Sm2 Network Connections


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Sm2 Network Connections

  1. 1. Network Connections Textbook Chapter 8 265 to 270
  2. 2. Efficiency in networks depends on: <ul><li>Type of access </li></ul><ul><li>Transmission Media </li></ul><ul><li>Type of connection </li></ul>
  3. 3. 1. Type of Access <ul><li>Direct access : A dedicated, direct connection through a LAN </li></ul><ul><li>Remote access : Network access via phone line, TV cable system or wireless link. </li></ul>
  4. 4. <ul><li>What type of access to the prepa TEC server, does your laptop have when being connected at school? </li></ul><ul><li>What type of access to the prepa TEC server, does your laptop have when being connected at home? </li></ul>
  5. 5. 2. Transmission Media <ul><li>Media refers to the means used to link a network’s nodes together. </li></ul><ul><li>Twisted-pair cables. </li></ul><ul><li>Coaxial cables. </li></ul><ul><li>Fiber-optic cables. </li></ul><ul><li>Wireless media (Wi-Fi, infrared, bluetooth) </li></ul>
  6. 6. a) Twisted-pair cables <ul><li>They normally consist of four pairs of wires. </li></ul><ul><li>Each pair has two wires separately insulated in plastic and then twisted around each other. </li></ul><ul><li>Nothing shields this type of wire from outside interference. </li></ul><ul><li>New cables support up to 1 Gbps (gigabit per second) </li></ul>
  7. 7. b) Coaxial cables <ul><li>It consists of a rigid copper wire, surrounded by insulating material. </li></ul><ul><li>It supports transmission speeds up to 10 Mbps (megabits per second). </li></ul><ul><li>It is more expensive than twisted-pair cables </li></ul><ul><li>It is becoming less popular as twisted-pair technology improves. </li></ul>
  8. 8. c) Fiber-optic cables <ul><li>It is a thin strand of glass that transmits light rather than electric current. </li></ul><ul><li>Its transmission speed approaches 100Gbps. </li></ul><ul><li>It is immune to electromagnetic interference. </li></ul><ul><li>It is extremely fast, it can carry enormous number of messages simultaneously and it is very secure. </li></ul>
  9. 9. d) Wireless Media: Wi-Fi <ul><li>The most popular is known as Wi-Fi (Wireless Fidelity) </li></ul><ul><li>It uses radio signals that travel through air from a base station up to 46 meters away (150 feet). </li></ul><ul><li>It is not as fast as a cable connection. </li></ul>
  10. 10. e) Wireless Media: Infrared <ul><li>It sends and receives digital information over short distances. </li></ul><ul><li>It is not widely used because of line-of-sight limitations (it cannot pass through walls). </li></ul><ul><li>Share of data is “beamed” through infrared links . </li></ul>
  11. 11. f) Wireless Media: Bluetooth <ul><li>Overcomes differences between mobile phones, handheld devices and computers. </li></ul><ul><li>It makes possible communication between all those devices regardless their operating system. </li></ul>
  12. 12. <ul><li>Which transmission media is the fastest? </li></ul><ul><li>Which transmission media do you have at home? </li></ul><ul><li>Which transmission media does the highschool have? </li></ul>
  13. 13. 3. Type of connections <ul><li>Connection to Internet could be through </li></ul><ul><ul><li>phone line and a modem </li></ul></ul><ul><ul><li>through broadband connections </li></ul></ul><ul><ul><li>through fiber-optic connections. </li></ul></ul>
  14. 14. Bandwidth <ul><li>In all cases, the bandwidth determines the data transfer rate – the quantity of data that can be transmitted through a communication medium in a given amount of time. </li></ul><ul><li>Large bandwidths are measured in kilobits (thousands of bits) or megabits (millions of bits) per second. </li></ul>
  15. 15. Broadband connections <ul><li>Connection with much greater bandwidth than standard modems are: </li></ul><ul><ul><li>Digital Subscriber Line (DSL) uses standard phone lines and is provided by phone companies in many areas. </li></ul></ul><ul><ul><li>Cable modems provide fast network connections through cable television networks in many areas. </li></ul></ul><ul><ul><li>High-speed wireless connections can connect computers to networks using radio waves rather than wires. </li></ul></ul><ul><ul><li>Satellite dishes can deliver fast computer network connections as well as television programs. </li></ul></ul>