Wireshark-dev: [Wireshark-dev] 802.11 Type/Subtype Field Incorrect

From: Dustin Johnson <dustin.johnson@xxxxxxxxxxxx>
Date: Tue, 10 Apr 2007 17:43:14 -0700
Hi all,
I have been looking at correcting the IEEE 802.11 Type/Subtype field, but would like to know if there are reasons against it. First let me explain what I think is wrong with the field:

The frame type "QoS Data" is displayed in Wireshark as 40. In IEEE 802.11ma-D9.0 the type field is defined as bits 3,2 and the subtype as bits 4,5,6,7. In this same document "QoS Data" is defined as type = 10 and subtype = 1000.

In the actual byte the data is presented as such -> 100010XX (Where the Xs are extraneous to the type/subtype). If this value is bit shifted right 2 then the value becomes 0x22 or D34.

Looking at the dissector code this is not the way that the type/subtype fields are put together. Instead it is done as such -> 101000 = 0x28 = D40. Thus, the type/subtype fields are switched. I would like to correct the problem but would like to know what type of impact that would have.

Thank you,
   Dustin Johnson



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