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.
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.
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.