Network Technology 2 Computer Networks


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  • <click> Read first line <click> Discuss IP address <click> Discuss packets
  • Baseband – slower transmission used for just text and numeric data Broadband –simultaneously transmit large amounts and types of data
  • Network Technology 2 Computer Networks

    1. 1. Network Technology
    2. 2. Computer Networks <ul><li>A network exists whenever two or more computers are linked together through some type of medium. Computer networks have many uses: </li></ul><ul><ul><li>Sharing information and resources </li></ul></ul><ul><ul><li>Handling the present by enabling transactions and capturing/storing transaction data </li></ul></ul><ul><ul><li>Remembering the past by providing access to shared data storage </li></ul></ul><ul><ul><li>Prepare for the future by providing communications to aid decision making </li></ul></ul>
    3. 3. Computer Networks: Network Type <ul><li>Networks may be classified by size: </li></ul><ul><li>Local Area Networks (LANs) </li></ul><ul><li>Wide Area Networks (WANs) </li></ul><ul><li>The Internet </li></ul><ul><ul><li>Connections to the Internet are through: </li></ul></ul><ul><ul><ul><li>LANS </li></ul></ul></ul><ul><ul><ul><li>Internet Service Providers (ISP) </li></ul></ul></ul>
    4. 4. Computer Networks: Network Backbone Internet Customer service LAN Distribution LAN Human Resources LAN Company Backbone
    5. 5. I S P Customer’s PC Regional Network Regional Network Internet Backbone Company Lan Employee PC ISP Connection to Internet
    6. 6. Wide Area Networks (WAN) Application Software Networking Software Physical Application Software Networking Software Physical Sender Receiver
    7. 7. WAN: Application Software Layer <ul><li>The software that the user sees and uses to send and receive messages. (E-mail, Web browser, etc) </li></ul><ul><li>Formats the messages to fit a protocol </li></ul><ul><ul><li>Simple mail transfer protocol (SMTP) </li></ul></ul><ul><ul><li>Hypertext transfer protocol (HTTP) </li></ul></ul><ul><ul><li>Electronic Data Interchange (EDI) </li></ul></ul><ul><li>May also process message in other ways ( encryption for example) </li></ul>
    8. 8. WAN: Networking Software Layer <ul><li>Works behind the scenes to format the message so that it may be sent over network. </li></ul><ul><li>Popular transmission protocols include: </li></ul><ul><ul><li>Transmission control protocol/internet protocol (TCP/IP) </li></ul></ul><ul><ul><li>Ansi X 12 or Edifact </li></ul></ul><ul><ul><li>Wi-Fi </li></ul></ul>
    9. 9. WAN: TCP/IP <ul><li>The transmission protocol for the Internet: </li></ul><ul><li>Converts address of destination computer to IP address </li></ul><ul><ul><li>  </li></ul></ul><ul><li>Divides message into packets </li></ul>11001101011100110011… 11001101010 11100110011
    10. 10. WAN: Physical Layer <ul><li>Once the message is ready, it is sent out over the physical layer. </li></ul><ul><li>The physical layer includes connection devices and various transmission media. </li></ul><ul><ul><ul><li>Twisted pair (standard telephone) </li></ul></ul></ul><ul><ul><ul><li>Coaxial Cable (cable television) </li></ul></ul></ul><ul><ul><ul><li>Fiber optic cable </li></ul></ul></ul><ul><ul><ul><li>Microwaves </li></ul></ul></ul>
    11. 11. WAN: Physical Layer Moderate Low-moderate Moderate Satellite Moderate Low-moderate Moderate Microwave Low Moderate Low Infrared Low Moderate Low Radio High –very high Very low High Fiber optics Low-high Low Moderate Coaxial cable Low-high Low Low Twisted Pair Speed Error Rates Cost Media
    12. 12. WAN: Transmission Speeds Used for commercial purposes. A single T-1 line costs over $1000 per month. 1.544M-275M T-1 to T-4 Cable must support 2-way communication; available in many locations but slows down as more people use it. As high as 30M but 2.5M to 500K on average TV Cable Becoming more available; doesn’t require special equipment. Doesn’t slow down as more people sign up. 1.544 M in; 128 K out DSL Available in most urban areas but requires special adapters 128 Kbps ISDN Available everywhere 56 Kbps Standard telephone Comments Speeds Media
    13. 13. WAN: Physical Layer Routing <ul><li>Packet switching – technology used to route the individual packets through the network to their final destination </li></ul><ul><li>Router – specialized computers on the network with the sole purpose of determining the best way to send packets to destination </li></ul>
    14. 14. Sending Data over the Internet Server Computer I S P Router Router Router Packets Packets Packets Packets Packets User’s PC Router Router Router
    15. 15. WAN: Electronic Data Interchange (EDI) <ul><li>EDI is a set of protocols for submitting common business documents between business partners. </li></ul><ul><li>Uses traditional communication channels (mostly phone) </li></ul><ul><li>Reduces human involvement and paperwork </li></ul><ul><li>Often sent over Value Added Networks (VANs) </li></ul>
