Bab 4 Politeknik Telkom 2008

IEEE 802.11 IEEE 802.11 WiFi (Wireless Fidelity) Type of WiFi IEEE 802.11a IEEE 802.11b IEEE 802.11g

IEEE 802.11a Radius 50 meter Not Compatible with 802.11b and 802.11g Maximum data rate 54 Mbps Frekuensi band 5 GHz Power 2 W - 2,5 W

IEEE 802.11b Radius 100 meter Compatible with wireless 802.11 Maksimum data rate 11 Mbps Frekuensi band 2,4 GHz Power 1 W

IEEE 802.11g Compatible with wireless 802.11 Maksimum data rate 54 Mbps Frekuensi band 2,4 GHz Power 1,5 W

Frekuensi 2,4 GHz  ISM frequency (Industrial, Scientific dan Medical). 802.11a and 802.16 for WMAN  5 GHz frequency

Teknik Spread spectrum Direct Sequence Spread Spectrum (DSSS)  11 channel, bandwidth/channel 22 MHz Frequency Hopping Spread Spectrum (FHSS)  79 channel, bandwith/channel 1 MHz

Device of WLAN Access Point Client device

Access Point

Access Point Access Point Mode : Root Repeater Bridge

Root mode WLAN client Access Point Jaringan kabel

Repeater mode Access Point Root mode WLAN client Repeater mode Jaringan kabel

Bridge mode Access Point Mode bridge Jaringan kabel

Client device PCMCIA PCI Wireless Adapter

SSID (Service Set Identifier) SSID  group identifier of WLAN SSID send in a Beacon by Access point to WLAN client Beacon use to control and synchronize communication in WLAN

Beacon information Synchronization Time Parameter FH and DS SSID Data Rate

Wifi Scanning  passive / active AP sending probe-response Client send authentication-request to AP AP receive authentication confirmation from client Client send association-request to AP AP confirm association-request from client