Post on 06-Apr-2018
8/2/2019 Internet&Mobile Computing 234
1/19
INTERNET
AND
MOBILE COMPUTING
\
Submitted by
G.Akhila B.Sujini
III/IV III/IV
(09A81A1276) (09A81A1269)akhilagadde1276@gmail.com sujini.bezawada@gmail.com
Department of InformationDepartment of InformationTechonologyechonology
SRI VASRI VASAVIAVI ENGINEERING COLLEGE,,
TADEPALLIGUDEMTADEPALLIGUDEM
mailto:akhilagadde1276@gmail.commailto:sujini.bezawada@gmail.commailto:akhilagadde1276@gmail.commailto:sujini.bezawada@gmail.com8/2/2019 Internet&Mobile Computing 234
2/19
8/2/2019 Internet&Mobile Computing 234
3/19
8/2/2019 Internet&Mobile Computing 234
4/19
computer desktops
supporting roaming
With device
portability the
communication device
moves (with or without
a user). Many
mechanisms in the
network and inside the
device have to make
sure that
communication is still
possible while it is
moving
Internet
What is the
Internet? The Internet is
latest in
communications
tools. Today, the
Internet is a part of
daily life. Even if you
don't use it regularly,
you hear about it
daily. Estimates tell
us that in US alone,
40 million computers
connect to the
Internet, and the
number is growing.
In India also, the
Internet connections
are growing
exponentially.
The Internet has
many features common
with our telephone
network. When we
make a phone call a
channel consisting of
copper wires, fiber
optic lines, and
perhaps a satellite
opens. Voice signals
on both sides are
converted into an
analogue electrical
signal, which the
phone system
manipulates and
transmit. A telephone
conversation
establishes a direct
channel between both
the parties.
The Internet is aworld wide "network
of networks". It is a
loose collection of
thousands of smaller
networks in different
countries around the
8/2/2019 Internet&Mobile Computing 234
5/19
globe enabling
millions of people
from diverse cultures
to share information
and resources. Internet
pathways exchange
digitized computer
data that travel through
complex networks.
Even the parts of a
single E-mail message
travel through
computers and lines
owned by dozens of
companies andgovernment entities
What Are the Types
of Internet
Connections?
There are many ways
to connect to the
Internet. The four most
practical for small
businesses are analog,
ISDN (Integrated
Services Digital
Network), DSL
(Digital Subscriber
Line) and cable.
Analog connectivity,
such as 56K modems,and ISDN connectivity
both require dial-up
access. This means that
every time you need to
access the Internet,
analog or ISDN
modems must dial a
number to secure a
connection. DSL and
cable modem
solutions, on the other
hand, are permanent
connections that are
always on. They
provide immediate
access to the Internet
without having to dial
any numbers
DSL and cable are
known as broadband
connections and aremuch faster than
analog or ISDN links.
They also tend to be
more costly than
analog and ISDN
connections. All have
their strengths,
however, and you need
to evaluate your needs
to determine which is
best for your
organization
8/2/2019 Internet&Mobile Computing 234
6/19
Understandi
ng the
World Wide
Web
We read and hear
daily about the Internet
or the "Net". And
associated with the
Internet, everyone
talks about "surfing the
Web" and "cruising
through cyberspace",
which refer to
"exploring the WorldWide Web." The term
World Wide Web, or
WWW, or Web is a
computer application
that is bringing masses
to the Internet. This
application has made it
possible for any
computer user to find
information on
anything the mind can
imagine. Before you
begin to explore the
Web, it is helpful to
know some basics
about the Web.
The Web and the Internet
The Web and the
Internet are two
separate entities thatwork together. The
Internet is a global
system of connected
computers. The Web is
a collection of
electronic documents
stored on computers
worldwide, which
means on the Internet.The Internet was
born in 1960s as an
experiment by the U.S.
Department of
Defense. The
Department developed
a network of
computers in which the
individual computers
of the network did not
depend wholly of the
main or central
computer and could
communicate with
each other without the
8/2/2019 Internet&Mobile Computing 234
7/19
help of the central
computer.
