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Rashedul Hasan
             What is it……
► Network   of the Networks.
► Network of Computers linking many
  different types of computer all over the
► The Internet is a global system of
  interconnected computer networks that
  interchange data by using the standardized
  Internet Protocol (TCP/IP).
Networks And Data Communications
Visualization of the various routes through a portion of
                      the Internet.
► The  Internet has its root in the ARPANET system
  of the Advanced Research Project Agency of the
  U.S department of Defense.
► ARPANET was the first WAN and had only 4 sites
  in 1969.
► Internet evolved from basic ideas of ARPANET.
► In 1989 the U.S. Govt. lifted restriction on use of
  the Internet and allowed it to be used for
  commercial purposes as well.
►   It has interconnects more
    than 30,000 networks.
►   Allowing more than 10
    million computers
►   More than 50 million users
►   In more than 150
    countries around the globe
    to communicate each
►   It continues to grow up at
    a rapid pace.

                                 The Server
Growth of the Internet

            Source: Internet Software Consortium
► By region, 40% of the world's Internet users
  are based in Asia,
► 26% in Europe,
► 17% in North America,
► 10% in Latin America and the Caribbean,
  4% in Africa,
► 3% in the Middle East
► and 1% in Australia.
► The  prevalent language for communication on the
  Internet is English.
► After English (30% of Web visitors) the most
  requested languages on the World Wide Web are
  Chinese (17%),
► Spanish (9%),
► Japanese (7%),
► French (5%)
► and German (5%).
            Governing Bodies…
► Because   the Internet is a distributed network
  comprising many voluntarily interconnected
  networks, the Internet has no governing body.
► ICANN's role in coordinating the assignment of
  unique identifiers distinguishes it as perhaps the
  only central coordinating body on the global
  Internet, but the scope of its authority extends
  only to the Internet's systems of domain names,
  IP addresses, protocol ports and parameter
               Governing Bodies…
►   The Internet
    Corporation for
    Assigned Names and
    Numbers (ICANN) is the
    authority that coordinates
    the assignment of unique
    identifiers on the Internet,
    including domain names,
    Internet Protocol (IP)
    addresses, and protocol
    port and parameter
                                    ICANN headquarters in
                                   Marina Del Rey, California,
                                         United States
                Common uses
► The   Internet carries various information resources
  and services, such as
► electronic mail,
► online chat,
► file transfer and file sharing,
► online gaming,
► and the inter-linked hypertext documents and
  other resources of the World Wide Web (WWW).
► Social Networking
         Current Uses of Internet
              Electronic Mail
► With  an Internet email account, users can
 communicate with anyone else on-line, any
 place in the world, with no long distance
 fees. Email can also be used to join mailing
 lists, bulletin boards, or discussion groups
 that cover a huge variety of subjects.
        Current Uses of Internet
           World Wide Web.
► The World Wide Web is not a physical place,
 not a set of files, nor even a network of
 computers. The heart of the WEB lies in the
 protocols (common communication rules
 and languages) that define its use. The
 WWW uses hypertext transfer protocols
 (http) to transport files from one place to
          World Wide Web.
► "Byusing standardized software, today
 users can navigate through most features of
 the Internet, including text data such as
 email, photo-image files, and video and
 audio clips.”
            World Wide Web.
► HTML    (HyperTextMarkup Language), the written
  code that creates Web pages and links, is a
  language that all computers can read, so
  computers with varying operating systems (such
  as Windows and Macintosh) can communicate
► JAVA, a HTML compatible language developed by
  Sun Microsystems in the mid 1990s, is also
  universally readable by computers and allows
  small interactive programs to run on Web pages,
  creating moving graphic elements such as three-
  dimensional animations
          Current Uses of Internet
      Internet chat, Social networking
►   Internet chat and instant messaging systems allow
    people to stay in touch in a convenient way while
    working at their computers. Messages can be sent
    and received instantly. In addition, these systems
    also allow file transfer, as well as voice and video
►   Social networking websites allow people to stay in
    touch with friends and family, and knowing their
    activities by viewing their profiles. The concept of a
    social networking website is to store people’s
    profiles and connecting them between one and
    another. A personal profile can include pictures and
    videos to be shared.
         Current Uses of Internet
► VoIP  (Voice over Internet Protocol) started from
  an optional two-way voice chat provided by some
  of the instant messaging systems that started
  around the year 2000. The benefit of VoIP is that
  it can be free or cost much less than a normal
  telephone call, because the Internet carries that
  voice traffic.
► VoIP is surely a cheap solution for long distance
             Business Use
► Fastermeans of communication:
 with the help of E-mail business can stay in
 touch worldwide with its customer, suppliers
 and regularities bodies. It can also help in
 making inexpensive phone call through VoIP
 and have teleconferencing.
 Provide product information
► It allows customer direct access to
  information about company’s products.
  Some people prefer to learn about products
  on their own. The Internet has an
  incomparable ability to make information
  about a company's products or services
  available to potential customers. It also
  provides the information whenever the
  customer wants it.
    Save on literature costs
► Providingthe information online reduces the
 need to print and mail product literature,
 thereby resulting in significant cost
             Business Use
► Product Advertising & Promotion:
 Internet become a very effective but cheap
 medium of advertisement and promotion.
 Web sites can be used to provide
 information on new product, recent
 strategic alliance, press release and other
 related information of potential interest to
 existing and prospective customers.
    Online advertising is booming,
► Reacha worldwide audience. The Internet is a
 worldwide network allowing the advertiser to reach
 people even very expensive advertising could not.

