Learn Bluetooth

Bluetooth stack is a software layer that enables Bluetooth devices to communicate with each other. It consists of various components that handle different aspects of Bluetooth communication, including:

1. Host Controller Interface (HCI)

The lowest layer of the stack. Provides a standardized interface between the host processor (e.g., a smartphone, laptop) and the Bluetooth controller (a specialized chip). Handles data transmission and control commands between the host and the controller.

Manages the physical connection between Bluetooth devices. Handles tasks such as frequency hopping, packet formatting, error correction, and power management. Ensures reliable data transmission over the wireless channel.

Provides multiplexing, segmentation, and reassembly of data packets. Allows different protocols (e.g., TCP/IP, SDP) to coexist on a single Bluetooth connection. Handles flow control and error recovery.

4. Service Discovery Protocol (SDP)

Enables Bluetooth devices to discover and advertise available services. Provides a mechanism for clients to find and connect to specific services on other devices. Uses a database to store information about services and their attributes.

5. Attribute Protocol (ATT)

Used for accessing and manipulating attributes within a Bluetooth service. Defines the structure and operations for reading, writing, and notifying attributes. Provides a framework for building various Bluetooth profiles and services.

6. Security Manager

Handles security aspects of Bluetooth communication. Manages authentication, encryption, and key exchange. Ensures data confidentiality and integrity.

7. Profiles

Define specific use cases and functionalities for Bluetooth devices. Provide a set of rules and procedures for how devices should interact in different scenarios.

Examples of profiles include

  • Hands-Free Profile (HFP) for hands-free calling
  • Headset Profile (HSP) for wireless headsets
  • Advanced Audio Distribution Profile (A2DP) for high-quality audio streaming
  • Personal Area Network Profile (PAN) for creating a personal network

Read more

Bluetooth Security Bluetooth Attacks