Introduction to Information Technology Lecture Slides PPT

1. Introduction to Information
Technology
Week-11

2. 2
Topics
 Internet
 Intranet vs Extranet
 Internet Service Provider
 Internet Address
 World Wide Web
 Web Browser
 URL
 Domain Name System
 Protocols
 Bluetooth
 Wi-fi

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Internet
 A network of networks in which user of any computer can get
information from other computer, if they have permission.
 The Internet is a global system of interconnected computer
networks that use the standard Internet Protocol Suite (TCP/IP)
to serve billions of users worldwide.
 It is a network of networks that consists of millions of private and
public, academic, business, and government networks of local to
global scope that are linked by a broad array of electronic and
optical networking technologies.
 The specific world wide network.
 The most notable internet is called Internet, in which connect more
than hundreds of thousands interconnected networks.

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Intranet
 An Intranet is an organization network,
 that uses Internet protocols, network connectivity to
securely share part of an organization information or
operation with its employee.
 An intranet belonging to an organization, usually a corporation,
accessible only by the organization's members, employees, or
others with authorization.

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Extranet
 An Extranet is designed to connect the offices of a large
organization situated in metropolitan area.
 Extranet is simply an external network.
 Intranet is accessible only to people who are members of the
same company or organization,
 An extranet provides various levels of accessibility to
outsiders like a company with its customers, suppliers, or other
business partners.
 You can access an extranet only if you have a valid username
and password.
 Extranets are becoming a very popular means for business
partners to exchange information.

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 Internet has linked numerous LANs into huge network.
 The LANs and computer connected to internet is maintained by
Internet Service Providers (ISPs)
 ISP sells internet services to netizen.
 Today most end users who want Internet connection use the
services of ISPs.
 There are :
 International ISPs,
 National ISPs,
 Regional ISPs and
 Local ISPs.
Internet Service Provider

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 The International ISPs that connect nations together.
 The National ISPs are backbone networks created and maintained by
specialized companies.
 The Regional ISPs are smaller ISPs that are connected to one or more
national ISPs.
 The Local ISPs provide direct services to the end users.
Internet Service Provider (Cont’d)

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 ISP (Internet Service Provider) List of Pakistan
 ISP City Website
 Asia Net Lahore www.asia.net.pk
 Brain Net Karachi, Lahore www.brain.net.pk
 Click Online Peshawar www.click.net.pk
 Comsats Islamabad, Karachi www.comsats.net.pk
 Cyber Access Karachi www.cyberaccess.com.pk
 Cyber Net Karachi www.cyber.net.pk
 Dancom Online Karachi www.dancom.com.pk
 Excel Net Islamabad www.excel-xl.net
 Expert Net Okara www.xpert.net.pk
 Iqra Net Peshawar www.iqranet.net
 Micro Net Islamabad www.micro.net.pk
Internet Service Provider (Cont’d)

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Internet Address
 Every computer on the Internet has a unique Internet address
(similar to telephone number), which can be accessed any other
computer by dialing to the other IP address.
 The existing version now-e-days IP VER-4.
 Static IP addresses
 When a computer uses the same IP address every time it connects
to the network, it is known as a Static IP address. In contrast.
 Dynamic IP addresses
 In situations when the computer's IP address changes frequently
(such as when a user logs on to a network through dialup), it is
called a Dynamic IP address

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World Wide Web
 WWW
 The World Wide Web (commonly abbreviated as "the Web") is a system of
interlinked hypertext documents accessed via the Internet
 Introduced in 1990 by Tim Berners-Lee
 Allows computer users to locate and view multimedia-based documents
 It allows users to explore and retrieve text and graphics from web
sites.
 Transferring text and graphics simultaneously
 Client/Server data transfer protocol
 Uses:
 Applications, E-mail, Product Display, Catalogs, Order placement
 W3C
 Founded in 1994 by Tim Berners-Lee
 Devoted to developing non-proprietary and interoperable
technologies for the World Wide Web and making the Web
universally accessible

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World Wide Web (Cont’d)
 Web site
 A web site is a collection of web pages with some common
ownership
 Like books, Web sites contain information and consist of pages.
 A Web site may consist of many pages or just a single page.
 Web page
 A World Wide Web page
 The individual pages that make up a Web site.
 You can view a single Web page at a time.
 Home page
 When accessing a Web site, the first page displayed is usually the Home
page. Often, like a book’s table of contents, it gives information about
what is available on that site.
 This is simply the first page displayed when you connect to the
Internet, or, the starting point of your Internet session.

