Glossary
RS232
An EIA standard for serial data communication between equipment and
computing devices.
Access Point
An internetworking device that seamlessly connects wired and
wireless networks. Access Points combined with a distributed system support the
creation of multiple radio cells that enable roaming throughout a facility.
Ad Hoc Network
A network composed solely of stations within mutual
communication range of each other (no Access Point connected). The Ad Hoc
network offers peer-to-peer connections between workstations, allowing
communication between computers within range that have an 802.11
DSSS compatible PC card installed.
BSS
Basic Service Set
. A set of stations controlled by a single coordination
function.
Channel
A medium used to pass data units that can be used simultaneously in
the same volume of space by other channels of the same physical layer, with an
acceptably low frame error ratio due to the absence of mutual interference.
CSMA/CA
Carrier Sensing Multiple Access/Collision Avoidance
The medium
access control method used by the 802.11 standard. Basically, a radio can start
transmitting signal only when no carrier from another radio is sensed and after a
randomized wait time has expired.
Encapsulated
An Ethernet address mode that treats the entire Ethernet packet
as a whole and places it inside an 802.11 frame along with a new header.
ESS
Extended Service Set
. A set of one or more interconnected Basic Service
Sets (BSS’s) and integrated Local Area Networks (LANs) can be configured as
an Extended Service Set.
Ethernet
The most widely used medium access method, which is defined by the
IEEE 802.3 standard. Ethernet is normally a shared media LAN; i.e., all the
devices on the network segment share the total bandwidth. Ethernet networks
operate at 10Mbps/100Mbps using CSMA/CD to run over 10BaseT/100BaseT
cables.
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Hidden Node
The situation where two or more radios in a multiple-radio network
fail to detect the RF signals from each other. For example, in a 3-radio network,
radio 2 and 3 both have good link to radio 1. Radio 2 and 3, however, are
isolated from each other by, say, a metal wall. Radio 2 therefore is a “hidden
node” to radio 3, and vice versa. Since an 802.11 network relies on the
CSMA/CA protocol to control network access, hidden nodes break down the
