IT Basics of Internet Theory

7/29/2019 IT Basics of Internet Theory

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BASICS OF INTERNET

SUBMITTED BY: GROUP 1

SUBMITTED TO: PROF.TAHEREEM

BARDI

L.S.RAHEJA COLLEGE OF ARTS

AND COMMERCESANTACRUZ (W)


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Contents

INTRODUCTION TO INTERNET.

EVOLUTION.

TYPES OF NETWORKS

CONNECTION OF THE INTERNET

PROTOCOLS

IP ADDRESS

OSI MODEL AND TCP/IP MODEL

DOMAIN NAME SYSTEM

DOMAIN EXTENSION TYPES

WEB BROWSER

URLS

SEARCH ENGINES

WEB PAGES

E-MAIL

BIBLIOGRAPHY

PROF. TAHEREEM BARDI Page 2


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INTRODUCTION TO INTERNET.

The Internet, sometimes called simply the Net is a worldwide

system of computer networks - a network of networks in which

users at any one computer can, if they have permission, getinformation from any other computer. It was conceived by the

Advanced Research Projects Agency (ARPA) of the U.S.

government in 1969 and was first known as the ARPANET. The

original aim was to create a network that would allow users of a

research computer at one university to be able to talk to

research computers at other universities. Today, the Internet is a

public, cooperative, and self-sustaining facility accessible to

hundreds of millions of people worldwide. Physically, the Internetuses a portion of the total resources of the currently existing

public telecommunication networks.

EVOLUTION OF THE INTERNET

In 1969,the PENTAGON, a military organization was developed

ARPA net (Advanced Research Project Agency net) was used for

military use. It was a network of computers from differentlocations

The merging of ARPANET with academic network called UsenetNews resulted into INTERNET

Data to be transmitted was divided into small packets and thesepackets could take different routes to the destination.

A side benefit of ARPAnet's design was that, messages could be

routed or re-routed in more than one direction; the network couldcontinue to function even if parts of it were destroyed in the

event of a military attack or other.

The first form of Internet which was developed years ago was

way different from the internet we are using today. Internet has



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taken many forms during its evolution. Many new innovations

have been introduced in the Internet since then And hence

today we are experiencing the Internet which is more

sophisticated and brims with higher speed, greater reliability, and

larger bandwidth.

TYPES OF NETWORKS

The Internet is the largest computer network in the world,connecting millions of computers. A network is a group of two

or more computer systems linked together.

There are three types of computer networks explained briefly in

the next three paragraphs to come:

Local Area Network (LAN):

A LAN means a connection of two or more connected computerssharing certain resources in a relatively small geographiclocation. A local area network(LAN) refers to a combination of

small computers, hardware and transmission media that isrelatively small

LANs normally do not exceed tens of kilometers in size andtend to use only one type of transmission medium.

For e.g., LAN is used in buildings, schools, etc.

Metropolitan Area Network ( MAN ):

It is a large computer network that usually spans a city or a largecampus. A MAN usually interconnects a number of local areanetworks (LANs) using a high-capacity backbone technology,such as fiber-optical links, and provides up-link services to widearea networks (or WAN) and the Internet.



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A metropolitan area network(MAN) is a network that islarger than LAN

It covers the area of City a Few Tens to about one hundredkilometers.

Wide Area Network (WAN):

A WAN typically consists of 2 or more LANs. The computers arefarther apart and are linked by telephone lines, dedicatedtelephone lines, or radio waves. The Internet is the largestWide Area Network (WAN) in existence.

Uses point to point links

Spans the entire country

Has a data rate below 1Mbps.

Can be owned by Multiple Organizations.

CONNECTION TO THE INTERNET

When you first get the connection to the internet, you need tohave the following things:

1. Computer

2.Modem(Modulator and Demodulator)

3.Telephone Line

4.ISP(Internet Service Provider)

You should have a computer with the modem properly

connected. Modem may be internal or external. A Modem is used

to convert the analog data to digital data or vice versa. Modem is

connected through phone line. You use one ISP through which

you can get the internet connection. The steps to connect are:



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1. First double click on My Computer

2. Double click on Dial-up networking

3. Click and open the My-connection

Most of the technical work is done by your ISP provider.

