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Lecture 13 Networks

Lecture 13 Networks. Computer Communications. Process in which Two or More Computers or Devices Transfer Data, Instructions, and Information. Definitions. Communication Is the Act of Transmitting A System for Communication The Technology for the Transmission of Data

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Lecture 13 Networks

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  1. Lecture 13 Networks

  2. Computer Communications Process in which Two or More Computers or Devices Transfer Data, Instructions, and Information

  3. Definitions Communication Is the Act of Transmitting A System for Communication The Technology for the Transmission of Data Telecommunications Is Any Form of Electronic Communication A Network Is any Facility for Electronic Communication between Computers

  4. Networks • Collection of Interconnected Computers and Hardware Devices • Improves Communication • Allows Mutual Hardware Components • Permits Data and Software Sharing

  5. Communication Network

  6. Network Applications • Internet • Television and Radio Broadcasting • Telephone Service • Video Conferencing • Telemedicine • Global Positioning Systems (GPS) • Inventory Monitoring Systems

  7. Personal Uses Text Messaging (Short Message System) Send/Receive Short Text Message Picture Messaging Send/Receive Picture and Sound Files Video Messaging Send/receive Short Video Clips

  8. Business Uses Means to Collaborate with Other Users Online Meetings Web Conferences Document Management Systems

  9. Network Architecture • Components Necessary to Operate the Enterprise Computer Systems • Physical Devices • Software Applications • Enterprise Services • Human and Technical Capabilities

  10. Infrastructure Eras Text

  11. Network Architecture Provides the Foundation for Serving Customers Working with Vendors Managing Business Processes

  12. Client-Server Networks • Client • Computer or Other Device on the Network that Requests and Utilizes Network Resources • Server • Computer Dedicated to Processing Client Requests

  13. Client-Server Network

  14. Peer-to-Peer Network Central Server Is Not Used All Computers on the Network Work at the Same Functional Level Direct Access to the Computers and Devices Attached to the Network Less Complicated and Less Expensive than Client-Server Networks

  15. Peer-to-Peer Network

  16. Network Characteristics PAN - Personal Area Network Connects Individual Personal Devices LAN - Local Area Network Limited Geographical Area MAN - Metropolitan Area Network Covers a Metropolitan Area WAN - Wide Area Network Connect LANs over Large Physical Area

  17. Types of Networks • Intranet • Private Network Designed to Be Used by an Organizations’ Employees • Set Up Like the Internet • Extranet • Network that Is Accessible by Authorized Outsiders

  18. Types of Networks • Virtual Private Networks (VPNs) • Secure Path that Provides Authorized Users a Secure Means of Accessing a Private Network Via the Internet • Internet • Most Well-known Computer Network Linking Millions of Computers Globally

  19. Public Network Access Wireless Access Point (WAP) Usually Public Location Cybercafé Provides Computers and Access

  20. Networks - Intranet - Internet • Local Area Network • Company Owns Infrastructure • Wide Area Network • Use Public or Private Infrastructure • Intranet • Data Access Limited to Company • Internet • Data Access to Public

  21. LAN Topologies Topologies - The Physical Configurations of Local Area Computer Networks Three Major Configurations Bus Ring or Token Ring Star or Hub

  22. Bus Topology Easiest Configuration to Implement Least Expensive Topology Nodes Connected to a Common Cable Called the “Bus” Data Packets Received by all Nodes Processed by the Addressed Node Only One Node Transmits at a Time Otherwise Data Collision Occurs

  23. Bus Network

  24. (Token) Ring Topology Next Easiest Configuration to Implement Second in Topology Costs Computers and Peripherals Connected in a Circular Ring Data Packets Circulate Only One Way One Node Can Monopolize the System Circulates a Special Code (Token) Node Can Only Transmit When in Possession of the Token

  25. (Token) Ring Network

  26. Star (Hub) Topology The Most Complex to Implement The Most Expensive Topology All Data Packets Are Sent to a Central Switching Point The Hub Hub Serves as a Main Data Store Best Configuration for Companies

