Alcatel Speed Touch 591s, Техническое руководство пользователя, Страница: 173 / 184

Glossary
Speed Touch 591s Technical Practices GL-5
February 2001 90-8785-01
LOS a) loss of signal
LOS is an indication that no valid signal can be detected at the transmission
interface.
b) loss of synchronization
MCT mild congestion threshold
MTCE maintenance
MTCE is an LED on the Speed Touch 591s, indicating that it is in a
maintenance state when lit (usually when a loopback is in progress).
NIWF network interworking function
An NIWF is an interworking function used to transport frame relay packets
across an intermediate network to another frame relay network.
NMTI node management terminal interface
The local user interface for an Alcatel network product.
NVM nonvolatile memory
NVM is memory that maintains its contents during power loss conditions.
OAM operations, administration, and maintenance
OAM includes network maintenance features such as connectivity
verification, alarm surveillance, continuity checking, and performance
monitoring.
PDU protocol data unit
The PDU is the unit of data in the OSI Reference Model. It contains both
protocol-control information and user data from the layer above and allows
the two processes to coordinate interactions.
PPP point-to-point protocol
PPP is a protocol that allows a computer to use TCP/IP with a standard
telephone line and a high-speed modem to establish a link between two (and
only two) terminal installations.
PSD power spectral density
PVC permanent virtual circuit
A PVC is a frame relay end-to-end logical connection that extends between
two user or network interfaces. A single PVC may pass through several
frame relay switching modes.
QoS quality of service
For ATM, the quality of service of a connection is defined by its traffic
characteristics such as cell loss probability, cell delay variation, and cell
delay.