that is accessed based on its contents, not by memory address

2) Cisco Access Manager

CAMP ON:

Refers to holding an incoming call for a busy line until the line becomes available; Refer to Call Waiting

CAMS: Classified AUTODIN Mail Server

CAN:

A data control character: A transmitting terminal would send a “CAN” (cancel) character to direct the receiving terminal to discard the message (block) being received.

CAP:
1) Carrier-less Amplitude/Phase modulation: Incoming data modulates a single carrier that is then transmitted via a telephone line. The carrier itself is suppressed before transmission since it contains no information and can be reconstructed at the receiver, hence the term ‘carrier-less’. CAP and DMT are two modulation schemes for ADSL.

2) Competitive Access Provider: An independent company providing local telecommunications services mainly to business customers in competition with an area's BOC (Bell Operating Company) or IOC (Independent Operating Company). Teleport and MFS are the two major CAP(s) operating in major metropolitan areas in the United States.

CAPACITANCE (Capacitor):

The ability to store an electrical charge (voltage) or an electrical component that can store an electrical charge

CAPACITY:

The highest possible reliable transmission speed (bit rate), that can be carried on a channel, circuit, or piece of equipment. Capacity may be expressed as total speed or throughput.

CAPTURE:

1) To assign a port to a printer; Documents for printing are sent to the printer through the captured port. 2) For a Network Monitor; the process for copying frames.

CAR:

1) Committed Access Rate: The CAR and DCAR (Distributed CAR) services limit the input or output transmission rate on an interface or sub-interface based on a flexible set of criteria.

2) Cisco Access Registrar: Provides RADIUS (Remote Authentication Dial-In User Service) to DOCSIS (Data-over-Cable Service Interface Specifications) MODEM(s) for the deployment of high-speed data services in a one-way cable plant requiring Telco-return for upstream data.

CARD, CARD MODULE or CIRCUIT CARD:

‘Card’ – A 12 row IBM card or an Electronic Accounting Machine (EAM) card, See IBM or EAM; ‘Card, Card Module or Circuit Card’ - A printed circuit board designed to plug into a computer or device chassis (slot).

CARD COLUMN:

Refers to a single column on a tabulating card (IBM or EAM); a punched column would contain only one alphanumeric character or special code.

CARD DIALER:

A combined desk top automatic dialer and telephone unit. Telephone numbers are coded on a plastic card, which is inserted in the dialer slot for automatic dialing or the card could be used for entering fixed data into a data processing system.

CARD FIELD:

1) A pre-assigned set of card columns, into which the same information is regularly punched.

2) Identifies a given section (portion) of the card.

CARD PUNCH:

A device that punches a card sequentially by columns based on the designated input data.

CARRIAGE RETURN:

See CR

CARRIER:

1) A continuous pre-determined frequency (Hz), that can be modulated by a voice or a data signal carrying information.

2) A voice grade channel (line / band / facility) or larger may be divided in sub carrier frequencies. Example: a voice grade channel provides a bandwidth of 4000 Hz with, depending on the equipment, a usable range which would probably fall between 300 to 3600 Hz. At first this 3600 Hz line bandwidth was divided into individual low speed 300 Hz channels (bands), with a buffer frequency of 10 to 30 Hz between each channel (band). This would provide 10 individual channels over one voice grade line. Later, as equipment and conditioning capabilities improved, and considering Bit Per Second Rates (bps) and type of equipment used, this was increased to 20 (approximately 150Hz channels). The individual sub channels would normally have a Carrier device, or the later developed MODEM, on each end of the individual sub channel. The lowest frequency (bandwidth) was used for the lowest Bit per Second rates. If the Bit Per Second rate of most of the sub channels was at the low end (50-WPM) more than 30 sub channels (bands) could be placed on the voice grade channel (line). There could be an intermix (bps rates) of sub channel bandwidths, low, medium and high speeds, and the number that could be accommodated on a voice grade channel would be determined by the frequency requirement for each sub channel

3) Carrier Device: pre MODEM modulator-demodulator device.

4) Depending on a person’s age, the term Carrier may also be used to specify a MODEM by maintenance personnel i.e. the 300 Hz channel (line) has a Carrier on each end.

5) The term Carrier is used to identify a provider of lines and equipment or telephone service, ‘Common Carrier’.

6) Carrier Systems – Describes a network of wires and / or equipment, such as, electrical house wire or the electrical grid used by Power Companies or equipment designed to support the operation.

7) The term Carrier may refer to a provider of good and services (non-communication).

8) Carrier:  A holder used for storing, transporting, hauling, and testing electronic devices that protects them from physical damage.

CARRIER ACCESS CODE (CAC):

The sequence an end user dials to select access to the switched services of a carrier. Carrier Access Codes for Feature Group D are composed of five digits, in the form 10XXX, where XXX is the Carrier Identification Code.

CARRIER ACCESS LINE CHARGE (CALC):

A per minute charge paid by long distance companies to local phone companies for the use of local public switched networks at either or both ends of a long distance call.

CARRIER CIRCUIT:

Transmission systems carrying High level circuits, such as DS-1, DS-3, to lower-level circuits, such as DS-0 and DS-1 systems.

CARRIER, DATA:

A frequency or tone that will be modulated by the information data stream; See Carrier.

CARRIER - DETECT (CD):

An RS-232 MODEM interface signal (Received Line Signal Detector ‘pin 8’) that indicates the local MODEM is receiving a signal from the remote MODEM; may also be called the Data Carrier Detect (DCD) signal.

CARRIER DEVICE:

The original MODEM since the Carrier device was a modulator-demodulator used on telephone (voice grade) facilities. The Carrier did not have protocol functions such as, RS232 signal and connection specifications, but did have the capability to accommodate different terminal operational functions.

CARRIER IDENTIFICATION CODE (CIC):

The three-digit number that uniquely identifies a carrier: The Carrier Identification Code is indicated by XXX in the Carrier Access Code dialed by customers in the form 10XXX. The same code applies to an individual carrier throughout the area served by the North American Numbering Plan.

CARRIER - SENSE MULTIPLE ACCESS(s):

See CSMA

CARRIER SENSE MULTIPLE ACCESS with COLLISION AVOIDANCE:

See CSMA/CA

CARRIER SENSE MULTIPLE ACCESS with COLLISION DETECTION:

See CSMA/CD

CARRIER SYSTEM:

1) A multi-channel telecommunications system in which a number of individual circuits (data, voice, or combination) are multiplexed for transmission between two points. In carrier systems, many different forms of multiplexing may be used, such as time division multiplexing and frequency division multiplexing.

2) A network consisting of house wiring or power company grid.

3) The equipment configured to operate a network.

CARRIER WAVE:

A sine wave (AC), alternating from positive to negative. The length of time it takes to go from the start point (0) to finish (0), with half the sine wave positive and half negative will be dictated by the frequency. The higher the frequency the narrower the sine wave, a shorter time from 0 to 0. Frequency (Hz) and amplitude (power level) are the basic terms when discussing carrier waves. Frequency is measured in the number of sine waves per second (Hz).

CARTERPHONE DECISION:

The 1968 FCC decision which held that existing telephone company tariffs containing blanket prohibition against the attachment of customer provided terminal equipment to the telecommunications network were unreasonable, discriminatory and unlawful. The FCC declared the telephone companies could set up reasonable standards for interconnection to insure the technical integrity of the telephone network. Following the Carter-phone Decision, the telephone companies filed tariffs for protective connecting arrangements to facilitate the interconnection of customer provided terminal equipment (CPE).

CARTRIDGE FONT:

A font contained in a plug-in cartridge and used to add fonts to laser, ink-jet, or dot-matrix printers. Cartridge fonts are distinguished both from internal fonts, which are contained in ROM in the printer, and from downloadable (soft) fonts, which reside on disk and can be sent to the printer as needed.

CAS:

Channel Associated Signaling: The transmission of signaling information within the voice channel. CAS signaling often is referred to as ‘Robbed-Bit’ signaling because user bandwidth is being robbed by the network for other purposes.

CASCADING HUBS:

A network configuration in which hubs are connected to other hubs

CASCADING STYLE SHEETS (CSS):

Style Sheets allow a person to control the composition of a Web document without compromising its structure. Example: fonts, colors, leading, margins, typefaces, and other aspects of style. Cascading Style Sheets (CSS) are a simple style sheet mechanism that allows authors and readers to attach style to Web pages. It uses common desktop publishing terminology which should make it easy for all individuals. Visual design issues, such as page layout, can thus be addressed separately from the Web page logical structure.

CATEGORY 1, 2, 3, 4 & 5 CABLING:

Category 1: UTP (Unshielded Twisted Pair) cabling described in the EIA/TIA-586 standard; used for telephone communications and is not suitable for transmitting data

Category 2: UTP (Unshielded Twisted Pair) cabling described in the EIA/TIA-586 standard; capable of transmitting data at speeds up to 4 Mbps.

Category 3: UTP (Unshielded Twisted Pair) cabling described in the EIA/TIA-586 standard; used in 10BaseT networks and can transmit data at speeds up to 10 Mbps

Category 4: UTP (Unshielded Twisted Pair) cabling described in the EIA/TIA-586 standard; used in Token Ring networks and can transmit data at speeds up to 16 Mbps

Category 5: UTP (Unshielded Twisted Pair) cabling described in the EIA/TIA-586 standard; can transmit data at speeds up to 100 Mbps

CATENET:

A network in which the hosts are connected to diverse networks, which themselves are connected with routers example: The Internet

CAT-5:

Category 5: Refers to network cabling that consists of four twisted pairs of copper wire terminated by RJ45 connectors. Cat-5 cabling supports frequencies up to 100 MHz and speeds up to 1000 Mbps. It can be used for ATM, token ring, 1000Base-T, 100Base-T, and 10Base-T networking.

Computers hooked up to LAN(s) are usually connected using Cat-5 cables

CAT 5e:

Category 5e cable is an enhanced version of Cat 5 that adds specifications for ‘far end crosstalk’.

CATHODE RAY TUBE:

See CRT

CATP: (Joke)

Caffeine Access Transport Protocol: Common method of moving caffeine across Wide Area Networks such as the Internet. CATP was first used at the Binary Cafe in Cyber-town and quickly spread world-wide. There are reported problems with short-circuits and rust and decaffeinated beverages are not supported at this time.

CATV:

Cable Television / Community Antenna Television: CATV is one of the most common data communication facilities found on broadband networks and generally uses 75-ohm coaxial cable.

CAUSE CODES:

A code that indicates the reason for an ISDN (Integrated Services Digital Network) call(s) failure or completion.

CAVITY VIRUS:

A cavity virus overwrites a part of its host file without increasing the length of the file while also preserving the host's functionality.

CAW:

Certification Authority Workstation - used to generate the FORTEZZA certificates, previously identified as LAW.

CBAC:

Context-based Access Control: Protocol that provides internal users with secure access control for each application and for all traffic across network perimeters. CBAC enhances security by scrutinizing both source and destination addresses and by tracking each application's connection status.

CBC:

Cipher Block Chaining: Prevents the problems associated with Electronic Codebook (ECB), where every block of ‘plain text’ maps to exactly one block of ‘cipher text’ by having each encrypted block cross-referenced with the previous block of Cipher-text. In this way identical patterns in different messages are encrypted differently, depending upon the difference in the previous data.

CBDS:

Connectionless Broadband Data Service: European high-speed, packet-switched, datagram-based WAN (Wide Area Networking) technology.

CBR:

Constant Bit Rate: A QoS (Quality of Service) class defined by the ATM Forum for ATM networks. CBR is used for connections that depend on precise clocking to ensure undistorted delivery.

