Beekman5 std ppt_10


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Beekman5 std ppt_10

  1. 1. Chapter 10 Inside the Internet and the Web
  2. 2. Topics <ul><li>The Internet: A Network of Networks </li></ul><ul><li>Internet Applications: Communication and Connection </li></ul><ul><li>Inside the World Wide Web </li></ul><ul><li>The Evolving Internet </li></ul>“ It’s a bit like climbing a mountain. You don’t know how far you’ve come until you stop and look back.” Vint Cerf
  3. 3. <ul><li>The Internet is an interconnected network of thousands of networks linking academic, research, government, and commercial institutions. </li></ul>The Internet: A Network of Networks
  4. 4. <ul><li>The Internet provides scientists, engineers, educators, students, business people, and others with a variety of services such as: </li></ul><ul><ul><li>Electronic mail (send/receive mail messages) </li></ul></ul><ul><ul><li>Remote login (T elnet - access to other computers) </li></ul></ul>Internet Services
  5. 5. Internet Services <ul><ul><li>Transferring files (FTP - accessing archives of data) </li></ul></ul><ul><ul><li>Newsgroups (Usenet - on-line public discussions) </li></ul></ul><ul><ul><li>World Wide Web (a collection of multimedia documents) </li></ul></ul>
  6. 6. Counting Connections <ul><li>Today, the Internet connects computers to about every country in the world. However, the Internet is: </li></ul><ul><ul><li>growing too fast to measure its growth </li></ul></ul><ul><ul><li>too decentralized to quantify </li></ul></ul><ul><ul><li>a network with no hard boundaries </li></ul></ul>
  7. 7. <ul><li>The language at the heart of the Internet is TCP/IP… </li></ul><ul><ul><li>Transmission Control Protocol/Internet Protocol </li></ul></ul><ul><ul><li>Allows cross-network communication </li></ul></ul>Internet Protocols
  8. 8. Internet Protocols <ul><li>TCP breaks messages into packets </li></ul><ul><ul><li>Each packet has all the information needed to travel from network to network </li></ul></ul><ul><ul><li>Host systems called Routers determine how to route transmissions </li></ul></ul>
  9. 9. Internet Protocols <ul><li>IP is the address for the packets </li></ul><ul><ul><li>Each Internet host computer has a unique IP Address </li></ul></ul><ul><ul><li>Each address is comprised of four sets of numbers separated by periods, such as </li></ul></ul>
  10. 10. Internet Addresses <ul><li>The host is named using DNS (domain name system), which translates IP addresses into a string of names. </li></ul>“ Each person on the “Internet” has a unique e-mail “address” created by having a squirrel run across a computer keyboard.” Dave Barry
  11. 11. Internet Addresses <ul><li>Top level domains include: </li></ul><ul><ul><li>. edu - educational sites </li></ul></ul><ul><ul><li>.com - commercial sites </li></ul></ul><ul><ul><li>.gov - government sites </li></ul></ul><ul><ul><li>.mil - military sites </li></ul></ul><ul><ul><li>.net - network administration sites </li></ul></ul><ul><ul><li>.org - nonprofit organizations </li></ul></ul>
  12. 12. Internet Addresses <ul><li>An Internet address includes: username@hostname.sub.dom </li></ul><ul><ul><li>username is the person’s “mailbox” </li></ul></ul><ul><ul><li>hostname is the name of the host computer and is followed by one or more domains separated by periods: </li></ul></ul><ul><ul><ul><li>host.subdomain.domain </li></ul></ul></ul><ul><ul><ul><li>host.domain </li></ul></ul></ul><ul><ul><ul><li>host.subdomain.subdomain.domain </li></ul></ul></ul>
  13. 13. Internet Addresses <ul><li>[email_address] </li></ul>Examples: [email_address] User President whose mail is stored on the host whitehouse in the government domain User hazel_filbert at the server for Lane County, Oregon, k-12 school district
  14. 14. <ul><li>Direct (dedicated) Connection </li></ul>Internet Access Options <ul><li>Computer has its own IP address and is attached to a LAN </li></ul><ul><li>No need to dial up </li></ul><ul><li>Files are stored on your computer </li></ul><ul><li>Response time is quick </li></ul>
  15. 15. Internet Access Options <ul><li>Dialup Connections </li></ul><ul><ul><li>limited connection using a modem </li></ul></ul><ul><ul><li>Full access dial up uses SLIP or PPP via modem </li></ul></ul><ul><li>Broadband Connections </li></ul><ul><li>DSL service is newer, faster, and cheaper than ISDN </li></ul><ul><li>Can share phone line with voice traffic </li></ul>
  16. 16. Internet Access Options <ul><li>Cable Modem Connection </li></ul><ul><ul><li>allow Internet connections using shared TV cables </li></ul></ul><ul><ul><li>can exceed DSL speeds </li></ul></ul><ul><ul><li>Carry increased privacy and security risks </li></ul></ul><ul><li>Satellite Connections </li></ul><ul><ul><li>provides connections using DirecTV satellite dishes </li></ul></ul>
  17. 17. Internet Access Options <ul><li>Internet Service Providers (ISPs) </li></ul><ul><ul><li>local ISPs provide connections through local telephone lines </li></ul></ul><ul><ul><li>national ISPs offer connections on a nationwide scale </li></ul></ul>
