Glossary
GL-20
Cisco 6260 Hardware Installation Guide
OL-2365-02
network
management
system
See
NMS
.
network timing
reference
See
NTR
.
NI-2 card
A second generation network interface card for Cisco DSLAMs. Board that works with the network
software and operating systems to transmit and receive messages on a network.
NMS
network management system. A system responsible for managing at least part of a network. An NMS
communicates with agents to help keep track of network statistics and resources.
node
Endpoint of a network connection or a junction common to two or more lines in a network. Nodes can
be processors, controllers, or workstations. Nodes can be interconnected by links and serve as control
points in the network. Node sometimes is used generically to refer to any entity that can access a
network, and frequently is used interchangeably with device. See also
host
.
node system save
file
See
NSS
file
.
noise margin
Noise margin is the margin between the signal and noise in decibels (dB). The recommended
minimum noise margin is typically 6dB. The 6dB noise margin was specified based on empirical
research and the resulting algorithms to allow the best performance (line rate and reach) while
maintaining the 10-7 bit-error rate. When RADSL is enabled for a DSL DMT application, the modem
will train to 1) the specified rate or 2) the highest rate possible given the line conditions while
maintaining a 6dB margin.
nonvolatile
random-access
memory
See
NVRAM
.
NSS file
node system save file. The file that is saved during the Save Configuration procedure or during a
software download. This file is required for the Restore Configurations procedure.
NTR
Network timing reference. In DSL, NTR enables the DSLAM to provide clocking for network devices
that reside beyond the CPE. The CPE must support NTR to enable this feature.
NVRAM
nonvolatile random-access memory. RAM that retains its contents when a unit is powered off.
O
OAM&P
operations, administration, management, and provisioning. Provides the facilities and the personnel
required to manage a network.
OC
Optical Carrier. Series of physical protocols (OC-1, OC-2, OC-3, and so on) defined for SONET
optical signal transmissions. OC signal levels put STS frames onto multimode fiber-optic line at a
variety of speeds. The base rate is 51.84 Mbps (OC-1); each signal level thereafter operates at a speed
divisible by that number (thus, OC-3 runs at 155.52 Mbps). See also
SONET
and
STS-3c
.
OC-
n
SONET optical carrier, Level
n
(such as
n
equals 3, 12, 48, 192).