THIS PPT DISRIBES INTRODUCTION TO MOBILE COMPUTING MOBILE COMPUTING APPLICATIONS CHARACTERISTICS WIRELESS COMMUNICATION MOBILE IP

1. INTRODUCTION TO MOBILE COMPUTING
Lecture
BY
BHUVANESWARI R
Assistant Professor in Computer Science &Applications
DKM College for Women
Vellore, Tamil Nadu, India

2. WHAT IS MOBILE COMPUTING?
 Mobile computing is a technologies that
 enable people to access network services anyplace, anytime, and
anywhere,
 with portable and wireless computing and communication devices. --
- (where is this referenced? Provide citation!)
 Aspects of mobility
 User mobility
 Between different geographical locations
 Between different networks
 Between different communication devices
 Between different applications
 Device portability
 Between different geographical locations
 Between different networks
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3. MOBILE COMPUTING
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 Mobile Computing is a generic term describing the application of small,
portable, and wireless computing and communication devices.
 This includes devices like laptops with wireless LAN technology, mobile
phones, wearable computers and Personal Digital Assistants (PDAs)
with Bluetooth or IRDA interfaces, and USB flash drives.

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CHARACTERISTICS OF COMMUNICATION DEVICES
 Fixed and wired: This configuration describes the typical desktop
computer in an office. The devices use fixed networks for performance
reasons.
 Mobile and wired: Many of today’s laptops fall into this category; users
carry the laptop from one hotel to the next, reconnecting to the
company’s network via the telephone network and a modem.
 Fixed and wireless: This mode is used for installing networks, e.g., in
historical buildings to avoid damage by installing wires, or at trade
shows to ensure fast network setup.
 Mobile and wireless: This is the most interesting case. No cable
restricts the user, who can roam between different wireless networks.
Most technologies discussed in this book deal with this type of device
and the networks supporting them. Today’s most successful example for
this category is GSM with more than 800 million users.

5. APPLICATIONS OF MOBILE COMPUTING
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 Although many applications can benefit from wireless networks and mobile
communications.
 Vehicles
 transmission of news, road condition, weather, music via DAB (Digital Audio Broadcasting)
 current position of the car is determined via the global positioning system (GPS)
 local ad-hoc network with vehicles close-by to prevent accidents, guidance system,
redundancy
 vehicle data (e.g., from busses, high-speed trains) can be transmitted in advance for
maintenance

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APPLICATIONS OF MOBILE COMPUTING

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APPLICATIONS OF MOBILE COMPUTING
 Medical
 Nurses/Doctors in Medical offices are now using Wireless Tablet PCs/WLAN to collect
and share patient information.
 Sales
 Sales representatives are using Tablet PCs with Smart phones for presentation,
transmitting/access information among office, hotel, and customer location.
 Emergencies
 Early transmission of patient data to the hospital, current status, first diagnosis
 Provide mobile infrastructure in dealing with Natural Disaster (earthquake, hurricane,
fire), terrorist attacks, war, ...

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NATURAL EVOLUTION OF COMPUTING
Freedom from Collocation
Single User
OS
Batch
Timesharing
Networking
LANs + WorkStations
Mobile Computing
More
Flexible
Resource
Usage

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CHALLENGES IN MOBILE COMPUTING
 Mobility means changes
 Hardware
 Lighter, smaller, energy management, user interface
 Low bandwidth, high bandwidth variability
 Kbit/s to Mbit/s, bandwidth fluctuation
 Security risk
 Devices more vulnerable, endpoint authentication harder
 Heterogeneous network
 Different devices, interfaces and protocols
 Location awareness
 Locality adaptation
 Higher loss-rates, higher delays, more jitter
 Connection setup time, hand-off
 Restrictive regulations of frequencies
 Frequencies have to be coordinated

