Glossary D
Centillion 1200N ATM Switch User Manual B-23
NTP 297-8103-903
DS-2
Digital Signal, Level 2: The North American Digital Hierarchy signaling standard
for transmission of 6.312 Mbps that is used by T2 carrier which supp ort s 96 c al ls .
DS-3
Digital Signal, Level 3: The North American Digital Hierarchy signaling standard
for transmission at 44.736 Mbps that is used by T3 carrier. DS-3 supports 28 DS-
1s plus overhead.
DS3 PLCP
Physical Layer Convergence Protocol: An alternate method used by older T ca rrier
equipment to locate ATM cell boundaries. This method has recently been moved
to an informative appendix of the ATM DS3 specification and has been replaced
by the HEC method.
DSE
Distributed Single-Layer Embedded (Test Method): An abstract test method in
which the upper tester is located within the system under test and there is a point
of control and observation at the upper service boundary of the Implementation
Under Test (IUT) for testing a protocol layer, or sublayer, which is part of a multi-
protocol IUT.
DSS2 Setup
Digital Subscriber Signaling #2: ATM Broadband signaling.
DSU
Data Service Unit: Equipment used to attach users' computing equipment to a
public network. Converts RS-232-C or other terminal interface to DSX-1
interface.Also called Digital Service Unit.
DTE
Data Terminal Equipment: A generic definition of extern al networking interface
equipment such as a modem.
DTL
Designated Transit List: A list of nodes and optional link IDs that completely
specify a path across a single PNNI peer group.
DTL Originator
The first switching system within the entire PNNI routing domain to build the
initial DTL stack for a given connection.