Megabit Modem 400F, 500L, 600F, and 700F User Manual 117
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GLOSSARY
10/100BASE-T The Institute of Electrical and Electronic Engineers (IEEE) 802.3 specification for
Ethernet over thin coaxial cable.
AAL5 ATM Adaptation Layer 5.
ADSL Asymmetric Digital Subscriber Line is a technology in which data is transferred from
the service provider to the subscriber at up to 7.552 Mbps, and transferred from
subscriber to service provider at up to 928 Kbps. ADSL is the implementation of the
physical layer for transmission of data.
ATM Asynchronous Transfer Mode is a high bandwidth, low delay, connection-oriented,
packet-like switching and multiplexing technique that uses 53-byte fixed-size cells to
transmit voice, video and data over a network. ATM layers define how cells are
formatted and provides the transport of the fixed length cells between the modem
and the service provider (or endpoints of the virtual connection).
attenuation The dissipation of the power of a transmitted signal as it travels over copper wire,
measured in decibels (dB).
authentication Security feature offered through PAP and CHAP with PPP sessions.
BER Bit Error Rate is a measure of transmission quality. The ratio of error bits to the total
number of bits transmitted.
bps bit-per-second is the number of bits transferred during each second of data
transmission.
CBR Constant Bit Rate is a Service Class for the modem. It provides constant bit rate data
with a timing relationship between the source and the destination. Also, a traffic class
that carries a guaranteed constant bandwidth. Best suited for applications that require
fixed bandwidth, such as uncompressed voice, video and circuit emulation. CBR is a
Quality of Service class defined by the ATM Forum for ATM networks.
cell A fixed-length packet. Also, the unit of data transmission used in ATM. Each ATM cell
contains a fixed-size frame (53 bytes) consisting of a five-byte header and a 48-byte
payload.