User manual

Glossary-10 July 2004 Wide Bank 28 DS3 - Release 2.4
Glossary
Line Terminating
Equipment
LTE. Network elements such as add/drop multiplexers or digital cross-connect systems
which can access, generate, and process Line Overhead.
Loss of Signal LOS. The DS3 LOS defect is declared upon observing 175 ± 75 contiguous pulse positions
with no pulses of either positive or negative polarity. The DS3 LOS defect is terminated
upon observing an average pulse density of at least 33% over a period of 175 ± 75
contiguous pulse positions starting with the receipt of pulse.
M23 Framing A DS3 frame format that uses the overhead C-bits to indicate stuffing. All three Cbits in a
subframe are set to one (1) if stuffing occurs, or to zero (0) if stuffing does not occur. See
Stuffing.
Megabits per second Mbps. one million of bits per second.
Multiplex MUX. To transmit two or more signals over a single channel.
Multiplexer A device for combining several channels to be carried by one line or fiber.
Narrowband Services requiring up to 1.5 Mbps transport capacity.
Operations System Sophisticated applications software that overlooks the entire network.
Orderwire A channel used by installers to expedite the provisioning of lines.
OSI Seven-Layer
Model
An Open System Interconnection (OSI) standard architecture for data communications.
Layers define hardware and software required for multi-vendor information processing
equipment to be mutually compatible. The seven layers from lowest to highest are:
physical, link, network, transport, session, presentation, and application.
Out of Frame OOF. A DS3 defect that is detected when any three or more errors in sixteen or fewer
consecutive F-bits occur within a DS3 M-frame. An OOF defect may also be called a
Severely Errored Frame (SEF) defect. An OOF defect is cleared when reframe occurs. A
DS3 Loss of Frame (LOF) failure is declared when the DS3 OOF defect is consistent for 2
to 10 seconds. The DS3 OOF defect ends when reframe occurs. The DS3 LOF failure is
cleared when the DS3 OOF defect is absent for 10 to 20 seconds.
Overhead Extra bits in a digital stream used to carry information besides traffic signals. Orderwire,
for example, would be considered overhead information.
P-bit Coding
Violation
PCV. For all DS3 applications, a coding violation error event is a P-bit Parity Error event.
A P-bit Parity Error event is the occurrence of a received P-bit code on the DS3 M-frame
that is not identical to the corresponding locally-calculated code.
P-bit Errored
Seconds
A second with one or more PCVs OR one or more Out of Frame defects OR a detected
incoming AIS. This gauge is not incremented when UASs are counted.
P-bit Severely
Errored Seconds
PSES. A PSES is a second with 44 or more PCVs OR one or more Out of Frame defects
OR a detected incoming AIS. This gauge is not incremented when UASs are counted.