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Glossary

BRI

Basic Rate Interface: The ISDN interface that facilitates circuit-

switched communication between video, data, and voice; it is made up of
two B channels (64Kbps each) and one D channel (16Kbps). Compare with:
PRI. See also: BISDN.

bridge

A device for connecting two segments of a network and transmit-

ting packets between them. Both segments must use identical protocols to
communicate. Bridges function at the Data Link layer, layer 2 of the OSI ref-
erence model. The purpose of a bridge is to filter, send, or flood any incoming
frame, based on the MAC address of that particular frame.

bridge group

Used in the router configuration of bridging, bridge groups

are defined by a unique number. Network traffic is bridged between all inter-
faces that are a member of the same bridge group.

bridge identifier

Used to find and elect the root bridge in a layer-2

switched internetwork. The bridge ID is a combination of the bridge priority
and base MAC address.

bridge priority

Sets the STP priority of the bridge. All bridge priorities are

set to 32768 by default.

bridging loop

Loops occur in a bridged network if more then one link to

a network exists and the STP protocol is not turned on.

broadband

A transmission methodology for multiplexing several inde-

pendent signals onto one cable. In telecommunications, broadband is classi-
fied as any channel with bandwidth greater than 4kHz (typical voice grade).
In LAN terminology, it is classified as a coaxial cable on which analog sig-
naling is employed. Also known as "wideband". Contrast with: baseband.

broadcast

A data frame or packet that is transmitted to every node on the

local network segment (as defined by the broadcast domain). Broadcasts are
known by their broadcast address, which is a destination network and host
address with all the bits turned on. Also called "local broadcast." Compare
with: directed broadcast.

broadcast address

Used in both logical addressing and hardware

addressing. In logical addressing, the host addresses will be all ones. With
hardware addressing, the hardware address will be all ones in hex (all Fs).

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