Protocol layers are a hierarchical model of network or communication functions. The divisions of the hierarchy are referred to as layers or levels, with each layer performing a specific task. In addition, each protocol layer obtains services from the protocol layer below it and performs services for the protocol layer above it. The Bluetooth system divides communication functions into protocol layers.
The Bluetooth system consists of many existing protocols that are directly used or have been adapted to the specific use of the Bluetooth system. Protocols are often divided into groups that are used for different levels of communication (a protocol stack). Lower level protocols (such as protocols that are used to manage a radio link between specific points) are only used to create, manage, and disconnect transmission between specific points. Mid-level protocols (such as transmission control protocols) are used to create, manage, and disconnect a logical connection between endpoints that may have multiple link connections between them. High level protocols (application layer protocols) are used to launch, control, and close end-user applications.
Some of the layers associated with the Bluetooth system include the baseband layer (physical layer), link layer, host controller interface (HCI), logical link control applications protocol (L2CAP), RF Communications protocol (RFCOMM), Object Exchange (OBEX), and service discovery.
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Overview of the content:
Introduction.
Technology Review.
Specification of Bluetooth technology.
Architecture of Bluetooth Protocol.
Protocols in Bluetooth Stack.
Advantages And Disadvantages Bluetooth.
Future of Bluetooth
Conclusion
Bibliography
3. Introduction.
▪ Wireless technology standard for
exchanging data over short distances.
▪ Personal Area Networks(PAN).
▪ Invented by telecom vendor Ericsson
in 1994.
4. Introduction.
▪ Originally was a wire
replacement technology.
▪ Applications: Mobile phones,
Laptops, Bluetooth Headsets,
Telehealth devices, etc.
5. Technology Review.
▪ Bluetooth uses radio technology called “Frequency Hopping
spread Spectrum”.
▪ Supports data rate of I mb/s (originally).
▪ Managed by the Bluetooth Special Interest Group (SIG).
▪ Bluetooth was standardized as IEEE 802.15.1, but the
standard is no longer maintained.
6. Specification of Bluetooth technology.
▪ Core Specification
Deals with lower layers of architecture and describes how
technology works.
▪ Profile Specification
Focuses on how to build inter operating devices using the core
technology.
8. Protocols Used In Bluetooth.
Radio:
▪ Is situated at the most bottom of all the layers.
▪ Used in the specification of the air interfaces like frequencies,
modulation, transmit power
▪ Bluetooth radio is a transceiver which transmits and receives modulated
electrical signals from peer Bluetooth devices
9. Protocols Used In Bluetooth.
Baseband:
▪ The Baseband and Link control layer enable the physical connection
between any Bluetooth enabled products.
▪ This layer also controls the synchronisation and the frequency hopping
sequence.
▪ The 2 different link types Synchronous Connection Oriented (SCO) and
Asynchronous Connectionless (ACL) are also managed by this layer.
10. Protocols Used In Bluetooth.
Audio:
▪ Audio transmissions can be performed between one or more Bluetooth
enabled units, using a number of different usage models.
▪ Audio data does not go through the L2CAP layer (see diagram 1) but
directly between 2 Bluetooth units.
11. Protocols Used In Bluetooth.
Host Controller Interface (HCI): :
▪ The Host Controller Interface provides an interface method for accessing
the Bluetooth hardware capabilities.
▪ It contains a command interface, which acts between the Baseband
controller and link manager and has access to hardware status.
▪ It contains the control and event registers.
12. Protocols Used In Bluetooth.
Link Manager protocol (LMP):
▪ The Link Manager Protocol, is responsible for link set-up between
Bluetooth enabled units.
▪ It handles the control and negotiation of packet sizes used when
transmitting data.
▪ The Link Manager Protocol also handles management of power modes,
power consumption, and state of a Bluetooth unit in a piconet.
▪ Finally, this layer handles generation, exchange and control of link and
encryption keys for authentication and encryption
13. Protocols Used In Bluetooth.
Logical Link Control and Adaption Protocol (L2CAP):
▪ The Bluetooth logical link control and adaptation protocol is situated over the Baseband
layer and beside the Link Manager Protocol in the Bluetooth protocol stack. The L2CAP
layer provides connection-oriented and connectionless data services to upper layers.
▪ The four main tasks for L2CAP are:
▪ Multiplexing - L2CAP must support protocol multiplexing since a number of protocols
(e.g. SDP, RFCOMM and TCS Binary) can operate over L2CAP.
