Ieee 80211 Wlan
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2IEEE 802.11 WLAN
P
1
ART
packetlife.net
IEEE Standards
802.11a
802.11b
802.11g
802.11n
Maximum Throughput
54 Mbps
11 Mbps
54 Mbps
300 Mbps
Frequency
5 GHz
2.4 GHz
2.4 GHz
2.4/5 GHz
Modulation
OFDM
DSSS
DSSS/OFDM
OFDM
Channels (FCC/ETSI)
21/19
11/13
11/13
32/32
Ratified
1999
1999
2003
2009
WLAN Types
WLAN Components
Ad Hoc
ESS
A WLAN between isolated stations with
IBSS
BSS
BSS
no central point of control; an IBSS
Infrastructure
A WLAN attached to a wired network via
an access point; a BSS or ESS
DS
Frame Types
Type
Class
Association
Management
Basic Service Area (BSA)
Authentication
Management
The physical area covered by the wireless signal of a BSS
Probe
Management
Basic Service Set (BSS)
Beacon
Management
A set of stations and/or access points which can directly
communicate via a wireless medium
Request to Send (RTS)
Control
Distribution System (DS)
Clear to Send (CTS)
Control
The wired infrastructure connecting multiple BSSs to form an ESS
Acknowledgment (ACK)
Control
Extended Service Set (ESS)
A set of multiple BSSs connected by a DS which appear to wireless
Data
Data
stations as a single BSS
Client Association
Independent BSS (IBSS)
An isolated BSS with no connection to a DS; an ad hoc WLAN
Measuring RF Signal Strength
Probe Request
Decibel (dB)
Probe Response
An expression of signal strength as compared to a reference signal;
Authentication Request
calculated as 10log
(signal/reference)
10
Authentication Response
dBm
Signal strength compared to a 1 milliwatt signal
Association Request
dBw
Signal strength compared to a 1 watt signal
Association Response
dBi
Compares forward antenna gain to that of an isotropic antenna
Modulations
Terminology
Scheme
Modulation
Throughput
Basic Service Set Identifier (BSSID)
DBPSK
1 Mbps
A MAC address which serves to uniquely identify a BSS
DSSS
DQPSK
2 Mbps
Service Set Identifier (SSID)
CCK
5.5/11 Mbps
A human-friendly text string which identifies a BSS; 1-32 characters
BPSK
6/9 Mbps
Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA)
The mechanism which facilitates efficient communication across a
QPSK
12/18 Mbps
OFDM
shared wireless medium (provided by DCF or PCF)
16-QAM
24/36 Mbps
Effective Isotropic Radiated Power (EIRP)
64-QAM
48/54 Mbps
Net signal strength (transmitter power + antenna gain - cable loss)
by Jeremy Stretch
v2.2
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