InternetA form of Network

What is internet?

Network

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• A network consists of 2 or more computers connected together, and they can communicate and share resources (e.g. information)

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Why Networking is needed?

• Sharing information — i.e. data communication

• Do you prefer these?

• Or this?

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Internet Introduction• Key Definitions:

– Internet: The internet is a global network of interconnected networks, connecting private, public and university networks in one cohesive unit.

– Intranet: An intranet is a private enterprise network that uses internet and web technologies for information gathering and distribution within an organization.

– Extranet: An extranet is a community of interest created by extending an intranet to selected entities external to an organization.

Internet connects

History of Internet:

History of Internet

• ARPANET• DARPA (defense advanced research projects

agency)• TCP/IP• World Wide Web• Internet

Internet history:

Early Arpanet

• TCP/IP (unifying protocol)– Transmission Control Protocol (how data is

broken up into packets and reassembled at the end)

– Internet Protocol (how packets reach their destination)

• FTP• Email• Telnet

The World Wide Web

• Created by Tim Berners Lee, a researcher for CERN, in 1989

• Originally to aid researchers find information through a linked texts

• Used HTTP for protocol and HTML for content of pages

• Still no images at this point

What do we need to connect to internet:

• Computer• Modem• Dial up Software• ISP Connection

– High speed connections• Digital Subscriber Line• Integrated Services Digital Network

• Web Browser

Uses of internet

Positive Uses Negative Uses

•Globalization

•Flow of information

•Better understanding

•Comfort in life

•knowledge

•Immorality

•Security Problems

•Viruses

•Wastage of Time

•Cyber Crimes

Internet Terminologies

Web browsers

Internet terminologies

Internet terminologies

Internet terminologies

Internet terminologies

Internet Addresses• IP addressing

– a numerical label assigned to each device or unique identifier for a computer assigned by ISP

– 32 bit number and consists of four number separated by dot e.g 127.80.144.30

– IP address of Server does not change• DNS Addressing

– A hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network

Parts of DNS

• Host name• Domain name / Top level Domain

– Institution that uses the address• Domain Name System: Method used to store

domain names and corresponding IP addresses

Types of Domains

Internet Services

Uses of WWW

• Advertisements• Shopping• Flight Information• Television Station• Celebrities• Government Authorities• News• Encyclopedias• Search Engines• Medical• News groups

Email• Method of exchanging digital messages from an author to one or

more recipientsEmail Attachment: An email attachment is a computer file sent along with an email message. One

or more files can be attached to any email message, and be sent along with it to the recipient.

Uses of Email:• Fast & timely

• Cheap & Inexpensive

• Send and receive messages any where in world

• Information sharing

• Pictures, sound, videos can be sent

Limitations of Email:

• Lack of privacy• Junk email• No emotions• Possible delay• Communications problems• Can send text files

Email Address

• User ID• Identify email service• Mailing list:

– Collection of email names and addresses given a single name

Ecommerce• Buying and selling of products or services over electronic

systems such as the Internet and other computer networks

• Role of Ecommerce:– Electronic banking– Electronic shopping– Conducting Auctions– Marketing and Advertising– Providing customer services– Online travel reservations– Online trading– Video confrencing

Types of ecommerce• B2B (Business-to-Business)

Companies doing business with each other such as manufacturers selling to distributors and wholesalers selling to retailers. Pricing is based on quantity of order and is often negotiable.

• B2C (Business-to-Consumer)Businesses selling to the general public typically through catalogs utilizing shopping cart software. By dollar volume, B2B takes the prize, however B2C is really what the average Joe has in mind with regards to ecommerce as a whole.

Having a hard time finding a book? Need to purchase a custom, high-end computer system? How about a first class, all-inclusive trip to a tropical island? With the advent ecommerce, all three things can be purchased literally in minutes without human interaction. Oh how far we've come!

• C2B (Consumer-to-Business)A consumer posts his project with a set budget online and within hours companies review the consumer's requirements and bid on the project. The consumer reviews the bids and selects the company that will complete the project. Elance empowers consumers around the world by providing the meeting ground and platform for such transactions.

• C2C (Consumer-to-Consumer)There are many sites offering free classifieds, auctions, and forums where individuals can buy and sell thanks to online payment systems like PayPal where people can send and receive money online with ease.

Advantages of ecommerce:

• Geographic Reach• Speed• Productivity• Information Sharing• New features• Lower costs• Competitive Advantage

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How many kinds of Networks?

• Depending on one’s perspective, we can classify networks in different ways

• Based on transmission media: Wired (UTP, coaxial cables, fiber-optic cables) and Wireless

• Based on network size: LAN and WAN (and MAN)• Based on management method: Peer-to-peer and

Client/Server• Based on topology (connectivity): Bus, Star, Ring …

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Types of Network

Topologies