Lucent Technologies PacketStar PSAX, User Manual, Page: 386 / 405

255-700-243 Glossary-45
PacketStar
®
PSAX 12-Port Medium-Density DS1 Multiservice Module User Guide , Issue 1 Release 8.0
Glossary
PVC Permanent Virtual Circuit. A virtual circuit that provides the
equivalent of a dedicated private line service over a packet
switching network between two DTEs. Virtual circuits and
SDNs are other types of virtual networks.
Q
QoS quality of service. An ATM Forum Protocol that is defined in
terms of an end-to-end ATM connection under ITU-T Recom-
mendation 1.350. QoS measures cell error ratio, severely
errored cell block ratio, cell loss ratio and cell misinsertion
rate, cell transfer delay, mean cell transfer delay, and cell
delay variability.
Quadserial A Lucent module, superseding multiserial and high-speed
modules.
quality of service See QoS.
queuing Stacking or holding calls to be handled by a trunk, or trunk
group, when there are insufficient trunks to handle the
amount of traffic.
R
R1 ITU name for a particular North American digital trunk proto-
col that uses multi-frequency (MF) pulsing.
R2 A series of ITU-T specs for European analog and digital trunk
signaling, which uses compelled handshaking on every MF
(multi-frequency) signaling digit.
radio frequency A group of electromagnetic energy whose wavelengths are
between the audio and the light range. The electromagnetic
waves transmitted usually are between 500 KHz and 300
GHz.
RAI remote alarm indication. This alarm indicates that a device on
the T1 line, DS3 line, or DS2 stream is detecting framing-error
conditions in the signal it receives. An RAI is also called a yel-
low alarm signal.
RAS remote access service. A network unit that enables branch
offices, telecommuters, and traveling computer users to gain
access to the corporate LAN backbone over dedicated or
dialed, digital, or analog lines.
RDI remote defect indication. An alert to a failure at the far end of
an ATM network. Unlike FERF (far-end remote failure), the
RDI alarm doesn’t indicate the specific circuit with failure.
ready to receive See RR.
ready to send See RTS.
recommended standard See RS.
redundancy The duplication of hardware or software within a network to
endure fault-tolerant or back-up operation.