  18. 18. <ul><li>The Internet use the client/server model for most Internet applications. </li></ul><ul><li>In the client/server model a client program asks for information, and a server program fields the request and provides the requested information from databases and documents. </li></ul>Internet Applications: Communication and Connection
  19. 19. <ul><li>An email server acts like a local post office for a particular Internet host—a business, an organization, or an ISP. </li></ul><ul><li>File servers are common within LANs, but they’re also used to share programs, media files, and other computer data across the Internet. </li></ul>Internet Applications: Communication and Connection
  20. 20. <ul><li>File transfer protocol (FTP) allows users to download files from remote servers to their computers and to upload files. </li></ul><ul><li>File compression saves storage space on disk and saves transmission time when files are transferred through networks. </li></ul>Internet Applications: Communication and Connection
  21. 21. <ul><li>An application server stores applications- PC office applications, databases, or other applications - and makes them available to client programs that request them. </li></ul><ul><li>An application server might be housed at an application service provider (ASP) - a company that manages and delivers application services on a contract basis. </li></ul><ul><li>A Web server stores Web pages and sends pages to client Web browsers. </li></ul>Internet Applications: Communication and Connection
  22. 22. <ul><li>WWW is a distributed browsing and searching system developed at CERN </li></ul><ul><li>System was designed to give Internet documents unique addresses </li></ul><ul><li>HTML language was created for encoding and displaying documents </li></ul><ul><li>Browser software was built for viewing documents from remote locations </li></ul>Inside the Web
  23. 23. Inside the Web <ul><li>Web pages are made up of text and images </li></ul><ul><li>A Web site is a collection of web pages </li></ul><ul><li>A Home page is the main entry to a Web site </li></ul><ul><li>A Web browser like Netscape Communicator or Internet Explorer allows you to explore the Web by clicking links </li></ul>Web site Jargon:
  24. 24. Inside the Web Hyperlinks (links) are words or pictures that act as buttons, allowing you to go to another Web page <ul><ul><li>Links are typically underlined or displayed in a different color </li></ul></ul>
  25. 25. Inside the Web <ul><li>More Web site Jargon </li></ul><ul><li>Links allow you to locate information without knowing its exact location (it may move from time to time) </li></ul><ul><li>Back and Forward buttons let you retrace your steps </li></ul><ul><li>Bookmarks and Favorites can be set up to mark your favorite Web locations </li></ul>
  26. 26. Web Addresses Pronounced Earl …like the name A typical URL looks like this:
  27. 27. Web Addresses <ul><li>Protocol for Web pages </li></ul><ul><li>Dissecting Web Page address: </li></ul>Resource Page http:// Path to the host help/database.html
  28. 28. Publishing on the Web <ul><li>An HTML document includes codes that determines the format, layout, and structure of a Web document </li></ul>HTML (Hypertext Markup Language) HTML is not WYSIWYG
  29. 29. Publishing on the Web <ul><li>This text coded as HTML … </li></ul>Appears like this on the screen … <ul><ul><li><H1>Welcome to Computer Confluence</H1> <b>Publishing on the Web</b> </li></ul></ul>
  30. 30. Publishing on the Web <ul><li>Alternatives to HTML… </li></ul><ul><li>Programs that convert document format features into HTML codes </li></ul><ul><ul><li>Microsoft Word, FileMaker </li></ul></ul><ul><li>Web authoring programs </li></ul><ul><ul><li>HomePage, GoLive, FrontPage </li></ul></ul>
  31. 31. From Hypertext to Multimedia <ul><li>Tables </li></ul><ul><li>Frames </li></ul><ul><li>Forms </li></ul><ul><li>Downloadable audio and video </li></ul><ul><ul><li>Streaming audio and video </li></ul></ul><ul><ul><li>Real-time live audio or video </li></ul></ul><ul><ul><li>3-D environments </li></ul></ul>Typical Web pages can contain:
  32. 32. From Hypertext to Multimedia <ul><li>Plug-Ins are software extensions that add new features. Examples include… </li></ul><ul><li>QuickTime </li></ul><ul><li>Shockwave/Flash </li></ul><ul><li>RealPlayer </li></ul><ul><li>Acrobat </li></ul>
  33. 33. Beyond HTML <ul><li>Dynamic HTML: </li></ul><ul><li>adds more programming power to HTML by allowing code to automatically modify itself under certain circumstances </li></ul>JavaScript: a simple language for enhancing HTML Web pages
  34. 34. Beyond HTML <ul><li>WML </li></ul><ul><li>Wireless Markup Language helps create Web documents containing stock quotes, phone numbers, and other small nuggets of information </li></ul><ul><li>XML </li></ul><ul><li>Will replace HTML plus provide additional features and extensions </li></ul><ul><li>VRML </li></ul><ul><li>Virtual Reality Modeling Language creates 3-D virtual worlds </li></ul>
  35. 35. Beyond HTML <ul><li>Java </li></ul><ul><li>A full-featured, cross platform, object-oriented programming language </li></ul><ul><li>Java applets </li></ul><ul><li>Small Java programs that can be automatically downloaded onto your client computer and can run on any platform </li></ul>