Beacons usually use radio channels, words too literally by Beacon, who transmit packets at intervals, which are accepted by the device like a smart machine, so ibeacons is a special application for simple low-power Bluetooth broadcasts, with special support added to the iOS side.
You try to intercept a Bluetooth broadcast packet, for example from Estimote Beacon, you will see the following data:
02 01 06 1A FF 4C 00 02 15 B9 40 7F 30 F5 F8 46 6E AF F9 25 55 6B 57 FE 6D 00 49 00
(Capture this data, if you use OSX, an additional downloadIncludes a Bluetooth scan and packet)
The above data already has the message, the fixed access address, the broadcast PDU head and the MAC address is removed; it only broadcasts data-30 bytes, so it adapts to the 31-byte limit.
What makes Bluetooth broadcasting a ibeacon? The format is stipulated by Apple, which breaks down as follows:
02 01 06 1A FF 4C 00 02 15: iBeacon prefix (fixed) B9 40 7F 30 F5 F8 46 6E AF F9 25 55 6B 57 FE 6D: proximity UUID (here: Estimote’s fixed UUID) 00 49: major 00 0A: minor C5: 2’s complement of measured TX power
IBeacon data format