User manual

Wide Bank 28 DS3 - Release 2.4 July 2004 Glossary-5
Glossary
Definitions
10Base-T An IEEE standard for operating Ethernet local area networks (LANs) on twisted-pair
cabling using the home run method of wiring (the same as the phone company uses) and a
wiring hub that contains electronics performing similar functions to a central telephone
switch. The full name for the standard is IEEE 802.3 10Base-T.
Add/Drop The process where a part of the information carried in a transmission system is
demultiplexed (dropped) at an intermediate point and different information is multiplexed
(added) for subsequent transmission. The remaining traffic passes straight through the
multiplexer without additional processing.
Add/Drop
Multiplexer
ADM. A multiplexer, like a terminal multiplexer, capable of extracting and inserting
lower-rate signals from a higher-rate multiplexed signal without completely
demultiplexing the signal.
Address Resolution
Protocol
ARP. A protocol used to map IP addresses to Ethernet addresses.
Alarm Indication
Signal
AIS. The DS3 AIS is framed with “stuck stuffing.” This implies that it has a valid
Msubframe alignments bits, M-frame alignment bits, and P bits. The information bits are
set to a 1010 sequence, starting with a one (1) after each M-subframe alignment bit, M-
frame alignment bit, X bit, P bit, and C bit. The C bits are all set to zero giving what is called
“stuck stuffing.” The X bits are set to one. The DS3 AIS defect is declared after DS3 AIS
is present in contiguous M-frames for a time equal to or greater than T, where
0.2 ms ≤ T ≤ 100 ms. The DS3 AIS defect is terminated after AIS is absent in contiguous
M-frames for a time equal to or greater than T.
Alternate Mark
Inversion
AMI. An AMI encoded signal is a bipolar pseudo-ternary signal conveying binary digits
(bits) in which successive “marks” are normally of alternating, positive and negative,
polarity. This is the traditional method of line encoding used with bipolar DS1 (T1) signals.
However, use of AMI does not preclude long strings of zeros being sent in the signal
entering the public network from the DTE in violation of the pulse density requirements
mandated in FCC Rules Part 68 and AT&T Publication 62411.
Asynchronous A network where transmission system payloads are not synchronized and each network
terminal runs on its own clock.
Asynchronous
Transfer Mode
ATM. A multiplexing/switching technique in which information is organized into fixed-
length cells with each cell consisting of an identification header field and an information
field. The transfer mode is asynchronous in the sense that the use of the cells depends on
the required or instantaneous bit rate.
Attenuation Reduction of signal magnitude or increased signal loss, usually expressed in decibels (dB).
Authentication Process whereby a received message is associated with a specific originating entity.