Glossary - JDS Uniphase HST-3000 User Manual

Glossary

54
D
DA — Destination address.
DS1 — Digital Signal 1. An
interface providing a framed or
unframed 1.544 Mb/s bit stream.
DS1 corresponds to the North
American and Japanese T1
designator.
DCE — Data Communications
Equipment. Equipment that
resolves issues between a Data
Terminal Equipment (DTE)
device and the network, such as
a modem. You can configure the
HST to emulate a DCE device
when testing frame relay service
on a data communications inter-
face.
DE — Discard Eligibility Indi-
cator bit.
DLCI — Data Link Connection
Identifier.
DS2 — Digital Signal 2. A digital
signaling rate of 6.312 Mbps,
corresponding to the North
American T2 designator
DS3 — Digital Signal 3. A digital
signal rate of 44.736 Mbps,
corresponding to the North
American T3 designator.
DSX — Digital System Cross-
connect frame.
HST-3000 Frame Relay Testing User's Guide
DTE — Data Terminal Equip-
ment. Equipment that serves as
the data transmission source,
data transmission destination, or
both, for the purpose of sending
for receiving data. Examples of
DTEs include personal
computers (PCs), data termi-
nals, and peripheral devices
such as printers. You can
configure the HST to emulate a
DTE device when testing frame
relay service on a data commu-
nications interface.
E
ES — Errored Second. A
second during which at least
one error or alarm occurred.
ESF — Extended Superframe.
The F bits from 24 consecutive
frames are used to provide
frame alignment, frame CRC
and out-of-band signalling.
EA — Extension Bit. A bit that
indicates whether the frame
uses a 3 or 4 byte header.
Encapsulation — A process by
which an interface device places
an end device's protocol-
specific frames inside a frame
relay frame. The network
accepts only frames formatted
specifically for frame relay;
therefore, interface devices
acting as interfaces to a frame
relay network must perform
encapsulation.