CBU:

Character Buffer Unit - See Character Buffers

CBWFQ:

Class-Based Weighted Fair Queue: Extends the standard WFQ functionality to provide support for user-defined traffic classes.

CBX:

See Computerized Branch Exchange

CC:

1) Country Code: Part of a numbering plan

2) Call Context

CCB:

1) Call Control Block.

2) Configuration Control Board

CCIE:

Cisco Certified Inter-network Expert.

CCD:

Charge Coupled Device: one of the two main types of image sensors used in digital cameras. When a picture is taken, the CCD is struck by light coming through the cameras lens. Each of the thousands or millions of tiny pixels that make up the CCD converts this light into electrons. The number of electrons, usually described as the pixels accumulated charge, is measured and then converted to a digital value. This last step occurs outside the CCD, in a camera component called an analog-to-digital converter.

CCIR:

French acronym for International Radio Consultative Committee: An International Telecommunications Union (ITU) body that mainly sets international standards for radio and satellite telecommunications. New designation: ITU-R

CCITT
Comite Consultaif Internationale de Telegraphie et Telephonie (International Telegraph and Telephone Consultative Committee): This is an international committee based in Geneva, Switzerland, that recommends telecommunications standards, including the audio compression/decompression standards (codecs) and the V. standards for modem speed and compression (V.32, V.34, etc.). Although this organization changed its name to ITU-T (International Telecommunications Union-Telecommunication), the Old French name lives on.

CCN UNIT:

Continuous Control Node Unit: Provides communication between the redundant sides of the administration shelf.

CCNA: Cisco Certified Network Associate.

CCO:

Cisco Connection Online: The name of Cisco Systems external Web site.

CCOT:

Cross Office Transfer Time

CCR:

Commitment, Concurrency, and Recovery: OSI (Open Systems Interconnection) application service element used to create atomic operations across distributed systems; used primarily to implement two-phase commitment for transactions and nonstop operations.

CCS:

1) Hundred-call seconds

2) Common Channel Signaling: Signaling system used in telephone networks that separates signaling information from user data. A specified channel is exclusively designated to carry signaling information for all other channels in the system.

CCSA:

Common Control Switching Arrangements – Refers to systems designed for users that have extensive private line communications requirements.

CCSRC:

Cisco Subscriber Registration Center: An integrated function for data-over-cable service providers, allows them to configure and manage broadband MODEM(s), and enables administer subscriber self-registration and activation.

CCSS7:

Common Channel Signaling System 7: Protocol used by the AT&T signaling network. The ICM(s) (Intelligent Call Management) NIC (network Interface Card) receives routing requests from the CCSS7 network and returns a routing label to the CCSS7 network.

CCTC:

Computer-to-Computer Transfer Channel: A high speed transfer media between two computers.

CCTV:

Closed Circuit Television: Two definitions for CCTV:

1) A localized video network limited to specific locations in a building or campus.

2) A LAN environment service often found on broadband networks.

CCU:

Communications Control Unit: A communications computer designed to relieve the host processor of the communications tasks, such as message handling, protocol, controls, code conversion, error control and application functions. In many circumstances this function could be handled by a minicomputer. Other terms: Front End and Communications Processor.

CD:

1) Channel Designator: Part of the ‘Transmission Identifier Line (TI)’, which identifies a particular channel (terminal). See TI.

2) Computer Disk

3) See Carrier Detect

CDB:

Call Detail Block: Consists of several Call Data Elements. The CDB is generated at a Certain Point in Call (PIC). For example, a CDB is generated when the call is answered, released, etc.

CDC:

1) Call Directing Code: Refers to a character or sequence of characters used for terminal selection (calling/polling). See Control Data Corporation (CDC).

2) Control Data Corporation: Provider and manufacturer of Software, Hardware (computers and peripherals) and service.

See Call Directing Code

CDDI:

Copper Distributed Data Interface: CDDI transmits over relatively short distances, about 90 yards / 100 meters, providing data transmission rates of 100 Mbps using dual-ring architecture to provide redundancy; based on the ANSI TPPMD standard.

CDE:

Call Detail Element: A data element that includes a basic information field within a billing record. Examples: Calling number, called number, etc.

CDF:

Channel Definition Format: Technology for ‘push’ applications on the World Wide Web. CDF is an application of XML (Extensible Markup Language).

CDMA:

Code Division Multiple Access: A method of dividing a radio spectrum to be shared by multiple users through the assignment of unique codes. CDMA provides spread spectrum transmission; a digital communication technology used by some carriers to provide PCS (Personal Communication Services), also known as IS-95A or cdmaOne.

Other technologies used are TDMA (Time Division Multiple Access) and GSM (Global Standard for Mobile).

CDP:

1) Communication Data Processor: A Central Processing Unit or main frame, which was the first main frame utilized in the AUTODIN system.

2) Cisco Discovery Protocol: Media and protocol-independent device-discovery protocol that runs on all Cisco-manufactured equipment, including routers, access servers, bridges, and switches. Using CDP, a device can advertise its existence to other devices and receive information about other devices on the same LAN (Local Area Network) or on the remote side of a WAN (Wide Area Network).

CDPD:

Cellular Digital Packet Data: Open standard for two-way wireless data communication over high-frequency cellular telephone channels. Allows data transmissions between a remote cellular link and a NAP (Network Access Point); Operates at 19.2 kbps.

CD-R:

Recordable Compact Disc (disk): Data can be copied to the CD on more than one occasion; however, data cannot be erased from the CD.

CDR:

Call Detail Record:

1) A record written to a database for use in post-processing activities. CDR files consist of several CDB(s) (Call Detail Block). These activities include many functions, but primarily are billing and network analysis. Cisco Call-Manager writes CDR records to the SQL (Structured Query Language) database as calls are made in a manner consistent with the configuration of each individual Cisco Call-Manager.

2) Used in the original telephony networks, and now extended to mobile wireless network calls, the CDR contains billing information for charging purposes. In a GPRS (General Packet Radio Service) network, the charging gateway sends the billing information within a CDR to the network service provider for a particular subscriber.

3) VNS (Virtual Networking Services) record of voice or data SVC(s) (Switched Virtual Circuit), which includes calling and called numbers, local and remote node names, data and time stamp, elapsed time, and Call Failure Class fields.

CD-ROM:

Compact Disc Read-only Memory

CD-RW:

Compact Disc Read/Write / Rewritable Compact Disc (disk): Data can be copied to the CD on more than one occasion and can be erased.

CDMA2000 1X (Also 1xRTT):

A 3G (Third Generation Wireless) wireless communications standard evolved from CDMA (Code Division Multiple Access) technology. It has double the voice traffic capacity of CDMA and provides peak data rates of 153 kbps.

CDMA2000 1xEV-DO (and 1xEV-DV):

A 3G (Third Generation Wireless) wireless communications standard further evolved from CDMA2000 technology. It is a standard optimized for data transmission providing a peak data rate of 2.4 Mbps with a typical user experience of 300 - 800 kbps. 1xEV-DV is optimized for both data and voice transmissions.

CDPD:

Cellular Digital Packet Data: A technology for transmitting data over analog cellular networks: Requires a special MODEM and the wireless carrier network must be upgraded to accommodate the data transmission rates.

CDSL:

Consumer Digital Subscriber Line: A Rockwell International trademarked technology.

CDV:

Cell Delay Variation: A component of cell transfer delay, which is induced by buffering and cell scheduling. CDV is a QoS (Quality of Service) delay parameter associated with CBR (Constant Bit Rate) and VBR (Variable Bit Rate) service.

CDVT:

Cell Delay Variation Tolerance: In ATM (Asynchronous Transfer Mode), a QoS (Quality of Service) parameter for managing specific traffic when a connection is initiated. In CBR (Constant Bit Rate) transmissions, CDVT determines the level of jitter that is tolerable for the data samples taken by the PCR (Peak Cell Rate).

CE ROUTER:

Customer Edge Router: A router that is part of a customer network and interfaces to a Provider Edge (PE) router.

CED:

Caller-Entered Digits: Digits entered by a caller on a touch-tone phone in response to prompts. For instance, peripherals, Automatic Call Distributor (ACD), Public Exchange (PBX), or the carrier network can prompt the CED.

CEF:

Cisco Express Forwarding

CELL PHONE / CELLPHONE / CELLUAR PHONE:

Millions of people in the United States and around the world use cellular phones. With a cell phone, individuals can talk to anyone on the planet from just about anywhere, where a cell tower exists. Depending on the cell phone model the following basic features are provided:

Store contact informatio

Record task or to-do lists

Keep track of appointments and set reminders

Use the built-in calculator for simple math

 Voice mail storage and retrieval

 Send or receive e-mail or text messages

Get information (news, entertainment, stock quotes) from the Internet

Play simple games

Integrate other devices such as PDA’s (Personal Digital Assistant), MP3 (CD) players and GPS (Ground Positioning System) receivers

   A cell phone is actually a radio, although it is an extremely sophisticated radio. Before cell phones individuals who needed mobile-communications ability installed ‘radio telephones’ in their cars. In the radio-telephone system, there was one central antenna tower per city, and perhaps 25 channels available on that tower. This central antenna required the phone in a car to have a powerful transmitter, one powerful enough to transmit 40 or 50 miles. It also restricted the number of people who could use radio telephones concurrently because of the limited number of channels (25).

   The cellular phone system divides a city and outlying areas into small ‘cells’. This allows extensive frequency reuse across broad areas; people can use cell phones simultaneously.

CELL:

The basic data unit for ATM (Asynchronous Transfer Mode) switching and multiplexing. Cells contain identifiers that specify the data stream to which they belong. Each cell consists of a 5-byte header and 48 bytes of payload.

CELLS:

A low powered radio communications system divided into subdivisions, repeater sites or relay stations referred to as ‘cells’ for wireless (cell phones) or mobile telephone service. The cells are normally connected to the local telephone company facilities through the cell carrier.

CELL PAYLOAD SCRAMBLING:

A technique using an ATM (Asynchronous Transfer Mode) switch to maintain framing on some medium-speed edge and trunk interfaces.

CELL RELAY:

Network technology based on the use of small, fixed-size packets, or cells: Because cells are fixed-length, they can be processed and switched in hardware at high speeds. Cell relay is the basis for many high-speed network protocols, including ATM (Asynchronous Transfer Mode), IEEE 802.6, and SMDS (Switched Multi-megabit Data Service).

CELLS PER SECOND:

Abbreviated cps: A data transmission rate measurement

CELLULAR RADIO:

A technology that uses radio transmissions to access telephone-company networks; service is provided in a particular area by a low-power transmitter

CELP:

Code Excited Linear Prediction compression: Compression algorithm used in low bit-rate voice encoding

CEN:

European Committee for Standardization: CEN(s) mission is to promote voluntary technical harmonization in Europe in conjunction with worldwide bodies and its partners in Europe. The organization works in partnership with CENELEC (Comite Europeen de Normalisation Electrotechnique) and ETSI (European Telecommunications Standards Institute).

CENELEC:

Comite Europeen de Normalisation Electrotechnique: CENELEC is the European Committee for Electro-technical Standardization. It was set up in 1973 and was officially recognized as the European Standards Organization in its field by the European Commission.

CENTRAL OFFICE (CO):

Other terms: ‘Exchange’, ‘Local Central Office’, ‘End Office’ or ‘Central Exchange’. A Common Carrier location or building where communications circuits would terminate and/or interconnect and the switching equipment would be located.

CENTRAL PROCESSING UNIT:

See CPU

CENTRALIZED:

Refers to Centralized Processing; a central Processing Unit (CPU), which supports remote terminals and job entry stations.

CENTREX:

LEC (Local Exchange Center) service that provides local switching applications similar to those provided by an onsite PBX (Private Branch Exchange); Centrex provides no onsite switching; all customer connections go back to the CO (Central Office).

