1 / 21

Chapter Three

Chapter Three. The Highways and Byways of the Network. Objectives. You will get a review of binary. You’ll examine different communications models. Here you’ll learn about different physical media types used to build networks. You’ll learn about wireless media as well. Reviewing Binary.

xanto
Download Presentation

Chapter Three

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter Three The Highways and Byways of the Network

  2. Objectives • You will get a review of binary. • You’ll examine different communications models. • Here you’ll learn about different physical media types used to build networks. • You’ll learn about wireless media as well.

  3. Reviewing Binary • Computers only know 0 and 1 • On and off • Yes and no • Open and closed • Based on the studies of George Boule

  4. Terms of Binary • Bit • A single 1 or 0 • Nibble • 4 bits transmitted as a unit • Byte • 8 bits used to generate a single character

  5. AM versus FM • Amplitude modulation (AM) • Data encoded by varying the relative strength (known as amplitude) of the signal • Frequency modulation (FM) • Data encoded by varying how many times per second the signal oscillates

  6. Communications Models • Simplex • A device can either send or receive, but not both. • Half-duplex • A device can both send and receive, but not at the same time. • Full duplex • A device can send and receive at the same time.

  7. Bounded Media • Fixed cable of some sort • Twisted pair • Coaxial • Fiber optics

  8. Twisted Pair (1 of 2) • Eight strands of wire carry the signals (or are null). • Strands are separated into four pairs that are twisted around each other to reduce crosstalk. • Unshielded twisted pair (UTP) has no external armor. • Shielded twisted pair (STP) is protected by a metal foil (or similar) wrapping. • Twisted pair cable is defined by its category.

  9. Pair 1 Orange -- white/orange striped Pair 2 Green --white/green striped Pair 3 Blue -- white/blue striped Pair 4 Brown -- white/brown striped Twisted Pair (2 of 2)

  10. Some Twisted Concepts • Limited to 100 meters without a repeater • Bandwidth limitations defined by category • Terminated by RJ-45 connector

  11. Category Frequency Supported Usage 1 Voice only, no data Telephone only 2 4Mhz Localtalk/ISDN 3 16Mhz Ethernet 4 20Mhz Token ring 5 100Mhz Fast Ethernet 5e 400Mhz Gigabit Ethernet/ATM to 622MB/sec 6 550Mhz Gigabit Ethernet/ATM to 2.4GB/sec

  12. Pin No. Signal Carried 568B 568A 1 Transmit (+) White/Orange White/Green 2 Transmit (-) Orange Green 3 Receive (+) White/Green White/Orange 4 Not Used Blue Blue 5 Not Used White/Blue White/Blue 6 Receive (-) Green Orange 7 Not Used White/Brown White/Brown 8 Not Used Brown Brown EIA/TIA Wiring Standards

  13. Coaxial Cable • Thinnet • RG-58 • Terminated with BNC connector • 10Mb/s throughput • 180M maximum run • Thicknet • RG-8 • Terminated with vampire clamp • 10Mb/s throughput • 500M maximum run

  14. Fiber Optics • Single mode • Very thin strands of fiber • Single signal transmitted over each fiber • Signals only travel in one direction • Multimode • Thicker strands carry multiple signals • Each one on a different frequency

  15. Unbounded Media • Infrared • Laser • Radio • Microwave

  16. Infrared • Line of sight • Two communicating devices must have an unblocked path between them • Used for linking peripherals to computers or a laptop to a desktop or a TV/VCR remote • Scatter infrared • Limited range • Used for small office/home office (SOHO) networks

  17. Laser • Line of sight • Requires precise alignment of transmitter and receiver • Capable of high speeds (155Mb/s to 622Mb/s) • Useful for creating pseudo-WAN links between offices

  18. Radio • Public band radio limited in range • Frequency ranges are 902Mhz t0 928Mhz and 5.72Mhz to 5.85Mhz. • Other frequencies monitored by FCC and require a license

  19. Single Frequency • Low power single frequency (LPSF) • Used in the public bands • Small networks with relatively low speeds • High power single frequency (HPSF) • Generally allows for line of sight communications • Atmospheric bounce can extend range

  20. Spread Spectrum • Signal bounced over multiple frequencies to increase security • Direct sequence spread spectrum • A specific pattern of frequency hops followed • Frequency hopping spread spectrum • Signal bounces between frequencies in a pseudo-random order for higher security

  21. Microwave • Terrestrial microwave • All line of sight • Range limited by the horizon • Relay stations can extend range • Satellite microwave • Global coverage • Expense can be prohibitive

More Related