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Chapter 0 Computers and the Internet

Chapter 0 Computers and the Internet. Chin-Shiuh Shieh ( 謝欽旭 ) http://bit.kuas.edu.tw/~csshieh D epartment of Electronic Engineering National Kaohsiung University of Applied Sciences, Taiwan. Outline. What are computers? Why computer networks? What are computer networks? The Internet

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Chapter 0 Computers and the Internet

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  1. Chapter 0Computers and the Internet Chin-Shiuh Shieh (謝欽旭) http://bit.kuas.edu.tw/~csshieh Department of Electronic Engineering National Kaohsiung University of Applied Sciences, Taiwan C.-S. Shieh, EC, KUAS, Taiwan

  2. Outline • What are computers? • Why computer networks? • What are computer networks? • The Internet • Evolution of connections • Applications C.-S. Shieh, EC, KUAS, Taiwan

  3. What Are Computers? • Computers are powerful tools for (generalized) computation • Numerical analysis, database, document processing, control, gaming, … • Computers are fast, precise, and highly flexible. • Complementary roles between man and machine • Human being: Thinking, innovating, … • Machine: Data processing, computation, … C.-S. Shieh, EC, KUAS, Taiwan

  4. Why Computer Networks? • A single computer, however powerful, is an isolated island. • A computer can increase its power by communicating with others: • More information, more computing power, more reliable service, … • Computer networks allow for information exchange at the speed of light. C.-S. Shieh, EC, KUAS, Taiwan

  5. What Are Computer Networks? • Computer networks consist of • Physical connections: • Cable, optical fiber, radio channel, … • Communication protocols: • Defining the format, timing of signals/packets at different layers. • Different protocols make different network systems. • Applications: • Client/server programs for different services. C.-S. Shieh, EC, KUAS, Taiwan

  6. What Are Computer Networks? (cont) • Directions of the evolvement of computer networks • Local Area Network (LAN) for file/printer sharing, such as Microsoft Network Neighborhood. • Wide Area Network (WAN) for global communications, such as the Internet. • The boundary is getting blurred. C.-S. Shieh, EC, KUAS, Taiwan

  7. The Internet • The Internet • A global network with the interconnection of hosts/networks running TCP/IP. • TCP/IP is a free/open standard. Any manufactures can incorporate it into their products. • Cross-platform with global coverage. C.-S. Shieh, EC, KUAS, Taiwan

  8. The Internet (cont) C.-S. Shieh, EC, KUAS, Taiwan

  9. The Internet (cont) C.-S. Shieh, EC, KUAS, Taiwan

  10. The Internet (cont) C.-S. Shieh, EC, KUAS, Taiwan

  11. The Internet (cont) • Typical applications • E-mail, remote login, file transfer, world-wide-web, remote control, instant message, voice over IP, video conference, blog, social network, … • Possible applications are limited only by one’s imagination. • All node on Internet are born to be equal. To be a client or a server depends on your decision. C.-S. Shieh, EC, KUAS, Taiwan

  12. The Internet (cont) • Service paradigms • Client-server architecture • Peer-to-peer architecture • Hybrid architecture C.-S. Shieh, EC, KUAS, Taiwan

  13. 6. Request for a particular web page. 4. Client machine is powered on and connected to Internet when necessary. 3. Web pages to be served are placed on server. 7. Response with requested web page. The Internet (cont) 1. Server machine is powered on and connected to Internet all the time. • Client-server architecture 2. HTTP server (web server), such as apache, is running on server machine. Internet 5. HTTP client (browser), such as Internet Explorer, is invoked. 8. HTTP client parses and displays web pages on screen. C.-S. Shieh, EC, KUAS, Taiwan

  14. Evolution of Connections • Core • Frame-relay • ATM • … • Edge (last mile) • Modem • ADSL • Cable-TV • Ethernet • 802.11 • 3G/UMTS • WiMAX • … Cited from James F. Kurose and Keith W. Ross, Computer Networking: A Top-Down Approach Featuring the Internet, 2nd Ed., Addison Wesley C.-S. Shieh, EC, KUAS, Taiwan

  15. Evolution of Connections (cont) • Modem • Using voice band (<4K Hz) • V.92 at 56Kbps • Free for now Internet Public Switching Telephone Network modem modem PSTN Internet Service Provider C.-S. Shieh, EC, KUAS, Taiwan