► WWW    popularity (graphics, sound, motion). Exciting
 graphics, sound and even motion can promote and
 display products, representing a huge advance over
 the useful but static information available for early
 email commerce. The Web’s ease of use and instant
 links to related products and ordering instructions
 has allowed consumers to respond immediately to
 online advertising.
     Online advertising is booming,
► Encryption (security for credit and bank card). By
  the mid 1990s, trustworthy encryption (coding and
  decoding) technologies made the online use of
  credit and bank card numbers, addresses, social
  security numbers and other sensitive information
  safer for both seller and buyer. (note: safer, not
  necessarily completely safe).
► Global marketers seek an alternative to television.
► Dozens of start ups want to make a splash in online
  commerce; their business plans practically force
  them to buy Internet ads.
► Online world is accommodating advertisers in ways
  that print and broadcast media would find
             Business Use

► Feedback  about Product:
 Business also use the internet to gather
 information about user satisfaction of
 existing product, market opportunity of a
 new product etc.
     Human Resource Issues:

Business can now accept resume/CV
through online and can even interview
online. Many companies provide current
information about job openings and
attract talented people from places
they could not reach otherwise.
                Business Use
► Customer   Support Service:
  Many businesses use the internet to provide timely
  and quick customer services.
► Online Shopping:
  internet also facilitate the introduction of a new
  market concept consisting of virtual shops. These
  shops remain open 24 hours all the year round
  and make sales happen through internet.
 Let customers try a sample of
    your product or service

► Many new Web tools are becoming available
 that will allow consumers to try out a
 sample of what the company have to offer
 before they buy. Gain a competitive
 advantage by offering a "test drive" of your
 product or service. For example, Test a
 software applications before you buy them.
              Internet connection
►   Telephone (Dial-up) Modem:
    Dial up networking technology provides PCs and
    other network devices access to a LAN or WAN via
    standard telephone lines.
    low speed but cheap & widely available.
    A 6 minute long music video takes 4 hours 45 minutes to
    be downloaded from WWW with a 28.8 kbps modem.
    Modem Stands for Modulator and Demodulator.
    Modulate: Converts digital signals to analog form
    Demodulate: Converts analog signals back to digital form.
        Internet connection
because telephone lines have traditionally been
analog, we need to use modem if our computer is to
send signals over a telephone line. The modem
converts the computer’s digital signals into
telephone line’s analog signals and analog signals
back into digital signals.
Modem means Modulator demodulator.
Modems are rated by their speed in moving data
from the computer to the telephone line. This
speed is measured in bits per second
(bps). Standard modern modems are rated at
28,800 bps, 33,600 bps and 56,400 bps.
Networks And Data Communications
       High Speed phone line
 ISDN stands for Integrated Services Digital
 Network. It is consists of hardware and software
 that allows data to be transmitted over traditional
 telephone wire.
 A 6 minute long music video takes 1 hour to be
 downloaded from WWW.
 : DSL
 Digital Subscriber line. Incoming data are faster
 then outgoing data. A 6 minute long music video
 takes 11 minutes to be downloaded from WWW.
                Cable Modem
             wireless connection
►A   cable modem connects a PC to a cable-TV
  system that offers an internet connection.
► Wireless system :
  it includes satellite based radio link connection,
  Wifi connection etc.
  ISP: Internet Service Provider: A company that
  connect you through your communication line to
  its server, which connect you to the internet via
  another company’s network access point.
Simplified Communications
    Model - Diagram
How the Internet Works
          How the Internet Works
Here's what happens to a piece of data (eg. a Web page)
  when it is transferred over the Internet:

►   It is broken up into a whole lot of same-sized pieces
    (called packets).
►   A header is added to each packet that explains where it
    came from, where it should end up and how it fits in with
    the rest of the packets.
►   Each packet is sent from computer to computer until it
    finds its way to its destination. Each computer along the
    way decides where next to send the packet. This could
    depend on things like how busy the other computers are
    when the packet was received. The packets may not all
    take the same route.
       How the Internet Works
► At the destination, the packets are examined. If
  there are any packets missing or damaged, a
  message is sent asking for those packets to be
  resent. This continues until all the packets have
  been received intact.
► The packets are reassembled into their original
► Each computer connected up to the Internet has
  software called TCP/IP (Transmission Control
  Protocol/Internet Protocol) which is responsible for
  receiving, sending and checking packets. TCP/IP is
  the 'glue' of the Internet.

