Field Guide to Wireless LANs for Administrators and Power Users, A

IEEE 802.11 WLAN Components

Before continuing with the discussion of the Access control methods and the Address fields in the IEEE 802.11 header, we will first briefly cover the terminology associated with the “intermediate nodes” (APs) in IEEE 802.11 WLANs. It is impossible to understand the reason for there being four Address fields in the IEEE 802.11 MPDU header unless one understands the nature and use of the AP.

Strictly speaking, an AP only serves to mediate communications between wireless stations in its vicinity, in particular those stations with which it has formed an “association.” Figure 6-7a illustrates the AP function, which facilitates wireless communication between various STAs with which it has associated.

Figure 6-7a. Wireless ...