CENTRONICS INTERFACE:

Refers to the 36-pin, parallel printer interface, designed by the Centronics Co.

CEP:

Certificate Enrollment Protocol: Certificate management protocol jointly developed by Cisco Systems and VeriSign, Inc. CEP is an early implementation of Certificate Request Syntax (CRS), a standard proposed to the Internet Engineering Task Force (IETF). CEP specifies how a device communicates with a CA (Certification Authority), including how to retrieve the public key of the CA, how to enroll a device with the CA, and how to retrieve a Certificate Revocation List (CRL). CEP uses Public Key Cryptography Standard (PKCS) 7 and PKCS 10 as key component technologies. The Public Key Infrastructure Working Group (PKIX) of the IETF is working to standardize a protocol for these functions.

 CEPT:

Conference of European Postal and Telecommunications: A European standards setting organization that discusses operational and tariff concerns. Membership includes the European Post, Telephone and Telegraphy Authorities.

CER:

Cell Error Ratio: In ATM (Asynchronous Transfer Mode), the ratio of transmitted cells that have errors to the total cells sent in a transmission for a specific period of time.

CERFnet:

California Education and Research Federation Network: TCP/IP (Transmission Control Protocol / Internet Protocol) network, based in Southern California that connects hundreds of higher-education centers inter-nationally while also providing Internet access to subscribers.

CERN:

Refers to the European Organization for Nuclear Research where the web was born.

CERT:

1) Computer Emergency Response Team: Chartered to work with the Internet community to facilitate its response to computer security events involving Internet hosts; to take proactive steps to raise the community's awareness of computer security issues, and to conduct research targeted at improving the security of existing systems.

2) Character Error Rate Testing: line testing using test characters to determine error percentages.

CERTIFICATE:

A digital document that is commonly used for authentication and to insure a secure exchange of information on open networks: Such as the Internet, extranets and intranets. A certificate securely binds a public key to the entity that holds the corresponding private key. Certificates are digitally signed by the issuing certification authority and can be issued for a user, a computer, or a service. The most widely accepted format for certificates is defined by the ITU-T X.509 version 3 international standards. Typically, a permanent storage where certificates, certificate revocation lists and certificate trust lists are stored.

CERTIFICATE REVOCATION LIST (CRL):

A document maintained and published by a certification authority that lists certificates that have been revoked.

CERTIFICATION AUTHORITY (CA):

An entity responsible for establishing and vouching for the authenticity of public keys belonging to users (end entities) or other certification authorities: Activities of a certification authority can include binding public keys to distinguished names through signed certificates, managing certificate serial numbers, and certificate revocation.

CERTIFICATION HIERARCHY:

A model of trust for certificates in which certification paths are created between certification authorities

CES:

Circuit Emulation Service: Enables users to multiplex or concentrate multiple circuit emulation streams for voice and video with packet data on a single high-speed ATM (Asynchronous Transfer Mode) link, without a separate ATM access multiplexer.

CET:

Cisco Encryption Technology

CFRAD:

Cisco Frame Relay Access Device: Cisco product that supports Cisco IOS Frame Relay SNA (Systems Network Architecture) services and can be upgraded to be a full-function multi-protocol router. The Cisco FRAD connects SDLC (Synchronous Data Link Control.) devices to Frame Relay without requiring an existing LAN (Local Area Network). However, the Cisco FRAD does support attached LANs and can perform conversion from SDLC to Ethernet and Token Ring.

CFS:

Communications Frame Structure

CGI:

Common Gateway Interface: A specification which defines how a Web server can communicate with a program (script or binary) that provides complete isolation of the server from the program, for the safety of the server; a set of rules that describe how a Web server communicates with another application running on the same computer and how the application (CGI program) communicates with the Web server. Any application can be a CGI program if it handles input and output according to the CGI standard.

CGI-BIN:  

The most common name for a directory on a web server in which CGI (Common Gateway Interface) programs are stored

CGS:

Communications Gateway System

CHAD:

A small piece of paper tape or punched card removed when punching holes to represent information (characters/symbols).

CHADLESS:

A function of punching paper tape and leaving the ‘chad’ fastened to the hole by not punching the hole completely. The chad is left fastened by about a quarter of the punched hole on the leading edge. Paper tape punched in this manner must be read by mechanical fingers because the clinging chad would interfere with electrical or photoelectric sensing.

CHAIN:

Could refer to a serial connected chain of devices (daisy chain) or a series of linked processing centers where information must pass through each one on a store and forward basis in order to reach the final destination.

CHAINING:

An SNA (Systems Network Architecture) concept in which RU(s) (Request/Response Unit) are grouped together for the purpose of error recovery

CHANNEL:

1) A path for data transmission between two or more points, i.e. computer to Computer, Computer to a disk, tape drive, printer, etc. Or a line, facility or circuit between devices (terminals / stations) may be called a channel.

2) A thin semiconductor layer, between the source region and drain region, in which the current is controlled by the gate potential.

3) Specific frequency allocation and bandwidth

CHANNEL ATTACHED:

Refers to the attachment of devices directly by data channels (input/output channels) to a computer

CHANNEL BANK:

Hardware typically used in a common carrier office that performs the end point multiplexing and de-multiplexing of individual channels to and from a telephone-type carrier system; including provision for supervisory signaling used by telephone switching systems.

CHANNEL COORDINATION:

Normally refers to the interaction between connected communication devices for the purpose of synchronization, exchange of messages (data), controls, etc.

CHANNEL INTERFACE:

See Channel and Interface

CHANNEL LOOPBACK:

A diagnostic test that forms the loop at the multiplexer's channel interface

CHANNEL, PRIMARY:

Refers to the higher speed of two channels, on one voice band, used for data transmission, where the lower speed (reverse) is used for low speed data transmission, Acknowledgments and error control. See Channel, Reverse

CHANNEL, REVERSE:

Refers to the lower speed (reverse) of two channels, on one voice band, normally used for acknowledgments and error control, where the higher speed is used for transmitting data.

See Channel, Primary.

CHANNEL SERVICE UNIT (CSU):

A device used to connect Data terminal Equipment (DTE) to a digital transmission line for Data-phone Digital Service (DDS). The CSU may also be may be part of a Data Service Unit (DSU).

CHANNEL, VOICE GRADE:

A Voice Grade Channel used for the transmission of speech, digital/analog data, or facsimile and normally has a usable frequency range of about 300 to 3300 Hz.

CHANNEL IDENTIFICATION (ID):

Designates the Frame Relay sub-channel ID for Voice over Frame Relay.

CHANNEL INTERFACE PROCESSOR (CIP):

Channel attachment interface for Cisco 7000 series routers. The CIP is used to connect a host mainframe to a control unit, eliminating the need for a FEP (Front End Processor) for channel attachment.

CHANNELIZATION:

Division of a larger capacity channel into a number of smaller channels

CHANNELIZED E1:

Access link operating at 2.048 Mbps that is subdivided into 30 B-channels and 1 D-channel

CHANNELIZED T1:

Access link operating at 1.544 Mbps that is subdivided into 24 channels (23 B channels and 1 D channel) of 64 kbps each: The individual channels or groups of channels connect to different destinations.

CHAP:

Challenge Handshake Authentication Protocol: Security feature supported on lines using PPP (Point to Point Protocol) encapsulation that prevents unauthorized access. CHAP does not itself prevent unauthorized access, but merely identifies the remote end. The router or access server then determines whether that user is allowed access.

CHARACTER:

Any letter, number (alphanumeric), punctuation mark, control character and symbols that may be contained in a message.

CHARACTER BUFFERS (CBU):

First installed (initial) buffer units utilized by the ADU (Accumulation and Distribution Unit); A character at a time was accumulated for transfer to the Data Memory.

CHARACTER DENSITY:

The number of characters that can be stored per unit of length (density), for instance a particular magnetic tape drive may store (record) 1600 bits per linear inch. This could be restated in the number of characters per inch. See BPI (Bits Per Inch)

CHARACTER ERROR RATE TESTING:

See CERT

CHARACTER INTERVAL:

The total number of unit (time) intervals, including synchronizing, intelligence, error checking or control bits required to transmit a character in a communication system. Bits not associated with individual characters are not included in the calculation.

CHARACTER MODE:

A display mode; the monitor can display letters, numbers, and other text characters, but no graphical images or character formatting (italics, superscript, etc.).

CHARACTER ORIENTED:

A communications protocol or transmission procedure that has control information transmitted in the form of special bytes called control characters. Also implies limitation to a particular character code set.

CHARACTER PARITY:

Character integrity is maintained through the use of a character parity bit. Each ASCII data character (7-bits) is transmitted with a following parity bit (8th bit). This parity bit is set to a 1 or 0 in order to ensure the number of one bit’s in the character (including the parity bit) will always be odd. Detection of an even number of one bit’s would result in an error. Even parity could also be used in the ASCII code.

CHARACTER READER:

Devices that can convert typed or hand written script directly into machine language. This may be accomplished optically or magnetically, if magnetic ink is used.

CHARACTER RECOGNITION:

Devices that can sense and encode written or printed material into machine language

CHARACTER SET:

A set (group) of characters (alphanumeric), including special symbols and control functions, for instance the ASCII, Baudot or EBCDIC code sets.

CHARACTER VALIDATION:

In addition to ‘Character Parity’ other means of character validation, or invalidation, may be used. The ITA2 (Baudot) code does not provide for character validation, therefore all characters are considered valid, including invalid characters. The ASCII code does use a character parity bit, which allows detection of invalid characters. In some cases, rather than reject a message because of an invalid or unreadable character, the switching center or terminal will replace the unreadable character with a readable character. Usually an asterisk (*) would be used as a replacement for the invalid character.

CHARACTERISTIC DISTORTION:

A data transmission distortion caused by modulation transients. The levels of characteristic distortion are dependent on the transmission and channel qualities.

CHARACTERS PER SECOND:

See CPS

CHARGED COUPLED DEVICE:

See CCD

CHARGEN:

Character Generation: Via TCP (Transmission Control Protocol), a service that sends a continual stream of characters until stopped by the client. Via UDP (User Datagram Protocol), the server sends a random number of characters each time the client sends a datagram.

CHARSET:

Character Set: Different character sets are used for different purposes such as the different characters used by different languages.

CHAT SCRIPT:

String of text that defines the login ‘conversation’ occurring between two systems: Consists of expect-send pairs that define the string that the local system expects to receive from the remote system and what the local system should send as a reply.

CHEAPERNET:

Industry term used to refer to the IEEE 802.3 10Base2 standard or the cable specified in that standard.

CHECK BIT:

Parity or special purpose bit: One bit of non-information that is added to a transmitted character, creating an odd or even number of 1 bits, which enables the receive terminal (device) to check each character for proper parity; or a bit added to a data block or other network data for a special purpose indicator.

CHECK CHARACTER or DIGIT:

One or more characters or digits inserted or attached to a block of information coded depending on the data in order to detect the occurrence of an error.

CHECK NUMBER:

A number composed of one or more digits used to detect equipment malfunctions during data transfers. The presence of only one digit would be considered a check digit.

CHECKPOINTS:

See Restore Point

CHECKSUM:

The information produced by a mathematical technique used to detect errors that may have been introduced into a data stream. Usually used for low-bit-rate data transmission; an identifying number calculated from file characteristics. The slightest change in a file changes its checksum. An error or manipulated file detection method.

CHILD PEER GROUP:

A peer group for which another peer group is the parent peer group

CHOKE PACKET:

Packet sent to a transmitter to tell it that congestion exists and that it should reduce its sending rate.

