User`s guide

Glossary
GL-3
7800-A2-GB26-80
May 1999
DTE Loopback. Loopback mode that loops the information received on the DTE T1
network interface back to the network as close to the network interface as possible.
Data Link Control Layer. SNA layer responsible for the transmission of data between two
nodes over a physical link.
Data Link Connection Identifier. The virtual circuit number corresponding to a particular
connection between two destinations. This number is used as part of the frame relay
header. The total number of DLCIs between endpoints make up the PVC. DLCIs are a
local means of identifying a PVC.
Digital signal level 0 (zero). A 64 kbps digital telecommunications signal or channel.
Digital signal level 1. A digital signal transmitted at the rate of 1.544 Mbps in North
America.
Digital Subscriber Line. The non-loaded, local-loop copper connection between the
customer and the first node within the network.
Digital Subscriber Line Access Multiplexer. A platform for DSL modems that provides
high-speed data transmission with POTS over traditional twisted-pair wiring.
Data Service Unit. Data communications equipment that provides timing, signal
regeneration, and an interface to data terminal equipment. A subrate DSU/CSU is normally
referred to as a DSU.
Digital Signal Cross Connect level 1. An interconnection point for terminals, multiplexers
and transmission facilities.
Data Terminal Equipment. The equipment, such as a computer or terminal, that provides
data in the form of digital signals for transmission.
Data Terminal Loopback. Loopback mode that loops the data for a particular synchronous
data port back to the port just before it is combined with the rest of the T1 data stream.
Excessive Error Rate. An error rate that is greater than the threshold that has been
configured in the device.
Exterior Gateway Protocol. Protocol that distributes routing information to the routers that
connect autonomous systems.
Electronic Industries Association. This organization provides standards for the data
communications industry to ensure uniformity of interface between DTEs and DCEs.
An Electronic Industries Association’s standard defining an interface.
MIB objects unique to a specific company’s devices.
Errored Second. A second with one or more ESF error events (one or more CRC6 error
events or OOFs).
Extended Superframe. The T1 transmission standard that specifies 24 frames as an
extended superframe to be used for frame synchronization and to locate signaling bits.
A leased or dial transmission path.
An alert that NMS displays indicating that the device has detected an abnormal condition
on the facility (line) that could cause data errors. The facility alarm only applies to leased
or Analog Private Line (APL) devices.
Facility Data Link. The selected framing bits in the ESF format used in a wide-area link that
are used for control, monitoring, and testing.
One identifiable group of bits that includes a sequence of bits for control, framing, etc.
DLBDL
DLDLCDL
DLCI
DS0
DS1
DSL
DSLAM
DSU
DSX-1
DTE
DTLB
EER
EGP
EIA
EIA-530A/RS449
V.35
Enterprise MIB
ES
ESF
facility
facility alarm
FDL
frame