Introduction to Introduction to Information TechnologyInformation Technology

Week-11Week-11

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TopicsTopics InternetInternet Intranet vs ExtranetIntranet vs Extranet Internet Service ProviderInternet Service Provider Internet AddressInternet Address World Wide WebWorld Wide Web Web BrowserWeb Browser URLURL Domain Name System Domain Name System ProtocolsProtocols BluetoothBluetooth Wi-fiWi-fi

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InternetInternet 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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IntranetIntranet 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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ExtranetExtranet 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 ProviderInternet 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 Internet Service Provider (Cont’d)(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 Internet Service Provider (Cont’d)(Cont’d)

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Internet AddressInternet 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 WebWorld 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 World Wide Web (Cont’d)(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 BrowserWeb 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 Web Browser (Cont’d)(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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URLURL 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.pkwww.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 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 Domain Name System (Cont’d)(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 Domain Name System (Cont’d) (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

CanadaThailand

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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.

ProtocolsProtocols

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ProtocolsProtocols Cont’dCont’d

http://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 Protocols (Cont’d)(Cont’d)

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BluetoothBluetooth 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-FiWi-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.