CHURN:

Refers to the occurrence of many subscriber additions and deletions

CI:

Cryptographic interface

CIA:

Classical Internet Protocol (IP) over ATM (Asynchronous Transfer Mode): Specification for running IP over ATM in a manner that takes full advantage of the features of ATM.

CIA/CDC:

Central Intelligence Agency / Control Data Corporation: Control Data Corporation 5800 machine Test and Maintenance routines.

CIC:

Refers to prefixes to select different long distance carriers, tie-lines, trunk groups, and WATS (Wide Area Telephone Service) lines; and private number plans, such as seven-digit dialing.

CICS:

Customer Information Control System: IBM application subsystem allowing transactions entered at remote terminals to be processed concurrently by user applications.

CICNet:

Refers to a regional network that connects academic, research, nonprofit, and commercial organizations in the Midwestern United States

CICS:

See Customer Information Control System

CID:

1) Craft Interface Device: Terminal- or PC-based interface that enables the performance of local maintenance operations.

2. Channel Identification (ID): Designates the Frame Relay sub-channel ID for Voice over Frame Relay.

CIDR:

Classless Inter-Domain Routing: Technique supported by BGP4 (Border Gateway Protocol Version 4) and based on route aggregation. CIDR allows routers to group routes together to reduce the quantity of routing information carried by the core routers. With CIDR, several IP (Internet Protocol) networks appear to networks outside the group as a single, larger entity. Example: With CIDR, IP addresses and their subnet masks are written as four octets, separated by periods, followed by a forward slash and a two-digit number that represents the subnet mask.

CIM:

Communications Improvement Memorandum: Configuration Management - A process used to evaluate changes or new releases of products and develop recommendations regarding the implementation of those changes/products as they relate to compatibility, control, options, impacts, etc.

CIO

Chief Information Officer: Responsible for the coordination of investment decisions in the support of new processes and technology.

CIP:  

Channel Interface Processor: Channel attachment interface for Cisco 7000 series routers. The CIP is used to connect a host mainframe to a control unit, eliminating the need for an FEP (Front End Processor).

CIPHER:

Refers to cryptographic algorithm(s) for encryption and decryption

CIPHERTEXT:

Data that has been transformed by encryption so that the data content (meaning) is no longer intelligible or directly available; must be de-encrypted

CIR:

Committed Information Rate: The rate, averaged over a minimum increment of time, at which a Frame Relay network agrees to transfer information under normal conditions. CIR is measured in bits per second and is one of the key negotiated tariff metrics.

CIRCUIT:

A communication line or electrical transmission facility between two devices or points

CIRCUIT CAPACITY (BANDWIDTH):

The number of communications channels (individual devices) which can be handled by a given circuit at the same time.

CIRCUIT CONDITIONING:

Modification of analog data circuits to bring transmission parameters of the channel into narrower limits than provided by randomly selected voice channels. Conditioning is also utilized to a lesser extent in certain other services, which results in reduced error conditions.

CIRCUIT, FOUR WIRE:

Communication circuits with two separate paths (2 wire each path) for simultaneous transmission in both send and receive directions (full duplex). See Four Wire Circuits

CIRCUIT GROUP:

A grouping of associated serial lines that link two bridges: If one of the serial links in a circuit group is in the spanning tree for a network, any of the serial links in the circuit group can be used for load balancing. This load-balancing strategy avoids data ordering problems by assigning each destination address to a particular serial link.

CIRCUIT STEERING:

(Port Snooping): A mechanism used by some ATM (Asynchronous Transfer Mode) switches to eavesdrop on a virtual connection and copy its cells to another port where an ATM analyzer is attached.

CIRCUIT SWITCHING:

Electrical-mechanical process: Physical circuits are automatically connected or switched in order to complete an exclusive use connection. A switching system in which a dedicated physical circuit path must exist between the sender and receiver for the duration of a call: Used primarily in the telephone company networks.

CISC:

Complex Instruction Set Computing: A type of microprocessor design. The CISC architecture contains a large set of computer instructions that range from very simple to very complex and specialized. Though the design was intended to compute complex instructions in the most efficient way, it was later found that many small, short instructions could compute complex instructions more efficiently. This led to a design called Reduced Instruction Set Computing (RISC), which is now the other major microprocessor architecture. Intel Pentium processors are mainly CISC-based, with some RISC facilities built into them, where the PowerPC processors are completely RISC-based.

CISCO BUS CONTROLLER:

Also Switch Processor (SP): Cisco 7000-series processor module that acts as the administrator for all CxBus (Cisco Extended Bus) activities.

CISCO DISCOVERY PROTOCOL (CDP):

Cisco Discovery Protocol: Media and protocol-independent device-discovery protocol that runs on all Cisco-manufactured equipment, including routers, access servers, bridges, and switches. Using CDP, a device can advertise its existence to other devices and receive information about other devices on the same LAN (Local Area Network) or on the remote side of a WAN (Wide Area Network).

CISCO-FUSION:

Refers to Cisco internetworking architecture that ‘fuses’ together the scalability, stability, and security advantages of the latest routing technologies with the performance benefits of ATM (Asynchronous Transfer Mode) and LAN (Local Area Network) switching; and the management benefits of VLAN(s) (Virtual Local Area Network).

CISCO INTERNETWORK OPERATING SYSTEM SOFTWARE (IOS):

Refers to Cisco system software that provides common functionality, scalability, and security for all products under the Cisco-Fusion architecture: Cisco IOS allows centralized, integrated, and automated installation and management of inter networks, and at the same time ensures support for a wide variety of protocols, media, services, and platforms.

CISCO IOS:

Cisco system software that provides common functionality, scalability, and security for all products under the Cisco-Fusion architecture: Cisco IOS allows centralized, integrated, and automated installation and management of inter-networks while ensuring support for a wide variety of protocols, media, services, and platforms.

CISCO LINK SERVICE (CLS):

A front-end for a variety of data-link control services

CISCO LINK SERVICES INTERFACE (CLSI):

Messages that are exchanged between CLS (Cisco Link Services) and data-link users: such as APPN (Advanced Peer-to-Peer Networking), SNA (Systems Network Architecture) service point and DLSw+ (data-link switching plus).

CISCO NETWORK REGISTER (CNR):

A software product that provides IP (Internet Protocol) addresses, configuration parameters, and DNS (Domain Name System) names to DOCSIS (Data-over-Cable Service Interface Specifications) cable MODEM(s) and PC(s) (Personal Computer); based on network and service policies. CNR also provides enhanced TFTP (Trivial File Transfer Protocol) server capabilities, including DOCSIS cable MODEM configuration files.

CISCO OPTICAL NETWORK PLANNER (ONP):

The Cisco Optical Network Planner is the trademarked network planning tool designed by Cisco Systems, Inc. It is designed for use with Cisco ONS 15900 Series Wavelength Router network elements to optimize available optical network bandwidth.

CISCO TRUNK (private line) CALL(s):

A Cisco-trunk (private line) call is established by the forced connection of a dynamic switched call. A Cisco-trunk call is established during configuration of the trunk and stays up for the duration of the configuration. It optionally provides a pass-through connection path to pass signaling information between the two telephony interfaces at either end of the connection.

CISCO VIEW:

See Cisco-trunk (private line) call

CISCO WAVELENGTH ROUTER MANAGER (WRM):

Cisco's trademarked element management system designed for use with the Cisco ONS 15900 Series Wavelength Router.

CISCO WRM:

See Cisco Wavelength Router Manager

CISCO WW TAC:

Cisco World-Wide Technical Assistance Center: It is the focal point of all Cisco software and hardware maintenance and support services.

C-ISUP:

Proprietary Cisco protocol based on ISUP (ISDN User Part SS7 protocol) layer that defines the protocol used to prepare, manage, and release trunks that carry voice and data between calling and called parties.

CIX:

Commercial Internet Exchange: A connection point between commercial Internet service providers.

CKTINT:

Circuit Inter-working software: A module in the SS7 application software that translates SS7 signals for the Cisco VCO/4K (Virtual Central Office /4K) and host applications. It also performs call processing and circuit maintenance tasks.

CLADDING:

In fiber optic cable, a low refractive index material surrounding the core of each optical fiber, which provides guidance to the light-waves within the fiber.

CLASS A IP (Internet Protocol) ADDRES:

A ‘unicast’ IP address that ranges from 1.0.0.1 through 126.255.255.254. The first octet indicates the network, and the last three octets indicate the host on the network. See unicast.

CLASS B IP (Internet Protocol) ADDRESS:

A ‘unicast’ IP address that ranges from 128.0.0.1 through 191.255.255.254. The first two octets indicate the network, and the last two octets indicate the host on the network. See unicast

CLASS C IP (Internet Protocol) ADDRESS:

A ‘unicast’ IP address that ranges from 192.0.0.1 to 223.255.255.254. The first three octets indicate the network, and the last octet indicates the host on the network. Network Load Balancing provides optional session support for Class C IP addresses, in addition to support for single IP addresses, to accommodate clients that make use of multiple proxy servers at the client site. See unicast

CLAW:

Common Link Access for Workstations: Data link layer protocol used by channel-attached RISC System/6000 series systems and by IBM 3172 devices running TCP/IP (Transmission Control Protocol / Internet Protocol). CLAW improves the efficiency of channel use and allows the CIP (Channel Interface Processor) to provide the functionality of a 3172 in TCP/IP environments and to support direct channel attachment. The output from TCP/IP mainframe processing is a series of IP data-grams that the router can switch without modifications.

CLEAN:

A computer, file or disk that is free of viruses; to remove a virus or other malicious software from a computer, file or disk.

CLEAR:

To turn off an option by removing the X or check mark from a check box; clear a check box by clicking it, or by selecting it and then pressing the ‘spacebar’.

CLEAR CHANNEL:

Any transmission path where the full bandwidth is available to the user: a channel that uses out-of-band signaling, as opposed to in-band signaling, so the channels entire bit rate is available.

CLEAR DDTS:

Clear Distributed Defect Tracking System: Development engineers and CSE(s) (Customer Service Engineers) use Clear DDTS to track bugs for software, hardware, and microcode products. CSE(s) also use Clear DDTS as a formal way to present an issue to developers. Customers use information derived from the Clear DDTS database to troubleshoot problems or to select a software version for an upgrade.

CLEAR TEXT:

Text not encrypted or in a language that is clearly written for the user, with no hidden meaning.

CLEAR TO SEND:

See CTS

CLEC:

Competitive Local Exchange Carrier: A company that builds and operates communication networks in metropolitan areas and provides its customers with an alternative to the local telephone company.

CLEI:

Common Language Equipment Identifier: The standard code used by suppliers to identify equipment parts and system configurations. CLEI is a registered trademark of Bellcore (later Telcordia).

CLI:

1) Command-Line Interface: An interface that allows the user to interact with the operating system by entering commands and optional arguments.

2) Command Language Interpreter: The basic Cisco IOS configuration and management interface.

CLICK:

To position the mouse over an object and then press and release the primary (left) mouse button.

CLID:

Calling Line Identification (ID) / Caller ID: Refers to a telephone exchange function that identifies the originating caller’s telephone number and also provides billing information. The CLID value might be the entire phone number, the area code, or the area code plus the local exchange.

CLIENT (User):

   Refers to a user (client) software program that is used to contact and obtain data from another user (client) computer program. Each Client program is usually designed to work with one or more specific kinds of Server programs, and each Server requires a specific kind of Client. A Web Browser can be viewed as a specific kind of Client.

   Any computer or program connecting to, or requesting services from, another computer or program: A Client can also refer to the software that enables the computer or program to establish the connection. Client can also refer to the user when connecting to the Internet.

   For a local area network (LAN) or the Internet, a computer that uses shared network resources provided by another computer (called a server).

