Agilent Technologies HSSI WanProbe J3916A - Manual (Page 157)

Glossary
137
Data Link Layer
Level 2 of the seven level OSI reference model defined by ISO. This layer
provides the link access control and reliability to networks.
Default Gateway Address
The address of the gateway which is closest to the probe.
Discard Eligibility Bit (D/E)
Frame Relay mechanism to allow the source of a data stream to prioritize frames
indicating those preferred to be discarded in the case of network congestion. If the
D/E bit of a frame is set to 1, the frame is a preferred candidate to be discarded.
DLCI (Data Link Connection Identifier)
The Data Link Connection Identifier (DLCI) is made up of six bits in a frame
relay frame. All DLCIs are listed in a table. A DLCI checks the integrity of the
frame using a Frame Check Sequence (FCS). If an error is found, the frame is
deleted.
DCE (Data Circuit-terminating Equipment)
Modems, line drivers, DSUs, ISDN NT1s and NT2s.
DRAM
Dynamic Random Access Memory, which is the main memory of a probe.
DSU/CSU (Data Service Unit/Channel Service Unit)
DSU/CSU is a term commonly applied to equipment at the customer premises
(equipment) side or the company (line) side of a network.
DTE (Data Terminal Equipment)
The device at the end of the link. The source or sink of the digital data. DTEs may
be CRTs, printers, plotters, PC’s, mini-computers, main-frames, or any other
device which makes use of a DCE.
EIA-232D
The Electronic Industries Association successor to RS-232. Common,
inexpensive level 1 interface with a specified 20 kbps top speed and 50 feet
maximum distance. EIA-232D formalizes the 25 pin and 9 pin implementations.