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INTERNET

INTERNET. A collection of networks. History. ARPANet – developed for security of sending in case of a nuclear attack IDEA – the system would not go down. Characteristics. Not all units directly connected Client/server type of connectivity Makes use of a router Makes use of a gateway

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INTERNET

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  1. INTERNET A collection of networks

  2. History • ARPANet – developed for security of sending in case of a nuclear attack • IDEA – the system would not go down

  3. Characteristics • Not all units directly connected • Client/server type of connectivity • Makes use of a router • Makes use of a gateway • Information transmitted by packets

  4. Internet service provider Subscribe to an ISP What is the first step in becoming an Internet user?

  5. Three basic services What am I buying?

  6. telnet FTP email

  7. Definitions • Telnet – allows communication with remote computers • FTP – file transfer protocol • Email – communication software

  8. You also get 2 protocols: • IP • TCP

  9. Definitions • IP – internet protocol • refers to type of topology • defines a packet to be 1500 bytes • does the routing • TCP – transmission control proto • Transmission will be through a sequence of packets • Assembles and disassembles the packets

  10. A Browser What else do I get? Software that is used to explore the Internet

  11. A Plug-In Can I get anything else? Software that adds to the browser (video)

  12. USES A SPIDER??? Additional software – SEARCH ENGINE Software that builds a database of searchable terms

  13. Search EnginesVary • InfoSeek – searches newsgroups, FAQs, and email addresses in addition to Web sites • AltaVista – indexes every word on a page • Excite – provides related hints and extra content • Google – results ranked by algorithm based on number of links from other pages • Lycos – numerous search options/a comprehensive directory • HotBot – excels at finding current news/fast • Northern Light – group results by subject, type, source, and language

  14. Two with the Broadest Coverage HOTBOT ALTAVISTA

  15. Directories YAHOO Sites are organized by content category

  16. Metasearch Engines MetaCrawler Dogpile Software that searches the search engines

  17. Boolean Logic AND NOT Narrowing the search OR

  18. And you might not You might Do I have access to the World Wide Web?

  19. World Wide Web(WWW) • provides a uniform type of access to all Internet services • A type of GUI (graphical user interface) • Characterized by HTML

  20. HTMLhypertext markup language • Hypertext – allows access to other addresses by pointing and clicking on a picture or text • The address is attached through the code of the hypertext format • <A HREF = www.whitehouse.gov main menu </A> main menu is the text which should be highlighted to access this address

  21. Other HTML symbols • <HTML> </HTML> • Goes at the beginning of the document and at the end to define it as using hypertext protocol • <HEAD> </HEAD> • Beginning and end of heading section • <B> </B> • Beginning and end of bold text

  22. If a website does not use the World Wide Web, it still has the same services. Access is no longer through graphics. Access is now done through a series of menu options. Important point.

  23. JAVA • A programming that allows permits dynamic Web pages

  24. dancing icons sound clips flashing messages scrolling banners applets – programs that provide code for these features ActiveX controls – Microsoft feature that provides the same features Allows the following:

  25. WARNINGS Must have a browser that is capable of running these applets Applets present some security risks.

  26. Disadvantage Not as user friendly. Advantage Downloading time will be less. Not downloading pictures, colors, etc.

  27. Internet Addresses URL’s (uniform resource locators) Each is an IP number. www.whitehouse.gov

  28. COM GOV NET ORG MIL EDU Six Domains

  29. BIZ UK PRO NAME AERO DE COOP INFO MUSEUM Other Domains Country designators

  30. COM GOV NET ORG MIL EDU Each Domain is a SERVER.

  31. NETWORK of DOMAINSCreatesA MESH TOPOLOGY

  32. WWW.WHITEHOUSE.MAJORDOMO.GOV Individual computer DOMAIN Defines use of hypertext protocol Subdivision of the individual computer

  33. http://www.fdu.edu/pwagner.html Individual computer DOMAIN Defines use of hypertext protocol File (web page) to get

  34. Wireless Internet Access • Types of devices • Text pagers • PDAs – personal digital assistants • Pocket computers • Web enabled cellular phones

  35. Wireless Internet Access • Additional hardware/software needed: • Account with wireless access service provider • Cellular modem card or adapter • Problem – limited display area • Wireless Application Protocol – used by providers to convert Web pages to capabilities of hand held devices

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