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    INTERNET

    AND

    MOBILE COMPUTING

    \

    Submitted by

    G.Akhila B.Sujini

    III/IV III/IV

    (09A81A1276) (09A81A1269)[email protected] [email protected]

    Department of InformationDepartment of InformationTechonologyechonology

    SRI VASRI VASAVIAVI ENGINEERING COLLEGE,,

    TADEPALLIGUDEMTADEPALLIGUDEM

    mailto:[email protected]:[email protected]:[email protected]:[email protected]
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    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

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    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

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    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

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    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

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    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:

    [email protected].

    net.in.

    But before youget your own Internet

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    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

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    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

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    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

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    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

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    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

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    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

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    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,

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    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

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    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

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    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:

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    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/