3Com CoreBuilder 2500 Getting Started Manual page 97

G
LOSSARY
A port
Each DAS contains two ports, one designated A and
one designated B. Port A is intended to be
connected to the primary ring on the incoming fiber
and the secondary ring on the outgoing fiber. A
properly formed trunk ring is composed of a set of
stations with the A port of one station connected to
the B port of the neighboring station. See B port.
ambient air temperature
The temperature of air or liquid surrounding any
electrical part or device. Usually refers to the effect
of such temperature in aiding or slowing down
removal of heat by radiation and convection from
the part or device in question.
attenuation
Power, measured in decibels (dB) that is lost as a
signal moves from transmitter to receiver.
ATM
Asynchronous Transfer Mode. A transmission
protocol that segments user traffic into small, fixed
cells. Cells are transmitted to their destination where
they are reassembled. During transmission, cells
from different users are intermixed asynchronously
to maximize utilization of network resources.
AUI
Attachment Unit Interface. The cable, connectors,
and transmission circuitry used to interconnect the
physical signaling and the MAU. See MAU.
B port
Each DAS contains two ports, one designated A and
one designated B. Port B is intended to be
connected to the incoming fiber of the secondary
ring and the outgoing fiber of the primary ring. A
properly formed trunk ring is composed of a set of
stations with the A port of one station connected to
the B port of the neighboring station. See A port.
B to M link
One of several detailed connection rules for a
specific port relative to other ports. The B to M
(master) port rule is a tree connection with
redundancy. With this link, a station must not go to
THRU state in Configuration Management (CFM).
Port B on one station has precedence for connecting
to an M port on a different station (single MAC
station).
backbone
The main segment of a building or campus LAN, to
which are attached department networks.