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HISTORY OF WIRELESS COMMUNICATION
 1896 Guglielmo Marconi,
 First demonstration of wireless telegraphy
 Based on long wave, requiring very large transmitters
 1907 Commercial Trans-Atlantic Wireless Service
 Huge ground stations: 30 x 100m antenna masts
 1920 Discovery of short waves by Marconi
 Cheaper, smaller, better quality transmitters by vacuum tube
 1982 Start of GSM in Europe (1G analog)
 1983 Start of AMPS in America (1G analog)
 1992 Start of GSM (2G digital)
 1997 Wireless LAN - IEEE802.11
 1998 Iridium satellite system
 66 satellites

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HISTORY OF WIRELESS COMMUNICATION
 1999 Standardization of additional wireless LANs
 IEEE standard 802.11b
 Bluetooth
 WAP (Wireless Application Protocol): access to many services
via the mobile phone
 2000 GSM with higher data rates (2.5G digital)
 HSCSD offers up to 57,6kbit/s
 First GPRS trials with up to 50 kbit/s
 2001 Start of 3G systems
 IMT - 2000, several “members” of a “family”, CDMA2000
in Korea, UMTS tests in Europe

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cellular phones satellites
wireless
LAN
cordless
phones
1992:
GSM
1994:
DCS 1800
2001:
IMT-2000
1987:
CT1+
1982:
Inmarsat-A
1992:
Inmarsat-B
Inmarsat-M
1998:
Iridium
1989:
CT 2
1991:
DECT
199x:
proprietary
1997:
IEEE 802.11
1999:
802.11b, Bluetooth
1988:
Inmarsat-C
analogue
digital
1991:
D-AMPS
1991:
CDMA
1981:
NMT 450
1986:
NMT 900
1980:
CT0
1984:
CT1
1983:
AMPS
1993:
PDC
2000:
GPRS
2000:
IEEE 802.11a
20??
Fourth Generation?
1G
2G
2.5G
3G
4G?
2003:
IEEE 802.11g
2007?:
IEEE 802.11N
OVERVIEW OF DEVELOPMENT

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OVERVIEW OF WIRELESS SERVICES
Data Rates
Coverage Area
Local Wide
10 Mbps
1 Mbps
10 Kbps
50 Kbps
Wireless
LAN
IR
Cellular: GSM,
GPRS, CDMA,
Satellite

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MOBILE AND WIRELESS DEVICES
 Now many mobile and wireless devices are
available, there will be many more in the future.
 The following list gives some examples of mobile
and wireless devices graded by increasing
performance (CPU, memory, display, input devices
etc.).
 Sensor, Embedded controllers, Pager, Mobile
phones, Personal digital assistant, Pocket
computer, Notebook/laptop

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 Sensor:
• A very simple wireless device
• sensor transmitting information EG: office door
 Embedded controllers:
 Many appliances already contain a simple or
sometimes more complex controller.
 Keyboards, mice, headsets, washing machines,
coffee machines, hair dryers and TV sets are just
some examples
MOBILE AND WIRELESS DEVICES

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 Personal digital assistant: PDAs typically
accompany a user and offer simple versions of
office software (calendar, note-pad, mail). The
typical input device is a pen, with built-in character
recognition translating handwriting into characters
 Pocket computer: The next steps toward full
computers are pocket computers offering tiny
keyboards, color displays, and simple versions of
programs found on desktop computers
MOBILE AND WIRELESS DEVICES

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MOBILE AND WIRELESS DEVICES
 Pager: As a very simple receiver, a pager can only
display short text messages, has a tiny display, and
cannot send any messages. Pagers can even be
integrated into watches.
 Mobile phones: The traditional mobile phone only
had a simple black and white text display and could
send/receive voice or short messages. Today,
Mobile phones with full color graphic display, touch
screen, and Internet browser are easily available.