The Web browser
The Web began itsrise in 1991 when Tim
Berners-Lee, a
consultant at the Swiss
research laboratory
CERN, used it to share
research data with
other physicists.
Berners-Lee and
CERN developerswrote a program that
ran on many types of
computer systems,
enabling scientists
everywhere to access
research documents via
the Internet. This
program became
known as a Web
browser.
In fact, the
popularity of Web rose
only after the creation
of Mosaicthe first
well-known graphical
Web browser. It was
developed by the
University of Illinois
National Center for
Supercomputing
Applications (NCSA)
and was distributed
freely over the Internet
Hypertext Markup
Language (HTML)
The World Wide
Web connects people
to more than 100million Web pages
from all over the globe
containing all kinds of
information. The
thread pulling it all
together is Hypertext
Markup Language
(HTML), the standard
code used for creatingand formatting Web
pages. HTML is a text-
based markup
language that all the
Web browsers are able
to understand and
intercept. HTML is a
way of representing
text and linking that
text to other kinds of
information such as
graphics, animation,
sound and multimedia
and allowing different
kinds of data to be
displayed together
URL UniversalResource Locator
Most importantly,
HTML tags also
designate which words
and graphics in a
8/2/2019 Internet&Mobile Computing 234
8/19
document are
hypertext links and
which page is to be
loaded when those
links are clicked. Each
hypertext link (also
called a hyperlink or
simply a link) points to
a certain Universal
Resource Locator
(URL, also called a
Web address), which is
like an address of a
document on the
Internet. URLs arestandardized shorthand
method of locating
documentson the
Internet. With the
correct URL, your
Web browser can find
and display any Web
page anywhere in the
world. An example of
URL on Web is
http://www.economicti
mes.com
First http part tells
that the information is
in hypertext format
and you need to use a
Web browser to accessthis information. Next
part
www.economictimes.c
om is the host machine
that is running the Web
server.
How Do I
Connect to
the Internet?For any individual
or a small business
organization to join the
Internet, he needs the
services of an Internet
Service Provider (ISP).
You have to begin by
visiting an office of an
ISP of your choice inyour city or contacting
them on telephone.
Even the computer
dealer/seller in your
area will be willing to
help you. When you
get an Internet account,
you will be asked to
provide your login andpassword. You will be
given e-mail address
and password. You
will also get phone
number to be dialed to
connect to the ISP and
helpdesk phone
numbers. An e-mail
address from VSNL's
Bombay office can beas:
rajan@giasbm02.vsnl.
net.in.
But before youget your own Internet
8/2/2019 Internet&Mobile Computing 234
9/19
account, it is better to
go through this article.
Because, before you
sign up you will need
to know, the type of
modem you require
and where to get the
necessary software and
other things. Many
educational institutions
and organizations are
already linked to the
Internet. It may be that
the computer on your
desk in your office hasall you need to gain
access. Otherwise, you
will probably have to
get individual access
for yourself.
MOBILECOMPUTIN
GAPPLICATIONS OF
MOBILE
COMMUNICATION
S
Although wirelessnetworks and mobile
communications can
be used for many
applications. Some of
them are given as
follows.
1.Vehicles:
Tomorrows cars
will comprise manywireless
communication
systems and mobility
aware applications.
Music, news, road
conditions, weather
reports, and other
broadcast information
are received via digital
audio broadcasting
(DAB) with 1.5
Mbits/s. For personal
communication, a
global system for
mobile
communications
(GSM) phone might be
available offering
voice and dataconnectivity with 384
kbits/s
2. Emergencies:
Just imagine the
possiblibities of an
ambulance with a high
quality wireless
connection to a
hospital. After an
accident, vital
information about
injured persons can be
sent to the hospital
immediately. There,
all necessary steps for
8/2/2019 Internet&Mobile Computing 234
10/19
this particular type of
accident can be
prepared or further
specialists can be
consulted for an early
diagnosis.
