Chapter 5

Introduction to the Internet

What is the Internet ?

•Internet is a network of networks.

•It is the largest ever known system of interconnected networks, carries a vast amount of information resources, and services.

• Accessible by billions of people over the world.

Internet Protocol Suite (TCP/IP)

•All communications are governed by

predefined rules called Protocols.

•TCP/IP is the set of communication protocols

used for the internet and other similar

networks.

•The name is driven from two of the most

important protocols

•1. Transmission Control Protocol(TCP)

•2. Internet Protocol(IP)

• which were the first two networking

protocols defined in this standard.

The Internet and WWW

• The terms Internet and World Wide Web(WWW) are not same.

• The Internet is a global data communication system.

• It is a hardware and software infrastructure that provides connectivity between computers.

• The web is one of the services that use the internet such as e-mail, instant messaging, videoconferencing and more.

Internet Services and Protocols

1. WWW(World Wide Web):

• Is a collection of connected web pages, documents and multimedia information linked by hyperlinks.

• Each web page or file in the web has its own URL(Uniform Resource Locator), which is the complete address for this page on a web server.

• Hyperlinks are special items- regularly text- in web pages that are associated with specific URLs, when clicked; it opens another web page

Protocols Used in WWW:

HTTP(Hyper Text Transfer Protocol):

• is the protocol used with the WWW to

transfer the web pages between web

servers and clients through internet.

• Web page is nothing but a Hyper Text that

is written using the HTML(Hyper Text

Markup Language).

2. E-mail(Electronic Mail):

• is used to send electronic messages from one mailbox to another.

• Every mail box has a unique name referred to as email account.

• E-mail address are written as

Email_Account@Domain_Name

The most popular domains that provide email service are Yahoo, Gmail and Hotmail

Protocols used in e-mail communication:

SMTP(Simple Mail Transfer Protocols)

POP(Post Office Protocol)

3. Downloading and Uploading Files:

• Is to collect or send files from or to the

internet.

• It is an important characteristics of the

internet.

• When we browse the web or when we

attach a file through an Email.

Protocols Used:HTTP: (Hyper Text Transfer Protocol)

FTP: File Transfer Protocol

BitTorrent Protocol:

One of the most common protocols for transferring large files.

This protocol downloads pieces of the file in a random approach while the previous protocols downloads them sequently.

This protocol makes many connections to different machines, while classic downloading makes only one connection to a single machine

4. Instant Messaging(IM) or Chatting:

• is a real-time system that allows two or more

people to use their personal computers to

communicate with each other by sending and

receiving text messages

• real-time means, when you send the

message it should appear immediately to the

other side computer.

• More advanced instant messaging software

allows enhanced communication, such as

voice chatting, file sharing and video calling.

Protocols used in Instant Messaging: IRC (Internet Relay Chat): used with mIRC

MSNP:(Microsoft Notification Protocol): used with Windows Live Messenger.

Skype Protocol: used with Skype

YMSG(Yahoo Messenger): used in Yahoo Messenger

OSCAR:(Open System for Communication in Real –Time) used with AIM(AOL Instant Messaging) and ICQ.

XMPP: (Extensible Messaging and Presence Protocol) used with Google-talk and Facebook chat

Web Addresses

Domain Names or Web Site addresses are composed of the following parts:

1- The Protocol: e.g. http followed by (:) and (//).

2- WWW: This means that this address is a World Wide Web address.

3- Domain Name: the name or the abbreviation of the registered Organization or, may be, the person who are registered to get a web address.

4- Top-Level Domains (TLDs)

TLD Purpose

.biz Businesses

.com Unrestricted, but intended for commercial

entities

.edu Educational institutions

.gov Government agencies

.info Unrestricted use

.mil Military

.net Unrestricted use, Group or network in a

specified field.

.org Unrestricted use, but intended for nonprofit

organizations and organizations that don't fit

elsewhere

5-Two letters (Usually) representing the

Home Country of the domain.

Abbreviation Country

ae Arab Emirates

jo jordan

sa Saudi Arabia

qa Qatar

bh Bahrain

eg Egypt

lb Lebanon

om Oman

Abbreviation Country

sy Syria

ku Kuwait

uk United Kingdom

au Australia

in India

Web Technologies

1. Search Engines

• Programs that are used to search for

information on the world wide web.

• Search results are presented in a list, and

it may contain web pages, images and

other types of files

Example: Google, Yahoo, Bing, AOL

Narrowing the Search Results

• A group of words with double quotes tells the search engine to only retrieve documents in those words appear side-by-side.

• Phrase Searching is a powerful search technique for narrowing the search results.

Examples: Google Advanced Search Page used to choose more options like exact wording or phrase, file type, language and a specific domain.

2. Video Sharing Websites

• Allows millions of people to watch and share originally created videos.

Features

• Video Embedding : where users can insert a video into Facebook, blogs or other web sites where anyone can watch them.

• Users can also add comments and rate any shared videos.

Example: You Tube

3.Blogs(Forums)

• Blog is a word made up from web log.

• Initially they began as online journals with

frequent comments on a few topics of

interest to the bloggers.

• Users can participate in many forums

according to their interests.

• Users can create new posts or respond to

any previously shared posts.

Example: Omani Sabla Forum

4.Social Networking

• Are websites that allow people to connect and build online communities that share common interests or activities.

• Users may use various ways to interact such as chatting, messaging and video sharing.

• Users can upload pictures and can be “friends” with other users.

• Users also have the ability to create groups that share the common interests.

• Examples: Facebook, Twitter, LinkedIn, MySpace and Hi5

5. E-Learning:

• Many specialized high school courses and some complete college programs are offered entirely on the web.

• Refers to the usage of electronic applications and process to learn, including web-based learning, computer based learning and virtual classrooms.

• Course content are delivered via the Internet, audio or video tapes and DVDs.

Examples: University of Nizwa EDUWAVE E-Learning System, University of Nizwa MOODLE E-Learning System, Arab Open University E-Learning System.

6. E-Commerce

• Refers to buying and selling items online.

• Most of the traditional companies established we sites for online business.

• Usually payments via those websites are handled by trusted intermediary companies such as PayPal.

Benefits:

• Considering more products and sellers

• Reaching a huge number of costumers and buying from different countries without moving a step

Example: eBay.com

7. E-Government

• Is the delivery of government services

through the Internet.

• Helps to simplify processes and enable

access to government information through

easier methods for public sector agencies

and citizens.

Example: Royal Oman Police Website

8. Wikipedia

• Is a free, online, collaborative encyclopedia

• Is an excellent example of collaborative projects among large numbers of strangers worldwide that produce extremely valuable product for public.

• Is one of the Internet’s most used reference sites, even so, some articles may contain errors.

• Thousands of volunteers write and continually edit and update Wikipedia.

• Anyone who chooses to participate can do so.

Web Browsing Application

Web Browser:

• is the application program used to open

any website.

• All web browsers are available free and

can be downloaded and updated

immediately from their websites.

Examples: Microsoft Internet Explorer,

Google Chrome, Mozilla Firefox, Opera,

Apple Safari.

Common features of most of the Web browsers

1. History: recently visited web pages, collectively known as “history” are stored so that you can review them later.

2. Bookmarks: a personal list of interesting web sites. Bookmarks make it quick and easy to get favorite places on WWW.

3. Add-ons (or) plug-ins (or) widgets: are set of software that adds specific capabilities to a larger software application.

4. Embedded Search: Using a search engine immediately from the tool-bar of the web browser.

5. Tabbed browsing: a tabbed document interface(TDI) is one that allows multiple documents to be contained within a single window.

What are the criteria we have to

consider to choose the perfect

browser?

