Avatar of super_mario25
super_mario25 asked on

802.11 frame size

Hi all,

I am a bit confused about the 802.11 frame size and how it changes when applying WEP and WPA.

Unencrypted 802.11 frame:
header    |   data          | FCS
(30)           (0-2312)        (4)  bytes

WEP frame:
header    | IV   |  EIV    |  data          | FCS
(30)           (4)     (4)      (0-2312)        (4)  bytes

WPA (TKIP) frame:
header    | IV   |  EIV    |  data          | MIC     |   ICV    |   FCS
(30)           (4)     (4)      (0-2312)        (8)           (4)       (4)  bytes

My questions is: Is the data of each of the above frames correct or does it decrease? If it doesnt decrease, than the total frame sizes will be 2346, 2354 and 2364 respectively. Is this correct? I am really confused because all literature says that the packet size of body (data) is 0-2312 but the largest frame size is 2346 (RTS Threshold default).

Any help will be appreciated, Thank you in advance,
Wireless NetworkingEncryptionWireless Hardware

Avatar of undefined
Last Comment
atlas_shuddered

8/22/2022 - Mon
atlas_shuddered

2304 (2312 is actually the maximum WEP encrypted payload) is your maximum payload - note payload, not frame - size before encryption.  Max encrypted frame - note: not payload- sizes are 2346, 2354 and 2364 as you have listed above.

Check this link for more information you may find useful:  http://www.cwnp.com/phpBB2/viewtopic.php?t=836&

Cheers
ASKER
super_mario25

can you please clarify this:
2304 (2312 is actually the maximum WEP encrypted payload) is your maximum payload

thank you again
atlas_shuddered

2304b is the actual maximum, unencrypted payload size.
2312 is the maximum payload after encryption.

These are both the maximum payload un/encrypted.  The maximum frame sizes are 2346, 2354, 2364 w/encryption.
I started with Experts Exchange in 2004 and it's been a mainstay of my professional computing life since. It helped me launch a career as a programmer / Oracle data analyst
William Peck
ASKER
super_mario25

Thank you again for the reply atlas,
Just to clarify everything, the payload you are refering to is the data part I have indicated on the diagram above, right?
So, agreeing with the maximum frame sizes, the payload of 2304 (unencrypted) and 2312 (encrypted) exists for No enryption, WEP and WPA frames or does it increase?

Thank you again.
ASKER CERTIFIED SOLUTION
atlas_shuddered

Log in or sign up to see answer
Become an EE member today7-DAY FREE TRIAL
Members can start a 7-Day Free trial then enjoy unlimited access to the platform
Sign up - Free for 7 days
or
Learn why we charge membership fees
We get it - no one likes a content blocker. Take one extra minute and find out why we block content.
See how we're fighting big data
Not exactly the question you had in mind?
Sign up for an EE membership and get your own personalized solution. With an EE membership, you can ask unlimited troubleshooting, research, or opinion questions.
ask a question