User Manual

Glossary
225
Glossary
CSU/DSU Channel service unit/data service unit. Channel service unit connects a digital phone line to a
multiplexer or other digital signal device. Data service unit connects a DTE to a digital phone
line.
customer edge device See CE device.
D
daemon Background process that performs operations on behalf of the system software and
hardware. Daemons normally start when the system software is booted, and they run as long
as the software is running. In the JUNOS software, daemons are also referred to as processes.
data circuit-terminating
equipment
See DCE.
data-link connection
identifier
See DLCI.
data service unit See CSU/DSU.
Data Terminal
Equipment
See DTE.
dcd The JUNOS software interface process (daemon).
DCE Data circuit-terminating equipment. RS-232-C device, typically used for a modem or printer,
or a network
access and packet switching node.
default address Router address that is used as the source address on unnumbered interfaces.
denial of service See DoS.
dense
wavelength-division
multiplexing
See DWDM.
DHCP Dynamic Host Configuration Protocol. Allocates IP addresses dynamically so that they can be
reused when they are no longer needed.
Dijkstra algorithm See SPF.
DIMM Dual inline memory module. 168-pin memory module that supports 64-bit data transfer.
direct routes See interface routes.
DLCI Data-link connection identifier. Identifier for a Frame Relay virtual connection (also called a
logical interface).
DoS Denial of service. System security breach in which network services become unavailable to
users.
DRAM Dynamic random-access memory. Storage source on the router that can be accessed quickly
by a process.
drop profile Drop probabilities for different levels of buffer fullness that are used by RED to determine
from which queue to drop packets.