Logical Link Control Adaptation Protocol (L2CAP)

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Logical Link Control and Adaptation Protocol (L2CAP) is a protocol used in the Bluetooth standard that provides adaption between higher layers and the baseband layer of the Bluetooth stack. It operates just above the host-controller interface (HCI) passing data frames from the higher layers to either HCI or Link Manager.

The following diagram shows the position of L2CAP in Bluetooth protocol architecture −

Functions of L2CAP

  • Adaptation between higher-layer frames and lower layer frames of the Bluetooth protocol stack.

  • Support for both connection-oriented as well as connectionless services.

  • Supporting two links for the Baseband layer −

    • Synchronous Connection-Oriented (SCO) links for real-time voice traffic using reserved bandwidth.

    • Asynchronous Connection-Less (ACL) links for best-effort traffic.

  • Multiplexing of higher layer protocols, which allows them to use the links provided by the lower layers.

  • Segmentation and reassembly of data packets of the upper layer that are larger than the capacity of the radio layer underneath.

  • Group management.

  • Quality of Service (QoS) for upper-layer protocols.

Updated on 22-May-2020 11:53:03