1-3
Cisco Aironet Wireless LAN Adapter s Inst all ation and Configuration Guide fo r MS-DO S
OL-1744-02
Chapter 1 Overview
Parts of th e Clien t Adap ter
Terminology
Througho ut th is do cu ment, the se t er m s ar e used:
• client adap ter—R efers to all three ty pes of adap ters
• PC card, LM c ar d, o r PCI cl ient adap te r— Refers on ly t o a sp ecific adap ter
• workstation (or station)—Refers to a co m p ut in g device w ith an instal led c li ent ad ap t er
• End Node—A client node that is loca ted at the end of the Network Tree.
• Infrastru ctu r e— The w ir el ess i nfr as t ruct ur e is t he co mm u n ica ti on s sy s te m that comb in es access
points, mobile nodes, and fixed nodes. Access points within the infrastructure can be either root
units, wh ich are p hys ic all y wi r ed to th e LA N ba ck bo n e, or can act as w i re les s re pe aters. Oth er R F
enabled devices serve as fixed nodes or mobile client nodes.
• Parent/Child Node—Refers to the relationships between nodes in the wireless infrastructure. The
complete set of relationships is sometimes described as a network tree. For example, the access point
(at the top of the t ree) would be the parent of the end nodes. Conversely, the end nodes would be the
children o f th e access p oi nt .
• Power Saving Protocol (PSP) a nd Non-Power Saving Protocol—The Power Saving Pr ot oc ol allows
computer s ( usu al ly p or t ab le c omputers) t o power u p on ly p art of the time to co ns er ve en ergy. If a
client node is using the Power Saving Protocol to communic ate with the network, the access point
must be aware o f th is mo de and imp le m en t ad di tio n al fe at ur es such as message st or e and f o rwar d .
If the clie nt node is powered from an AC line, do not use PSP.
• Repeater—A repeater is an access point that extends the radio range of the infrastructure. A repeater
is not physically attached to the wired LAN, but communicates through radio to another access
point, which is either a root unit or another repeater.
• Root Unit—The root unit is an a ccess point that is located at the top, or starting point, of a wireless
infrastructure. A root unit provides the physical connection to the wired LAN and contains
configuration information in its association table that covers all nodes that access the wired network
(backbone ). A ll ac ces s p o in ts di re ctl y att ach ed t o th e w i re d LA N b ack bo n e a re r oot un it s .
Parts of the Client Adapt er
The clie nt ad ap ter is composed o f th r ee major p arts : a r ad io, a radio an tenna, an d tw o LED s.
Radio
The client adapter conta ins a direct-sequen ce spread spectrum (DSSS) radi o that operates in the 2.4-GHz
license-free Indus trial Scientific Medical (ISM) band. The radio t ransmits data over a half-duplex radio
channel operating at up to 11 Mbps.
DSSS technology causes radio signals to be transmitted over a wide frequency range, using multiple
frequencies simultaneously. The benefit of this te chnology is its ability to protect the data transmission
from inte rf eren ce. Fo r ex amp le , if a part i cula r f reque nc y e ncoun te rs no ise , in te rf eren ce, or b oth, enoug h
redundancy is built into the signal on other frequencies that the client adapter usually is successful in its
transmission.