802.11 Control Frames

 

802.11 Control Frames

 

Control frames are controlling the access to the medium

They have type value of 01. The subtype value defines the function of the frame.

Below you can find where the Type and Subtype can be found in a frame.


Example


 

The subtype and associated values

Also, you can find the wireshark filter for every type

 

All Control Frames                                                    wlan.fc.type == 1

 

Subtype: 0000 – 0110    Reserved

Subtype: 0111 – Control Wrapper                            wlan.fc.type == 1 and wlan.fc.subtype == 7

Subtype: 1000 – Block Ack Req                              wlan.fc.type == 1 and wlan.fc.subtype == 8

Subtype: 1001 – Block Ack                                      wlan.fc.type == 1 and wlan.fc.subtype == 9

Subtype: 1010 – PS-Poll                                          wlan.fc.type == 1 and wlan.fc.subtype == 10

Subtype: 1011 – Request-To-Send (RTS)                wlan.fc.type == 1 and wlan.fc.subtype == 11

Subtype: 1100 – Clear-To-Send (CTS)                    wlan.fc.type == 1 and wlan.fc.subtype == 12

Subtype: 1101 – Acknowledgement (Ack)              wlan.fc.type == 1 and wlan.fc.subtype == 13

Subtype: 1110 – CF-End                                          wlan.fc.type == 1 and wlan.fc.subtype == 14

Subtype: 1111 – CF-End + CF-Ack                         wlan.fc.type == 1 and wlan.fc.subtype == 15


References

CWAP Study and Reference Guide Chapter 4

https://www.cwnp.com/cwap-study-guide403/

https://www.cwnp.com/802.11-mac-series-ndash-basics-mac-architecture-ndash-part-2-3/

https://community.cisco.com/t5/wireless-mobility-documents/802-11-management-control-and-data-frames/ta-p/3155885



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