Glossary Section "C" ( Definitions )
CA Call Appearance
caching A form of replication in which information learned during a previous transaction is used to process later transactions.
CAD Computer Assisted Design is a form of drafting on computers.
Carrier A continuous signal at a fixed frequency that is capable of being modulated with a second (information carrying) signal.
CAT5 Category 5 network cabling consists of four twisted pairs of copper wire. The connectors are RJ45. CAT-5 cabling supports speeds up to 100 Mbps.
CAP Competitive Access Provider. A company that builds and operates communication networks in metropolitan areas and provides its customers with an alternative to the local telephone company. See CLEC.
CAS Channel Associated Signaling is used in T1 circuits. Instead of having a specific timeslot dedicated to provide signal (as is true with ISDN) , signaling bits for on-hook and off-hook are within the sixth, twelfth, eighteenth and twenty-fourth frames of each time slot. CAS is sometimes called RBS (robbed bit signaling) because it takes bits from the bearer channels for signaling.
CBR Constant Bit Rate. A data transmission that can be represented by a non-varying, or continuous, stream of bits or cell payloads. Applications such as voice circuits generate CBR traffic patterns. CBR is an ATM service type in which the ATM network guarantees to meet the transmitter's bandwidth and Quality of Service requirements. See ABR, UBR, VBR.
CCD Charge-Coupled Device
CCIS Common Channel Inter-Office Signaling
CCITT Consultive Committee for International Telegraphy and Telephony
CCR Commitment, Concurrency, and Recovery. An OSI application service element used to create atomic operations across distributed systems. Used primarily to implement two-phase commit for transactions and nonstop operations.
CCSA Common Control Switching
CDP Conditional Di-Phase. A digital encoding technique which is not sensitive to polarity of wires (wires in a pair can be crossed).
CEPT Committee of Euorpean Postal and Telecommunications
CERN European Laboratory for Particle Physics. Birthplace of the World-Wide Web.
CERT Computer Emergency Response Team. The CERT is 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. The US CERT is based at Carnegie Mellon University in Pittsburgh, regional CERTs are,
CFV Call For Votes. Prior to generating a new newsgroup, a Call For Votes is issued to help determine the need for the group.
Channel Bank Equipment that connects multiple voice channels to high speed links by performing voice digitization and Time Division Multiplexing.
Charlie-Foxtrot (colloquial usage) seriously beyond all hope. Very badly broken.
checksum A computed value which is dependent upon the contents of a packet. This value is sent along with the packet when it is transmitted. The receiving system computes a new checksum based upon the received data and compares this value with the one sent with the packet. If the two values are the same, the receiver has a high degree of confidence that the data was received correctly.
circuit switching A communications paradigm in which a dedicated communication path is established between two hosts, and on which all packets travel. The telephone system is an example of a circuit switched network.
CLE Customer Located Equipment
CLI Command Line Interface
client-server model A common way to describe network services and the model user processes (programs) of those services. Examples include the nameserver/nameresolver paradigm of the DNS and fileserver/file-client relationships such as NFS and diskless hosts.
CLNP Connectionless Network Protocol. The OSI protocol for providing the OSI Connectionless Network Service (datagram service). CLNP is the OSI equivalent to Internet IP, and is sometimes called ISO IP.
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. The 051 equivalent of UDP.
CMIP Common Management Information Protocol
CMIS Common Management Information Services
CNAME records are domain name aliases. The most common use is to have a web-server point one url to another. For example "bestdatasource.com" to "www.bestdatasource.com". It could also be used to point "cutternetworks.com" to "www.bestdatasource.com".
CO Central Office
concatenate To join by attaching one group to another end to end. This is frequently associated with computer data file handling. If file "A" consists of "1234" and file "B" consists of "5678" and you concatenate "B" to "A", the result is "12345678".
compression There are several types of compression but the idea is same. Basically compression is used to reduce the amount of bandwidth required to transmit information. Frequently, this accomplished in part by having a character(s) that represents a number of blank spaces without the need for transmitting the blanks themselves. In voice compression, various manufacturers use different techniques. (example of voice compression product)
connectionless The model of interconnection in which communication takes place without first establishing a connection. Sometimes (imprecisely) called datagram. Examples: Internet IP and OSI CLNP, UDP, ordinary postcards.
connection oriented The model of interconnection in which communication proceeds through three well-defined phases: connection establishment, data transfer, connection release. Examples: X.25, Internet TCP and OSI TP4, ordinary telephone calls.
congestion Congestion occurs when the offered load exceeds the capacity of a data communication path.
CORBA Common Object Request Broker Architecture. CORBA is the Object Management Group's (0MG) 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 no matter where they are located or who has designed them. CORBA was introduced in 1991 by OMG which defined the Interface Definition Language (IDL) and the Application Programming Interfaces (API) that enable client/server object interaction within a specific implementation of an Object Request Broker (ORB). See IIOP.
CORE Council of Registrars. The operational organization composed of authorized Registrars for managing allocations under gTLDs.
core gateway Historically, one of a set of gateways (routers) operated by the Internet Network Operations Center at BBN. The core gateway system formed a central part of Internet routing in that all groups would advertise paths to their networks from a core gateway, using the Exterior Gateway Protocol (EGP). See EGP, backbone.
CPE Customer Premise Equipment
CRC Cyclic Redundancy Check. A number derived from a set of data that will be transmitted. By comparing it to the value originally transmitted, the receiving node can detect some types of transmission errors. See checksum.
CRDI Corporation for Research and Educational Networking.
CRM is a broad term meaning customer relationship management. CRM can be software, computer data bases or procedures. Generally, it means collecting detailed information about the customer to provide them with more personalized service.
CSNET Computer+Science Network. Was a large computer network, mostly in the U.S. but with international connections. CSNET sites included universities, research labs, and some commercial companies. Later merged with BITNET to form CREN. See BITNET.
CSU Channel Service Unit is a digital DCE used to terminate digital circuits (such as DDS or T1 lines) at the customer site. It conditions the line, ensures network compliance with FCC rules, and responds to loopback commands from the central office; it also ensures proper ones density in transmitted bit streams and corrects bipolar violations.
CTI Computer Telephony Integration. The name given to the merger of traditional telecommunications (PBX) equipment with computers and computer applications. The use of Caller ID to automatically retrieve customer information from a database is an example of a CTI application.
CWDM Coarse Wavelength Division Multiplexing allows for multiple wavelength signals to be sent over a fiber optic connection. This allows for more traffic over the fiber but generally the distance is shorter.
Cyberspace A term coined by William Gibson in his fantasy novel Neuromancer to describe the "world" of computers, and the society that gathers around them. Often used to refer to the Internet, the World-Wide Web or some combination thereof.