The format of Advertising data and Scan Response data is shown in Figure
11.1 . The data consists of a significant part and a non-significant part. The sig
nificant part contains a sequence of AD structures. Each AD structure shall
have a Length field of one octet, which contains the Length value, and a Data
field of Length octets. The first octet of the Data field contains the AD type field
The content of the remaining Length – 1 octet in the Data field depends on the
value of the AD type field and is called the AD data. The non-significant part
extends the Advertising and Scan Response data to 31 octets and shall con-
tain all-zero octets.
If the Length field is set to zero, then t he Data field has zero octets. This shall
only occur to allow an early termination of the Advertising or Scan Response
data
Only the significant part of the Advertising or Scan Response data needs to be
sent over the air.
The Advertising and Scan Response data is sent in advertising events. The
Advertising Data is placed in the AdvData field of ADV_IND,
ADV_NONCONN_IND, and ADV_SCAN_I ND packets. The Scan Response
data is sent in t he ScanRspData field of SCAN_RSP packets
All AD types are listed in the Bluetooth Assigned Numbers document.
https://www.bluetooth.org/zh-cn/specification/assigned-numbers/generic-access-profile