    16. 16. Local Area Networks (LAN) <ul><li>Two main types in use today: </li></ul><ul><li>Dedicated server networks </li></ul><ul><ul><li>Servers – computers dedicated to managing all or part of the network </li></ul></ul><ul><ul><li>Clients – computers that individuals may use to connect to the network </li></ul></ul><ul><li>Peer-to-peer networks </li></ul><ul><ul><li>Designed for smaller networks where emphasis is on sharing files between computers </li></ul></ul><ul><ul><li>Each computer functions as both a client and a server </li></ul></ul>
    17. 17. LAN Components <ul><li>Network cabling – physically connects each component to the network </li></ul><ul><li>Hub – a device that allows cables to be connected together </li></ul><ul><li>Network interface card – allows network cabling to be connected to a computer </li></ul><ul><li>Network Operating System – software that controls the network </li></ul><ul><li>Bus – a main cable to which all clients and servers are connected </li></ul><ul><li>Ethernet - protocol for transmitting packets over a bus </li></ul>
    18. 18. Wireless Networks <ul><li>The fastest growing trend in networks – no wires are necessary to make connections </li></ul><ul><li>Wireless Application Protocol (WAP) – a special protocol that allows mobile telephones to connect to the Internet </li></ul><ul><li>Short Message Service (SMS) – a service for sending text messages up to 160 characters long to mobile phones </li></ul><ul><li>Global System for Mobile (GSM) communication protocol – the most widely used mobile telephone protocol worldwide </li></ul>
    19. 19. Wireless Networks: Wireless LANs <ul><li>LAN cabling is replaced with wireless transmissions between computers </li></ul><ul><li>Uses radio frequencies to transmit information between individual computers </li></ul><ul><li>Hubs and routers are used as connection devices between the computers and as bridges to traditional wired networks </li></ul><ul><li>Wi-Fi (wireless fidelity) which uses the IEEE 802.11b standard is currently the most popular approach to wireless LANs </li></ul>
    20. 20. <ul><li>Can be thought of as a “Network of Networks” </li></ul><ul><li>Server address – part of Internet address that identifies the computer what you want to connect to </li></ul><ul><li>Domain name – a server address that identifies the computer using several parts ranging from specific to general (top-level) </li></ul><ul><li>E-mail address – combination of username and server address </li></ul>The Internet sales @ User name Server address
    21. 21. Internet: Internet Operations Transfer text, images, video, and sound to your computer; search for information on the Internet World Wide Web Synchronously exchange electronic messages with other Internet users IRC Work on a computer elsewhere on the Internet Telnet Participate in a wide variety of online discussion groups Newsgroups Download files (software, documents, or data) from or upload to a server located on the Internet FTP Asynchronously exchange electronic messages with other Internet users E-Mail
    22. 22. The World Wide Web <ul><li>The Web – software, protocols and conventions based on hypertext and multimedia that make the Internet easy to use and browse </li></ul><ul><li>Hypertext – a method of linking related information in which there is no hierarchy or menu system </li></ul><ul><li>Multimedia – an interactive combination of text, graphics, animation, images, audio, and video displayed by and under the control of a personal computer </li></ul>
    23. 23. The World Wide Web: Browser <ul><li>Browser - application software that allows your computer to act as a client when contacting servers of the Internet (client-server network) </li></ul><ul><li>Hypertext Markup Language (HTML) – computer language used to create Web pages that consist of text, links, and multimedia elements </li></ul><ul><li>Web Page – a special type of document (file) that contains HTML and hypertext links to other documents or elements </li></ul><ul><li>Web Site – an Internet server that stores a collection of related Web Pages </li></ul><ul><li>Uniform Resource Locator (URL) – a standard means of locating Web pages or other resources over the web </li></ul>
    24. 24. The World Wide Web Can be created using word processor and printer Can be created with HTML and saved to a server Creation Can be linked only through a separate index Can be linked to other pages through hypertext Links to other pages Restricted to text and images Can include text, images, audio, and video information Types of information Restricted to single piece of paper Can extend beyond a single screen Amount of information Ink on paper Electronic Form Physical Page Web Page Characteristics