Oct 15, 2016

MAC header - Frame Control - Protocol Version, Type and Subtype

The first two bytes of the MAC header is called as Frame Control Field, which includes Protocol Version, Type, SubType, To DS, From DS, More Fragments, Retry, Power Management, More Data, Protected Frame, and Order. As you could see from the following picture.

Above the picture from CWAP

Protocol is a 2 bit field at the beginning of MAC heard. After protocol version, the Type field and Subtype file are used to identify the function of the frame. 

The following wireless packet capture shows the these three fields 


All 802.11 frames aways set Protocol Version as 0. All other values are reserved. 
There are 4 types fames, as the following 

Above the picture from CWAP

The subtype field are 4 bits and the combinations are shown as the following,
Above pictures from CWAP

At last, I list Filters of wireshark for these three fields
wlan.fc.version  ----> Proctocol version
wlan.fc.type      ----> Type
wlan.fc.subtype ----> Subtype

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