  16. Evolution of Connections (cont) • ADSL (Asymmetric Digital Subscriber Line ) • Using band beyond voice (>4K Hz) • ADSL modem, Ethernet card • 1M/64K, 2M/256K, 8M/640K, … • 2M/256K at NT$840 per month (Hinet) C.-S. Shieh, EC, KUAS, Taiwan

  17. Evolution of Connections (cont) • Cable-TV • Using channels not for casting • Cable modem • 1.5M/64K, 3M/256K, 6M/256K, … • 3M/256K at NT$850 per month (Giga.net) C.-S. Shieh, EC, KUAS, Taiwan

  18. Evolution of Connections (cont) • Ethernet • Ethernet card, hub, switching hub • 10Mbps, 100Mbps, 1000Mbps • Carrier Sense Multiple Access with Collision Detection (CSMA/CD) C.-S. Shieh, EC, KUAS, Taiwan

  19. Evolution of Connections (cont) Ethernet LAN Ethernet LAN Internet Ethernet LAN router hub hub switching hub C.-S. Shieh, EC, KUAS, Taiwan

  20. Evolution of Connections (cont • IEEE 802.11 • Wireless LAN, Wi-Fi • 802.11 wireless network card, access point • 11Mbps (802.11b), 55Mbps (802.11g) • Tens of meters or next two doors • Wireless extension to Ethernet C.-S. Shieh, EC, KUAS, Taiwan

  21. Evolution of Connections (cont) Internet access point router hub hub switching hub C.-S. Shieh, EC, KUAS, Taiwan

  22. GSM/GPRS UMTS Evolution of Connections (cont) • Networking via Mobile Phone Systems Gateway Internet Gateway C.-S. Shieh, EC, KUAS, Taiwan

  23. Evolution of Connections (cont) • Networking via Mobile Phone Systems • 1G: Advanced Mobile Phone System • 2G: GSM (Global System for Mobile Communication) • Circuit-switched • 14.4 Kbps • 2.5G: GPRS (General packet Radio Service) • Packet-switched • 160Kbps (30-80 Kbps in practice) C.-S. Shieh, EC, KUAS, Taiwan

  24. Evolution of Connections (cont) • 3G: UMTS (Universal Mobile Telecommunication System) • 1920 Kbps (384 Kbps in practice) • 3.5G: HSDPA (High Speed downlink Packet Access) • 14.4 Mbps C.-S. Shieh, EC, KUAS, Taiwan

  25. Evolution of Connections (cont) • WiMAX • Worldwide Interoperability for Microwave Access, 中文譯名為「無線都會區域網路」 • IEEE 802.16-2004 (WiMAX), IEEE 802.16e (Mobile WiMAX) • Up to 75Mbps, 50Km, Wireless MAN (Metropolitan Area Network) • Last mile alternative to cable and DSL • Scheduling MAC (Media Access Control), OFDM (Orthogonal Frequency Division Modulation) • 行政院經濟部「台灣WiMAX發展藍圖」, 「WiMAX加速計畫」 C.-S. Shieh, EC, KUAS, Taiwan

  26. C.-S. Shieh, EC, KUAS, Taiwan

  27. Network Topology in My House IEEE 802.11 Access Point ADSL Modem 10Mbps C.-S. Shieh, EC, KUAS, Taiwan

  28. C.-S. Shieh, EC, KUAS, Taiwan

  29. Applications • Classical applications • E-mail, file transfer, remote login, bullet board system, gopher, archie, netnews, IRC (Internet Relay Chat, exchange text messages interactively with other people all over the world) , … • Attachments in E-mails allow for the transfer of files of any types. • Web-based E-mail client is convenient when you are out. C.-S. Shieh, EC, KUAS, Taiwan

  30. Applications (cont) • The raise of world-wide-web • Hyper-Text Markup Language • Presentation with multimedia, including text, graph, audio, video, animation, … • Hyperlinks for cross-reference • Integration of other services, such as E-mail, file downloading, telnet, … • Excellent platform for promotion for both enterprises and individuals. C.-S. Shieh, EC, KUAS, Taiwan