CLIENT–SERVER ARCHITECTURE:

In client-server architecture, the computing load is distributed among the many clients (individual computers) in a network, drawing information from central servers. On the Internet, a web browser is a client that runs software locally that processes information received from central servers. The opposite of client server architecture is the situation where a central computer does all the processing, feeding the results to dumb terminals which do little more than communicate requests and feed back the results processed centrally.

CLIENT / SERVER COMPUTING:

Term used to describe distributed computing (processing) network systems in which transaction responsibilities are divided into two parts: client (front end) and server (back end). Both terms (client and server) can be applied to software programs or actual computing devices.

CLIENT / SERVER MODEL:

Common way to describe network services and the model user processes (programs) of those services. Examples include the name-server / name-resolve(r) paradigm of the DNS (Domain Name Server) and fileserver / file-client relationships, such as NFS (Network File System) and diskless hosts.

CLIENT-SERVER PROTOCOL:

A communication protocol between networked computers

CLNP:

Connectionless Network Protocol: The OSI (Open System Interconnection) network layer protocol that does not require a circuit to be established before data is transmitted.

CLNS:

Connectionless Network Service: The OSI (Open System Interconnection) network layer service that does not require a circuit to be established before data is transmitted. CLNS routes messages to their destinations independently of any other messages.

CLOCK or CLOCKING:

Usually refers to a master timing device, or device timing, used for synchronous data transmission.

CLOCK RATE:

Refers to the time rate at which timing pulses are emitted from the clock. The pulse rate would be determined by the requirements of the connected devices.

CLONE (Cloning):

1) A wireless phone that has been programmed to mimic another wireless phone: Often used to defraud a wireless carrier by placing illegal calls without any intention of payment.

2) Creating and configuring a virtual access interface by applying a specific virtual template interface. The template is the source of the generic user information and the router-dependent information. The result of cloning is a virtual access interface configured with all the commands in the template.

CLOSED ARCHITECTURE:

A term used to identify a restricted use computer system, which is only compatible with software and hardware from one particular vendor.

CLOSED USER GROUP:

See CUG

CLP:

Cell Loss Priority: Field in the ATM (Asynchronous Transfer Mode) cell header that determines the probability of a cell being dropped if the network becomes congested. Cells with CLP = 0 are insured traffic, which is unlikely to be dropped. Cells with CLP = 1 are best-effort traffic, which might be dropped in congested conditions to free up resources to handle insured traffic.

CLR:

Cell Loss Ratio: In ATM (Asynchronous Transfer Mode), the ratio of discarded cells to cells that are transmitted successfully. CLR can be set as a QoS (Quality of Service) parameter when a connection is set up.

CLTP:

Connectionless Transport Protocol: Provides for end-to-end Transport data addressing (via Transport selector) and error control (via checksum), but cannot guarantee delivery or provide flow control. It is the OSI (Open System Interconnection) equivalent of UDP (User Datagram Protocol).

CLUSTER:

1) A group of local terminals connected to a single controller. 2) A collection of interconnected computer servers, working together as a single processing resource in an application environment

CLUSTER CONTROL UNIT:

Terminal Control Unit: A device (micro/minicomputer) that controls the communications to and from a cluster (group) of terminal devices. Other functions: polling, protocol and error control, and formatting.

CLUSTER CONTROLLER:

1) An intelligent device that provides the connections for a cluster of terminals to a data link.

2) In SNA (Systems Network Architecture), a programmable device that controls the input/output operations of attached devices; typically, an IBM 3174 or 3274 device.

CLUSTER SERVER:

Two or more servers linked together to balance the workload or to provide continuous operation if one server fails.

CLUSTER VIRUS:

Cluster viruses modify the directory table entries so the virus starts before any other program. The virus code only exists in one location, but running any program runs the virus as well. Because they modify the directory, cluster viruses may appear to infect every program on a disk.

CM:

1) Configuration Management: A process used to evaluate changes or new releases of products and develop recommendations regarding the implementation of those changes/products as they relate to compatibility, control, options, impacts, etc.

2) Cable MODEM: Device used to connect a PC (Personal Computer) to a local cable TV line, which allows the reception of data at much higher rates than ordinary telephone MODEM(s) or ISDN (Integrated Services Digital Network.

CMI:

1) Coded Mark Inversion: ITU-T line coding technique specified for STS-3c transmissions. Also used in DS-1 systems. 2) Control Mode Idle.

CMIP:

Common Management Information Protocol: OSI (Open System Interconnection) network management protocol created and standardized by ISO for the monitoring and control of dissimilar networks.

CMIS:

Common Management Information Services: OSI (Open System Interconnection) network management service interface created and standardized by ISO for the monitoring control of dissimilar networks.

CMNM:

Cisco MGC Node Manager: The management system providing fault, performance, and security management for the VSC3000 (MGC) node.

CMNS:

Connection-Mode Network Service: Extends local X.25 switching to a variety of media (Ethernet, FDDI (Fiber Distributed Data Interface) & Token Ring).

CMOS:

Example – RAM (Random Access Memory): See Complimentary Metal Oxide Semiconductor

CMS:

1. Call Management System: A reporting package used on ACD(s) (Automatic Call Distributor) and PBX(s) (Private Business Exchange) made by Lucent.

2. Configuration Management System

CMT:

Connection Management: FDDI (Fiber Distributed Data Interface) process that handles the transition of the ring through its various states (off, active, connect, etc), as defined by the ANSI (American National Standards Institute) X3T9.5 specification.

CMTS:

Cable MODEM Termination System: Typically located at the cable head-end.

C/N:

Difference in amplitude between the desired radio frequency (RF) carrier and the noise, within in a portion of the spectrum

CNS/AD: Cisco Networking Services for Active Directory

CO:

Commanding Officer or See Central Office

CO FRAD:

Central Office Frame Relay Access Device

COAXIAL (COAX) CABLE:

Consists of a conductor suspended in the center of an insulated housing (tube) with a grounded shield formed around the insulated housing. One or more conductor may be used within a single cable. The outer shell of the cable is usually composed of a grounded metal shielding material.

COAXIAL CONVERTER (Protocol Converter):

An IBM systems term defining a device (unit) used to convert the 3270 synchronous protocol to asynchronous protocol.

COBOL:

Common Business-Oriented Language: Developed in 1960 by a team led by the National Bureau of Standards (now the National Institute of Standards and Technology ‘NIST’) COBOL was the first standardized business computer-programming language. Since COBOL was intended for business use, many functions, such as payroll and accounting, are still executed using programs written in this language.

CODE:

In communications: A system of rules and symbols (alphanumeric/control) used in code sets such as ASCII, Baudot and EBCDIC; could also refer to writing the code for a program.

CODE CONVERSION:

The process of converting a communication code of some predetermined bit structure to a second code with a different bit structure, for instance, the Baudot code to the ASCII code, or Binary Coded Decimal (BCD) to any other code set.

CODE LEVEL:

A term sometimes used to describe the number of bits used to represent one character in a code set. Examples: Baudot, 5 bits, ASCII, 7 bits plus parity (8) and EBCDIC, 6 bits plus parity (7).

CODE SET:

A pattern (group) of bits used to represent characters, with a different pattern for each character. Example: the ASCII code set uses 7 bits plus a parity bit (total 8), while the Baudot code set uses 5 bits plus a start and stop bit (total 7).

CODEC / CODEX:

1) Coder – De-Coder: A digital device for the coding and decoding of video and/or audio signals, usually performed to allow transmission in a compressed data form.

2) ntegrated circuit device that typically uses pulse code modulation to transform analog signals into a digital bit stream and digital signals into analog signals.

3) In Voice over IP (Internet Protocol), Voice over Frame Relay, and Voice over ATM (Asynchronous Transfer Mode): a DSP (Digital Signal Processor) software algorithm used to compress/decompress speech or audio signals.

CODING:

Electrical techniques used to convey binary signals

CO-IPX:

Inter-network Packet Exchange (IPX) / Connection Oriented IPX (Inter-network Packet Exchange):  Native ATM (Asynchronous Transfer Mode) protocol based on IPX under development by Novell.

COLD BOOT:

To start the computer by cycling the power (off to on). A cold boot using a rescue disk (a clean floppy disk with boot instructions and virus scanning capabilities) is often necessary to clean or remove boot sector infectors.

COLLAPSED BACKBONE:

A non-distributed backbone in which all network segments are interconnected by way of an internetworking device: A collapsed backbone might be a virtual network segment existing in a device, such as a hub, a router, or a switch.

COLLISION:

A term used to describe a condition in a Local Area Network where two stations attempt to use a shared line simultaneously; In Ethernet, the result of two nodes transmitting simultaneously. The frames from each device impact and are distorted when they meet on the physical communication media.

COLLISION DOMAIN:

In Ethernet, the network portion where frames that have collided are propagated: Repeaters and hubs propagate collisions; LAN (Local Area Network) switches, bridges, and routers do not.

COLMUX:

Communications Line Multiplexer (programmable): Provided for more than one line (circuit) to be connected to a single computer channel.

CO-LOCATION:

Refers to a server that belongs to one person or group that is physically connected on an Internet network that belongs to another person or group; Usually this is done because the server owner wants the machine (computer) to be connected via a high-speed Internet connection and/or does not want the security risks of having the server on their own network.

COLOR DEPTH:

The number of colors per pixel the monitor and graphics adapter support

COLOR GAMUT:

The particular range of colors that a device is able to produce: A device such as a scanner, monitor, or printer can produce a unique range of colors, which is determined by the characteristics of the device.

COLOR PROFILE:

A profile that contains the data needed for translating the values of a color gamut. This data includes information about color, hue, saturation, and brightness.

COM:

Common Equipment: Items used by more than one channel or equipment function.

COMBINED STATION:

Balanced station’: Refers to a High-Level Data Link Control (HDLC) protocol, where a station can assume the role of either a primary or secondary station.

COM FILE:

A type of executable file limited to 64 kb. These simple files are often used for utility programs and small routines. Because COM files are executable, viruses can infect them. This file type has the extension COM.

COMLOGNET:

Communications Logistics Network: A predecessor communications system to AUTODIN. The original system was designated COMLOGNET and then as the use and scope expanded it was re designated AFDATACOM and then re designated AUTODIN.

COMMAND PORT:

‘Master Console’, ‘System Console’: The focal point for system monitoring and control.

COMMAND PROMPT WINDOW:

A window displayed on the monitor screen used to interface with MS-DOS (Microsoft Disk Operating System). MS-DOS commands are typed at an entry point identified by a blinking cursor.

COMMON  BATTERY:

A DC power source in the central office that supplies power to switching equipment and to subscribers

COMMON CARRIER:

A Telephone Company or similar supplier of telecommunications services

1) In general usage, a common carrier is any supplier in an industry that undertakes to ‘carry’ goods, services or people from one point to another for the public in general.

2) In telecommunications, telephone companies ‘carry’ voice and data services over the telecommunications network. In the United States, a common carrier company that offers communications to the public is subject to state and federal regulation by the FCC, and the PSC / PUC.

COMMON CARRIER PRINCIPLE:

The regulatory concept that limits the number of companies that provide needed services in a particular geographic area.

COMMON CONTROL SWITCHING ARRANGEMENTS:

See CCSA

COMMON GROUPS:

Groups that appear in the program list on the Start menu for all users who log on to the computer. Only administrators can create or change common groups.

COMMUNICATION:

Refers to the transmission of information from one point to another by means of analog or digital signals, or to the transfer of information of any kind from one person to another person

COMMUNICATIONS ACT of 1934:

The Congressional Act, passed in 1934 setting a goal of universally available, quality telephone service for a reasonable cost. The Act also established the FCC and transferred all foreign and interstate radio and wire transmission to this Commission. It stipulates that prices and regulations for transmission and equipment service be just, reasonable and not unreasonably discriminatory

COMMUNICATION CENTER:

An agency and/or assembled equipment responsible for the receipt, protection, transmission and delivery of messages.

