C

Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)

The method of access used by most wireless communication. A device that wants to send data on the wire will first send a short message to make sure that the signal can be received.

Carrier Sense Multiple Access with Collision Detection (CSMA/CD)

The method of access used by Ethernet, which senses the wire first to determine whether data is currently on the wire before sending its data.

cathode-ray tube (CRT)

The earliest method of creating a display from computer-generated output. Consists of an electron gun that fires a series of electrons through a vacuum tube onto a phosphorous screen very much like a television screen. This is still the most common type of display used on computers today.

certificate

An electronic piece of identification received from a certificate authority. The certificate contains information about the certificate holder, including the public keys used for signatures and encryption.

certificate authority (CA)

A certificate server that has the authority to issue certificates for security purposes. Some CAs are considered root CAs, while others, called subordinate servers, derive their authority from a root CA.

Challenge Handshake Authentication Protocol (CHAP)

A remote access authentication protocol that uses a three-way handshake and is therefore considered one of the most secure remote access protocols that can also be used by multiple types of clients.

checksums

Error corrections that are used during computer communication on a network to ensure received data was not damaged in transit.

circuit switching

A technology whereby a single channel is opened at the start of a session and is used throughout the communication session.

classes

Ranges of IPv4 addresses that are defined by using a default subnet mask and a range of numbers for the first octet of the address.

Client Services for NetWare (CSNW)

A service that is installed on Microsoft clients to allow them to connect directly to a NetWare server and use resources contained on the server, provided that the client is given permissions for the resources.

cluster

A group of servers that are configured to share a common database such that any of the servers can provide the resources for clients.

clustering

The process of providing fault tolerance and load balancing through the use of multiple computers that share the same resource database.

cold site

An alternate site that is an agreement between two parties and can be used to contain computers and network equipment in the event of a disaster. This type of alternate site is not tested, and power and connectivity are not guaranteed.

cold spare

A device such as a hard drive or network interface card that is suitable to replace the primary device and is stored in a location where it can be found easily by the network administrator.

collision

An occurrence that is caused by two computers attempting to send data on the same media at exactly the same instant. Collisions cause all network traffic to stop for a short period of time before it is restarted.

Common Internet File System (CIFS)

The newest version of the SMB communication protocol that is used on Windows 2000 and Windows XP clients and the latest Microsoft server operating systems.

computer name

A generic term used to describe a computer in a network. This is usually also the NetBIOS name and the hostname of a computer on a network using TCP/IP.

cookies

Small files that contain a user's personal information and can be used to automatically log on to websites and provide information. Cookies can also be abused by other entities and should be controlled carefully.

Creator Owner

The user who originates a document. The Creator Owner has default permissions assigned by the system.