WLAN Analysis with Wireshark (Radiotap Header Section, Part 1)

The radiotap header format is a mechanism to supply additional information about frames. A generic radiotap header format should look very similar like the following diagram:

Header Length: The header length, for the same STA MAC may not remain the same, depending upon the destination, as well as the type of 802.11 frames being transmitted. Take the following diagram as an example, frame 1000/1001 are heading to the same destination / same type QoS wireless frame, but, one has header length 44, another one 52.

The item with header length 44 carries the following sub-fields:

On the other hand, header length 52 is embedded with below sub-fields.

If taking a close look, you would realize that frame 1000 has additional sub-fields: VHT information: