24 Beacon Management Frame

Within every wireless network is a frame type that is known as the beacon management frame (beacon). It is an integral and an important part of a wireless network. Its main job is to indicate the presence of the AP's so that they can easily be located by the systems.

These have the potential of being automatically detected by the wireless clients, which then try to establish wireless connection.

In an infrastructure design, the beacon frame is sent out by the AP and in case of ad hoc design, beacons are only sent out if they are connected. A beacon frame consists of different parts and all are used by the client frame to gather information about the AP. These parts are:

- Channel Information: This contains information about the channel used by the AP.

- Supported Data Rates: This contains information about the data transfer rates identified by the AP configuration.

- SSID: This contains the name of the wireless network name.

- Time Stamp: This contains Synchronization information. It is used by the client system to synchronize its clock with the AP.

A beacon is let out from the AP at an interval of every ten minutes. Since these add overheads to the networks, some AP's increasing the time gap and hence reducing the number of beacons that are sent. Before connection can be made to an AP by a client system, the AP has to be located. This location can be detected actively or passively. After it is detected, the beacon frame provides the information necessary for the system to access the AP.