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 Notebook/laptop: Finally, laptops offer more or
less the same performance as standard desktop
computers; they use the same software – the only
technical difference being size, weight, and the
ability to run on a battery. If operated mainly via a
sensitive display (touch sensitive or
electromagnetic), the devices are also known as
notepads or tablet PCs.
MOBILE AND WIRELESS DEVICES

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OVERVIEW OF MOBILE DEVICES
performance
Pager
• receive only
• tiny displays
• simple text
messages
Smart phone
• voice, data
• simple graphical displays
PDA
• graphical displays
• character recognition
Wearable device
• human wearable
• non standard I/O
Sensors,
embedded
controllers
Laptop
• fully functional
• standard applications

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ROLE OF IETF IN MOBILE COMMUNICATION
 Mobile IP (or MIP) is an Internet Engineering Task
Force (IETF) standard communications protocol that is
designed to allow mobile device users to move from one
network to another while maintaining a permanent IP
address.
 Mobile IP for IPv4 is described in IETF RFC 5944, and
extensions are defined in IETF RFC 4721.
 Mobile IPv6, the IP mobility implementation for the next
generation of the Internet Protocol, IPv6, is described
in RFC 6275.

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WIRELESS LAN
 IEEE 802.11 standard: a family of specifications for wireless
LAN technology. The IEEE accepted the specification in
1997.
 802.11 specifies an over-the-air interface between a
wireless client and a base station or between two wireless
clients.
 802.11: up to 2 Mbps in the 2.4 GHz band.
 802.11b: up to 11 Mbps in the 2.4 GHz band.
 802.11a/g: up to 54 Mbps in the 5/2.4 GHz band.
 802.11n: up to 220+ Mbps in the 2.4/5 GHz band (two proposals not
approved yet). Vendors already selling 802.11pre-n devices.
 802.11 promises true vendor interoperability. Every vendor
must have a viable 802.11 product strategy.

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WIRELESS LAN SECURITY
 WEP: Wired Equivalent Privacy.
 A basic wireless LAN security mechanism.
 Easy to set up, commonly used.
 Don’t rely on WEP for wireless security. There are a number of flaws
in the WEP.
 Many wireless home networks don’t even use WEP, which
makes bad situation worse.
 MAC address based access control mechanism doesn’t
work.
 Use other security mechanisms such as VPN, PEAP and
TTLS.
 Research project on PEAP / TTLS in our research group in
University of Colorado.

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 Wireless Ad Hoc Network (peer to peer)
 A collection of autonomous nodes that communicate with each other
by forming a multi-hop radio network in a decentralized manner.
 No infrastructure, no default router available
 “every” node needs to be a router
 Mobile Ad Hoc Networks (MANET)
 Host movement frequent
 Topology change frequent
 Wireless Ad Hoc Sensor Networks
 A number of sensors spread across a geographical area.
 Limited resources on sensors
WIRELESS AD HOC NETWORK

24. MOBILE IP
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 Mobile IP is designed to allow mobile device users to move
from one network to another while maintaining their
permanent IP address.
 Motivation:
 Changing the IP address is not desired when host moves.
 However, traditional scheme requires to change IP address when
host moves between networks.
 Mobile IP provides an efficient, scalable mechanism for
node mobility within the Internet. Mobile IP allows moving
devices to maintain transport and higher-layer connections
while moving.
 Applications:
 Mobile IP is most often found in wireless WAN environments where
users need to carry their mobile devices across multiple LANs with
different IP addresses.

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MOBILE IP: BASIC IDEA
25
Internet
sender
Foreign Agent (FA)
Home Agent (HA)
Mobile Node (MN)
home network
foreign
network
receiver
1
2
3
1. Sender sends to the IP address of MN,
HA intercepts packet (proxy ARP)
2. HA tunnels packet to COA, here FA,
by encapsulation
3. FA forwards the packet to the MN
COA: ?

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MOBILE IP: BASIC IDEA
Internet
receiver
FA
HA
MN
home network
foreign
network
sender
1
1. Sender sends to the IP address
of the receiver as usual,
FA works as default router
CN