Furthermore,
wireless
networks are the only
means of
communication in the
case of natural
disasters such as
hurricanes or
earthquakes.3.Business
Todays typical
traveling salesman
needs instant access to
the companys
database: to ensure that
the files on his or her
labtop reflect the
actual state, to enable
the company to keep
track of all activities of
their traveling
employees, to keep
databases consistent
etc., with wireless
access, the laptop can
be turned into a true
mobile office
MOBILE AND
WIRELESS
DEVICES
Currently, laptops are
considered to be the
upper end of the
mobile device range.
Following list gives
some examples of
mobile and wireless
devices graded by
increasing
performance (CPU ,
Memory , Display ,
Input devices etc.,)
Sensor:
A very simplewireless device is
represented by a sensor
transmitting state
information. An
example for such a
sensor could be a
switch sensing the
office door. If the door
is closed, the switch
transmits this state to
the mobile phone
inside the office and
the mobile phone will
not accept incoming
calls. Thus, without
user interaction the
semantics of a closed
door is applied to
phone calls.
Pager:
A very simple
receiver, a pager can
only display short text
messages, has a tiny
8/2/2019 Internet&Mobile Computing 234
11/19
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,
however, mobile phones migrate more
and more toward
PDAs. Mobile phones
with full color graphic
display, on the internet
browser are available.
Personal digital
assistant:
PDAs typically
accompany a user and
officer very simple
versions of office
software (calendar,
notepad, mail). The
typical input device is
a pen, with built in
character recognition
translating handwriting into characters.
Web browsers and
many other software
packages are already
available for these
devices.
Palmtop/pocket
computer:
The next step
toward full computer
are pocket computers
offering tiny
keyboards, color
displays, and simple
versions of programs
found on desktop
computers (Text
processing, SpreadSheets etc.,).
Notebook/Laptop:
Finally, laptops
offer more or less the
same performance as
standard desktop
computers; use the
same software, the
only technical
difference being size,
Weight, and ability to
run on a battery.
Wireless Application
Protocol WAP
Where does WAP Fit
in the Wireless
ComputingApplication?
Three are three
essential product
components that you
need to extend your
host applications and
8/2/2019 Internet&Mobile Computing 234
12/19
data to WAP-enabled
devices. These three
components are:
13193. WAP
Microbrowser
residing in the
client handheld
device
13194. WAP
Gateway
typically on
wireless ISPs
network
infrastructure
13195. WAPServer - residing
either on ISPs
infrastructure or
on enduser
organizations
infrastructure
Lots of WAP browsers
and emulators are
available free of cost
which can be used to
test your WAP pages.
Many of these
browsers and
emulators are specific
to mobile devices. For
example the R380s
WAP emulator is
intended to be used for
testing WMLapplications developed
for the WAP Browser
in the Ericsson
Smartphone R380s.
You can find a list of
downloadable WML
Browsers/ Emulators at
WAP emulators can be
used to see how your
site will look like on
specific phones. As
these images show, thesame thing can look
different on different
mobile phones. So, the
problems that web
developer faces with
the desktop browsers
(Netscape/Iexplorer) is
present here also. So,
make sure you testyour code on different
mobile phones (or
simulators)
WAP Products -
Microbrowser, WAP
Gateway, WAP
servers WAP
Gateway
The idea behind WAP
specifications is toconnect the mobile
networks to the
Internet.To connect
these two mega-
networks, the WAP
Specification assumes
8/2/2019 Internet&Mobile Computing 234
13/19
there will be a WAP
Gateway.
At its simplest level,
this is a stack
converter, which will
convert the WAP
request into a Web
request and the Web
response into a WAP
response. WAP
Gateway is a piece of
software that sits
between the mobile
device and the external
network like theInternet. The gateway
does the job of
converting Internet
content i.e. the WML
pages into byte code
(WMLC) which can be
understood by a WAP
device. Usually located
on a server of a mobile
operator it handles
incoming requests
from your WAP
phone, takes care of
the conversion
required during
WTLS/SSL sessions
and handles incoming
requests from your
WAP phone. Althoughin theory, the gateway
could also be made to
convert the HTML
page content itself on-
the-fly as well, there
are some problems.
