Week-2 Internet & WWW

7/28/2019 Week-2 Internet & WWW

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ELECTRONICBUSINESS



Abdus Salam 2

Lecture-3 & 4 Internet History of Internet Intranet vs Extranet Internet Service Provider Internet Address

World Wide Web Web Browser URL Domain Name System Protocols

Server Bandwidth and Modem



Abdus Salam 3

Internet

A network of networks in which user of any computer can getinformation from other computer, if they have permission. An internet (note the lowercase letter i) is two or more networks

that can communicate with each other.

It is a generic term used to mean an interconnection of networks.

The second is the name of a specific world wide network. The most notable internet is called Internet (uppercase letter I),

in which connect more than hundreds of thousands interconnectednetworks.



Abdus Salam 4

History of Internet

The extraordinary communication system “Internet” came intobeing in 1969. In mid-1960, mainframe computers in research organization were

stand-alone devices. Computers from different manufacturerswere unable to communicate with one another.

The ARPA in the DoD was interesting in in finding a way to connectcomputers, so

In 1967, at an Advance or Association for Computing Machinery(ACM) meeting, ARPA presented its ideas for ARPANET, a smallnetwork connected computes.

The basic purpose to create a network that allows the researchers ofone university to able, to talk or share their research to Researcherscomputers.

The network was designed to work without centralized control. This means if one portion of network fails or destroy in disaster or in

military attack, the remaining portion will be able to route packetsfrom sender to receiver through alternate path.



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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 oroperation with its employee.

An intranet belonging to an organization, usually a corporation,accessible only by the organization's members, employees, or

others with authorization.



Abdus Salam 6

Extranet

An Extranet is designed to connect the offices of a largeorganization 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 otherbusiness partners.

You can access an extranet only if you have a valid usernameand password.

Extranets are becoming a very popular means for businesspartners to exchange information.



Abdus Salam 7

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 byspecialized companies.

The Regional ISPs are smaller ISPs that are connected to one or morenational 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)

http://www.asia.net.pk/

http://www.brain.net.pk/

http://www.click.net.pk/

http://www.comsats.net.pk/

http://www.cyberaccess.com.pk/

http://www.cyber.net.pk/

http://www.dancom.com.pk/

http://www.excel-xl.net/

http://www.xpert.net.pk/

http://www.iqranet.net/

http://www.micro.net.pk/

http://www.micro.net.pk/

http://www.iqranet.net/

http://www.xpert.net.pk/




http://www.dancom.com.pk/

http://www.cyber.net.pk/

http://www.cyberaccess.com.pk/

http://www.comsats.net.pk/

http://www.click.net.pk/

http://www.brain.net.pk/

http://www.asia.net.pk/



Abdus Salam 10

Internet Address

Every computer on the Internet has a unique Internet address(similar to telephone number), which can be accessed any othercomputer 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



Abdus Salam 11

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 interoperabletechnologies for the World Wide Web and making the Webuniversally 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.



Abdus Salam 13

Web Browser

Application Software that allows users to view Web content such astext, images, videos, music, games and other information located on aweb page at a web site on the www. Or

A program on a computer that accepts requests for information,processes the requests and allows you to navigate to resources on theInternet.

Microsoft Internet Explorer Mozilla Firefox Netscape Navigator Google Chrome

Web browsers were introduced by companies like Mozilla,Netscape, and Microsoft. More recently, Google entered thebrowser market.

On the Web, you navigate--commonly known as browsing or surfing



Abdus Salam 14

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 eitherwithin 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



Abdus Salam 15

URL

Uniform Resource Locator is a fancy term for the address of a WorldWide 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 forthat 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

http://www.vbs.com/welcome/main.html

http://www.vbs.com/welcome/main.html



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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 theInternet.

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

http://www.google.com/

http://www.google.com/



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The .edu is the top level domain – the top level in which a sitewants to register.

The second level domain is typically the company or brand namefor 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

.org Non-profit organizations

.mil Used for military websites e.g. www.usa.mil

.net Networking organizations. It represents an organization that isworking on network

.ca

.th

Canada

Thailand

http://www.yahoo.com/

http://www.lums.edu.pk/

http://www.usa.mil/

http://www.usa.mil/

http://www.lums.edu.pk/

http://www.yahoo.com/



Abdus Salam 19

A communication protocol is set of rules that control datacommunication. 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 amessage.

A protocol defines what is communicated, how it is communicated,and when it is communicated.

Protocols



Abdus Salam 20

Protocols Cont’d http://

HTTP is the protocol that supports communication between webbrowsers 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.



Abdus Salam 21

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 andreceive email from and to a mail server.

Protocols Cont’d



Abdus Salam 22

Server Server is computer that provides network resources or services. Server based network also called client-server network, containing Client &

the server that support them.

The Web is known as a client-server system. Your computer is the client;the remote computers that store electronic files are the servers.Examples include file, print or communication servers.



Abdus Salam 23

Bandwidth

Bandwidth refers to the capacity of transmission media. The total media capacity or bandwidth can be divided into channels. A channel is simply a portion of the bandwidth that can be used for

transmitting data.

Backbone A high-speed line or series of connections that forms a major

pathway within a networks.



Abdus Salam 24

Modem MODEM short for modulator/demodulator. A device, either internal or external, which connects the user to

their ISP, which in tern connects the user to the internet.

The modem is necessary because the phone network transmitsaudio, not data bits.

Modulation is a prescribed method of encoding digital (or analog)signals onto a waveform (the carrier signal).

Once encoded, the original signal may be recovered by an inverseprocess called demodulation.

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