User`s guide

Aironet Wireless Communications, Inc. 3-7 Confidential and Proprietary
State 1:
Unauthenticated,
Unassociated
State 2:
Authenticated,
Unassociated
State 3:
Authenticated
and Associated
Successful
Authentication
Successful
Association or
Disassocaiation
Notification
DeAuthentication
Notification
Class 1
Frames
Class 1 & 2
Frames
Class 1, 2 & 3
Frames
DeAuthentication
Notification
Reassociation
Figure 3.4 - Relationship Between State Variables and Services
The current state existing between the source and destination station determines the 802.11 frame types
which may be exchanged between that pair of stations (see section 7 of the 802.11 specification). The
state of the sending station given by Figure 3.4 is with respect to the intended receiving station. The
allowed frame types are grouped into classes and the classes correspond to the station state. In State 1
only Class 1 frames are allowed. In State 2 either Class 1 or Class 2 frames are allowed. In State 3, all
frames are allowed (Class 1, 2 and 3). The frame classes are defined as follows:
Class 1 frames (permitted from within States 1, 2 and 3):
Control Frames:
• RTS
• CTS
• ACK
• CF-End+ACK
• CF-End
Management Frames:
• Probe Request/Response
• Beacon
• Authentication
Successful authentication enables a station to exchange Class 2 frames. Unsuccessful
authentication leaves the Station in state 1.
• Deauthentication
Deauthentication notification when in state 2 or state 3 changes the station’s state to
state 1.
The station must become authenticated again prior to sending class 2 frames.
• ATIM
Data frames:
• Data
Data frames with FC control bits "To DS” and “From DS" both false.