hasan.rashed = User ID [identifies who is at the
gmail = domain [a location on the internet]
.com = top level domain.
.bd = identifies the name of the country.
           Top level domain
        Domain             Description
.biz               Business
.com               Commercial
.edu               Educational & Research
.gov               Government
.info              Information
.int               International Organization
Mil                Military Organization
.net               network
.org               Non-profit & Professional
► ElectronicMail.
► Internet e-mail messages consist of two major
► Header — includes sender, receiver, and other
  information about the e-mail
► Body — The message itself as unstructured text;
  sometimes containing a signature block at the end
               Header fields

► The  message header usually includes at least the
  following fields:
► To: The e-mail address [es], and optionally name
  [s] of the message's recipient [s]
► CC : Carbon copy, for copying message to others.
► Bcc: Blind Carbon Copy, for copying others
  without the primary recipient knowing it.
► Subject: A brief summary of the contents of the
► Attachment
 Large file, music video or MP3 music can be
 attached and send to the destination
► Spamming   is unsolicited commercial e-mail.
► Because of the very low cost of sending e-mail,
  spammers can send hundreds of millions of e-mail
  messages each day over an inexpensive Internet
  connection which may results in information
  overload for many computer users who receive
  huge unsolicited email each day
            Email Spoofing
► Emailspoofing is a kind of forgery. Mails
 appear to be sent from a known sender but
 they are actually not so. Spoofing involves
 forging the email headers, by altering the
 header information
             Email Bombing
► Itrefers to transferring a huge amount of
  emails to victim, ensuing the victim's email
  account crash. An easy way of attaining this
  would be to subscribe the victim's email
  address to a huge number of mailing lists.[
              Online chat
► Online chat can refer to direct one-on-one
 chat or text-based group chat using tools
 such as instant messengers, Internet Relay
 Chat, talkers etc.
► Windows   Live Messenger
► Yahoo! Messenger
► Google Talk
► Internet Relay Chat (IRC)
► Pal talk
          WWW & Web Browser
► WWW: World Wide Web.
► Web Browser: is a software that enables users to view
  web pages and to jump from one page to another.
► Internet Explorer is the mostly widely used web browser.
► Usage share for Q4 2008
► Internet Explorer: 70.72%
► Firefox: 20.27%
► Safari: 6.77%
► Chrome: 0.78%
► Opera: 0.73%
► Netscape: 0.48%
► Other: 0.24%
► URLs:   Uniform Resource Locator.
  It is the web site’s address.
http://= protocol, stands for Hyper Text
          Transfer Protocol.
  It is a set of communication rules for
  exchanging information. It allows brewers
  to connect with web server.
►   = web server name. it is the
  particular computer on which this web site
  is located.
► Yose/ = the directory name. it is the name
  on the server for the directory or folder
  from which the browser needs to pull the
► Camping.htm = file name. the particular
  page or document that you are looking for.
Web Browser
Web Browser
Web Browser
Web Browser
Web Browser
Web Browser
      Web Site, Web page & Web
►   Web Site is the location of a web domain name in a
    computer somewhere on the internet. It is actually a
    collection of web pages, images, videos or other digital
    assets that is hosted on one or more web servers, usually
    accessible via the Internet. On the other hand,
►   Web page is document on the WWW that can include
    text, picture, sound and video. The first page we see at a
    website is like the title page of a book. This is the Home
    Page, or welcome page, which identifies the web site and
    contains links to other pages at the site.
►   Web Portals is the website that group together in one
    convenient location popular features such as search tools,
    e-mail, and electronic commerce and discussion group etc.
    portal can be customized to fit user’s interest. The most
    popular portal are YAHOO, MSN, EXCITE Network etc.
   Web portal & Search engines
► Web    portal:
► Web sites that group together in one
► Search engine:
► It allows us to find specific documents
  through keyword search.
  web portal.
         A                                       W
                    Babel Fish Translations
Account Information                           Weather
   Address Book                              Web Hosting
      Alerts                                  Widgets
     Alibaba                                  Wireless
     Answers                                   Women              Z
   Audio Search
                                  C                            Zimbra
      Avatars                 Calendar
                           Company Info
                     Creative Commons Search            Y
                                                Yahoo! for Good
                                               Yahoo! Search Blog
                                                  Yellow Pages
Search engine
Pak & Indian MP3 Song
►A  network server is a computer designed
  to process requests and deliver data to
  other (client) computers over a local
  network or the Internet.
► Web servers
► proxy servers
► FTP servers
► online game servers
► ProxyServers : A proxy server acts an
 intermediate gateway between you and
 your Internet connection.

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