The document discusses the components and architectures of wireless networks. It describes basic service sets (BSS) which can be either ad-hoc or infrastructure networks, and extended service sets (ESS) which connect multiple BSS through a distribution system. It also outlines the 802.11 protocol stack and frame formats, including the frame control field and address fields.

4. Network Components
Wireless Stations Access Point

5. Types of Architectures
Basic Service Set Extended Service Set
Stationary or Mobile Distributed System
wireless stations
Uses LAN to connect
Optional Central Base Central Stations form
Station Basic Service Sets

6. BASIC SERVICE SET [BSS]
AD HOC NETWORK INFRASTRUCTURE NETWORK

7. EXTENDED SERVICE SET [ESS]
DISTRIBUTION SYSTEM
BSS BSS BSS

8. TYPES OF STATIONS
NO Transition
BSS Transition
ESS Transition

9. 802.11 Protocol Stack

11. 802.11 define 3 classes of
frames :
DATA
CONTROL
MANAGEMENT

12. 802.11 FRAME FORMAT

13. FRAME CONTROL

14. PROTOCOL VERISION
0 : current version

15. 00 : Management frame
01 : Control frame
10 : Data frame
11 : Unspecified

16. Control (01)- RTS (1011)
CTS (1100)
ACK (1101)

17. ToDS- 1: frame is addressed to AP for forwarding
it to DS
0: other frames
FromDS- 1: frame coming from DS
0 : other frames

18. 1 : When there are more fragments
0 : Sent fragment is last

19. 1 : Frame is retransmitted
0 : Frame is transmitted for the first time

20. 1 : Station in in sleep mode
0 : active mode

21. 1 : indicates that the sender has
additional frames

22. 1 : frame body is encrypted
0 : not encrypted

23. 1 : frames transmitted in order
0 : not transmitted in order

24. Data, Management frame : defines duration of
transmission
Control frame : defines ID of frame

25. Address1 : next device
Address2 : Previous device
Address3 : final destination if not defined by
addr1
Address4: original source if not defined by
addr2

26. CASE 1:
ToDS : 0
FromDS :0
CASE 2:
ToDS : 0
FromDS :1

27. CASE 3:
ToDS : 1
FromDS :0
CASE 4:
ToDS : 1
FromDS : 1

28. Sequence field (16 bits) has 2 subfields:
1. Fragment no.(4 bits)
2. Sequence no.(12 bits)

29. It can transmit frame with max payload of 2312
bytes

30. Its is 32bits field containing 32 bits CRC

31. MANAGEMENT FRAME

32. CONTOL FRAMES
RTS FRAME
CTS FRAME
ACK FRAME