The Attribute Protocol (ATT) provides the means for an attribute server to expose a set of attributes and their associated characteristic values to a requesting client device. These attributes can be discovered, read, and written by peer devices. The ATT is further used in a service framework described by the Generic Attribute Profile (GATT) and hosts a variety of application profiles which define the collection of attributes and permissions needed for these attributes to be used in communications. The Defensics Bluetooth LE ATT Server Test Suite can be used to evaluate Bluetooth ATT implementations for security flaws and robustness problems.
Vol 3, Part F Attribute Protocol ATT
Vol 3, Part G Generic Attribute Profile GATT