Chapter03 a - network media


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Basic Networking Guide

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Chapter03 a - network media

  1. 1. 1Lesson 2—Networking BASICS Networking BASICS Network Media Unit 1 Lesson 2
  2. 2. Lesson 2—Networking BASICS2 Types of Networks • There are two types of networks by which information is transmitted: – circuit switched networks – packet switched networks
  3. 3. Lesson 2—Networking BASICS3 Circuit Switched Network • There is a dedicated and direct physical connection between sender and receiver. • No other transmissions can take place while the connection is active. • Once the transmission is ended, other connections can be made with other devices. • It is ideal for voice communications because there are no interruptions from other devices or delays.
  4. 4. Lesson 2—Networking BASICS4 Packet Switched Network • This network requires data transmission be broken into smaller units called packets. • Each packet is sent independently through the network. • It is used for data transmission because data is not as time-sensitive as voice communication. • It allows multiple devices to share one line or frequency. • It facilitates error correction.
  5. 5. Lesson 2—Networking BASICS5 Signaling Techniques • There are two ways that a signal is sent across a network medium: – baseband signaling – broadband signaling
  6. 6. Lesson 2—Networking BASICS6 Baseband Signaling • Sends one data signal across the network media • Entire capacity of the media is used for the one data signal • Signals are transmitted in a digital format • Many devices can send and receive across the medium, but only one at a time
  7. 7. Lesson 2—Networking BASICS7 Baseband Signaling
  8. 8. Lesson 2—Networking BASICS8 Broadband Signaling • Divides the cable into several different channels • Signals are transmitted at different frequencies in an analog mode • Allows many different signals to be sent simultaneously on a single cable • Signal sent in only one direction • Used for computer network data transmissions
  9. 9. Lesson 2—Networking BASICS9 Broadband Signaling
  10. 10. Lesson 2—Networking BASICS10 Factors Affecting Transmissions • The flow of a signal down the network media can become distorted. • Common types of distortions are attenuation and interference.
  11. 11. Lesson 2—Networking BASICS11 Attenuation • Loss of signal power • Measured by the decrease in decibels (db) over a specific distance
  12. 12. Lesson 2—Networking BASICS12 Interference • Interference is caused when a strong external signal interferes with a signal. • Radio frequency interference (RFI) - interference caused by broadcast signals from a radio or television transmitter. • Electromagnetic interference (EMI) - motor or source of intense electrical activity creates an electromagnetic signal that interferes with a data signal. • Near end crosstalk (NEXT) and Far end crosstalk (FEXT) - interference from another data signal being transmitted on adjacent wire.
  13. 13. Lesson 2—Networking BASICS13 Transmission Media •Copper cables •Fiber optic cables •Wireless
  14. 14. Lesson 2—Networking BASICS14 Copper Cables • Thin coaxial • Shielded twisted pair (STP) • Unshielded twisted pair (UTP) • UTP rated by Category 1 - 6
  15. 15. Lesson 2—Networking BASICS15 Copper Cables
  16. 16. Lesson 2—Networking BASICS16 Copper Cables
  17. 17. Lesson 2—Networking BASICS17 Fiber Optic • This cable uses a thin cylinder of glass to send light impulses. • The cable consists of a strand of glass (core) surrounded by a glass tube (cladding). • Single mode - one light source flashes a light down the cable. • Multimode - supports many simultaneous light transmissions.
  18. 18. Lesson 2—Networking BASICS18 Fiber Optic
  19. 19. Lesson 2—Networking BASICS19 Wireless • Transmission is sent and received through invisible waves • Less expensive than copper or fiber optic lines. • Allows the user to move freely around the office or campus and still remain connected to the network • Fastest-growing segment of network media today
  20. 20. Lesson 2—Networking BASICS20 Wireless Transmissions • Infrared transmits data using infrared (IR) light. • IR shares many of the same properties as visible light . • Radio frequency signals can be transmitted over radio waves similar to local radio station transmissions. • The signal comes in at a lower power level and does not reach as far.
  21. 21. Lesson 2—Networking BASICS21 Network Interface Card • The NIC serves as the connection between the personal computer and the network media. • It connects to the computer on its base by plugging into an expansion slot of the computer. • Another connection is accessible from the outside of the computer and has connections for the cables to plug into the network.
  22. 22. Lesson 2—Networking BASICS22 Network Interface Card • Changes from parallel to serial transmission • Creates packets • Determines when to send • Transmits packet
  23. 23. Lesson 2—Networking BASICS23 Network Interface Card