COMMUNICATIONS CHANNEL:

A path (circuit) used for the transmission (flow) of information. See Channel

COMMUNICATIONS CONTROL UNIT:

See CCU

COMMUNICATION CONTROLLER:

1) In SNA (Systems Network Architecture), a sub-area node, such as an IBM 3745 device that contains an NCP (Network Control Program).

2) Communications processor that connects asynchronous devices to a LAN (Local Area Network) or a WAN (Wide Area Network) through network and terminal emulation software: Performs only asynchronous routing of IP (Internet Protocol) and IPX (Inter-network Packet Exchange). Compare with access server.

COMMUNICATION LINE:

A physical link: Wire, circuit, line, channel, fiber, etc that connects one or more devices to one or more other devices.

COMMUNICATIONS LINE CONTROL:

Any device (hardware/software) designed to perform the necessary transmission, protocol and control functions for a data communications line.

COMMUNICATIONS PROCESSOR:

A computer and associated devices utilized for the processing of messages for all connected terminals or other devices. This would include receiving, protecting, controls, transmitting and other special processing requirements. See CDP

COMMUNICATIONS MEDIUM:

An entity that provides a communications link, such as coaxial cable, twisted pair or unbounded (radio-air)

COMMUNICATIONS MONITOR:

Refers to the mainframe (host) software that provides shared interface and access between application programs and communications devices

COMMUNICATIONS NETWORK:

Refers to an Interconnection of organizations and/or geographic locations via a communications medium; See Network or Networks

COMMUNICATIONS PORT:

A port on a computer that allows asynchronous communication of one byte (character) at a time (in series); A communication port is also called a serial port.

COMMUNICATIONS PREPROCESSOR (FRONT-END):

A computer connected between a general-purpose processor and the communications channels (lines). This allows communications and general-purpose functions to be performed more efficiently than would be possible if the general-purpose processor performed both communications functions and general-purpose functions.

COMMUNICATIONS SATELLITE:

A microwave repeater, orbiting in a typically geosynchronous orbit, 22,300 miles above the earth, designed to relay signals between communications stations.

COMMUNICATION SETTINGS:

Operating parameters, such as bits per second (bps) and MODEM type that applies to serial ports on a computer.

COMMUNICATIONS SYSTEM:

A series of interconnected communications networks, circuits, stations (terminals), computers and facilities for the purpose of handling communication needs.

COMMUNITY:

In SNMP (Simple Network Management Protocol): A logical group of managed devices; in NMS(s) (Network Management System) devices in the same administrative domain.

COMMUNITY NAME / COMMUNITY STRING:

Text string that acts as a password and is used to authenticate messages sent between a management station and a router containing an SNMP (Simple Network Management Protocol) agent. The community string is sent in every packet between the manager and the agent.

COMOPS:

Communications Operating Performance Summary

COMPANDING:

A contraction derived from the opposite processes of compression and expansion. Part of the PCM (pulse code modulation) process where analog signal values are rounded logically to discrete scale-step values on a nonlinear scale. The decimal step number then is coded in its binary equivalent prior to transmission. The process is reversed at the receiving terminal using the same nonlinear scale.

COMPANDOR (Compressor–Expander):

An electronic device: Expands the incoming speech (voice) volume and compresses the outgoing speech volume on a long-distance telephone circuit; or a device that improves the signal to interference (noise) ratio.

COMPANION VIRUS:

Companion viruses use a feature of DOS that allows software programs with the same name, but with different extensions, to operate with different priorities. Most companion viruses create a COM file which has a higher priority than an EXE file with the same name.

   A virus may see that a system contains the file PROGRAM.EXE and then will create a file called PROGRAM.COM. When the computer attempts to execute the PROGRAM.EXE file from the command line the virus (PROGRAM.COM) runs before the actual PROGRAM.EXE. Often the virus will execute the original program afterwards so the system appears normal.

COMPATIBILITY MODE:

A feature of a computer or operating system that allows it to run programs written for a different system. Programs often run slower in compatibility mode.

COMPILE:

To produce a sequentially ordered machine (computer) language program from a series of symbolic operation codes or statements. A special compiling program is used to perform this transformation from a non-machine code (language) to a machine code.

COMPILER:

A program that translates programming language statements into the necessary machine language (code) instructions

COMPLEMENTARY METAL OXIDE SEMICONDUCTOR (CMOS):

A type of semiconductor technology that requires very little power: The term has been popularized to mean a storage area, such as RAM, or where the system keeps track of certain hardware parameters, such as the size of your hard disk, the number of serial ports, etc

COMPONENTS:

Sub elements or sub assemblies of a set or system, which are integral to the basic function of that set or system. In AUTODIN all the devices would be considered sub assemblies.

COMPOSITE:

A term used to describe the side of a concentrator or multiplexer that includes all the multiplexed data. Composite video (Signal) - A video signal format that includes the complete visual wave form, which includes color, brightness, blanking pedestal, field, line, color sync pulses and field equalizing pulses

COMPOSITE CLOCK:

A bipolar timing signal containing 64 khz (kilohertz) bit-clock and 8 khz byte-clock frequencies

COMPOSITE LINK:

A circuit or line that connects a pair of concentrators or multiplexers

COMPOUND OPTION:

A DOCSIS (Data-over-Cable Service Interface Specifications) option that is composed of a number of sub-options: For example, options 4 and 24 are compound options.

COMPOUND TERMINAL:

IBM punched card remote send/receive terminal; uses the FIELDATA code set.

COMPRESSED / COMPRESSION:

File Compression - Example: Data files downloaded over the Internet are typically compacted (compressed) in order to save server space and reduce transfer times. The running of a data through an algorithm that reduces the required data storage space or the bandwidth required to transmit the data.

COMPRESSION (Compaction):

Analog compression: The analog transmission bandwidth is reduced where possible.

Data compression: The number of transmitted bits is reduced. Repetitious bits, such as ‘zeros’, would be deleted and a special flag (code) inserted to represent the zeros, this could also be accomplished with other repetitious bit patterns or characters (bytes).

COMPRESSOR:

Not an air compressor, but an electronic device used to perform analog compression and reduce transmission time or compress the volume range of a signal.

COMPROMISE:

To access or disclose information without authorization

COMPUTER ADMINISTRATOR:

A user who manages a computer system: The system administrator makes system-wide changes to the system, including the installation of programs and accessing all files on the computer, and can create, change and delete the accounts of other users.

COMPUTER CODE CHECKING:

Refers to the process of checking for parity errors: Examples: character (byte) parity, block parity and cyclic parity check.

COMPUTER UTILITY:

A ‘Time Shared’ computer system with resident programs and data that may be shared or privately owned usually accessed via data communications sub systems.

COMPUTERIZED BRANCH EXCHANGE (CBX):

A Public Branch Exchange (PBX) using electronics and a computer to accomplish automatic network switching.

COMSAT:

Communications Satellite

COMSEC:

Communications Security

COMSTAT:

Communications Status

COMTAC:

Tactical Communications

CONCATENATION:

Linking of transmission media (devices) by looping (connecting) through a multiple of devices; Other names: Daisy Chaining, Multiple Wiring (telephony), parallel / series connections, Loop connections.

CONCENTRATOR:

A communications device that provides a shared transmission medium in order to accommodate multiple terminals on one shared channel (line).

CONCURRENT:

Two or more events or activities occurring at the same interval of time

CONDITIONED CIRCUIT:

A circuit with added equipment to obtain more efficient, error free, characteristics for data transmission. The addition of such equipment is called ‘conditioning ‘; see Circuit Conditioning and Conditioning Equipment.

CONDITIONING:

A term normally used when referring to voice grade (VG) lines (channels), which is an action taken to Improve the transmission quality of the voice grade line. Usually additional or special equipment is used to accomplish this task.

CONDITIONING EQUIPMENT:

Equipment added to a circuit for the express purposes of matching transmission levels and impedance’s or equalizing transmission and delay to bring circuit losses, levels, and distortion within specified limits of CCITT standards, or in U.S. practice, common carrier tariffs.

CONF:

Configuration Failure: A resource that is OOS (Out of Service) because of inconsistent provisioning information.

CONFIGURATION DIRECT VCC:

In ATM (Asynchronous Transfer Mode), a bi-directional point-to-point VCC (virtual channel Connection) set up by an LEC (Local Exchange Carrier) to an LES (LAN Emulation Server); one of three control connections defined by Phase 1 LANE (LAN Emulation).

CONFIGURATION MANAGEMENT:

One of five categories of network management defined by ISO (International Organization for Standardization) for the management of OSI (Open System Interconnection) networks. Configuration management subsystems are responsible for detecting and determining the state of a network.

CONFIGURATION REGISTER:

In Cisco routers, a 16-bit, user-configurable value that determines how the router functions during initialization: The configuration register can be stored in hardware or software. In hardware, the bit position is set using a jumper. In software, the bit position is set by specifying a hexadecimal value using configuration commands.

CONFIGURATION TOOL:

1. Service Management Tool with a GUI (Graphical User Interface).

2. Element Management Service Tool with a GUI (Graphical User Interface).

CONGESTION:

Traffic that exceeds network designed capacity

CONGESTION AVOIDANCE:

A mechanism used by an ATM (Asynchronous Transfer Mode) network to control the traffic entering the network to minimize delays. To use resources efficiently, lower-priority traffic is discarded at the edge of the network if conditions indicate that it cannot be delivered.

CONGESTION COLLAPSE:

A condition in which the retransmission of frames in an ATM (Asynchronous Transfer Mode) network results in little or no traffic successfully arriving at the destination. Congestion collapse frequently occurs in ATM networks composed of switches that do not have adequate and effective buffering mechanisms that are complimented by intelligent packet discard or ABR (available bit rate) congestion feedback mechanisms.

CONNECT TIME or HOLDING TIME:

The amount of time a switched circuit is in use.

CONNECTED, USER AUTHENTICATED:

A user’s status when a telephone connection has been established and the user has entered a correct user name and password: If the user has callback permission and has requested callback, the connection is followed by the calling-back phase. If the calling-back phase is followed by a waiting-for-call phase, then the server was unable to reach the user at the specified number. The user may have supplied an inaccurate callback number, in the case of set-by-caller callback, or an unauthorized attempt to access the network may be under way, in the case of preset-to callback.

CONNECTING BLOCK:

Usually part of a distribution frame and is used to terminate or cross connect wires and cables. The block provides an easy media to originally connect circuits or to make changes.

CONNECTION (X-CONNECT):

Wire connections running between two points on a distribution frame, or between binding posts in a terminal wiring box. The physical attachment of a line or circuit, or establishing a transmission path. X Connect = Cross Connection

CONNECTION ORIENTED:

Term used to describe data transfer that requires the establishment of a virtual circuit.

CONNECTIONLESS:

A term used to describe data transfer without the existence of a virtual circuit.

CONNECTIVITY:

The ability of hardware devices or software to communicate with other hardware or software through common interfaces

CONNECTOR:

An electrical component: Connects cables to cables or devices, with male and/or female configurations (pins or pin acceptance holes).

CONP:

Connection Oriented Network Protocol: OSI (Open System Interconnection) protocol providing connection-oriented operation to upper-layer protocols.

CONS:

Connection Oriented Network Service

CONSOLE:

A computer system manual control unit, with many switches and indicators and an input/output capability, and normally used by operations or maintenance personnel. Example: control the computer through manual input, correct errors, determine status (operational/storage) and make revisions.

