The set of all LAN wiring and connection panels in a building. This set includes both fiber and copper wiring.
A computer network that encompasses all Local Area Networking technology in a set of closely situated buildings.
See Campus Area Network.
See CSMA/CA.
See CSMA/CD.
Also called Cat-3, a specification for unshielded twisted-pair copper cabling. It was commonly used for 10Mbps Ethernet and 4 and 16Mbps Token Ring networks. It can also be used for Fast Ethernet with the less common 100BaseT4 standard.
Also called Cat-5, a specification for unshielded twisted-pair copper cabling. It can be used anywhere Category 3 cable is used, as well as for higher speed networks such as Fast Ethernet and, with limits, Gigabit Ethernet.
Enhanced Category 5 Cable, also called Cat-5e. This specification is an updated version of the Category 5 Cable specification that includes features designed to make it appropriate for Gigabit Ethernet.
Also called Cat-6, a further refinement on previous standards for unshielded twisted- pair copper cabling that is designed for higher-speed networks.
Controlled Access Unit. For Token Ring network, a CAU is a manageable version of a MAU. See also MAU.
Constant Bit Rate. In ATM Quality of Service, CBR is used for applications that require reliable delivery of cells with end-to-end clocking to ensure minimal jitter.
In ATM networking, the basic unit of data transmission. Each ATM cell consists of a 5-byte header followed by 48 bytes of data.
See CSU.
Classless Inter-Domain Routing. Defined in IETF RFCs 1518 and 1519, CIDR is a standard for addressing and routing in IP networks. It abandoned the earlier Class- based system in favor of being able to divide up ranges of 32-bit IP addresses at any bit.
See COS.
See CIDR.
In Ethernet networks, what happens when two devices attempt to send frames onto the same segment simultaneously.
In 802.3 Ethernet networks, a network segment. The name comes from the fact that if any two devices in the same collision attempt to transmit simultaneously, they will cause a collision.
A Layer 2 device, such as a hub or a switch, that is used to connect several other devices or groups of devices into a larger network.
See CBR.
See CAU.
Class of Service. In 802.1q VLAN tags, the COS field contains a code that specifies how the frame should be handled by the Quality of Service mechanisms in times of congestion.
Cyclic Redundancy Checksum.
Carrier Sense Multiple Access/Collision Avoidance. This is the name for the method that 802.11 wireless LAN protocols use to handle congestion. It is similar to the Ethernet CSMA/CD system except that it is not possible to reliably generate collision information in a wireless network.
Carrier Sense Multiple Access/Collision Detection. This is the name for the method that 802.3 Ethernet uses to handle congestion. The name means that before any device attempts to transmit, it first listens for a carrier signal that would indicate that another device is already using the network. Then, if another device starts transmitting before the first device has finished transmitting, both devices detect the collision and send a jamming signal to prevent either packet from being partially received. They then both wait a random back-off period before trying again.
Channel Service Unit. When connecting network equipment to WAN circuits, the CSU enables the connection of the user device, such as a router. See also DSU.
See CSU and DSU.
See CRC.