• Piconet : Know The insides of Bluetooth Architecture

    by  • March 23, 2009 • Ethical hacking • 0 Comments

    Bluetooth is an open system that enables short range wireless communication of data and voice. It comprises of a hardware & a software components.

    Bluetooth Architecture consist of the master and the slave arrangement, both are symmetric i.e in same device. In Bluetooth architecture the communication occurs between a master unit and a slave unit, while they share same channel for communication. Each device has a 48 bit unique address that is fixed. Two or more radio devices together form ad-hoc networks called Piconets. These Piconets consist of one master and seven slaves as shown in figure.

    Activation of the Piconet is known by the 3 bit active device address . The piconet form the link of one bluetooth device to another bluetooth device .The master is only responsible for establishing the bluetooth link  in the same  device . The slaves are not allowed to communicate between themselves.

    Piconet

    Piconet

    During the communication there are various protocol are also responsible are as follows-
    Bluetooth core protocol – Baseband ,LMN ,L2CAP, SDP 
    Cable Replacement Protocol – RFCOMM
    Telephony Control Protocol – TCS Binary, AT Commands
    Adopted Protocols–  PPP, TCP/IP, OBEX, WAP, vCard, vCal, IrMC, WAE

    The description of each protocol at each layer:

    The RF layer:
    The RF layer is lowest defined layer of bluetooth architecture.The Bluetooth air interface is based on a nominal antenna power of  extensions for operating at up to 100 mW  worldwide.
    The nominal link range is 10 centimeters – 10 meters, but can be extended to more than 100 meters by increasing the transmit power to 100 mW.

    The Bluetooth  Baseband :
    This layer defines the timing , frame , packets and the flow control on the link.

    The Link Manager 
    Responsible for managing connection states enforcing fairness among slaves & power management..

    The logical Link Control And Adaptation Protocol
    These layer Handles multiplexing, segmentation and reassembly of large packets and device discovery.

    Audio
    The audio maps the data directly to the Baseband layer.

    So, this was the basic introduction of Bluetooth Technology which is today a widely used media for data communication. We are covering this topic so as to give more knowledge for all Ethical Hacking & Bluetooth security interested people.