Generic Attribute Profile (GATT)

The Generic Attribute Profile (GATT) establishes how data will be organized and exchanged over a Bluetooth^® Low Energy (BLE) connection.

Certain use-case-specific profiles (GATT-Based Profiles) are standardized by the Bluetooth Special Interest Group (SIG):

• Heart Rate Profile
• Proximity Profile
• etc.

GATT uses the Attribute Protocol (ATT) as a transport mechanism, as well as a means of organizing your data into easily transmitted bits or attributes.

GATT defines these and other fundamental operations in a standard, universally understood manner. It's important to understand GATT, since most BLE implementations provide GATT APIs for applications wishing to use this functionality.

Key aspects of GATT include:

• Universally Unique Identifiers (UUIDs)
• Roles
• Attributes
• Data Organization

GATT Example

The following depicts a GATT Server having two services (one public, one private), with a GATT Client executing several GATT operations to read/write the data (characteristics) in those services.