Basic Choreography

Let’s look at some of the relevant message exchanges to understand how the frames fit together to form cohesive and meaningful interactions.

Beacon

An AP sends the beacon message on a periodic basis. Figure 4-8 shows the beacon frame.

Figure 4-8. Beacon Frame

The beacon was designed as the primary discovery mechanism for the STAs to get a list of all APs in a BSS. However, this is terrible in terms of security because any wanderer can get the list of all APs, SSID, and capabilities. Therefore, inside enterprises, the periodic broadcasting of beacons is usually turned off. But for public WLANs and ad-hoc ...

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