A beacon frame is one of the management frames in IEEE 802.11 based WLANs. Beacon frames are transmitted periodically by the access point (AP) or clients in an ad-hoc network.
WiFi Beacon
A beacon frame is one of the management frames in a IEEE 802.11 based WLAN. It contains all the information about the access point and its maximum capabilities to allow clients to discover the access point.
Beacon frames are transmitted periodically by the access point (AP) in an infrastructure basic service set (BSS). In IBSS network beacon generation is distributed among the stations.
Beacon Interval
The default beacon interval for most access points is 100 time units (a time unit is 1.024 ms, so every 102.4 ms). Some access point configuration or management systems allow this value to be increased or decreased.
Usually a longer beacon interval (e.g. 300 time units or 307.2 ms) will reduce overhead in the channel but could impact access point discovery and/or roaming.
Beacons are transmitted at the lowest speeds and each SSID requires its own beacon so having more SSIDs increases the number of beacons and can consume a significant amount of air time and degrade performance, especially in 2.4 GHz networks where there are only 3 non-overlapping channels.