Siemens IEEE802.11 Manuel d'utilisateur télécharger pdf (Page 54)

WLAN-IEEE802.11 Tutorial (Maximilian Riegel), 021018-wlan-tutorial.ppt Page 54 © Siemens, 2002

Mobility inside a WLAN ‘hotspot’

by link layer functions...

n Station decides that link

to its current AP is poor

ORFDOGLVWULEXWLRQQHWZRUN

n Station uses scanning

function to find another AP

− or uses information from

previous scans

n Station sends Reassociation

Request to new AP

n If Reassociation Response is successful

− then station has roamed to the new AP

− else station scans for another AP

n If AP accepts Reassociation Request

− normally old AP is notified through Distribution System

− AP indicates Reassociation to the Distribution System

1 2 ... 49 50 51 52 53 54 55 56 57 58 59 ... 83 84

Maximilian Riegel 1
The ubiquitous WLAN 2
WLAN has taken off 3
Part 1: 5
Internet/Web Applications 6
Layering means encapsulation 7
,QWHUQHW 8
IP based network architecture 9
Wireless LAN IEEE802.11 10
Part 2: IEEE802.11 Overview 12
Wireless IEEE802.11 Standard 13
IEEE802.11 Configurations 14
Wireless LAN Standardization 17
Part 3: Physical layer 18
IEEE802.11 19
AMPLITUDE 20
FREQUENCY 20
Spectrum 21
IEEE802.11a 5GHz PHY Layer 23
IEEE802.11g: Further Speed 24
Extension for the 2.4GHz Band 24
IEEE802.11h: Spectrum and 26
Transmit Power Management 26
… when will 5 GHz WLANs come? 27
PHY Terminology 28
PLCP Protocol Data Unit 29
Part 4: Medium Access Control 30
CSMA/CA Explained 32
CSMA/CA + ACK protocol 33
Station 1 34
Station 2 34
Station 3 34
Station 4 34
“Hidden Node” Provisions 35
IEEE802.11e: MAC Enhancements 36
Contention Free Period 37
Contention Period 37
CFP repetition interval 37
Frame Formats 39
Address Field Description 40
Part 5: MAC layer management 42
Scanning 45
Active Scanning Example 46
Power Management Approach 48
Power Management Procedure 49
MAC Management Frames 50
Part 6: WLAN Mobility 51
IEEE802.11 Ad Hoc Mode 52
Distribution System (DS) 53
ORFDOGLVWULEXWLRQQHWZRUN 54
IEEE802.11f: 55
Part 7: WLAN security 56
• a 40 bit secret key 57
WEP privacy mechanism 58
Shared key authentication 59
IEEE802.11i: 61
Robust Security Network (RSN) 61
Summary: MAC Functionality 63
FXVWRPHUHTXLSPHQW 65
VHOIH[SODLQLQJ 65
Probably to consider … 68
Selection of billing method 69
How does it work: 70
Web based access control 70
GSM/GPRS/UMTS 75
WLAN IEEE802.11 75
WLAN – UMTS Interworking: 76
ORJDULWKPLFVFDOH 78
Conclusions for 79
Mobile Network Operators 79
'+&3 82
SMS containing Password 82

Commentaires sur ces manuels

Pas de commentaire

Siemens IEEE802.11 Manuel d'utilisateur Page 54

Commentaires sur ces manuels

Produits connexes et manuels pour Mise en réseau Siemens IEEE802.11