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Web Browser
 Application Software that allows users to view Web content such as
text, images, videos, music, games and other information located on a
web page at a web site on the www. Or
 A program on a computer that accepts requests for information,
process the requests and allows you to navigate to resources on the
Internet.
 Microsoft Internet Explorer
 Mozilla Firefox
 Netscape Navigator
 Google Chrome
 Web browsers were introduced by companies like Mozilla,
Netscape, and Microsoft. More recently, Google entered the
browser market.
 On the Web, you navigate--commonly known as browsing or surfing

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Web Browser (Cont’d)
 Hyperlinks/ Links
 One way to navigate the WWW is by clicking on a link.
 A link is an area of a Web page that, when you click on it, will take
you from the page you are presently viewing to another page either
within the same site or to an entirely different site.
 Links can be anything on a page.
 Examples:
 Graphical or textual elements
 Underlined text; Images; color varies but is often blue, Objects in
motion etc

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URL
 Uniform Resource Locator is a fancy term for the address of a World
Wide Web page or other resource.
 Used to identify web pages
 Example: http://www.vbs.com/welcome/main.html
 The first part is protocol “http://”
 Second is host name (name.domain name) or is the Fully Qualified
Domain Name (FQDN).
 This name identifies the web site containing the page.
 The term “FQDN" refers to a complete website or other
computer's name on the Internet.
 The term "domain name" usually refers only to the last part of the
host name, in this case “vbs.com”, which has been registered for
that particular company's exclusive use.
 The 3rd part of the URL “welcome/main.html” is the path at which
this particular web page is located on the web server.
Protocol Hostname File Path

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 DNS server translate symbolic name (such as www.upesh.edu.pk)
into numerical IP address.
 Symbolic names are a great convenience because they are easier
to remember than numerical addresses.
 Domain Name System (DNS) is a database which keeps track of
computer’s names and their corresponding IP addresses on the
Internet.
 It’s like a phone book.
 DNS helps users to find their way around the Internet.
 http://www.google.com here the domain name is google. Com
 The www is not necessary and most commercial sites register
their name both with and without it.
 ICANN, is responsible for managing and coordinating the DNS.
Domain Name System

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 The .edu is the top level domain – the top level in which a site
wants to register.
 The second level domain is typically the company or brand name
for most marketers.
Domain Name System (Cont’d)
. (root)
com
toronto.edu
goveduorg
uci.edu
ece.toronto.edumath.toronto.edu
neon.ece.toronto.edu
Top-level
Domains

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Domain Name System (Cont’d)
.com it is used for commercial websites.
They earn money from advertisements e.g. www.yahoo.com
.edu it is used for educational websites e.g. www.lums.edu.pk
.gov Government institutions www.hec.gov
.org Non-profit organizations
.mil Used for military websites e.g. www.usa.mil
.net Networking organizations. It represents an organization that is
working on network
.ca
.th
Canada
Thailand

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 A communication protocol is set of rules that control data
communication.
 The protocol determine the following:
 The types of errors
 How the sending device will indicate that it has finished sending a
message.
 How the receiving device will indicate that it has received a
message.
 A protocol defines what is communicated, how it is communicated,
and when it is communicated.
Protocols

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Protocols Cont’d
 http://
 HTTP is the protocol that supports communication between web
browsers and web servers.
 The heart of the Web
 Protocol for client/server communication
 Very simple request/response protocol
 Client sends request message,
 server replies with response message
 Stateless
 Do not confuse this with the Hypertext Markup Language (HTML).
HTML is a language used to write web pages.

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 FTP
 FTP is the standard mechanism provides for a copying a file from
one host to another.
 SMTP
 SMTP is used for transferring electronic mail.
 SMTP connects to remote machines and transfer mail message
 POP
 POP is an older method used by programs Netscape to send and
receive email from and to a mail server.
Protocols (Cont’d)

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Bluetooth
 Bluetooth is wireless protocol for exchanging data over short
distances (using short length radio waves) from fixed and mobile
devices, creating personal area networks (PANs).
 Wireless control of and communication between a mobile phone and a
hands-free headset.
 This was one of the earliest applications to become popular.
 Wireless networking between PCs in a confined space and where little
bandwidth is required.
 Wireless communication with PC input and output devices, the most
common being the mouse, keyboard and printer.

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Wi-Fi
 A Wi-Fi enabled device such as a personal computer, mobile phone, MP3 player
or personal digital assistant can connect to the Internet, within range of a
wireless network.
 The coverage of one or more interconnected access points — called a hotspot
 The Wi-Fi Alliance is a global, non-profit industry association of more than 300
member companies devoted to promoting the growth of wireless Local Area
Networks (WLANs).
 Wi-Fi is a traditional Ethernet network, and requires configuration to set up
shared resources, transmit files, and to set up audio links (for example,
headsets and hands-free devices).
 Wi-Fi uses the same radio frequencies as Bluetooth, but with higher power,
resulting in a stronger connection.
 Wi-Fi is sometimes called "wireless Ethernet." This description is accurate, as
it also provides an indication of its relative strengths and weaknesses.
 Wi-Fi requires more setup but is better suited for operating full-scale
networks; it enables a faster connection, better range from the base station,
and better security than Bluetooth.