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Glossary

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broadcast domain

A group of devices receiving broadcast frames initi-

ating from any device within the group. Because they do not forward broad-
cast frames, broadcast domains are generally surrounded by routers.

broadcast storm

An undesired event on the network caused by the

simultaneous transmission of any number of broadcasts across the net-
work segment. Such an occurrence can overwhelm network bandwidth,
resulting in time-outs.

buffer

A storage area dedicated to handling data while in transit. Buffers

are used to receive/store sporadic deliveries of data bursts, usually received
from faster devices, compensating for the variations in processing speed.
Incoming information is stored until everything is received prior to sending
data on. Also known as an "information buffer."

bursting

Some technologies, including ATM and Frame Relay, are consid-

ered burstable. This means that user data can exceed the bandwidth nor-
mally reserved for the connection; however, this cannot exceed the port
speed. An example of this would be a 128Kbps Frame Relay CIR on a T-1--
depending on the vendor, it may be possible to send more than 128Kbps for
a short time.

bus topology

A linear LAN architecture in which transmissions from var-

ious stations on the network are reproduced over the length of the medium
and are accepted by all other stations. Compare with: ring and star.

bus

Any physical path, typically wires or copper, through which a digital

signal can be used to send data from one part of a computer to another.

BUS

broadcast and unknown servers: In LAN emulation, the hardware or

software responsible for resolving all broadcasts and packets with unknown
(unregistered) addresses into the point-to-point virtual circuits required by
ATM. See also: LANE, LEC, LECS, and LES.

BX.25

AT&T's use of X.25. See also: X.25.

bypass mode

An FDDI and Token Ring network operation that deletes

an interface.

bypass relay

A device that enables a particular interface in the Token

Ring to be closed down and effectively taken off the ring.

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