C
Glossary
B-14
Centillion 1200N ATM Switch User Manual
NTP 297-8103-903
CBR
Constant Bit Rate: An ATM service category which supports a constant or
guaranteed rate to transport services such as video or voice as well as circuit
emulation which requires rigorous timing control and performance parameters.
CCITT
Comite Consutarif International Telegraphique at Telephonique: The Consultive
Committee on International Telegraph and Telephony.The CCIT is known as the
ITU-T (International Telecommunications Union Telecommunications Services
Sector), based in Geneva Switzerland.The scope of its work is now much broader
than just telegraphy and telephony.It now also includes telematics, data, new
services, systems and networks (like ISDN).
CCR
Current Cell Rate: The Current Cell Rate is an RM-cell field set by the source to
its current ACR when it generates a forward RM-cell. This field may be used to
facilitate the calculation of ER, and may not be changed by network elements. CCR
is formatted as a rate.
CCS
Common Channel Signaling: A form signaling in which a group of circuits share a
signaling channel. Refer to SS7.
CDF
Cutoff Decrease Factor: CDF controls the decrease in ACR (Allowed Cell Rate)
associated with CRM.
CD-ROM
Compact Disk-Read Only Memory: Used by a computer to store large amounts of
data. Commonly used for interactive video games.
CDV
Cell Delay Variation: CDV is a component of cell transfer delay, induced by
buffering and cell scheduling. Peak-to-peak CDV is a QoS delay parameter
associated with CBR and VBR services. The peak-to- peak CDV is the ((1-a)
quantile of the CTD) minus the fixed CTD that could be experienced by any
delivered cell on a connection during the entire connection holding time. The
parameter "a" is the probability of a cell arriving late. See CDVT.
