Glossary
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,
EIA-232D
The Electronic Industries Association successor to
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