http://wikiless.i2p/wiki/Radio_beacons?lang=en
Wi-Fi beacons [ edit ] In the field of Wi-Fi (wireless local area networks using the IEEE 802.11b and 802.11g specification), the term beacon signifies a specific data transmission from the wireless access point (AP), which carries the SSID , the channel number and security protocols such as Wired Equivalent Privacy (WEP) or Wi-Fi Protected Access (WPA). This transmission does not contain the link layer address of another Wi-Fi device, therefore it can be received by any LAN client. [ 9 ]...