Cisco BPX 8620 Installation And Configuration Manual page 573

See CLLM.
consollidated link
layer management
See CBR.
constant bit rate
See CCITT.
Consultive
Committee for
International
Telephone and
Telegraph
An RS-232 port on the face plate of a back card for a controller card (BCC, NPC, NPM.) that may used
control port
for connecting a control terminal. This port is bidirectional.
class of service.
CoS
The priority assigned each user connection. Defines which circuits get rerouted first during a network
failure.
class of service buffer.
CoSB
A buffer or queue that serves connections with similar QoS requirements. Also called "qbin" (though
a qbin is a platform-specific instance, such as a BXM card.
See CoSB.
CoS Buffer
A component of a Service Class Template that contains CoSB configurations indexed by the CoSB
CoSB Descriptor
number.
Template
A qbin is a platform-specific (BXM in this case) instance of the more general CoSB.
See Class of Service Buffer.
CoSB
A software feature that is used to conserve network bandwidth by automatically "downing" a voice
courtesy downing
connection when the signaling status indicates an inactive (on-hook) circuit. The circuit is
automatically "upped" when the circuit becomes active.
cyclical redundancy check.
CRC
A method of error checking that detects errors in a block of data. Unlike parity checks, the CRC can
detect multiple data errors within the block and thus equipment using a CRC error check can derive a
error rate.
A two-dimensional data switch type that is arranged in a matrix of all input connections along one axis
crosspoint switch
and all output connections along the other axis. Each input and output line has a switch point where the
two axis intersect that can be enabled (switch closed) or disabled (switch open). The central matrix
switch providing the switching matrix for traffic routing by the BPX switch.
channel service unit.
CSU
A network protection unit that terminates any T1 span line connected to the carrier's central office,
providing receive direction regeneration and maintenance loopback for the 1.544 Mbps signal.
See CSU.
channel service
unit
See CRC.
cyclical redundancy
check
Release 9.3.30, Part Number 78-12907-01 Rev. E0, May 2005
Cisco BPX 8600 Series Installation and Configuration
Glossary
GL-7