802.11 Network Structures

From
Jump to navigation Jump to search

zuallererst sollten wir mal die struktur festlegen (is jetz die ausm skript), sprich sachen rausstreichen, dann den ganzen kram befüllen ...--Cb 20:52, 11 July 2006 (CEST)


Traditional 802.11

  • 802.11 =

** „wireless ethernet“ ** Wi-fi (from Wi-Fi Alliance, wireless fidelity)

IEEE 802.11 as part of IEEE 802

  • IEEE 802.11x =
    • IEEE = Institute of Electronics and Electrical Engineers
    • 802 = project group (Entwicklung von LAN-Standards)
    • 11 = working group (Entwicklung eines wireless-LAN Standards)
    • x = task groups
  • erstmalige Spezifikation 1997, Änderungen 802.11-1999, 802.11-2003
  • the 802.11 Task Groups


Structure of a wireless network

Types of Networks

Independent BSS (IBSS, Ad-Hoc networks)
Infrastructure BSS
ESS

Distribution system

Using the MAC

CSMA/CA

The hidden node problem and RTS/CTS

DCF, PCF, NAV

MAC-Zugriffsmodi: Coordination Functions
Timing beim Zugriff auf das MAC: NAV
Interframe Spacing (nur erwähnen)

Network operations and services

Network services overview

Frame format

Frame Arten
Frame Fragmentation
allg. Format

Management

Scanning a Network: Probes and Beacons

Passive Scanning Active Scanning Beacon Frame Probe Request Frame Probe Response Frame Scan Report

Joining a network

1.4.3.2.1 802.11 Authentication 21 1.4.3.2.2 Preauthentication 22 1.4.3.2.3 Association Procedure 22 1.4.3.2.4 Association Request Frame 22 1.4.3.2.5 Association Response Frame 23 1.4.3.2.6 Mobility support: Transitions 23 1.4.3.2.7 Reassociation procedure 24 1.4.3.2.8 Reassociation Request Frame 25 1.4.3.2.9 Association and authentication states 25

Vertraulichkeit und Zugangskontrolle

WEP
802.11i

Controlling the MAC

Control Frames
RTS/CTS
ACK
PS-Poll

Moving data

Prinzipien

1.4.6.1.1 Broadcast Data, Multicast Data und Management Frames 29 1.4.6.1.2 Unicast Data (Management und Daten) 30 1.4.6.1.3 PowerSave Sequenzen 31

Data frames
Distribution
Integration/Encapsulation of ethernet frames

1.4.6.4.1 Prinzip 33 1.4.6.4.2 Ablauf des Bridging zwischen 802.11 und Ethernet 34 wireless2wired 35 wired2wireless 35

Misc. stuff

Spectrum management
multirate-support

„Ad-hoc Multi-hop Mesh“-Netzwerke

Besonderheiten

802.11s

Quellen: