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  1. Using MIS 4eChapter 6 Data Communication

  2. This Could Happen to You: “$175,000 to Hook Up a Computer?” Wired vs. Wireless? What devices are needed? How much will it cost? Where to start? Scenario Video Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  3. Study Questions Q1: What is a computer network? Q2: What are the components of a LAN? Q3: What are the alternatives for connecting to a WAN? Q4: What are the fundamental concepts you should know about the Internet Q5: What processing occurs on a typical web server? Q6: How do organizations benefit from virtual private networks (VPNs) and firewalls? Q7: 2021? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  4. Q1: What Is a Computer Network? Network • Collection of computers • Communicate with one another over transmission line Basic types of Network Topologies Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  5. WANs Connects computers across metropolitan, state, regional, national areas Uses communication networks from vendors Licensed by government Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  6. Internet Seamless flow of data provided by standardized layered Protocol Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  7. Internets and the Internet “Internets” connect LANs, WANs, and private internets “The Internet” (with an uppercase letter I), is a collection of public networks used when you send email or access a website Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  8. Ethics Guide: Personal Work at Work Scenario A • You email 12 pictures of your surfing skills from New Zealand to a friend who works at some company in Ohio. • Each picture is 6.2 megabytes in size. • Packets of email and picture transmitted to Ohio company router and from router to its email server. Your message consumed processing cycles on router and email server. A copy of your pictures stored on email server until your friend deletes them. • Friend uses company LAN to download the pictures to his desktop computer. • Friend reads his email during his working hours. Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  9. Scenario A Questions Is it ethical for you to send the email and picture to your friend at work? Does your answer to question 1 change depending on size of pictures? Does your answer change if you send 100 pictures? If you send 1,000 pictures? If your answer does change, where do you draw the line? Once pictures are stored on company’s email server, who owns pictures? Who controls those pictures? Does Ohio company have right to inspect contents of its employees’ mailboxes? If so, what should managers do when they find your pictures that have absolutely nothing to do with company’s business? What is greater cost to your friend’s company: Cost of infrastructure to transmit and store your email or cost of time your friend takes at work to read and view your pictures? Does this consideration change any of your answers above? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  10. Ethics Guide: Personal Work at Work Scenario B: Pictures not emailed [Update: 2008] You use Facebook page for photos. A friend uses his computer to view them. Pictures no longer stored on company’s servers, but they are still being transmitted over its data communications network Scenario C: Cell phone used [Update: 2010] Assume friend uses his cell phone or iPad with a WAN wireless connection to read your Facebook page and tweets. Then, he is not using any of his company’s data communications network – just using company time. Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  11. Questions for Scenarios B and C How does 2008 update change ethics of situation? Is it ethical for your friend to read and update Facebook using company’s computers? How does 2010 update change ethics of situation? Is it any of company’s business what your friend does with his iPhone or other device at work? Describe a reasonable policy for computer/phone/ communicating device use at work. Consider email, Facebook, and Twitter as well as 2008 and 2010 updates. Endeavor to develop a policy that will be robust in likely data communication changes in future. Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  12. Q2: What Are the Components of a LAN? Typical Small Office/Home Office (SOHO) LAN Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  13. Wired Connectivity Switch • Special purpose computer that receives and transmits messages Gateway Network interface card (NIC) UTP (unshielded twisted pair) Optical fiber cable Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  14. IEEE 802.11 Protocol LAN Protocol IEEE 802.3 Protocol Wireless LAN Wired LAN Most popular 802.11g (2010) 10/100/1000 Mbps Ethernet Bluetooth • Common wireless protocol for transmitting data over short distances, wireless mice, keyboards, and cell phones Protocol specifies hardware characteristics, cables, and how messages are packaged and processed Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  15. Summary of LAN and WAN Networks Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  16. Q3: What Are the Alternatives for Connecting to a WAN? WANs connect computers at separate sites • Use routers and public communications links between sites • Cable connections made through licensed public telecommunications companies Internet service provider (ISP) • A company that provides customers access to the Internet • Provides legitimate Internet address • Serves as gateway to Internet • You pay for Internet access Alternatives for a WAN (video) Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  17. What Are the Alternatives for a WAN? Connecting personal computers to ISP requires digital signals coming out of computer are converted to analog signals. Analog signals coming into a personal computer must be converted to digital signals. Analog vs. Digital Signals Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  18. Personal Computer (PC) Internet Access Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  19. DSL Modems Operates over telephone lines Data signals do not interfere with voice telephone service 256 kbps to 6.544 Mbps Digital Subscriber Line (DSL) Faster data transmission than dial-up Asymmetric digital subscriber lines (ADSL) DSL modems use their own protocols Download and upload speeds differ Symmetrical digital subscriber lines (SDSL) Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  20. Cable Modems Provide high-speed data transmission Use cable television lines • High-capacity optical fiber cable to neighborhood • Optical fiber cable connects to regular cable-television cables that run to subscribers home or business. Does not interfere with television transmission • Up to 500 users share a line • Performance varies based on number of people connected • Download speed up to 50 Mbps, upload up to 512 kbps Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  21. WAN Wireless Connection Amazon’s Kindle uses a Sprint wireless network to provide wireless data connections Variety of WAN wireless protocols exist. Sprint and Verizon use EVDO; AT&T supports iPhone and T-Mobile use HSDPA; WiMax by Clearwire WAN wireless provides average performance of 500 kbps, with peaks of up to 1.7 Mbps, as opposed to the typical 50 Mbps for LAN wireless Narrowband lines transmission speeds less than 56 kbps Broadband lines speeds in excess of 256 kbps Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  22. Q4: What Are the Fundamental Concepts You Should Know About the Internet? Using the Internet for a Hotel Reservation Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  23. TCP/IP Protocol Architecture Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  24. Application Layer Protocols Hyper Text Transport Protocol (http) • Protocol used between browsers and web servers SMTP or Simple Mail Transfer Protocol • Used for email transmissions ftp or File Transfer Protocol • Used to move files over Internet • Web- Internet-based network of browsers and servers that process http or https. When you use ftp or smtp, you are using Internet, not web. Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  25. TCP and IP Protocols TCP or Transmission Control Protocol • Breaks traffic up into pieces and send each piece along its way IP(Internet Protocol) • Specifies routing of pieces of data communication through networks that comprise any internet • Packetis a piece of a message that is handled by programs that implement IP. • Router is a special purpose computer that moves packet traffic according to rules of IP protocol Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  26. IP Addressing Public IP Addresses • Identify a particular device on public Internet • Public IP addresses must be unique, worldwide • Assignment controlled by ICANN(Internet Corporation for Assigned Names and Numbers) Private IP Addresses • Identify a particular device on a private network, usually on a LAN Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  27. Use of Private IP Addresses Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  28. Functions of the LAN Device • Switch processing IEEE 802.3 wired LAN traffic • Access-point processing IEEE 802.11 wireless LAN traffic • Translating between IEEE 802.3 and IEEE 802.11 • Modem converting between analog and digital • Server that assigns private IP addresses assigning private IP addresses • Private/public IP address translation converting between private and public IP addresses • Internet router routing packets Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  29. Q5: What Processing Occurs on a TypicalWeb Server? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  30. Watch the Three Tiers in Action! Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  31. Hypertext Markup Language (HTML) Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  32. XML, Flash, Silverlight, HTML 5 XML (eXtensible Markup Language) • Fixes several HTML deficiencies • Program-to-program interaction over web Flash and Silverlight • Add-ons to browsers • Provides animation, movies, and other advanced graphics inside a browser • New version of HTML supports animation, movies, and graphics HTML 5.0 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  33. Q6: How Do Organizations Benefit FromVirtual Private Networks and Firewalls? Remote Access Using VPN; Apparent Connection Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  34. WAN Using VPN Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  35. Firewalls Outside organizational network Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  36. Packet-Filtering Firewall Capabilities Prohibit outsiders from starting a session with any user behind firewall Disallow traffic from particular sites, such as known hacker addresses Prohibit traffic from legitimate, but unwanted, addresses, such as competitors’ computers Filter outbound traffic Keep employees from accessing specific sites: Competitors’ sites, sites with pornographic material, or popular news sites Access control list (ACL), encodes rules stating which addresses allowed and which prohibited Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  37. Q7: 2021? ISPs will charge based on number of bits sent and received. More states will collect sales taxes on Internet purchases regardless of whether seller has physical presence in the state. (Streamlined Sales Tax Project) Ubiquitous connectivity and interconnectivity (Microsoft Office Communicator). Receiving email via phone (a voice will read it to you), and phone via email (a voice-recognition system will type it). All messages, of whatever medium, will be stored in one location. Telediagnosis, telesurgery, telelaw enforcement: Remote systems in dangerous locations; tele-action in lower-value services. Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  38. Guide: Thinking Exponentially Is Not Possible, But… Nathan Myhrvold claimed that humans: • Cannot think exponentially • Think of fastest linear change and extrapolate from there Was writing about growth of magnetic storage Applies to growth of computer network phenomena Ubiquitous and cheap connectivity is growing exponentially • What are the threats and opportunities? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  39. Guide: Thinking Exponentially Is Not Possible, But…(cont’d) Social progress occurs in small, evolutionary, adaptive steps Technology doesn’t drive people to do new things (?) Technology may enable a capability, but people may not want it • People want to do what they are doing more easily • They want to solve existing problems Respond by hedging your bets The more time involved, the more potential for error Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  40. Ethics Guide: Human Networks Matter More Six degrees of separation • Social networks are crucial in connecting you to everyone in six degrees • In general, people you know least contribute most to your network Build personal social networks for success • Someone, somewhere, you need to know or will need to know • Meet people at professional and social situations • Pass out and collect business cards • Converse to expand network • Look for new channels Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  41. Active Review Q1: What is a computer network? Q2: What are the components of a LAN? Q3: What are the alternatives for connecting to a WAN? Q4: What are the fundamental concepts you should know about the Internet Q5: What processing occurs on a typical web server? Q6: How do organizations benefit from virtual private networks (VPNs) and firewalls? Q7: 2021? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  42. Case Study 6: Keeping Up with Wireless WiMax—a standards-based technology for wireless broadband access, alternative to cable and DSL Internet access (How WiMax works) Last-mile problem—getting broadband access into homes and small businesses WiMax Forum CertifiedTM systems to have capacity of 40 Mbps per channel, for fixed, nomadic, portable, and mobile applications IEEE 802.16-2004 and IEEE 802.16e wireless standards Clearwire and Craig McCaw Wireless Broadband Introduction (education) Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  43. Case Study 6: Keeping Up with Wireless Substantial portions of the knowledge you gain from this chapter will be obsolete within the first 5 years of your career. What is the problem of the last mile? The bottleneck on data communications into homes, and into smaller businesses, is the last mile. Problem with optical fiber infrastructure—it cannot be used by mobile devices. WiMax standard includes two usage models—fixed and mobile. Former akin to LAN wireless in existence today; latter for mobile access. Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  44. Case Study 6: Keeping Up with Wireless (cont’d) December 1, 2008, Clearwire merged with Sprint Nextel and received a $3.2 billion outside investment. Clearwire gained access to Sprint Nextel’s spectrum holdings Products are marketed as Sprint Xohm • List five possible commercial applications for mobile WiMax. Consider applications that necessitate mobility. • Select the three most promising applications and justify your selection. • Explain why Clearwire share price has dropped since 2007. Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall

  45. Case Study 6: Keeping Up with Wireless (cont’d) Search the web for LTE versus WiMax comparisons and compare and contrast these two technologies. Where will this end? On which of these technologies would you be willing to invest $100 million? Why? Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall