Introduction to Internet and World Wide Web

1. Introduction to Internet and World Wide Web Lecture 31 By Prof. Dr. Sajjad Mohsin

2. Today’s Outline • We will discuss today • Basic Networking Interfaces • Internet • World Wide Web • Applications and Usage

3. Terms & Definitions Client A client is the requesting program in a client/server relationship, e.g, the user of a Web browser is effectively making client requests for pages from servers all over the Web.

4. Terms & Definitions Server In general, a server is a computer program that provides services to other computer programs in the same or other computers.

5. Terms & Definitions Web browser: The web client, called a browser, is the software that allows you to interact with information available on the Internet. e.g Netscape Navigator, Microsoft Internet Explorer, MOSAIC.

6. Terms & Definitions HTML (Hypertext Markup Language): HTML is a tagging language used to compose documents that will be viewed by a web browser. It is a standard adopted so that no matter what computer platform someone is using, the web browser knows how to display the web document.

7. Web Page: A mixture of text, graphics, sound and animation in the HTML format, to make information accessible in a easy to understand format using the Internet. Web Site: A collection of web pages connected (linked) by Hypertext clickable links. Web Site Storage/Hosting: After a web site is designed it must be stored on a computer that can be accessed through the Internet and the World-Wide Web .

8. PROTOCOL: It is a set of conventions governing the processing and especially the data in an electronic communications system. TCP/IP (Transmission Control Protocol/Internet Protocol ): TCP/IP is a set of protocols developed to allow cooperating computers to share resources across a network. They provide a few basic services that everyone needs (file transfer, electronic mail, remote logon, etc…) across a very large number of client and server systems.

9. URL (Uniform Resource Locator): The URL is a "standard" way of easily expressing the location and data type of a resource. URLs in general take the form "protocol://address" where protocol is something like HTTP, FTP, telnet, and so on, and the address is merely the server name of a given resource or page.

10. DNS (Domain Name Services): DNS refers to a network service that associates host names (alphanumeric) with their equivalent TCP/IP address. This is done by the means of a standard look-up table. Example: Translation from domain names: http://www.comsats.edu.pk into correct TCP/IP addresses, e.g. 203.124.43.105.  Telnet : Telnet is the way you can access someone else's computer, assuming they have given you permission.

11. SMTP (Simple Mail Transfer Protocol): SMTP is the standard protocol used to exchange Internet mail between TCP/IP hosts. “Message Handling Systems”

12. Domain (s) • On the Internet, a domain is basically a registration category identifying geographic or purpose commonality. • There are seven top-level domains currently in use: • com - A commercial organization. The largest domain extension currently used. • edu - An educational establishment such as a school or university. • gov - A branch of the government that is strictly reserved for that purpose. • int - An international organization such as the United Nations.

13. Domain (s) (Cont.) • net - A network organization. • org - A non-profit organization. • mil - A branch of the military that is strictly reserved for that purpose. • In other parts of the world the final part of the domain name represents the country in which the server is located like pk for Pakistan, bb for Barbados, ca for Canada and uk for Great Britain.

14. Internet: • At its most basic level, theInternet is an utility connecting localized computer networks (that might exist in a lab, in a building, in a department, or on a campus) with computer networks that extend across a wider area, like a region or a continent. • Technically, what distinguishes the Internet is its use of a set of protocols called TCP/IP. Two recent adaptations of the Internet technology are the Intranet and the Extranet. • The term 'Internet' comes out of the concept of 'internetworking'

15. World-Wide Web: The World-Wide Web (WWW) is a pair of software applications, which allow both distribution of and access to information on the Internet. The webis not the Internet but a means of distributing and accessing the information that is on it.

16. 3D Map of WWW

17. E-COMMERCE / E-BUSINESS: • "E-Commerce" (Electronic Commerce or EC) is the buying and selling of goods and services on the Internet, especially on the World-Wide Web. • Example of E-Commerce Website: Amazon.com (http://www.amazon.com)

18. FIRE WALL: • A firewall is a program, usually an Internet gateway server, that protects the resources of one network from users from other networks. Any enterprise will want a firewall to prevent outsiders from accessing its own private data resources. • There are a number of firewall screening methods. A simple one is to screen requests to make sure they come from acceptable domain names and IP addresses. Another is to not allow Telnet access into your network except for your own users.

19. Firewall INTERNET

20. HTTP: The Hypertext Transfer Protocol is the set of rules for exchanging files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web.

21. User request document from browser. 6 1 BROWSER Display web page. USER 5 Send request. Send response. 3 2 Open connection of web server. WEB SERVER Searching for the document. 4 HTTP (HyperText Transfer Protocol):

22. Web Server: • Stores and transmits web documents (files). It uses the HTTP protocol to connect to other computers and distribute information. • Example: IIS, Apache, Sun Java System Web Server FTP (File Transfer Protocol): • FTP is the standard used to transfer files over the Internet. • FTP allows you to copy any kind of computer file (text, software, images, sounds, fonts, etc...) from one computer to another via a network using the Internet. • FTP is not platform-specific, so as long as you have a computer (DOS, Macintosh, Unix, etc.) that is connected to the Internet, you can copy files.

23. COMSATS Web Server

24. ISP (Internet Service Provider): • An ISP is a company that provides individuals and other companies access to the Internet and other related services such as Web site development and hosting (web site storage). • The larger ISPs have their own high-speed leased lines so that they are less dependent on the telecommunication providers and can provide better service to their customers.

25. ISPs and Backbone Service Providers 3. Your request goes to anetwork access point(NAP). NATIONAL 4. Your request goes to anational backbone network. Click to view animation. Click once only. 1.You request a Web page. REGIONAL LOCAL 5. Your request reaches the Web site’s server and the Web page is sent back to you in packets. 2. Your request goes to your ISP’spoint of presence(POP). YOU ARE HERE

26. Java Applet: An applet is a small program run on the Web, using Java, the object-oriented programming language. It can be can be sent along with a Web page to a user. It can perform interactive animations, immediate calculations without having to send a user’s request back to the server.

27. XML (eXtensible Markup Language): • XML is a flexible way to create information formats and shared on the World Wide Web, intranets, and elsewhere, • Example, computer makers might agree on a standard or common way to describe the information about a computer product (processor speed, memory size, …) and then describe the product information format with XML.

28. XML (eXtensible Markup Language): • Such a standard way of describing data would enable a user to send an intelligent agent (a program) to each computer maker's Web site, gather data, and then make a valid comparison. • XML can be used by any individual or group of individuals or companies that wants to share information in a consistent way.

29. XML (eXtensible Markup Language): • XML is currently a formal recommendation from the World-Wide Web Consortium (W3C) as a way to make the Web a more versatile tool. • XML is similar to the language of today's Web pages, HTML in that both contain markup symbols to describe the contents of a page or file. HTML, however, describes the content of a Web page (mainly text and graphic images) only in terms of how it is to be displayed and interacted with. Example: a <P> starts a new paragraph.

30. XML (eXtensible Markup Language): • XML describes the content in terms of what data is being described. e.g., a <PHONENUM> could indicate that the data that followed it was a phone number. • This means that an XML file can be processed purely as data by a program or it can be stored with similar data on another computer or, like an HTML file, that it can be displayed.

31. How XML codes look like <note><to>Employee</to><from>Supervisor</from> <heading>Reminder</heading> <body>Don't forget me this weekend!</body></note>

32. History of the Internet: • The Internet grew out of many developments in computer networking and telecommunications research. • Early projects undertaken in early 1960’s by the US military (known as DARPAnet). • Started with a dozen of Networked computer systems of universities and institutions, allowing computers to be shared. • Allowing fast communication between researchers through Emails.

33. History of the Internet (Cont.) • Only people in the government, military and academic had access to the network. • In 1991, the National Science Foundation (NFS) gradually started backing off from its subsidy of the backbone network, then allowed commercial access to the internet. • With commercial access to the Internet, businesses and all kinds of agencies began to use the Internet to communicate, exchange data and distribute information;

34. History of the Internet (Cont.) • A host of businesses called Internet Service Providers (ISPs) sprang up. ISPs provide dialup access to the Internet; an individual or a business opens an account with the ISP, dials into the ISP's computer and via the ISP's computer connects to the Internet.

35. History of the Internet (Cont.) • Internet traffic grew, • Many businesses spent heavily to improve the internet, therefore to better service their customers. • Big competition among communication carriers, hardware and software suppliers. • As a result, Internet’s bandwidth climbed high, & cost went down!

36. The Internet’s History • Significant events in the history of the Internet. Click on the dates for more information. J.C.R. Lickliter conceives of the idea of a “galactic network”. The World Wide Web is developed. The first graphical Web browser is developed. Ray Tomlinson invents e-mail. 1962 1972 1989 1994 1969 1983 1995 Barriers to commercial activity are lifted. Internet protocols begin. ARPANET goes online, connecting four computers.

37. The Future of the Internet • Key changes in the Internet need to take place to handle the growing number of users and the speed of the connections. • Future changes include: • More bandwidth • Internet 2 (I2) is being developed and tested to establish gigabits per second Points of Presence (gigaPOP).

38. History of the World-Wide Web • WWW allows computer users to locate and display multimedia-based documents, • Introduced in 1990 by Tim Berners-Lee of CERN (Geneva). • Today’s Internet mixes computing and communications technologies. • It makes our work easier. • It is changing the nature of the way business is done.

39. History of the World-Wide Web (Cont.) • It makes information instantly and conveniently available to anyone with a connection • Communities can stay in touch with one another. • Researchers can learn of scientific and academic breakthroughs worldwide.

40. The Internet and Web: What’s the Difference? • The Internet is the physical connection of millions of networks. • The Web uses the Internet for its existence. • The Web consists of hypertext embedded on Web pages that are hosted on Web sites.

41. 2. Internet Applications • Internet Protocols HTTP (HyperText Transfer Protocol): which are the basis for information exchange on the Internet), HTTP is an application protocol. HTTPs (“s” stands for security): is the same way as HTTP but used securely.

42. FTP (File Transfer Protocol) Telnet Other alternative in the Market: Terminal Services, PC Anywhere • Email (Electronic Mail) • E-mail is the exchange of computer-stored messages by telecommunication. • you can send messages (text, graphic images and sound files) as attachments.

43. Email (Electronic Mail) (Cont.) • E-mail was one of the first uses of the Internet. Probably it is still the most widely used internet application. • A large percentage of the total traffic over the Internet is e-mail. • It uses Simple Mail Transfer Protocol orSMTP.

44. Search Engines • Web sites that sort through by keywords and categories: • Google (www.google.com) • Yahoo (www.yahoo.com) • Lycos (www.lycos.com) • Altavista (www.altavista.com) • Store information in databases. • Returns list of sites as hyperlinks.

45. Search Engines (Cont.) • Meta-search engines: • No Database maintenance. • Combine results from multiple search engines. • Microsoft MSN: www.msn.com • IE5.5 has a built-in meta-search engine that is accessed by clicking the search button on the toolbar.

46. 3. Internet Architecture & Topologies • Internet Service Providers (ISPs) • To get to the internet we need to pay “people at access points”, are the ISPs • Because they have high speed connections to the internet, and dedicated hardware. • They sell their services back to users like Email, web storage, slower internet access dialup or dedicated line.

47. Internet Service Providers (Cont.) • Commercial ones out there: www.aol.com, join.msn.com, www.NetZero.com, … www.Guno.com, … …..

48. Domains Internet registration category identification for geographic and Common purposes, e.g. .com, .com.my, others like .ac.uk, .co.uk • Intranets • What is an Intranet?Intranets are private corporate information and collaboration systems that use Internet software and standards. • Why an IntranetThe Intranet can increase market share, profitability, and efficiency.

49. Why Intranet (Cont.) • Ideal place for publishing continuously updated Corporate information. • Powerful, not expensive communications alternative that can provide information anywhere at anytime. • Intranet technology can be used across wide area networks. • Web server software inter-operates well. • Web servers do not need large capital expenditures in hardware.

50. How can Intranet help a company? Intranets can be relatively easy to install, and inexpensive to administer. Also eliminate Printing, and out-of-date information • Procedures Manuals • Company Practices • Company phone book • Catalog and Inventory lists • Employee benefits information (Health-care benefits) • Bulletin boards • Job Postings • In-house newsletters or publications