  31. Applications (cont) • Interactive technologies bring WWW into new dimensions • E-commerce, database access, web search, remote control, … • Programming is involved • JavaScript / VBScript at client end • Active Server Page (ASP, Microsoft) / PHP: Hypertext Preprocessor at server end • Common Gateway Interface Programming (CGI) C.-S. Shieh, EC, KUAS, Taiwan

  32. Applications (cont) • Web 2.0 • Not a brand new technology, but a new concept • blogs and wikis • A wiki is a type of website that allows users to easily add, remove, or otherwise edit and change some available content, sometimes without the need for registration "Wiki-wiki" means "hurry quick" in Hawaiian. It also refers to a type of native fish of the islands (from wikiapedia). C.-S. Shieh, EC, KUAS, Taiwan

  33. Applications (cont) • Users turn their roles from audiences to authors • 人人皆可著書立說 • Web 3.0 • Social networks C.-S. Shieh, EC, KUAS, Taiwan

  34. Applications (cont) • Recent applications • Instant message • Voice over IP • Multimedia streaming • Remote login, Wake-On-LAN • P2P • Cloud Computing • App • … C.-S. Shieh, EC, KUAS, Taiwan

  35. Applications (cont) • Instant message • Microsoft MSN Messenger, Yahoo Messenger, ICQ, … • Presence service • Text chatting, voice conference, video conference, file transfer, … C.-S. Shieh, EC, KUAS, Taiwan

  36. 1. Alice login 2. Bob login 3. Bob is online 3. Alice is online 4. Text chatting, voice conference, video conference, file transfer, … Alice Applications (cont) Presence Server Internet Bob C.-S. Shieh, EC, KUAS, Taiwan

  37. Applications (cont) • Voice over IP • Skype, Microsoft MSN Messenger, Google Talk, … • Presence service, gateway to PSTN, GSM • Free for PC-to-PC • Charged for PC-to-Phone (Skype Out) • € 0.017 per minute to USA, UK, Taiwan, China, … • € 0.082 per minute to Taiwan mobile • http://www.skype.com/intl/zh-Hant/products/skypeout/rates/all_rates.html C.-S. Shieh, EC, KUAS, Taiwan

  38. Alice Applications (cont) Skype Out GSM/3G Gateway Presence Server PSTN David Gateway Internet Cindy Bob C.-S. Shieh, EC, KUAS, Taiwan

  39. Applications (cont) • Video on Demand • Real-time Streming • Multimedia casting • Network radio, network TV, Web-TV… • EZTV v 2.018 by 全球網通科技 C.-S. Shieh, EC, KUAS, Taiwan

  40. Applications (cont) • Live casting • SimpleCam v1.3 by Dead Pirate Software • For surveillance or just show off C.-S. Shieh, EC, KUAS, Taiwan

  41. Applications (cont) • Remote login • Telent is a text-based remote login. • SSH is a secure replacement of telnet. • Remote login with graphic user interface (GUI) • Remote Desktop for Microsoft Windows • Virtual Network Computing (VNC), TeamView for cross-platform • As if you are in front of the target machine. C.-S. Shieh, EC, KUAS, Taiwan

  42. Remote login Applications (cont) Internet C.-S. Shieh, EC, KUAS, Taiwan

  43. connect to VPN Applications (cont) • Virtual Private Network (VPN) • As if you and your machine are in the target domain • For access of restricted data in the target domain Internet hub VPN server C.-S. Shieh, EC, KUAS, Taiwan

  44. Applications (cont) • Peer-to-Peer (P2P) applications • Each node acts both as a client and a server • Distribution of large files • eMule, BitTorrent, … • Warning: illegal use of legal applications C.-S. Shieh, EC, KUAS, Taiwan

  45. Applications (cont) C.-S. Shieh, EC, KUAS, Taiwan

  46. Applications (cont) C.-S. Shieh, EC, KUAS, Taiwan

  47. Applications (cont) C.-S. Shieh, EC, KUAS, Taiwan

  48. Applications (cont) C.-S. Shieh, EC, KUAS, Taiwan

  49. Applications (cont) C.-S. Shieh, EC, KUAS, Taiwan

  50. Cloud Computing • Free E-mail service • Google service • 通訊錄, 工作表, 日曆, … • Cloud Storage • Dropbox • Cloud Computing C.-S. Shieh, EC, KUAS, Taiwan

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