CONSOLE TREE:

The left pane in a Microsoft Management Console (MMC) that displays the items contained in the console. By default it is the left pane of a console window, but it can be hidden. The items in the console tree and their hierarchical organization determine the capabilities of a console.

CONSTRAINT BASED ROUTING:

Procedures and protocols that determine a route across a backbone by determining resource requirements and resource availability instead of simply using the shortest path

CONTEL-ASC:

Continental Telephone Corp - ASC (American Satellite Corp.)

CONTENDED ACCESS:

Refers to a shared access feature found in a Local Area Network (LAN) operation, which allows first come, first served station access.

CONTENTION:

First come first served method of line control where terminals must make a request to transmit, or wait for a polling sequence. Transmission can proceed only when the channel is free and the requesting terminal has been selected. Contention could also occur in a computer program due to the many competing software routines, I/O interruptions, error routines, communication functions, etc. An access method in which network devices compete for permission to access the physical medium

CONTINUOUS:

A term used for the continuous ‘Block-by-Block’ data transmission mode. The continuous operational mode allows the transmitter to begin the next block of data while awaiting an ACK for the previous block. This requires that the receiver be capable of storing more than one block of data.

CONTINUOUS VARIABLE SLOPE DELTA MODULATION:

See CVSD

CONTROL CARD:

A term originally used to identify a punched card that informed the operating system what its next task would be. Presently it would have a different meaning and may refer to magnetic or optical input.

CONTROL CHARACTER (S):

A Function Control character(s) (flag) - Used for control of functions or devices. The ASCII code set provides control characters as do other code sets and computer programmers utilize flags for control of computer operations and functions. When the ITA#2 (Baudot) code set (no individual control characters) is used pairs of individual characters (contiguous) will be designated as control characters. These designated control character sequences are usually prearranged between the transmitter and receiver.

CONTROL DIRECT VCC:

In ATM (Asynchronous Transfer Mode), a bidirectional VCC (Virtual Channel Connection) set up by an LEC (Local Exchange Carrier) to a LES (LAN Emulation Server); one of three control connections defined by Phase 1 LANE (LAN Emulation).

CONTROL-DISTRIBUTE VCC:

In ATM (Asynchronous Transfer Mode), a unidirectional VCC (Virtual Channel Connection) set up from a LES (LAN Emulation Server) to a LEC (Local Exchange Carrier); one of three control connections defined by Phase 1 LANE (LAN Emulation). Typically, the VCC is a point-to-multipoint connection.

CONTROL MESSAGES:

Refers to signaling messages that provide the control of setup, maintenance, and teardown of L2TP sessions and tunnels

CONTROL MODE:

The state data terminals must be in to permit line control (handshaking) actions to occur. See Mode and Mode 1 through Mode 5.

CONTROL PROGRAM:

A program that would include the functions of input/output driver, executive (execute instructions), monitor and supervisor. For example: handle input/output for terminals and file storage, establishing processing priorities, maintain waiting lists for work in process, activating and controlling operational programs and performing other miscellaneous and supervisory functions.

CONTROL SIGNAL:

Synchronization clock, control characters/bits, RS232 MODEM signals, etc.

 CONTROL SIGNALS:

Signals passed between parts of a communications system (devices) to control operation and configuration of the system. In telephony, supervision signals are a form of control signal.

CONTROL SIGNAL:

Synchronization clock, control characters/bits, RS232 MODEM signals, etc.

CONTROL UNIT:

A computer (CPU) hardware device that controls and coordinates the sequence of peripheral input/output functions, interprets coded instructions and initiates commands to execute instructions; the mechanical or electronic central processor of a telephone switching exchange. Or a terminal device providing the control and protocol functions.

CONTROLLER (S):

A controller converts bits or bytes into words, converts (translates) data codes, matches the speed of a device to the speed of memory and controls the devices, i.e. communications controller, disk controller, magnetic tape controller, etc.

CONSTANT:

Data, flags or information: Remains constant and is not normally revised; could be a fixed value referenced by various programmers rather than maintaining their own data.

CONUS:

Continental United States: The 9 original AUTODIN AESC(s) (ASC), within the continental United States, including Hawaii.

CONVERGENCE:

Speed and ability of a group of inter-networking devices running a specific routing protocol to agree on the topology of an inter-network after a change in that topology.

CONVERSATIONAL MODE:

Usually refers to a situation where there is a direct online interaction (dialog) between the user and the computer, or between two user terminals.

CONVERSATION:

In SNA (Asynchronous Transfer Mode), a LU 6.2 session between two transaction programs

CONVERT:

To change information from one number base to another base or to transfer information from one recorded medium to a different medium. See Code conversion

COOKIE:

   The ‘Cookie’ on the Internet normally refers to a piece of information sent by a Web Server to a Web Browser. The Browser software is expected to save the cookie information and send it back to the Server whenever the browser makes additional requests for information from the Server.

   Depending on the type of Cookie, and the Browser settings, the Browser may accept or not accept the Cookie, and may save the Cookie for either a short time or a long time.

    Cookies may contain information such as log-in or registration information, online ‘shopping cart’ information, user preferences, etc.

   When a Server receives a request from a Browser that includes a Cookie, the Server is able to use the information stored in the Cookie. After reviewing this information the Server may customize what is sent back to the user, or keep a log of a particular user’s requests.

COOS:

Commanded OOS (Out-of-Service): A resource may be OOS because it was entered as a command.

COPS:

Common Open Policy Service: A Quality of Service (QoS) policy exchange protocol proposed as an IETF (Internet Engineering Task Force) standard, which involves communicating network QoS policy information.

COR:

Functionality that provides the capability to deny certain call attempts based on the incoming and outgoing class of restrictions applied to the dial peers. COR specifies which incoming dial peer can use which outgoing dial peer to make a call.

CORBA:

Common Object Request Broker Architecture: OMG (Object Management Group) answer to the need for interoperability among the rapidly proliferating number of hardware and software products available today. Simply stated, CORBA allows applications to communicate with one another regardless of location or who has designed them.

CORE:

Refers to a form of magnetic memory prior to the availability of solid state and semiconductor (chip) memory systems; actually uses small circular shaped (donut shape) units, one for each bit to be stored and these were mounted and wired in a container (enclosure) with 4096 bits total per container.

CORE GATEWAY:

Refers to the primary routers in the Internet

CORE ROUTER:

In a packet-switched star topology, a router that is part of the backbone and serves as the single pipe through which all traffic from peripheral networks must pass when communicating with other peripheral networks.

CoS:

Class of Service: A defined definition of how an upper-layer protocol requires a lower-layer protocol to treat its messages. A CoS definition is composed of a virtual route number and a transmission priority field.

COS:

Corporation for Open Systems: Organization that promotes the use of OSI (Open System Interconnection) protocols through conformance testing, certification, and related activities.

COSINE:

Cooperation for Open Systems Interconnection Networking in Europe: European project financed by the EC (European Community) to build a communication network between scientific and industrial entities in Europe. The project ended in 1994.

COT:

Continuity Test: A requirement of the SS7 protocol specifications. A Continuity Test checks the bearer channels status using either loop-back or tone detection and generation.

COTS:

Commercial-off-the-shelf software: An item of software produced by a vendor and is available for general purchase.

COUNT to INFINITY:

A problem that can occur in routing algorithms that are slow to converge; routers continuously increment the hop count to particular networks. Typically, some arbitrary hop-count limit is imposed to prevent this problem

COUNTRY CODE:

Most countries in the world that are connected to the Internet have been assigned two-letter country codes by the international standard ISO 3166. These two letter codes are the major domain addresses for the country.

COUPLING:

Connecting two or more devices in such a manner that information can be transferred from one to the other.

CP:

1. Control Point: In SNA (Systems Network Architecture) networks, an element that identifies the APPN (Advanced Peer-to-Peer Networking) components of a PU 2.1 (Physical Unit type 2.1) node, manages device resources, and provides services to other devices.

CPC:

Calling Party Category

CPCS:

1) Common Part Convergence Sub-layer: One of the two sub-layers of any AAL (ATM Adaptation Layer). The CPCS is service-independent and is further divided into CS(s) (Convergence Sub-layer) and the SAR (Segmentation and Reassembly) sub-layer. The CPCS is responsible for preparing data for transport across the ATM (Asynchronous Transfer Mode) network, including the creation of the 48-byte payload cells that are passed to the ATM layer.

2. Call Processing Control System

CPE:

Customer Provided Equipment / Customer Premises Equipment: Telecommunications or data processing equipment that is provided by the customer and connected to the telephone company facilities. This includes telephones, MODEM(s), terminals, routers, setup (control) boxes, etc.

CPI:

Computer Private Automatic Branch Exchange (PABX) Interface: A Local Area Network (LAN) term that refers to Digital Equipment Corporations (DEC) T1 transmission technology, with 56 kbps channels.

CPI-C:

Common Programming Interface for Communications: Platform-independent API (application program interface) developed by IBM and used to provide portability in APPC (Advanced Program-to-Program Communication) applications.

CPM:

Characters per Minute or Cards per Minute: Refers to the number of characters or cards that can be transmitted in one minute.

CPNIE:

Called Party Number Information Element

CPP:

Combinet Proprietary Protocol

CPU:

Central Processing Unit: The main frame portion of a computer system, which basically includes the Control Unit, Storage (memory), registers and the arithmetic/logic unit.

cps:

1) Cells per second: A Unit of measurement used in ATM (Asynchronous Transfer Mode) switch volumes.

2) Cycles per second

CPS:

Characters per Second: A count of the number of characters transmitted in one second. This would not be the same under all conditions. The count (rate) varies based on the transmission speed, lines and device capability. The size of a character, number of bits, varies based on the code set. Usually expressed in Characters per Minute (CPM)

CQ:

Custom Queuing

CR:

Carriage Return: A control character used in the Baudot, EBCDIC or ASCII character sets to position the cursor at the left margin on a Cathode Ray Terminal (CRT) or position the printer mechanism at the left margin.

CRACKER:

A person who attempts to break into a network or computer system, often with the intent to steal material or perform malicious destruction of files or just to show it can be done. Crackers try to exploit weaknesses in system security or in some cases, the weaknesses of its users who can be tricked into revealing passwords.

CRAFT INTERFACE DEVICE (CID):

Terminal or PC (Personal Computer) based interface that enables the performance of local maintenance operations

CRAM / CRAMMING:

Cramming is the practice by some phone companies where they add false charges to your phone bills for calls you never made.

CRANKBACK:

A mechanism used by ATM (Asynchronous Transfer Mode) networks when a connection setup request is blocked because a node along a selected path cannot accept the request. In this case, the path is rolled back to an intermediate node, which attempts to discover another path to the final destination using GCAC (Generic Connection Admission Control).

CRC:

1) Cyclical (Cyclic) Redundancy Check: CRC is a mathematical technique used to check for errors when sending data by MODEM. If the CRC fails to calculate correctly, the receiving end of a data transmission sends a NAK (negative acknowledgment) signal. The data will be retransmitted until it is error free. CRC techniques are also used in tape backups and other streaming communications.

2) Some Government terms: Control and Reporting Center; Circuit Routing Chart; CONUS Replacement Center and COOP Response Cell.

CREN:

Corporation for Research and Educational Networking: The result of a merger of BITNET (Because It's Time NET-work) and CSNET (Computer Science Network). CREN is devoted to providing Internet connectivity to its members, which include the alumni, students, faculty, and other affiliates of participating educational and research institutions, via BITNET III.