HTML pages can be
full of graphics and
with inline scripting.
Converting these to
WML may return
something that is not
of any relevance to
anybody. Some of the
WAP Gateway
products that are now
coming on to the
market (such as
Nokia's WAP Server)
also provide hosting
capabilitiesthemselves. In future it
could be possible to
integrate your WAP
Server into the mobile
network to gain
information about the
subscriber's location.If
you host your own
gateways, then it may
be required to maintain
some sort of
connection with the
mobile network. For
example, in case of
GSM networks you
may need to have say a
dial up connection
with the network's
SMS engine or youmay need to provide
dial in modems for
8/2/2019 Internet&Mobile Computing 234
14/19
CSD access
(Circuit Switched
Data, around 9.6 kbps
data rate)
Source: WAP for webdevelopers,
anywhereyougo.com
A WAP server is
simply a combined
web server and WAP
gateway. WAP devices
do not use SSL.
Instead they use
WTLS. Most existing
web servers should be
able to support WAP
content as well. Some
new MIME types need
to be added to your
web server to enable it
support WAP content.
MIME stands for
Multipurpose Internet
Mail Extension, and inthe web context,
MIME can be thought
of as a piece of header
information that comes
down with every file
sent from a web server
to a browser.
WAP Applications
At first, the most
popular mobile
Internet service is
likely to be e-mail.
SMS (short message
service) messages have
proved a big success in
the Nordic nations andvolumes are growing
rapidly throughout
western Europe
One of the most
significant advantages
of Internet access from
mobile rather that your
PC is the ability to
instantly identify usersgeographic location.
This opens up a huge
opportunity for highly
customized services.
As Ericsson puts it,
Some of the interesting
applications of WAP
(already existing or
being worked on) are:*0 Computer
Sciences Corporation
(CSC) and Nokia are
working with a Finnish
fashion retailer who
plans to send clothing
8/2/2019 Internet&Mobile Computing 234
15/19
offers direct to mobile
telephones using a
combination of
cursors, touch screen
technology and WAP
to allow would-be
shoppers to hot-link to
order-entry pages on
the web.
*1 In Finland,
children already play
new versions of
competitive games
such as "Battleships",
via the cellular networks. In the music
world, Virgin Mobile
in the UK offers to
download the latest
pop hits to customers
in a daily offering.
*2 Scala has
developed several
WAP products for
small to medium-sized
companies which
would allow, for
example, a field sales
force to access
customer order
information and stock
availability details via
a WAP handset.
*3 A key growtharea for the technology
will be business-to-
workforce, with
companies using WAP
applications to reach
employees at any time.
Scala is currently
working on time-sheet
applications and
techniques for entering
and filing expense
claims via the mobile
phone.
*4 Nokia says
applications that will
benefit from WAP
include customer care
and provisioning,
message notification
and call management,
e-mail, mapping andlocation services,
weather and traffic
alerts, sports and
financial services,
address book and
directory services and
corporate intranet
applications.
As brought out by [1]
and the examples
above WAP services
are currently limited to
simple information
services, but as higher
speeds become
available and some of
the technical issues
specific to WAP are
resolved, several newservice types will
emerge, including:
*5 Infotainment :
They could include
weather forecasts,
8/2/2019 Internet&Mobile Computing 234
16/19
stock quotes,
horoscopes and news
*6 Messaging :
services such as e-
mail, voicemail and
unified messaging
*7 Personal
information
management : services
such as call
management and
personal directories,
which enable the
modification of
personal information*8 Financial
services : mobile
banking and mobile e-
commerce services
*9 Location-based
services : services that
are dependent on
location include
mapping and vehicle
location information
WIRELESS
LAN
Wiless LAN
technology constitute a
fast-growing market
introducing the
flexibility of wireless
access into office,
home, or production
environments.
