- 1. Wireless Fundamentals Examining Wireless Media Access
2. Sending a Frame 3. Sending a Frame (Cont.) 4. Sending a Frame
(Cont.) 5. After a Frame Is Sent 6. 802.11 Frame Shape 7. Frame
Types
-
-
- Beacon, probe request, probe response
-
-
- Authentication request, authentication response
-
-
- Association request, association response
-
-
- Deauthentication, reassociation request, reassociation
response
-
-
- Announcement Traffic Indication Message (ATIM)
8. Frame Types (Cont.)
-
-
- Request to send (RTS), clear to send (CTS), acknowledgment
(ACK),
-
-
- Power Save Poll (PS-Poll),
-
-
- Null function (empty frame)
9. 802.11 Frame Speeds 10. Discovering the Network (Mgmt Frames)
11. Connecting (Mgmt Frames) 12. Staying Connected (Mgmt Frames)
13. Control Frames
- ACK is used after each frame.
RTS and CTS are used in 802.11b and g mixed cells and in hidden
node situations. 14. WMM Enhancement 15. Power Save Mode 16.
Summary
-
- Sending a frame requires a timing and acknowledgment system
that is based on CSMA/CA.
-
- 802.11 frames have a specific shape with headers containing
specific information and different parts that are sent at different
speeds.
-
- Beacons and probes help discover the network.
-
- Authentication and association frames are used to join the
cell.
-
- Some other management frames may be used while the client is
connected.
-
- Control frames improve the communication framework by allowing
special messages in specific cases, such as RTS and CTS or
PCF.
-
- Some stations may use the power save mode to increase battery
time, which means there must be specific exchanges with the
AP.
17.