CRF:

Concentrator Relay Function: CRM (Customer Relationship Management) Cell Rate Margin: One of three link attributes exchanged using PTSP(s) (PNNI Topology State Packet) to determine the available resources of an ATM (Asynchronous Transfer Mode) network. CRM is a measure of the difference between the effective allocated bandwidth per traffic class and the allocation for sustainable cell rate

CRITICOMM:

Critical Intelligence Communications System

CRJE:

Conversational Remote Job Entry: Refers to an IBM operation where a terminal user uses conversational language when submitting jobs and controlling their processing.

CRL:

Certificate Revocation List: Data structure that compiles and lists digital certificates that have been invalidated by their issuer prior to the scheduled expiration date.

CRM:

Customer Relationship Management: CRM refers to solutions and strategies for managing business relationships with customers. With the advent of Web retailing, companies have found it hard to develop relationships with customers since the e-commerce interface is so impersonal.

CROSS BAR:

Past automatic telephone electrical-mechanical switching system: Used movable switches mounted on bars. The switching path is tested and selected electrically-mechanically based on the dialed input.

CROSS BAR SWITCH:

A switch having numerous vertical and horizontal paths, electromagnetically operated by a mechanical method, which allows the interconnection of vertical and horizontal paths

CROSS-PLATFORM:

Systems that are operating system independent and can operate across different system platforms.

CROSS-TALK:

A signal leak from one channel to another: Often the cause of noise and distortion. Unwanted energy (speech, tone or digital pulses) transferred from one transmission path to another. Comprises part of the ‘noise’ observed on communications circuits.

CRP:

Customer Routing Point: AT&T terminology for third-party processors that accept routing requests from the CCSS7 network. Within ICM (Intelligent Call Management), the Network Interface Controller (NIC) acts as a CRP.

CRT:

Cathode Ray Tube: In communications, a television like picture tube used in visual display terminals.

CRV:

Call Reference Value: Number carried in all Q.931 (I.451) messages that provide an identifier for each ISDN (Integrated Services Digital Network) call.

CRX: (See Carrier)

1) An unvarying transmitted frequency that can be modulated with one or more signal(s) carrying information.

2) A long-distance company that provides transmission facilities, Common Carrier

CRYPTO:

Cryptographic: An encoding or data scrambling technique used to prevent data transmission interception and decoding.

CRYPTOGRAPHIC ALGORITHM:

Algorithms that employ the science of cryptography: Includes: encryption algorithms, cryptographic hash algorithms, digital signature algorithms, and key agreement algorithms

CRYPTOGRAPHIC KEY:

‘Key’: Input parameter that varies the transformation performed by a cryptographic algorithm.

CRYPTOGRAPHY:

See Private Key and Public Key Cryptography

CS:

Convergence Sub-layer: One of the two sub-layers of the AAL CPCS (ATM Adaptation Layer / Common Part Convergence Sub-layer), which is responsible for padding and error checking. PDU(s) (Protocol Data Unit) passed from the SSCS (Service Specific Convergence Sub-layer) are appended with an 8-byte trailer (error checking and control information) and are padded, if necessary, so that the length of the resulting PDU is divisible by 48. These PDU(s) then are passed to the SAR (Segmentation and Reassembly) sub-layer of the CPCS for further processing.

CSA:

Canadian Standards Association: Canadian agency that certifies products that conform to Canadian national safety standards.

CS-ACELP:

Conjugate Structure Algebraic Code Excited Linear Prediction: CELP voice compression algorithm providing 8 kbps, or 8:1 compression, standardized in ITU-T Recommendation G.729.

CSC:

Customer Service Centers: User information regarding interruptions to service, and information pertinent to removal or installation of equipment, is transmitted by the customer or maintenance personnel to the Customer Service Centers. The CSC also originates portions of the system input.

CSD BOX:

Control Signal Distribution Box: Bulkhead splitter box that distributes the clock and control system signals within a system.

CSFS:

Customer Support Forwarding Service: Facility within the ICM (Intelligent Call Management) Logger that receives events from all parts of the ICM, filters them, and saves the appropriate messages. The Data Transfer Process (DTP) sends these messages to Cisco Customer Support.

CSI:

Called Subscriber Identification: An identifier whose coding format contains the telephone number from a calling remote fax terminal

See Customer Self-Install

CSLIP:

Compressed Serial Link Internet Protocol: Extension of SLIP (Serial Line Internet Protocol) that, when appropriate, allows just header information to be sent across a SLIP connection, reducing overhead and increasing packet throughput on SLIP lines

CSM:

1) Call Switching Module

2) Cisco Service Management

CSMA:

Carrier Sense Multiple Access: A Local Area Network (LAN) contention based access method where stations sense (check) the network prior to transmitting, send a packet of data, then release the line so other stations can transmit. Even though stations are not supposed to transmit until the line is clear, transmission collisions still occur.

CSMA/CA:

Carrier Sense Multiple Access with Collision Avoidance: A CSMA protocol using a Time Division Multiplexer (TDM) to minimize a collision occurrence.

CSMA/CD:

Carrier Sense Multiple Access with Collision Detection: A Local Area Network (LAN) access method where all stations attached to the network sense (check) for an existing transmission before attempting to transmit. If two or more devices begin transmitting at the same time, each will stop for a random time period before attempting to re-transmit.

CSN:

Channel Sequence Number: A part of the “Transmission Identifier Line (TI)”, which provides for message accountability. Each message when prepared for transmission is sequentially numbered. See TI.

CSNET:

Computer Science Network: Large inter-network consisting primarily of universities, research institutions, and commercial concerns. CSNET merged with BITNET to form CREN.

CSNP:

Complete Sequence Number PDU: PDU (Protocol Data Unit) sent by the designated router in an OSPF (Open Shortest Path First) network to maintain database synchronization.

CSO:

Composite Second Order beat: A peak level, maximum average level, of distortion by-products due to second-order non-linear signals in cable system equipment.

CSP:

Communications Support Processor: An Automated Message Processing Exchange (AMPE) which provides communications services for the receipt and transmission of General Service (GENER) and Defense Special Security Communications System (DSSCS) messages.

CSPDN:

Circuit Switched Public Data Network

CSS:

Cascading Style Sheet: A standard used to specify the appearance of text and other elements. CSS is typically used to provide a library of styles that are used over and over throughout a large number of related documents, as in a web site. For example: a CSS file might specify that all numbered lists are to appear in ‘Italics’.

CSU:

1) Channel Service Unit: Digital interface device that connects end-user equipment to the local digital telephone loop.

2) Circuit Switching Unit: A non store and forward electrical-mechanical Circuit Switching unit. The CSU provides a direct connection between two remote locations (terminals) and may have a direct connection to the Communication Data Processor.

CSV:

Comma Separated Values: Common no-frills text file format used for import from and import to spreadsheets and SQL (Structured Query Language) databases.

CT:

Communications Terminal

CTB:

Composite Triple Beat: Peak of the average level of distortion due to third-order non-linear signals in cable system equipment.

CTD:

Cell Transfer Delay: In ATM (Asynchronous Transfer Mode), the elapsed time between a cell exit event at the source UNI (User-Network Interface) and the corresponding cell entry event at the destination UNI for a particular connection. The CTD between the two points is the sum of the total inter-ATM node transmission delay and the total ATM node processing delay

CTI:

Computer Telephony Integration: The name given to the merger of traditional telecommunications PBX (Private Business Exchange) equipment with computers and computer applications. Example: Using the caller ID (Identification) to retrieve customer information automatically from a database.

CTS:

1) Clear to Send: An RS-232 MODEM interface control line (circuit/pin 5) which indicates to the terminal device transmission may begin. RS-449 (Pin 9A & 27B) a DCE (Data Communication Equipment) reply to the DTE (Data Terminal Equipment) following a DTE Request to send.

2) Common Transport Semantic: Cornerstone of the IBM strategy to reduce the number of protocols on networks. CTS provides a single API (Application Program Interface), which enables network software and applications to run over APPN (Advanced Peer-to-Peer Networking), OSI (Open System Interconnection), and TCP/IP (Transmission Control Protocol/Internet Protocol).

CU:

Coding Unit: A type of access device

CUG:

Closed User Group: A term that refers to a predefined set of terminal users that only accept connection (send/receive) requests (calls) from their user group.

CURRENT LOOP:

A digital transmission method that recognizes current flows as compared to voltage changes.

A method of connecting and transmitting signals to Teletype data terminals, where a mark is represented by the presence of current and a space is represented by the absence of current (USA). In other countries, a mark is represented by current in one direction, while a space is represented by current in the other.

CURSOR:

A position indicator used in video terminals (CRT) to indicate where the next event or input will occur on the screen.

CUSTOMER INFORMATION CONTROL SYSTEM (CICS):

An IBM central processing software facility for remote terminal transactions

CUSTOMER PROVIDED EQUIPMENT:

See CPE

CUSTOMER SELF INSTALL (CSI):
Refers to customer-installed low-pass micro-filter for each line analog device, telephones, fax machines, etc., to filter out any DSL signal noise from your voice service. This allows both voice and data to share common inside wiring. The filters are placed between the analog devices and the phone jack(s) and do not require any tools for installation.

CUT THROUGH:

Connecting of a path for signaling and/or communications between two points through an intermediary or transit point

CUT THROUGH PACKET SWITCHING:

A packet switching approach that streams data through a switch so the leading edge of a packet exits the switch at the output port before the packet (end) finishes entering the input port. A device using cut-through packet switching reads, processes, and forwards packets as soon as the destination address is determined and the outgoing port is determined.

CV:

Coding Violation: Occurrence of bit error(s) during transmission, as detected by examining a redundancy check code embedded within the signal (data) format. CV also refers to the performance parameter, which is the count of detected transmission errors on the line and section levels.

CVSD:

Continuous Variable Slope Delta modulation: A modulation process that converts speech (voice) to digital signals by using a one bit sample to encode the difference between two successive signal levels, with the sampling occurring about 32,000 times a second.

CWAF:

Cisco Web Application Framework: The underlying framework that manages the Web GUI (graphical user interface) for user registrar and MODEM registrar.

C:\WINDOWS:

Systemroot’: The path and folder name where the Windows system files are located. Typically, this is C:\Windows, although a user can designate a different drive or folder when Windows is installed. An individual can use the value %systemroot% to replace the actual location of the folder that contains the Window system files. Example: To identify the systemroot folder, click Start, click Run, type %systemroot%, and then click OK.

CxBUS:

Cisco Extended Bus: Data bus for interface processors on Cisco 7000 series routers.

CXR:

A term that refers to a ‘Carrier’ device or a data communications signal, Carrier Detect, that may be used by a terminal controller to indicate an intention to transmit data.

CYBERPUNK:

Cyberpunk was originally a cultural sub-genre of science fiction taking place in a not-so-distant future over-industrialized society. The term grew out of the work of William Gibson and Bruce Sterling and has evolved into a cultural label encompassing many different kinds of human, machine, and punk attitudes. It includes clothing and lifestyle choices as well.

CYBERSPACE:

A Term often used to describe a whole range of information resources available through computer networks. Often used when referring to the Internet and/or the World Wide Web

CYBERSQUATTING:

The act of registering a company name as a domain name by someone outside the company in hopes of selling it to the company for a profit; anti-Cyber-squatting legislation has been introduced to make it illegal.

CYCLE (HERTZ / HZ):

A term applied to alternating current (AC). Specifically, the time required for an electric current to start at zero, go through some positive value, through zero, then through some negative value and return to zero. Expressed in Hertz (cycles per second); or a regularly repeated sequence of operations.

CYCLE TIME:

The unit of time that individual elements of the central processing unit require to complete their functions

CYCLES PER INSTRUCTION:

The number of cycles necessary to process an instruction

CYCLIC CHECK CHARACTER:

See CRC

CYCLIC REDUNDANCY CHECK:

See CRC