Glossary-10
data link connection
See
DLC
data link connection identifier
See
DLCI
data rate or data signalling rate
A measure of how quickly data is transmitted. It is best expressed in bps. It
is, however, often incorrectly expressed in baud. Data rate is synonymous
with speed.
dB, decibel
A comparative (logarithmic) measure of signal power, a ratio.
dBm
An absolute measure of signal power, where 0 dBm is equal to one milliwatt
into 600 ohms.
dc signalling
A configurable option in an E&Mstrapped voice/fax channel.
DCE, data communications equipment
The equipment that provides the functions required to establish, maintain,
and terminate a connection (including signal conversion) for communications
between a data terminal equipment (DTE) and a telephone line or data
circuit. Also, interface signals typically presented by this equipment.
DDS, dataphone digital services
A communications service offered by the telephone company to transmit data
in digital form.
DE, discard eligibility
A userset bit indicating that a frame may be discarded in preference to other
frames if congestion occurs, to maintain the committed quality of service
within the network. Frames with DE bit set are considered Be data.
delta topology
The simplest form of ring and mesh topology, involving three nodes that are
fully interconnected with one another. If one link fails or if there is link
congestion, there is an alternate path for all nodes.
See also
mesh topology.
