1. Chapter 9 THE INTERNET

2. RECAP: Computer Networks LAN WAN

3. HARDWARE Hub: LAN hardware that transmits data to the nodes on the LAN “rude”. Switch: Hardware connectivity through which data travels. More efficient. keeps a record of the MAC addresses of all the devices connected to it.

4. Transmission Line Types, Uses, and Speed

5. WHAT IS INTERNET? A network of networks, joining many government, university and private computers together and providing an infrastructure for the use of E-mail, bulletin boards, file archives, hypertext documents, databases and other computational resources The vast collection of computer networks which form and act as a single huge network for transport of data and messages across distances which can be anywhere from the same office to anywhere in the world. Written by William F. Slater, III 1996 President of the Chicago Chapter of the Internet Society

6. History of THE internet 1969 : ARPANET was born. 4 nodes were inter-connected: UCLA,SRI,UCSB, U. of Utah Charley Kline from UCLA sent 1st packet. 1972 : First computer-to-computer chat program at UCLA. 1975 : First mailing list was created by Steve Walker. 1984 : DNS (Domain Name System) was introduced. 1988 : First Internet Worm. 1990 : AOL, CompuServe provided dial-up service. 1991 : WWW was created by Tim Berners-Lee from CERN 1994 : Commercial network. Shopping mall. Can order pizza online. 1998 : 2M domain names registered. Compaq bought altavista.com for $3.3M. Google founded 2003 : Facebook launched

8. Internet is composed of two parts: the infrastructure (hardware), and the software (applications and protocols)

9. Hardware:

10. cables, routers, computers, and servers.

11. Software:

12. applications, programming languages, databases, and protocols that make communicationTHE INTERNET

13. Internet characteristics The power of the Internet: 1. Ubiquity 2. Low cost 3. Global Reach 4. Open and Shared ownership 5. Richness – complexity and content of the message 6. Interactivity

15. The world wide web consortium (W3C) definition of the web: "The World Wide Web is the universe of network-accessible information, an embodiment of human knowledge"

16. Provides information access in ways not previously possible

17. Hyperlinked (Hypertext)

18. Graphical user interface

19. Pictorial and non-text information

20. Information that changes rapidly

21. Immediate access

22. Anyone can author a web site

23. Multi-user access to the same information (try that with a book)

25. The Universal Resource Locator (URL) Each page of information on the web has a unique address called the URL at which it can be found http://faculty.uscupstate.edu/atzacheva/lecture1.html The document can be obtained using the Hypertext Transfer Protocol (HTTP) Host Name - The Name of Web Server Path to the Web Page Denotes that the File is Written in HTML HyperText Markup Language File Name 1 2 3 File Name Protocol Host Name

26. HTML HTML is a universal, simple language for formatting text. It also allows embedding of graphics, and linking of documents via ‘hyperlinks’. ‘Hypertext’ documents allow readers to freely move around the document, following links to subjects of interest. HTML is a language that is used to specify the structure of documents for retrieval across the Internet using browsers.

27. HTTP The standard Web transfer protocol is HTTP (HyperText Transfer Protocols). It is used for document exchange between servers and clients (typically browsers) in the WWW. To retrieve a document, the client first sends a request to the web server and waits for a reply An HTTP daemon/service (a program that waits for http requests) on the server then handles the request and the document is sent to the client (over a connection established using TCP/IP – Transmission Control Protocol / Internet Protocol) We recall from previous lectures, that a Protocol is “Agreed upon sets of rules that provide order to a system or situation.” In this case, a set of rules/standards for communicating on the Internet.

30. TCP/IP TCP = TRANSMISSION CONTROL PROTOCOL (Breaks messages into packets, Checks the integrity of incoming Packets and reassembles them) IP = INTERNET PROTOCOL (routes packets around the Internet)

31. WWW: What is it? Is a distributed collection of hypermedia documents that are inter-linked together. Web servers store the information (text, images, sound clips, video clips), and Web clients or browsers access this information. Domain addresses are governed by the standard Universal Resource Locator (URL) and end in suffixes that indicate the type of domain ownership. i.e commercial sites end in .com, not-for profit entities use the .org suffix, government (.gov)

33. Converts IP address to domain names

34. Hierarchical structure top is root domain, followed by top-level domains, second-level domains, and third-level domainsExample: Domain name: www.orbitz.com IP: 198.151.61.100 Convert Domain Name to IP address Internet Addressing and Architecture The Domain Name System is a hierarchical system with a root domain, top-level domains, second-level domains, and host computers at the third level.

36. The Internet Corporation for Assigned Names and Numbers (ICANN), assigns IP addresses

38. Server responds Client makes requests Client-Server Architecture SERVER INTERNET

39. Client/Server Computing on the Internet Client computers running Web browser and other software can access an array of services on servers over the Internet. These services may all run on a single server or on multiple specialized servers.