Station States and Corresponding Frame Types

Station States and Corresponding Frame Types
The state existing between a source and destination station (see Figure 3.10) governs which
IEEE 802.11 frame types the two stations can exchange. The following types of functions can occur within each class of frame:
Class 1 Frames
• Control frames
Request to send (RTS)
Clear to send (CTS)
Acknowledgment (ACK)
Contention-free (CF)
• Management frames
Probe request/response
Beacon
Authentication
Deauthentication
Announcement traffic indication message (ATIM)
• Data frames
Class 2 Frames
• Management Frames
Association request/response
Reassociation request/response
Disassociation
Class 3 Frames
• Data frames
Management frames
Deauthentication
Control frames
Power Save Poll
To keep track of station state, each station maintains the following two state variables:
• Authentication state Has values of unauthenticated and authenticated.
• Association state Has values of unassociated and associated. As mentioned in this chapter, the 802.11 wireless LAN standard certainly has benefits that an
organization should consider when selecting components that provide LAN mobility. IEEE 802
is a solid family of standards that will provide much greater multiple-level interoperability than
proprietary systems. The 802.11 standard has the backing of IEEE, having an excellent track
record of developing long-lasting standards, such as IEEE 802.3 (ethernet) and IEEE 802.5
(token ring).
Chapters 4 and 5 cover the details of the 802.11 standards