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Data Communications and the Cloud

Chapter 6. Data Communications and the Cloud. Study Questions. Q1: What is a computer network? Q2: What are the components of a LAN? Q3: What are the fundamental concepts you should know about the Internet? Q4: What processing occurs on a typical Web server?

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Data Communications and the Cloud

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  1. Chapter 6 Data Communications and the Cloud

  2. Study Questions Q1: What is a computer network? Q2: What are the components of a LAN? Q3: What are the fundamental concepts you should know about the Internet? Q4: What processing occurs on a typical Web server? Q5: Why is the cloud the future for most organizations? Q6: How does this chapter help you?

  3. Q1: What Is a Computer Network? Network • Collection of computers that communicate with one another over wired and wireless transmission media. Major types of network topologies Others include PAN, HAN, MAN, SAN, CAN, etc.

  4. Q2: What Are the Components of a LAN?

  5. WANs Connects computers across metropolitan, state, regional, national areas Uses communication networks from vendors Licensed by government

  6. Wired Connectivity Switch • Special purpose computer that receives and transmits messages Gateway Network interface card (NIC) UTP (unshielded twisted pair) Optical fiber cable

  7. IEEE 802.11 Protocol LAN Protocol IEEE 802.3 Protocol Wireless LAN Wired LAN Most popular 802.11g (2010) 10/100/1000 Mbps Ethernet*1 2 4 Bluetooth802.15.1 • Common wireless protocol for transmitting data over short distances—wireless mice and keyboards, cell phones Protocol specifies hardware characteristics, cables, and how messages are packaged and processed *: Gigabit Ethernet, 10 gigabit Ethernet between network switches for WAN

  8. Three Common Alternatives for Connecting a SOHO to the Internet

  9. What Are the Alternatives for a WAN? • 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

  10. DSL and Cable Internet Access

  11. DSL Modems Operates over telephone lines Data signals do not interfere with voice telephone service 256 kbps to 40 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) DSL Router = Modem + Router

  12. Cable Modems (IEEE 802.14) 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 run to subscribers home or business. Does not interfere with television transmission. • Up to 500 users share facility • Performance varies based on number of people connected • Download speed up to 50 Mbps, upload up to 512 kbps Cable Modem Flap: Connection problems.

  13. WAN Wireless Connection (WWAN) Amazon’s Kindle uses a Sprint wireless network to provide wireless data connections Variety of WAN wireless protocols exist. Sprint and Verizon use EVDO (based on CDMA2000); AT&T supports iPhone and T-Mobile use HSDPA (3G+); WiMax (802.16e, 4G) 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 speed <= 56 kbps vs. <=4mbps Broadband lines speeds in excess of 256 kbps by OECD EVDO: Evolution-Data Optimized WiMax: Worldwide Interoperability for Microwave Access

  14. Q3: What Are the Fundamental Concepts You Should Know About the Internet? Using the Internet for a Hotel Reservation Gateway: including protocol translators, rate convertors, and signal translators to insure system interoperability

  15. Key Digital Networking Technologies • Client/server computing • Packet Switching • TCP/IP connectivity

  16. Packed-Switched Networks and Packet Communications

  17. TCP/IP Architecture (Model) Internet Protocol Suite

  18. Application Layer Protocols Hyper Text Transfer Protocol (HTTP) • Protocol used between browsers and web servers. Simple Mail Transfer Protocol (SMTP) • Used for email transmissions. File Transfer Protocol (FTP) • 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. How about HTTPS?

  19. TCP and IP Protocols TCP or Transmission Control Protocol • Breaks traffic up into data packets and sends each packet along its way (reliable and ordered data packets) IP(Internet Protocol) • Specifies routing of pieces of data communication through networks that comprise any Internet • Packet is 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 (i.e., IPv4, IPv6)

  20. 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 • Major benefits • Public IP: All devices on LAN share a public IP address • Private IP address, need not register device with ICANN-approved agencies

  21. 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 • Converting between Analog and Digital • Assigning private IP addresses • Converting IP address between private and public IP addresses • Routing packets • And more…

  22. Use of Private IP Addresses Source: http://www.broadband-help.com/articles/networking/networking-guide-part2-tcpip-explained#b10

  23. Public IP Addresses and Domain Names • IPv4Supports (232) or 4,294,967,296 addresses • Four decimal dotted notation like 165.193.123.253 • IPv6 - Supports 2128 addresses Domain name • Unique name affiliated with public IP address URL (Uniform Resource Locator)http:// or ftp:// Domain Registrar Co. IPv6 Example: 2001:0DB8:AC10:FE01:: 2001:0DB8:AC10:FE01:0:0:0:0

  24. The Domain Name System

  25. Q4. What processing occurs on a typical Web server? Three-Tier Architecture

  26. Sample of Commerce Server Page

  27. Web Farm Servers (cluster of servers) Web servers • Programs that run on a server tier computer • Manage HTTP traffic by sending and receiving web pages to and from clients Commerce servers • Application programs that run on a server tier computer • Receives requests from users via web server, takes some action, and returns a response to users via the web server Microsoft Commerce Server 2009: create e-commerce solutions and Web sites that simplify setup, management, and administration tasks.

  28. Hypertext Markup Language (HTML)

  29. 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, other advanced graphics inside a browser • New version of HTML supports animation, movies, and graphics HTML 5.0 Adobe Flash, Microsoft Silverlight

  30. How Do Organizations Benefit From Virtual Private Networks (VPNs) Virtual private network • Uses Internet or private network to create appearance of point-to-point connections • Uses public Internet to create appearance of private network VPNs can connect individual users to a remote network or connect multiple networks together.

  31. WAN Using VPN Remote Access: Actual Connections Remote Client (Apparent connection) Actual connections (P2P leased lines*) *: A dedicated circuit connecting two end points for transferring and sharing data between them.

  32. Remote Access Using VPN: Apparent Connection Remote user perspective

  33. WAN Using VPN

  34. Q5: Why Is the Cloud the Future for Most Organizations? • What is the Cloud? • Elastic leasing of pooled computer resources over the Internet • Elastic? • Dynamically increasing/decreasing leased resources programmatically in short time span, and only pay for resources used

  35. Apple Data Center in Maiden, NC

  36. Why Is the Cloud Preferred to In-House Hosting?

  37. Why Is the Cloud Preferred to In-House Hosting? (cont’d)

  38. Why Now? • Technology now supports construction and use of enormous data centers • Processors, data communication, data storage nearly free • Web farms providing virtual machine for about 1.5¢ per hour • Virtual Private Server (VPS)

  39. When Does the Cloud Not Make Sense? • Law or industry standard practices require physical control over the data • Private cloud • In-house hosting, delivered via Web service standards • Community Cloud

  40. How Can Organizations Use the Cloud? Three Fundamental Cloud Type

  41. How Does the Knowledge In This Chapter Help You? • Provides general knowledge needed by business professionals • Helps you develop project plans and budgets involving IT and data communications • Helps you be a better consumer of IT services • Helps you understand how your organization can weave cloud-based applications into its strategy

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