Adaptation protocols

Link Manager.

• Carries out link setup, above baseband, with authentication, link configuration and other protocols.

  • Support protocol multiplexing.

    • BT may support other protocols besides IP.

  • Segmenting and reassembly.

Link Layer Control & Adaptation (L2CAP).

• Link control protocol, provides connection-oriented and connectionless data services to upper layer protocols.

  • Handles ACL and SCO connections.

  • Handle QoS specifications per connection (logical channel).

  • Manages concepts as “group of connections”.

Host Controller Interface (HCI).

• Allows command line access to the baseband layer and LM for control and status information.

  • Current interfaces: USB; UART; RS-232.

• Made up of three parts:

  • HCI firmware, HCI driver, Host Controller Transport Layer.

Interlayer communication

Protocols (middleware)

a - common protocol; b - Bluetooth dedicated protocol

• SDP: Service Discovery Protocol.

• OBEX: Facilitates binary transfers between BT devices.

• TCP-BIN: Telephony-control protocol binary (call control).

Middleware

Service Discovery Protocol (SDP).

• Provides a way for applications to detect which services are available and their characteristics.

• Protocol question <=> answer.

  • (search and browsing of services).

• Defines a format for service registry.

  • Information provided by the service attributes, a name (ID) + value.

  • IDs can be universal (UUID).

Protocol reusage.

• BT aims to reuse older protocols (e.g. WAP, OBEX–IrDA).

  • Interaction with applications and phones, as commonly done before.

RFCOMM.

• Based on GSM TS07.10.

• Emulates a serial port, supporting all traditional applications that were able to use a serial port.

• Supports multiple ports over a single physical channel between two devices.

Telephony Control Protocol Spec (TCS).

• Handles call control (setup, release).

• Group management for gateways, serving multiple devices.

  • Audioconference, e.g.