MODEM

Modems are networking devices that convert analog and digital

data for computer-to-computer communication. Several

kinds of modem devices exist for dial-up, broadband and cellular

networking.A broadband modem is a type of digital modem, different from

traditional analog modems, used with high-speed DSL or cable

Internet service

ROUTERRouters are physical devices that join multiple wired or wireless

networks together. Technically, a wired or wireless router is aLayer gateway meaning that the wired/wireless router connectsnetworks (as gateways do). The router operates at the networklayer of the OSI model.

HUB

As the name suggests, the meaning of hub is a center of

activities. In network terminology, a hub is a device where the

entire connecting mediums come together. A hub is a medium

used to collect signals from the input line(s) and redistribute

them in various available wirings around a topology

Hub basically acts as signal splitter.



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There are three main types of hubs: Passive hub, Active hub andIntelligent hub.

DIFFERENCE BETWEEN A HUB AND A ROUTER

Most of the time, there is confusion as to what is the differencebetween a Hub and a Router when both can be used to connectto the net.

A hub is much like a route, but in a hub you have to manually seteach computer's IP address where as the router dynamicallyassigns an IP address to each system connected to it.

PROTOCOLS

A protocol is a set of agreements used between two or moreend points (or machines if you will). It is a well defined layout forcommunication. So machines know how to talk to each other.

There are two types of protocols TCP/ IP

TCP/IP (Transmission Control Protocol/Internet Protocol) is the

basic communication language or protocol of the Internet. It can

also be used as a communications protocol in a private network

(either an intranet or an extranet). When you are set up with

direct access to the Internet, your computer is provided with a

copy of the TCP/IP program. In a similar manner other computers

that you may send messages to or get information from also

have a copy of TCP/IP.

TCP/IP is a two-layer program. The higher layer, Transmission

Control Protocol, manages the assembling of a message or fileinto smaller packets that are transmitted over the Internet and

received by a TCP layer that reassembles the packets into the

original message. The lower layer, Internet Protocol, handles

the address part of each packet so that it gets to the right

destination.



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Several protocols are used on the Internet, including Electronic

Mail (e-mail), File Transfer Protocol (FTP), HTTP (World Wide

Web), News (or Usenet), Gopher and Telnet.

IP ADDRESS

Every device connected to the public Internet is assigned aunique number known as an Internet Protocol (IP) address. IPaddresses consist of four numbers separated by periods (alsocalled a 'dotted-quad') and look something like 127.0.0.1.

Since these numbers are usually assigned to internet service

providers within region-based blocks, an IP address can often beused to identify the region or country from which a computer isconnecting to the Internet. An IP address can sometimes be usedto show the user's general location.

OSI AND TCP/IP MODELS

The OSI (Open System Interconnection)In 1983, the International Standards Organization (ISO)created the OSI, or X.200, model. It is a multilayered model forfacilitating the transfer of information on a network. The OSImodel is made up of seven layers, with each layer providing adistinct network service. By segmenting the tasks that each layerperforms, it is possible to change one of the layers with little or

no impact on the others.TCP/IP Model

The TCP/IP model is a description framework for computernetwork protocols created in the 1970s by DARPA (DefenseAdvanced Research Projects Agency) an agency of the United



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States Department of Defense. It evolved from ARPANET, whichwas the world's first wide area network and a predecessor ofthe Internet. The TCP/IP Model is sometimes called the InternetModel or the DoD Model.

DOMAIN NAME SYSTEMAs there are a number of users and computers on the internet, it

is necessary to identify each machine, which is done by allocating

an address to each machine.

The entire network of computer is divided according to countrys

type of organization as follows; it is called as domain name

system

Every top level domain contains sub-domains.