WLANs are typically
restricted in their
diameter to buildings,
a campus, single rooms
etc. and are operated
by individuals, not by
large-scale network
providers. The global
goal of WLANs is to
replace office cabling
and, additionally, to
introduce a higher
flexibility for ad hoc
communication in, eg.
Group meetings. The
following pointsillustrate some general
advantages and
disadvantages of
WLANs compared to
their wired
counterparts.
Some advantages
of WLANs are:
Flexibility:
Within radio
coverage, nodes can
communicate without
further restriction.
Radio waves can
penetrate walls,
senders and receivers
can be placed
anywhere (also non-
visible, eg. Within
devices, in walls etc.).
Furthermore ,
sometimes wiring is
8/2/2019 Internet&Mobile Computing 234
17/19
difficult if firewalls
separate buildings (real
firewalls made out of,
eg.bricks, not routers
set up as a firewall).
Penetration of a
firewall is only
permitted at certain
points to prevent fire
from spreading too
fast.
Planning:
Only wireless ad
hoc networks allow forcommunication
without previous
planning, any wired
network needs wiring
plans. As long as
devices follow the
same standard, they
can communicate. For
wired networks,
additional cabling with
the right plugs and
probably interworking
units (such as
switches) have to be
provided.
Design:
Only wireless
networks allow for thedesign of small,
independent devices
which can for example
be put into a pocket.
Cables not only restrict
users but also
designers of small
PDAs, notepads etc.
Furthermore, wireless
senders and receivers
can be hidden in
historic buildings, i.e.,
current networking
technology can be
introduced without
being visible.
Robustness:
Wireless
networks can survive
disasters, eg.,earthquakes or users
pulling a plug. If the
wireless devices
survive, people can
still communicate.
Networks requiring a
wired infrastructure
will typically break
down completely.
Some
Disadvantages of
WLANs:-
Quality of Service:
WLANs
typically offer lower
quality than their wired
counterparts. The
main reasons for this
drawback are the lower
bandwidth dur to
limitations in radio
transmission (eg., only
8/2/2019 Internet&Mobile Computing 234
18/19
1-10 Mbits/s), higher
error rates due to
interference(eg., 10-4
instead of 10-10 for
fibre optics), and
higher delay/delay
variation.
Cost:
While, e.g.,
high-speed Ethernet
adapters are in the
range of some 10 E,
wireless LAN
adapters, e.g., as PC-Card, still cost some
100 E.
Proprietary Solutions:
Due to slow
standardization
procedures, many
companies have come
up with proprietary
solutions offering
standardized
functionality plus
many enhanced
features (typically a
higher bit rate using a
patented coding
technology).
However, these
additional features
only work in a
homogeneous
environment, i.e, when
adapters from the same
vendor are used for all
wireless nodes.
Restrictions:
All wireless
products have to
comply with national
regulations. Several
government and non-
governement
institutions worldwideregulate the operation
ad restrict frequencies
to minimize
interference.
Consequently, it takes
a very long time to
establish global
solution like, e.g.,
IMT-2000. WLANs
are limited to low-
power senders and
certain licence-free
frequency bands.
Safety and Security:
8/2/2019 Internet&Mobile Computing 234
19/19
CONCLUSION:
From the abovediscussions, it could be
inferred that Internet
has grown quite
rapidly from its origin
as a small defense
network and today
spans the globe
connecting hundreds of
thousands of
computers on many
different computer
networks
Mobile Computing and
Communications is
useful for wireless
Networks. Today,however, mobile
phones migrate moreand more toward
PDAs. Mobile
phones with full color
graphic display, on the
internet browser are
available.
REFERENCES: The Internet
book second
edition By
DOUGLAS
E.COMER
www.3com.com
Success with
Internet
BY ALLENL.WYATT Mobile
Communication
s book by
JOHEN
SCHELLER.
Web Site From
MobileComputi
ng.Com
http://www.3com.com/http://www.3com.com/