3Com SuperStack 3 NBX, Administrator'S Manual

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466 G
LOSSARY
client/server
computing
The division of an application into two parts that are linked by a network.
A typical example is a database application in which the database and
application software reside on a server, and the interface for entering or
retrieving information resides on individual workstations (clients).
CLI See caller ID.
CLIR Calling Line Identity Restriction. A telephone company option that allows
the caller to withhold caller identity from the person being called.
coaxial cable High-capacity networking cable that is formed by an outer braided wire
or metal foil shield surrounding a single inner conductor, with plastic
insulation between the two conducting layers. “Coax” cable is used for
broadband and baseband communications networks. Ethernet employs
thin coaxial cable in 10BASE2 and thick cable in 10BASE5.
CODEC CO mpressor/ DEC ompressor. A hardware circuit or software routine that
compresses and decompresses digitized audio, video, or image data.
Most codecs include the functions of A/D and D/A conversion as well as
compression and decompression.
CO der/ DEC oder. A hardware circuit that converts analog audio or video
signals into digital code, and vice versa, using techniques such as pulse
code modulation and delta modulation. A CODEC is an A/D and
D/A converter.
collapsed backbone Network architecture in which the backplane of a device, such as a hub,
performs the function of a network backbone. Example: The backplane
routes traffic between desktop nodes and between other hubs serving
multiple LANs.
collision The result of two devices on a shared transmission medium, like Ethernet,
transmitting simultaneously. Both devices must retry their transmissions.
A delay mechanism used by both senders drastically reduces the chances
of another collision.
collision detection Ethernet devices detect collisions instantly and attempt to resend. This is
the principle on which CSMA/CD (Carrier Sense Multiple Access with
Collision Detection) is based and the access control method for Ethernet.
concentrator A central chassis into which various modules, such as bridging,
supervisory, and 10BASE-T cards are plugged.