ADTRAN 1200275L1, User Manual

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Appendix D. Glossary
61200275L1-1 TSU IQ+ User Manual D-11
point-to-point
Type of communications link that connects a single device to another single
device, such as a remote terminal to a host computer.
PVC
permanent virtual circuit. A frame relay logical link, whose endpoints and class
of service are defined by network management. Analogous to an X.25 perma-
nent virtual circuit, a PVC consists of the originating frame relay network ele-
ment address, originating data link control identifier, terminating frame relay
network element address, and termination data link control identifier. Originat-
ing refers to the access interface from which the PVC is initiated. Terminating
refers to the access interface at which the PVC stops. Many data network cus-
tomers require a PVC between two points. Data terminating equipment with a
need for continuous communion use PVCs. See also DLCI.
red alarm
A red alarm is declared on detection of an LOS or OOF not caused by an alarm
indication signal (AIS) that persists for two seconds.
remote configuration
A feature designed into ADTRAN products that allows remote units to be con-
figured from a local unit or VT 100 compatible terminal.
router
A device that supports LAN-to-LAN communications. Routers may be
equipped to provide frame relay support to the LAN devices they serve. A
frame-relay-capable router encapsulates LAN frames into frame relay frames
and feeds those frame relay frames to a frame relay switch for transmission
across the network. A frame-relay-capable router also receives frame relay
frames from the network, strips the frame relay frame off of each frame to pro-
duce the original LAN frame, and passes the LAN frame on to the end device.
Routers connect multiple LAN segments to each other or to a WAN. Routers
route traffic on the Level 3 LAN protocol (e.g., the internet protocol address).
See also bridge.
SDLC
synchronous data link control. A link-level communications protocol used in an
IBM systems network architecture (SNA) network that manages synchronous,
code-transparent, serial information transfer over a link connection. SDLC is a
subset of the HDLC protocol developed by ISO.