▪ Segmentation and Reassembly - Data packets exceeding the Maximum Transmission
Unit, MTU, must be segmented before being transmitted. This and the reverse
functionality, reassemble, is performed by L2CAP.
▪ Quality of Service - The establishment of an L2CAP connection allows the exchange of
information regarding current Quality of Service for the connection between the two
Bluetooth units.
▪ Groups - The L2CAP specification supports the mapping of groups on to a piconet.
14. Protocols Used In Bluetooth.
Service Discovery Protocol (SDP):
▪ The Service Disocvery Protocol defines how a client's Bluetooth enabled
application will discover available Bluetooth server' services and
characteristics upon entering a Bluetooth server area.
▪ SDP also provides functionality for detecting when a service is no longer
available.
15. Protocols Used In Bluetooth.
RFCOMM:
▪ RFCOMM protocol is a serial port protocol.
▪ The protocol covers applications that make use of serial ports of the unit.
▪ RFCOMM emulates RS-232 control and data signals over the baseband.
▪ It also provides capabilities for the upper service levels such as OBEX,
which uses a serial line as a transport mechanism.
16. Protocols Used In Bluetooth.
Telephony control protocol:
a. Telephony Control – Binary
b.Telephony Control – AT Commands
▪Bit-oriented protocol, which defines
the call control signalling for the
establishment of speech and data
calls between Bluetooth units.
▪Are supported for transmitting
control signals for telephony control.
▪Provides functionality to exchange
signalling information unrelated to
ongoing calls.
▪ITU-T Recommended.
▪These use the serial port emulation,
RFCOMM, for transmission.
17. Protocols Used In Bluetooth.
Adopted protocols
▪ This section describes a number of protocols that are defined to be
adopted to the Bluetooth protocol stack.
▪ Note some of these adaptations are at the moment incomplete.
a. Point-to-Point Protocol - PPP
– Designed to run over RFCOMM to accomplish point-to-point
connections.
– packet-oriented protocol and must therefore use its serial
mechanisms to convert the packet data stream into a serial data
streams.
18. Protocols Used In Bluetooth.
Adopted protocols
▪
b. TCP/UDP/IP
– Defined to operate in Bluetooth units allowing them to
communicate with other units connected, for instance, to the
Internet.
– Bluetooth can acts like a bridge to internet
– The TCP/IP/PPP protocol configuration is used for all Internet
Bridge usage scenarios in Bluetooth 1.0 and for OBEX in future
versions.
– The UDP/IP/PPP configuration is available as transport for WAP.
19. Protocols Used In Bluetooth.
Adopted protocols
▪
c. IrOBEX, shortly OBEX Protocol
– Optional application layer protocol designed to enable units
supporting infrared communication to exchange a wide variety of
data and commands in a resource-sensitive standardized fashion.
– Client-server model and is independent of the transport
mechanism and transport API.
– Defines a folder-listing object, which is used to browse the contents
of folders on remote device.
– RFCOMM is used as the main transport layer for OBEX.
20. Protocols Used In Bluetooth.
Adopted protocols
▪
d. Wireless Application Protocol, WAP
– wireless protocol specification that works across a variety of widearea wireless network technologies bringing the Internet to mobile
devices.
– Bluetooth can be used like other wireless networks with regard to
WAP, it can be used to provide a bearer for transporting data
between the WAP Client and its adjacent WAP Server.
– Furthermore, Bluetooth’s ad hoc networking capability gives a
WAP client unique possibilities regarding mobility compared with
other WAP bearers.
21. Protocols Used In Bluetooth.
Adopted protocols
▪
e. Content formats
– Formats for transmitting vCard and vCalendar information are also
defined in the Bluetooth specification.
– The formats do not define transport mechanisms but the format in
which electronic business cards and personal calendar entries and
scheduling information are transported.
– vCard and vCalendar is transferred by OBEX.
22. Advantages And Disadvantages Bluetooth.
Disadvantages
Advantages
▪ Short ranged.
▪ Eliminates wires.
▪ Facilities data
communication.
and
▪ Standardized protocols.
▪ Free of charge.
▪ Easy to use.
voice
▪ Less secured
▪ Interference
devices.
with
other
23. Future Of Bluetooth.
▪ Very good future ahead as it need basic needs of connectivity.
▪ Latest versions are improving both in securities and capabilities.
▪ New versions will meet high speed and large range.
▪ Many companies are developing Bluetooth applications in
demand.
24. Conclusion
▪ A new global standard for voice and data.
▪ Eliminates cables.
▪ Low power, low range, low cost network device.
▪ Further improvements are planned to made in
– Data Rate.
– Power Reduction
– Range