Transcript Chapter 7 - dhimas ruswanto

Computer Data Communications
Types of Wireless Networks
2
Benefits of Wireless Network
 Mobility
 Provide users with access to real-time information
anywhere in their organization.
 Installation Speed and Simplicity
 Installing a wireless system can be fast and easy and can
eliminate the need to pull cable through walls and
ceilings
 Eliminate wiring costs
 Expensive, unattractive to wire and re-wire existing
homes
3
Benefits of Wireless Network
 Flexible configuration of networks
 Easy relocation and modification to network structures
 Peer to peer network or infrastructure
 Scalability
 Can easily scale to large installation that enable roaming
over broad area.
4
Bluetooth
Bluetooth is a Radio Frequency (RF) specification for
short-range, point-to-multipoint voice and data transfer.
 Always-on, short-range radio hookup that resides on a microchip.
 Can transmit through solid, non-metal objects.
 Low-power short-range wireless standard for a wide range of
devices
 Nominal link range from 10 cm to 10m, but can extended to
100m by increasing transmit power
5
Bluetooth
 Two Bluetooth devices within 10 m of each other can share
up to 720 kbps of capacity
 Uses 2.4-GHz band (available globally for unlicensed low-
power uses)
 Facilitates adhoc connections for stationary and mobile
communications.
6
Examples of Bluetooth Capability
 Make calls from a wireless headset connected remotely to a cell
phone
 Eliminate cables linking computers to printers, keyboards, and
the mouse
 Hook up MP3 players wirelessly to other machines to download
music
 Set up home networks to remotely monitor air conditioning,
appliances, and Internet surfing
 Call home from a remote location to turn appliances on and off,
set the alarm, and monitor activity.
7
Bluetooth Applications
 Up to eight devices can communicate in a small
network called a piconet; ten of these can coexist in
the same coverage range of the Bluetooth radio.
 Bluetooth provides for three general application areas
short-range wireless connectivity:
 Data and voice access points
 Cable replacement
 Ad hoc networking
8
Bluetooth Applications
 Data and voice access points
 Bluetooth facilitates real-time voice and data
transmissions by providing effortless wireless
connection of portable and stationary communications
devices.
 Cable replacement
 Bluetooth eliminates the need for numerous, often
proprietary, cable attachments for connection of
practically any kind of communication device.
Connections are instant and are maintained even when
devices are not within line of sight. The range of each
radio is approximately 10m but can be extended to
100m by increasing transmit power.
9
Bluetooth Applications
 Adhoc networking
 A device equipped with a Bluetooth radio can establish
instant connection to another Bluetooth radio as soon as
it comes into range.
10
Bluetooth Vision
11
Bluetooth Standards Documents
 The Blue standards documents are divided into two
groups: core and profile specifications.
 Core Specifications
 Describes layers of the protocol architecture, from radio interface
to link control
 Profile Specifications
 Discusses the use of the technology defined in the core
specifications to implement a particular usage model
 General access profile specifies how the baseband architecture
should be used between devices that implement one or multiple
profiles
 Other profiles fall into one of two categories: cable replacement
or wireless audio
12
Bluetooth Protocol Stack
13
Bluetooth Protocol Architecture
 Bluetooth is defined as layered protocol
architecture consisting of:
 Core protocols

The core protocols form a five layer stack consisting of the
following elements:
 Radio, Baseband, Link Manager Protocol (LMP), Logical link
control and adaptation protocol (L2CAP), Service discovery
protocol (SDP).
 Cable replacement protocols (RFCOMM)

presents a virtual serial port that is designed to make replacement
of cable technologies as transparent as possible
14
Bluetooth Protocol Architecture
 Telephony Control Protocol (TCS BIN)
 a bit-oriented protocol that defines the call control signaling
for the establishment of speech and data calls between
Bluetooth devices
15
Bluetooth Protocol Architecture
 Adopted Protocols
 The adopted protocols are defined in specifications
issued by other standards-making organizations and
incorporated into the overall Bluetooth archictecture.
The Bluetooth strategy is to invent only necessary
protocols and use existing standards whenever possible.
 The adopted protocol includes the following:

PPP: The point-to-point protocol is an Internet Standard
protocol for transporting IP datagrams over a point-to-point
link

TCP/UDP/IP: These are foundation protocols of TCP/IP
protocol suite.
16
Bluetooth Protocol Architecture
 Adopted Protocols
 The adopted protocol includes the following:

WAE/WAP: Bluetooth incorporates the wireless application
environment and the wireless application protocol into its
archictecture.

