Section 4 C Terms Flashcards
Cable
The transmission media of a network.
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 value.
Cache
A group of memory locations set aside for temporary storage ofdata, especially frequently-used data or data needing high speedretrieval by the CPU.
Call Admission Control
Traffic management mechanism used in ATM networks thatdetermines whether the network can offer a path with sufficient bandwidth for a requested VCC.
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
The time required to establish a switched call between DTE devices.
CAM
Content-addressable memory. See associative memory.
Card
A circuit board that plugs into a computer’s bus to extend the computer’s capability.
Carrier
Electromagnetic wave or alternating current of a single frequency, suitable for modulation by another, data-bearing signal.
Case Insensitive
Referring to a system in which upper case letters are not differentiated from their lower case form.
Case Sensitive
Referring to a system in which upper case letters are differentiated from their lower case form.
Category 1 Cabling
One of five grades of UTP cabling described in the EIA/TIA-586 standard. Category 1 cabling is used for telephone communications and is not suitable for transmitting data. Compare with Category 2 cabling, Category 3 cabling, Category 4 cabling, and Category 5 cabling. See also EIA/TIA-586 and UTP.
Category 2 Cabling
One of five grades of UTP cabling described in the EIA/TIA-586 standard. Category 2 cabling is capable of transmitting data at speeds up to 4 Mbps. Compare with Category 1 cabling, Category 3 cabling, Category 4 cabling, and Category 5 cabling. See also EIA/TIA-586 and UTP.
Category 3 cabling
One of five grades of UTP cabling described in the EIA/TIA-586 standard. Category 3 cabling is used in 10Base T networks and can transmit data at speeds up to 10 Mbps. Compare with Category 1 cabling, Category 2 cabling, Category 4 cabling, and Category 5 cabling. See also EIA/TIA-586 and UTP.
Category 4 cabling
One of five grades of UTP cabling described in the EIA/TIA-586 standard. Category 4 cabling is used in Token Ring networks and can transmit data at speeds up to 16 Mbps. Compare with Category 1 cabling, Category 2 cabling, Category 3 cabling, and Category 5 cabling. See also EIA/TIA-586 and UTP.
Category 5 cabling
One of five grades of UTP cabling described in the EIA/TIA-586 standard. Category 5 cabling is used for running CDDI and can transmit data at speeds up to 100 Mbps Compare with Category 1 cabling, Category 2 cabling, Category 3 cabling, and Category 4 cabling. See also EIA/TIA-586 and UTP.
Catenet
Network in which hosts are connected to diverse networks, which themselves are connected with routers. The Internet is a prominent example of a catenet.
CATV
Cable television. Communication system where multiple channels of programming material are transmitted to homes using broadband coaxial cable. Formerly called Community Antenna Television.
CBDS
Connectionless Broadband Data Service. European high-speed, packet-switched, datagram-based WAN networking technology. Similar to SMDS.
CBR
Constant bit rate. QOS class defined by the ATM Forum for ATM networks. CBR is used for connections that depend on precise clocking to ensure undistorted delivery.
CCITT
Consultative Committee for International Telegraph and Television and Telephone. International organization responsible for the development of communications standards. Now called the ITU-T.
CCS
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
CD
Carrier Detect. Signal that indicates whether an interface is active. Also, a signal generated by a modem indicating that a call has been connected.
CDDI
Copper Distributed Data Interface. Implementation of FDDI protocols over STP and UTP cabling. CDDI transmits over relatively short distance (about 100 meters), providing data rates of 100Mbps using a dual-ring architecture to provide redundancy. Based on the ANSI Twisted-Pair Physical Medium Dependent (TPPMD) standard.
CDEV
The designation of a Control Panel Device in Macintosh System 6and earlier (obsolete).
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. Operates at 19.2 Kbps.
CDVT
Cell delay variation tolerance. Parameter defined by the ATM Forum for ATM traffic management. In CBR transmissions, determines the level of jitter that is tolerable for the data samples taken by the PCR.
CEDI
Cayman Encapsulated DDP in IP. An Apple Talk tunneling protocol developed by Cayman.
Cell
The basic unit for ATM 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. See also cell relay.
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, IEEE802.6, and SMDS.
Cells Per Second
Abbreviated cps.
Cellular Radio
Technology that uses radio transmissions to access telephone-company networks. Service is provided in a particular area by a low-power transmitter.
Centrex
AT&T PBX that provides direct inward dialing and automatic numbering identification of the calling PBX.
CEPT
Conférence Européenne des Postes et des Télécommunications. Association of the 26 European PTTs that recommends communication specifications to the ITU-T.
CERTnet
California Education and Research Federation Network. TCP/IP network, based in Southern California, that connects hundreds of higher-education centers internationally while also providing Internet access to subscribers. CERFnet was founded in 1988 by the San Diego Supercomputer Center and General Automics and is funded by the NSF.
Chaining
SNA concept in which RUs are grouped together for the propose of error recovery.
Channel
- A communication path. Multiple channels can be multiplexed over a single cable in certain environments. 2. In IBM, the specific path between large computers (such as mainframes) and attached peripheral devices.
Channel-attached
Pertaining to attachment of devices directly by data channels (input/output channels) to a computer.
Channelized E1
Access link operating at 2.048 Mbps that is subdivided into 30 B-channels and 1 D-channel, Supports DDR, Frame Relay, and X.25. Compare with channelized T1.
Channelized T1
Access link operating at 1.544 Mbps that is subdivided into 24 channels (23 B-channels and 1D-channel) of 64 Kbps each. The individual channels or groups of channels connect to different destinations. Supports DDR, Frame Relay, and X.25. Also referred to as fractional T1. Compare with channelized E1.
CHAP
Challenge Handshake Authentication Protocol. Security feature supported on lines using PPP encapsulation that prevents unauthorized access. CHAP does not itself prevent unauthorized access, it merely identifies the remote end. The router or access server than determines whether that user is allowed access. Compare to PAP.
Character
- A symbol such as a letter, number or punctuation mark that canbe arranged to represent higher units of meaning, such as wordsand sentences. 2. The group of bits that represents such a symbol.
Chat Script
String of text that defines the login “conversation” that occurs between two systems. Consist 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. Compare with Thinnet. See also 10Base2, Ethernet, and IEEE 802.3.
Checksum
The result of a mathematical operation that uses the binary representation of a group of data as its basis, usually to check the integrity of the data.
Choke Packet
Packet sent to a transmitter to tell it that congestion exists and that it should reduce its sending rate.
CICNet
Regional network that connects academic, reserach, nonprofit, and commercial organizations in the Midwestern United States. Founded in 1988, CICNet was a part of the NSF NET and was funded by the NSF until the NSFNET dissolved in 1995. See also NSFNET.
CICS
Customer Information Control System. IBM application subsystem allowing transactions entered at remote terminals to be processed concurrently by user applications.
CIDR
Classless interdomain routing. Technique supported by BGP4 and based on route aggregation. CIDR allows routers to group routes together in order to cut down on the quantity of routing information carried by the core routers. With CIDR, several IP networks appear to networks outside the group as a single, larger entity.
CIR
Committed information rate. The rate at which a Frame Relay network agrees to transfer information under normal conditions, averaged over a minimum increment of time. CIR, measured in bits per second, is one of the key negotiated tariff metrics.