1. Features: (Discussed in the previous

slides)

2. Ease of Use: User friendly ?

3. Security: browsers should protect their

users against hazards, such as viruses?

4. Speed: browsers should help the users

to surf fastly and efficiently.

Internet Service Provider(ISP)

• ISP is a company that provides access to the internet.

• Users can connect to the Internet Immediately by connecting with the ISP.

• ISP can provide different methods for Internet connections with different characteristics and different costs.

• ISP gives you a software, username, password and access phone number. Equipped with a modem, you can then log on to the internet.

Internet Connection Types

• There are two categories of Internet connections: 1. Normal(dial-up)

2. Fast(broadband).

• The choice will depend on a number of factors, the most important one is the speed and other factors are availability and cost.

1. Dial-up connection

• slow and most inexpensive(cheap)

To connect using dial up,

• First your PC must have a standard

modem and it should be connected with

the telephone line.

• Then you can use a dial up connection

software with the account and phone

number given to you by the ISP.

• Your PC dials a phone number and

connects to the ISP and, therefore, the

Internet.

2. ADSL Connections: stands for

• Asymmetric Digital Subscribers Line

• Offers incredible performance compared with dial-up.

• Becoming the first choice of broadband for most Internet subscribers.

• ADSL connections are not available every-where.

• Needs a special ADSL modem and ADSL filters.

• Quite expensive compared with dial-up

• It splits the phone line into two separate

channels: one for data (Internet) one for

voice (phone calls).

• So users can talk on the phone and be

connected to the Internet at the same

time.

• Depending on the ISP, ADSL have

different speed specifications such as

512Kbps, 1Mbps, 2Mbps, 4Mbps and

8Mbps

Internet Ethics

• Internet Architecture Board (IAB) issued a

statement of policy concerning Internet ethics.

Unethical and Unacceptable statements are:

• Seek to gain unauthorized access to the resources

of the Internet

• Disrupt (Disturb) the intended use of the Internet.

• Waste resources (people, capacity, computer)

through such actions

• Destroy the integrity of computer-based information.

• Compromise the privacy of users.

Internet Privacy

• Is the ability to control what information you would accept to be revealed about yourself over the Internet, and control who can access that information.

Example Problems

1. Your personal email can be used by third parties without your knowledge.

2. Without you knowledge, third parties can track the websites you have visited or whether web sites you visit can collect and store information about you.

Ways to Protect your Privacy on the

Internet :

1. E-mails can be encrypted

2. Proxies can be used to prevent the ISPs

from knowing which sites you visit and

with whom you communicate.

Internet Security

• The Internet represents an insecure channel for exchanging information, leading to a high risk of Intrusion or Phishing.

• Intrusion: is breaking into computers and computer networks, either for profit or just a challenge.

• Phishing: is the criminally fraudulent process of attempting to acquire sensitive information, such as username, passwords and credit card details.

Methods to Protect the Transfer of Data

1. Encryption:

• is the process of transforming original

information into unreadable data before

sending through the Internet.

• Usually encrypted web pages are

identified by “https” instead of “http” for

the protocol in their web address starter.

2. Antivirus Programs and Internet Security Programs: are also useful in protecting your computer from:

Viruses: are small pieces of software that attach themselves to a real program.

Worms: are self-replicating computer programs.

Trojan horses: are harmful piece of software that look legitimate.

Spyware: is software that collects information about users without their knowledge and send them to a third party.

Adware: is a software package, which automatically plays, or displays advertisements to a computer

Popular Anti-virus and Internet Security

Softwares are

1. Norton Internet Security

2. Kaspersky Internet Security

3. Webroot Internet Security

4. Panda Internet Security

5. BitDefender Total Security

6. McAfee Total Protection.

3. Firewall:

• It is hardware or software that controls the

access between networks.

• It is usually used as a shield between

private networks and the Internet.

• All the messages whether incoming or

outgoing must pass through the firewall,

and only authorized traffic is allowed.