Each sub domain has many servers, each of which has a

computer network attached to it

Types of Domain Name Extensions

.COM - a communication or commerce site, this is usuallythe most popular and used for business or personal

purposes.

.ORG - means "organization" and usually for non-profits orsocial groups..

.NET - a "network" of people usually like a social network orwriter's guild..

.GOV - a "government" site.

WEB BROWSER

A webbrowser is a software application for retrieving,

presenting, and traversing information resources on the World

Wide Web. An information resource is identified by a Uniform



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Resource Identifier (URI) and may be a web page, image, video,

or other piece of content. Hyperlinks present in resources enable

users to easily navigate their browsers to related resources.

Although browsers are primarily intended to access the WorldWide Web, they can also be used to access information

provided by Web servers in private networks or files in file

systems. Some browsers can be also used to save information

resources to file systems.

Types of web browsers are:

Internet explorer, safari, Mozilla Firefox, Opera Mini, Google

Chrome, etc

URLSURL stands for Uniform Resource Locator, which means it is

a uniform (same throughout the world) way

to locate a resource (file or document) on the Internet

The URL specifies the address of a file and every file on the

Internet has a unique address.

Web software, such as your browser, uses the URL to retrieve a

file from the computer on which it resides.

The actual URL is a set of four numbers separated by periods. An

example of this would be 202.147.23.8 but as these are difficult

for humans to use, addresses are represented in alphanumeric

form that is more descriptive and easy to remember. Thus, the

URL of a site which is URL 209.164.80.192 can also be written aswww.simplygraphix.com. The Internet Domain Name System

translates the alphanumerical address to numeric.

SEARCH ENGINES



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A web search engine is designed to search for information on

the World Wide Web. The search results are generally presented

in a list of results and are often called hits. The information may

consist of web pages, images, information and other types of

files. Some search engines also mine data availablein databases or open directories. Unlike Web directories, which

are maintained by human editors, search engines

operate algorithmically or are a mixture of algorithmic and

human input. E.g., Google, Yahoo, AOL, Ask etc.

WEB PAGES

A web page is the basic part of the World Wide Web. Theinformation displayed on the web page includes graphics, video

and audio. Several web pages link together to form the World

Wide Web

These hypertext documents are marked using the code HTML

(Hyper Text Markup Language).The protocol HTTP (Hyper Text

Transfer Protocol) is used to connect the hypertext documents.

An address is given to each website. It is called URL (Uniform

Resources Locator).

E-MAILElectronics mail or e-mail, as it is popularly known has become a

very convenient, economical and fast way of communication.

It also leaves a copy of message on the computer which can be

forwarded

One more advantage is that the same message can be sent to a

group of people at the same time.

E-mail address consist of three parts



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The first part is user name or user ID

The second part is name of the server or host computer on which

mails will be received.

The third part is the domain address

E.g.: [email protected]



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BIBLIOGRAPHY

List of Website Links that have been referred for this project:

www.wikipedia.org/wiki/Internet

www.wikipedia.org/wiki/History of the Internet

www.webopedia.com/internet.html

http://www.google.com/search?

hl=en&defl=en&q=define:Host+computer&sa=X&ei=4Ux3T

I3VGYqHcd2Jrd0F&ved=0CBYQkAE

http://learn-networking.com/tcp-ip/how-encapsulation-

works-within-the-tcpip-model

http://www.ccnacertificationguide.com/The_OSI_Reference_

Model.php

http://www.buzzle.com/editorials/2-6-2005-65413.asp

http://compnetworking.about.com/cs/routers/g/bldef_router.

htm

http://technoparadigm.blogspot.com/2007/11/computer-

networks.html

http://en.wikipedia.org/wiki/TCP/IP_model

http://www.meaningofnames.biz/domain-extension-

meanings.htm

http://techraga.com/category/basics-of-networking/osi-

model-and-layers/

http://hireme.geek.nz/ftp-ng.html

http://en.wikipedia.org/wiki/OSI_model



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IT Basics of Internet Theory