OBEX: The object exchange protocol is a session-level
protocol developed by the Infrared Data Association for the
exchange of objects. OBEX provides functionality similar to
that of HTTP but a simpler fashion. It also provides a model
for representing objects and operations. Examples of content
formats by OBEX are vCard and vCalendar, which provide the
format of an electronic business card and personal calendar
entries and scheduling information, respectively.
17
Bluetooth Core Protocols
 The core protocols form a five-layer stack consisting
of the following elements:
 Radio: Specifies details of the interface, including
frequency, the use of frequency hopping, modulation
scheme and transmit power.
 Baseband: Concerned with the connection
establishment within a piconet, addressing, packet
format, timing and power control.
18
Bluetooth Core Protocols
 The core protocols form a five-layer stack consisting
of the following elements:
 Link manager protocol (LMP) : Responsible for link
setup between Bluetooth devices and ongoing link
management. This is includes security aspects such as
authentication and encryption, plus the control and
negotiation of baseband packet sizes.
 Logical link control and adaptation protocol
(L2CAP) : Adapts upper-layer protocols to the baseband
layer. L2CAPS provides both connectionless and
connection-oriented.
19
Bluetooth Core Protocols
 The core protocols form a five-layer stack consisting
of the following elements:
 Service discovery protocol (SDP) : Device
information, services and the characteristics of the
services can queried to enable the establishment of a
connection between two or more Bluetooth devices..
20
Bluetooth Core Protocols : Bluetooth Radio
 Frequency 2.4 GHz (ISM band)
 Time Division Duplex (TDD)
 79 (or 23) channels, 1 MHz spacing
 Frequency hopping, peak Tx power 20 dBm
 1 Mbps gross data rate ( 432.6 kbps sym. / 721 – 57.6
kbps asym)
 CVSD voice encoding – 64 kbps
21
Bluetooth Core Protocols : Bluetooth Baseband
 Piconet
 2 or more Bluetooth units sharing a channel (hopping)
form a piconet


Connected units can be master or slave. Master is the device
that initiates the formation of piconet.
Master can connect to maximum 7 slaves per piconet
simultaneously.
 In forming a piconet, master gives slaves its clock and
device ID.


Unique hopping pattern for each piconet
All devices in a piconet hop together.
 Each piconet has a maximum total capacity of 1 Mbps.
22
Bluetooth Core Protocols : Bluetooth Baseband
 Piconet
23
Bluetooth Core Protocols: Bluetooth Baseband
 Scatternet
 When 2 or more piconets partially overlap in time and
space, a scatternet is formed.
 Each piconet has a single master and a set of slaves. A
slave can participate in more than one piconet by in turn
establishing connections with and synchronizing to
different masters in proximity. A single device can act as
a slave in one piconet but assume the role of master in
another piconet.
24
Bluetooth Core Protocols:Bluetooth Baseband
 Scatternet
 The scatter topology provides a flexible method by
which devices maintain multiple connections. This
could be especially useful for mobile devices which
frequently move into and out of proximity to the other
devices.
25
Bluetooth Baseband:Piconets and Scatternets
26
Bluetooth Baseband:Operational States
27
Bluetooth
High-Priority Usage Models
 File Transfer
 Internet Bridge
 LAN Access
 Synchronization
 Three-in-one Phone
 Headset
28
Bluetooth Product
 Palm Bluetooth SD Card
 Nokia 7650
 Ericsson T68i
 Compaq iPaq H3870
 Sony Ericsson Headset
 Sony Vaio SRX-51P
 Hp 995c Bluetooth Printer
29
Competing Technologies
 IrDA
 Inexpensive but
 Requires direct line-of-sight
 Limited to point-to-point connections
 Limited range
 IEE802.11
 Higher transmission capacity
 Number of simultaneous users is higher but
 Hardware size is bigger
 Module is more expensive
30
Competing Technologies
 Home RF
 Wireless technology optimized for the home
environment
 Open industry specification for wireless digital
communication between PCs & consumer electronic
devices anywhere in and around
 Support more units per net
 Just 50 frequency hops per second
31