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IEEE 802.11 Header Flags (DS Status)

kfarrington
Level 3
Level 3

Hi Guys,

Just reading up on what the DS flag is and I have the following definition below. I have also included 3 types of DS flag packets.

Are there any more flags? I have seen stuff like station did not make it to DS etc etc etc? But cannot see much documentation on this subject from the IEEEE?

Any help would be fantastic.

Kind regards,

Ken

The Distribution System (DS) Status field wlan.fcds

represents the direction the frame is

traveling in. Wireshark represents two

unique fields as one display entry:

From DS and To DS. When From DS is

set to 1 and To DS is set to 0, the frame

is traveling from the AP to the wireless

network. When From DS is set to 0 and

To DS is set to 1, the frame is traveling

from a wireless client to the AP.

Note Flags: T (To DS, I am assuming)

------------------------------------

IEEE 802.11 Data, Flags: .......T

Type/Subtype: Data (0x20)

Frame Control: 0x0108 (Normal)

Version: 0

Type: Data frame (2)

Subtype: 0

Flags: 0x1

DS status: Frame from STA to DS via an AP (To DS: 1 From DS: 0) (0x01)

.... .0.. = More Fragments: This is the last fragment

.... 0... = Retry: Frame is not being retransmitted

...0 .... = PWR MGT: STA will stay up

..0. .... = More Data: No data buffered

.0.. .... = Protected flag: Data is not protected

0... .... = Order flag: Not strictly ordered

Note Flags: F (From DS, I am assuming)

--------------------------------------

IEEE 802.11 Data, Flags: ......F.

Type/Subtype: Data (0x20)

Frame Control: 0x0208 (Normal)

Version: 0

Type: Data frame (2)

Subtype: 0

Flags: 0x2

DS status: Frame from DS to a STA via AP(To DS: 0 From DS: 1) (0x02)

.... .0.. = More Fragments: This is the last fragment

.... 0... = Retry: Frame is not being retransmitted

...0 .... = PWR MGT: STA will stay up

..0. .... = More Data: No data buffered

.0.. .... = Protected flag: Data is not protected

0... .... = Order flag: Not strictly ordered

Note Flags: FT (From DS to DS, I am assuming)

---------------------------------------------

IEEE 802.11 Data, Flags: ......FT

Type/Subtype: Data (0x20)

Frame Control: 0x0308 (Normal)

Version: 0

Type: Data frame (2)

Subtype: 0

Flags: 0x3

DS status: Frame part of WDS from one AP to another AP (To DS: 1 From DS: 1) (0x03)

.... .0.. = More Fragments: This is the last fragment

.... 0... = Retry: Frame is not being retransmitted

...0 .... = PWR MGT: STA will stay up

..0. .... = More Data: No data buffered

.0.. .... = Protected flag: Data is not protected

0... .... = Order flag: Not strictly ordered

1 Reply 1

kfarrington
Level 3
Level 3

This doco is excellent.

The 802.11-2007 standard from the IEEEE (cannot attach as 14 meg) download from

http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?tp=&isnumber=4248377&arnumber=4248378&punumber=4248376

Thx

Ken

Review Cisco Networking products for a $25 gift card