  27. Star (Hub) Network

  28. Data Transmission • Bandwidth • The Amount of Data that Can Be Transferred in a Given Period of Time • Measured in Bits Per Second (bps) • Kilobits Per Second (Kbps) • Megabits per Second (Mbps) • Gigabits per Second (Gbps) • Terabits per Second (Tbps)

  29. Data Transmission • Serial Data Transmission • Data Sent One Bit at a Time Along a Single Path • Parallel Data Transmission • Data Sent at Least 8 Bits at a Time with Each Bit Along a Different Path • 32-bit and 64-bit Systems

  30. Data Transmission

  31. Data Transmission • Synchronous Transmissions • Blocks of Data Transferred Between Computers at Specified Intervals • Asynchronous Transmission • Data Is Sent at Non-specific Intervals • Contain Start and Stop Bits Used to Identify Each Byte

  32. Data Transmission

  33. Wired Transmission Media • Twisted Pair • Traditional Media Used with Telephones • Coaxial Cable • Basic Configuration for AT&T's Network • Optical Fiber • Data Transferred in Optical Form

  34. Twisted-Pair Cable

  35. Coaxial Cable

  36. Optical Fiber

  37. Wireless Transmission Media • Data Sent Through Airwaves Radio Signals • Microwave • Line of Sight (ca. 30 miles) • Satellite • Geostationary Orbit (22,300 miles) • Bluetooth • Low-cost Short-range (max. 200 feet)

  38. Microwave

  39. Satellite

  40. Bluetooth

  41. Network Protocols • Protocol • Set of Rules for a Particular Situation • Communications Protocol • Rules that Determine How Devices on a Network Communicate • Computer Devices Cannot Transfer Data without Using a Same Protocol

  42. TCP/IP Protocol • Widely Used Communications Protocol • Built into Most Operating Systems • Used to Identify Computers and Devices on Networks • Consists of Two Protocols • Transmission Control Protocols (TCP) • Responsible for Delivery of Data • Internet Protocols (IP) • Addressing and Routing Information

  43. Internet Protocols • For Displaying Web Pages • HTTP: Hypertext Transfer Protocol • HTTPS: HTTP Secure • For Transferring Files Over the Internet • FTP: File Transfer Protocol • For Delivering E-mail Over the Internet • SMTP: Simple Mail Transfer Protocol • POP3: Post Office Protocol 3 • IMAP: Internet Message Access Protocol

  44. Network Standards • Standard • Criteria (Requirements) Approved by a Recognized Standards Organization • Networking Standards • Address How Networked Computers Connect and Communicate • Needed to Ensure Products Can Work with Other Products

  45. Ethernet (802.3) • Widely Used Standard for Wired Networks • Typically Used with Star Topology • Continually Evolving • Most Common Today • Fast Ethernet • Gigabit Ethernet • 10 – 40 – 100 Gigabit Ethernet

  46. Wi-Fi (802.11) • Current Standard for Wireless Networks in Homes and Offices • Medium-range Transmission • Wi-Fi Hardware Built into Most Portable Computers and Consumer Devices • Printers, Digital Cameras, E-book Readers, Televisions

  47. Wimax (802.16) • Standards for Longer Range Wireless Networking Connections • Typically MANs • Fixed Wimax • Designed To Provide Internet Access Fixed Locations (Hotzones) • Hotzone Radius: 2 to 6 Miles

  48. Wi-Fi – Wimax Standards

  49. Power over Ethernet (POE) • Allows Electrical Power and Data to be Sent Over an Ethernet Network • Used to Power Network Devices • Requires Special Hardware and Devices Designed for POE • Eliminates Need for Electrical Outlets • Similar to USB Technology Included in Many Handheld Devices

  50. Cellular Phones • 1G (First Generation) • Analog and Voice Only • 2G (Second Generation) • Digital Voice and Data – Faster • 3G (Third Generation) • Digital Voice and Data – 1.5 Mbps • 4G (Fourth Generation) • Digital Voice and Data – 3 to 12 Mbps

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