Ch%208:%20The%20Internet%20and%20the%20Web%20-%20Content

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CHAPTER
The Internet and the Web
Irfan A. Ilyas
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Points to cover

• Internet Backbone
• Internet Administration
• Details of World Wide Web
• Details of Web Standards
• Document Format
• Web Addressing
• Details of Emailing
• Email Structure
• Mechanism used
• Domain Name Addressing (DNS)

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Internet Architecture

• Internet Backbone
• A collection of relatively fast computers on the
  internet, mainly responsible for providing high
  speed data communication across regional or
  national distances
• Public computers will then be connected to these
  compu
• Video Clip Demo (Web Publishing CD)

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Who Owns the Internet Now??
ISOC Created in 1992
IAB is a voluntarily based Technical Advisory
Group. Consists of members of ISOC IETF.
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Introducing World Wide Web

• WWW is a collection of dissimilar computers on
  Internet.
• These computers can participate in exchanging
  information objects (text/ pictures/ sound etc.)
  among each other
• In other words, WWW is an interface of Internet
  contents (stuff on Internet Computers)
• This information exchange is made possible by
  implementing some web standards like
• Standard for Web document format (HTML)
• Standard for Web transaction mechanisms (HTTP)
• Standard for Web addressing (URL)

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Details of Web Standards

• Web Document Format HTML
• All web documents are required to be in a
  standard (agreed upon) format
• Named as Hyper Text Marked Up Language (HTML)
• Lets a Web Author to write a formatted hypertext
  document in form of simple text codes (tags)
• The document file should have an extension .html
  or .htm
• Reading an HTML Document
• A HTML document in its simple form is not
  smoothly readable by humans.
• Can only be shown by a browser program (web
  client programs) after proper interpretation of
  HTML codes.

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HTML The Web Document Format

• Explaining HTML Capabilities
• Formatted
• Produces visual effects (bold/ underline/
  different fonts/ blinking etc.) on different
  document units
• Hypertext
• A hypertext document allows the reader to read in
  n-dimensions (freely), using cross-referencing of
  topics being discussed.
• Different from sequential reading.
• A hyperlink is used to access a cross-referenced
  document.

ltH1gt This is a first-level heading lt/H1gt
ltA HREF"http//www.yahoo.com"gt Link to Yahoo
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Example A HTML Code
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Details of Web Standards

• Web Transaction Mechanisms (HTTP)
• For a smooth web transaction, some internal
  handshake of messages are needed
• The set of rules governing these handshakes
  (request-response), are collectively called Hyper
  Text Transfer Protocol (http)
• Complete list of messages included in HTTP rules
  are well known.
• In case a problem happens (broken link etc.),
  client will wait for server response for a fixed
  period, then print a Request Timeout Message

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Web Transaction Mechanisms (HTTP)
A List of HTTP request/ response messages for Web
Transactions
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Details of Web Standards

• Web Addressing (URLs)
• To access resources (html files/ jpeg images/
  sounds etc.) saved on different WWW computers
• A unique address is assigned to each resource,
  called Universal Resource Locator (URL)
• To be unique in addressing, a standard addressing
  format is used.

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Web Addressing (URLs)

• URL Format http//computer_name/ path
• where
• http ? Name of the mechanism used to access the
  resource.
• Computer_name ? a unique computer name for the
  Internet computer
• path ? file path of the resource (html code/
  picture etc.) on that computer

Example http// www.yahoo.com / index.html
A domain based naming scheme, called DNS is used
to assign this name
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WWW Important Terms

• Hyperlinks
• Active sentences on a web document
• Let the user to jump on another web page
• Home page
• On any web site (web document collection), the
  Grand Central Station (the place users start
  their hypertext journey)
• Browsing
• The process of reading hypertext documents
• May not be organized (wild hyperlink clicks)
• Navigation
• An organized browsing experience
• Make use of tools Favorite list, History, Next,
  Back etc. to help the user in the event of
  Getting Lost on a web system

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.WWW Important Terms

• Browser
• A computer program (web client) which let the
  user to start browsing a web system
• Web Page Authoring
• The process of creating hypertext documents
• Recent authoring tools (Front Page, Dream weaver,
  Home Site etc.) makes the experience easy and
  joyful

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Details of Emailing

• Most common first of its kinds Internet
  activity
• Allows global access to all Internet Users
• Basic elements of an email message
• Header
• Composed of Subject, Addresses, Date, Attachments
• Message
• The body of the email
• Signature
• More details about the sender

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Details of Emailing

• A basic emailing activity involves three
  computers
• Email Server Computer
• The computer runs an email server program.
• It is connected permanently to the Internet.
• The computer has a unique Internet address
  attached with it.
• Also, there are more than one user email accounts
  (mail boxes, maintained in different folders) on
  the server computer.

Computer Internet Address kfupm.edu.sa
User Email Accountsirfansarazaiskhan
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Details of Emailing

• Email Sender (Client) Computer
• The computer runs an email client program like
  Outlook Express
• The computer doesnt need to be connected
  permanently, gets connected whenever needs to do
  an emailing activity
• The client program lets the user to send an email
  message to any server computer connected on the
  Internet.
• The email address used in the mail header, tells
  exactly
• Which computer is being addressed?
• Which user account of that computer will receive
  this mail?

To irfan_at_kfupm.edu.saSubject blah
blahHello,..
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Details of Emailing

• Email Receiver (Client) Computer
• The computer also runs an email client program
  like Outlook Express
• The computer doesnt need to be connected
  permanently, gets connected whenever needs to do
  an emailing activity
• The program lets the user to receive his email by
  contacting the server computer Outlook Express
  should be setup with the address of the server
  computer
• The server computer lets the client computer
  receive its mails after authenticating it with a
  username password.

To irfan_at_kfupm.edu.saSubject blah
blahHello,..
User irfanPasswd
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Explaining E-Mail Addresses

• Domain name system (DNS)
• An addressing scheme used by Internet authorities
  to assign names (addresses) to computers and
  people.
• The main theme of the scheme is Unique Name
• The name is assigned in chunks by dividing the
  whole address space into different addressing
  domains
• An addressing domain represents a set of all
  possible names which can be assigned with the
  trailing part as .domain

Domain Code edu.sa
Domain kfupm
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Explaining E-Mail Addresses

• An Email Address has three parts
• Domain code
• Domain name
• User name

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Common Internet Domain Codes
com Commercial
org Other organizations
gov Government
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