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2. CHAPTER. The Internet and the Web. Irfan A. Ilyas Lecture 23. Points to cover. Introducing Internet What is available on the Internet? How to get connected with Internet? Main Internet Facilities World Wide Web Electronic Mailing Telnet FTP Gopher
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2 CHAPTER The Internet and the Web Irfan A. IlyasLecture 23
Points to cover • Introducing Internet • What is available on the Internet? • How to get connected with Internet? • Main Internet Facilities • World Wide Web • Electronic Mailing • Telnet • FTP • Gopher • Basic Working Model of Internet Services
Introducing Internet • Internet is • a connection of billions of computers (similar/ dissimilar) AND • the technologies (hardware/ software) which makes the whole setup interoperable.
What is available on the Internet? • Internet offers its users many services including • Communication with others • Using emails, chatting (online messaging) • Shopping • Buy goods (and sell also) • Searching • Reading materials from real as well as virtual libraries • Entertainment • Games, Magazines, Interactive games etc. • Education (e-learnings) • Take online classes, get academic degrees.
How to get connected with Internet? Internet Service Provider (ISP) • An ISP is a commercial based organization • ISP charge their customers on hourly or fixed basis (unlimited access) How it works? • An ISP already had its computer connected with the Internet (backbone) • ISP allows their users to get connected with their local computer through a modem (telephone line) • After the user is connected, he becomes a part of the Internet (using different services)
…How to get connected with Internet? • Internet Service Providers( ISP ) • Commercial Organizations • Available for all public • Centers are locally available to different areas [saves telephone charges]. • Examples: • Saudi Online, Nasjeet etc. • Provide their customers with different numbers in Riyadh, Dammam, Jeddah etc. • University & Colleges • Only available for University attached people (students, faculty, staff) • Cannot be used from other localities • Example: KFUPM Connection
User Name: 99847756Password: fdjfdkfkdjfddfd …How to get connected with Internet? Procedure for an ISP connections • Step#1: Getting Tel# & User Account • Subscribers are provided with • A telephone number to the ISP computer (local to the subscriber’s locality) • A username & password Note: pre-paid card from commercial ISPs normally have this information printed over it. Saudi Online Saudi Online Prepaid Card with necessary information printed over it
…Procedure for an ISP connections • Step#2: System Setup for a dialup Connection • To prepare the subscriber’s (user) system for the connection, one of the following will also be provided: • A step-by-step manual setup procedure OR • A small program which will automatically do the required setup using a dialogue from the user.
…Procedure for an ISP connections • Step#3: Connecting the ISP • Using the dialup connection created in the last step, • Users dial the ISP number • System tries to connect (strange noise) • A successful connection message appears
…Procedure for an ISP connections • Step#4: Using Internet Facilities • Users can now start browsing etc. For more info: http://www.saudionline.com
Access Providers • Common way to attach to the Internet • Internet service providers (ISP) • National • Regional • Wireless
Main Facilities on Internet • World Wide Web • WWW allows Internet computers to exchange information objects (text/ pictures/ sound etc.) among each other through easy to use web pages. • WWW is an interface of Internet contents • Electronic Mailing • Sending and receiving messages using Internet • Telnet • Running programs on a remote computer (with its screen and keyboard control available locally)
….Main Facilities on Internet • FTP • Transferring file from/ to a remote computer on the Internet • Gopher • It allows a client computer to access different resources on a server computer using a menu based interface (text based menus) • Not very popular after Web Interface became available. • Complex and painful.
A Web Client Computer [running the client program] The Basic Working Model of Different Internet Services • All Internet facilities work on the same principle as does the Web Service. • A client program is provided to Internet users • WWW: Internet Explorer, Netscape Navigator • Email: Outlook Express, Netscape Mailer, Eudora Mail • FTP: Cute FTP for windows, • Telnet: Microsoft Windows Telnet client Server Responses Client Requests A Server Computer running the server program
Example: Client Programs • Cute FTP for Windows • Microsoft Window Telnet Client
… Working Principle of Different Internet Services • A server program must be running on the computers providing any related service. • Normally available as “Operating System Services” • Services start automatically when windows starts Service handling a Telnet Server Facility Service handling a WWW Server Facility
… Working Principle of Different Internet Services • The transaction mechanisms needed in each service will be different but already standardized • Email: Simple Mail Transfer Protocol (SMTP) • FTP: File Transfer Protocol (FTP) • Gopher: Gopher Protocol • Web: Hyper Text Transfer Protocol (http)