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Network+ Guide to Networks 5 th Edition

Network+ Guide to Networks 5 th Edition. Chapter 3 Transmission Basics and Networking Media. Objectives. Explain basic data transmission concepts, including full duplexing, attenuation, latency, and noise Describe the physical characteristics of coaxial cable, STP, UTP, and fiber-optic media

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Network+ Guide to Networks 5 th Edition

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  1. Network+ Guide to Networks5th Edition Chapter 3 Transmission Basics and Networking Media

  2. Objectives • Explain basic data transmission concepts, including full duplexing, attenuation, latency, and noise • Describe the physical characteristics of coaxial cable, STP, UTP, and fiber-optic media • Compare the benefits and limitations of different networking media • Explain the principles behind and uses for serial connector cables • Identify wiring standards and the best practices for cabling buildings and work areas Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  3. Transmission Basics • Transmit • Issue signals along network medium • Transmission • Process of transmitting • Signal progress after transmitted (My NIC transmitted a message and transmission took 10 sec to reach the server due to slow network) • Transceiver • Transmit and receive signals • NIC is a transceiver Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  4. Analog and Digital Signaling • Important data transmission characteristic • I) Signaling type: analog or digital • Volt • Electrical current pressure • Electrical signal strength • Directly proportional to voltage • Signal voltage • Signals • Current, light pulses, electromagnetic waves Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  5. Figure 3-1: An example of an analog signal • Analog data signals • Voltage varies continuously • Properties • Amplitude, frequency, wavelength, phase Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  6. Analog and Digital Signaling (cont’d.) • Amplitude • Analog wave’s strength • Frequency • Number of times amplitude cycles over fixed time period • Measure in hertz (Hz) • Wavelength • Distance between corresponding wave cycle points • Inversely proportional to frequency • Expressed in meters or feet Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  7. Figure 3-2: Waves with a 90-degree phase difference • Phase • Wave’s progress over time in relationship to fixed point Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  8. Analog and Digital Signaling (cont’d.) • Analog signal benefit over digital • More variable • Convey greater subtleties with less energy • Drawback of analog signals • Varied and imprecise voltage • Susceptible to transmission flaws (noise) • Digital signals • Pulses of voltages • Positive voltage represents a 1 • Zero voltage represents a 0 Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  9. Figure 3-3 An example of a digital signal • Binary system • 1s and 0s represent information • Bit (binary digit) • Possible values: 1 or 0 • Digital signal pulse Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  10. Figure 3-4 Components of a byte • Byte • Eight bits together • Computers read and write information • Using bits and bytes • Find decimal value of a bit • Multiply the 1 or 0 by 2x (x equals bit’s position) Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  11. Analog and Digital Signaling (cont’d.) • Convert byte to decimal number • Determine value represented by each bit • Add values • Convert decimal number to a byte • Reverse the process • Convert between binary and decimal • By hand or calculator Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  12. Binary to Decimal conversion • Binary numbers are sometimes written prefixed with 0b • 0b0001 = 0*8 + 0*4 + 0*2 + 1*1 = 1 • 0b1010 = 1*8 + 0*4 + 1*2 + 0*1 = 10 • 0b1011 = 1*8 + 0*4 + 1*2 + 1*1 = 11 Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  13. Decimal to Binary • 14 = 8+4+2 = 1*8 + 1*4 + 1*2 + 0*1 = 0b1110 • 3 = 2+1 = 0*8 + 0*4 + 1*2 + 1*1 = 0b0011 • 6 = 4+2 = 0*8 + 1*4 + 1*2 + 0*1 = 0b0110 Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  14. Larger Values 128= 1*128 + 0*64 + 0*32 +0*16 +0*8 +0*4 + 0*2 +0*1 128 = 0b10000000 162= 128 + 32 + 2 162= 1*128 + 0*64 + 1*32 +0*16 +0*8 +0*4 + 1*2 +0*1 162 = 0b10100010 0b1111000 = 1*128 + 1*64 + 1*32 +1*16 +0*8 +0*4 + 0*2 +0*1 0 = 128 + 64 + 32 +16 = 240 Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  15. Analog and Digital Signaling (cont’d.) • Digital signal benefit over analog signal • More reliable • Less severe noise interference • Digital signal drawback • Many pulses required to transmit same information • Overhead • Nondata information • Required for proper signal routing and interpretation • Such as addressing information Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  16. Data Modulation • Important data transmission characteristic • II) Data modulation • Technology used to modify analog signals to make it suitable for carrying data over communication path • Why ? • Data relies on digital transmission but network connection (telephone lines used to connect with ISP) may handle only analog signals • Need to make signals conform to a specific pathway • Issue multiple signals to the same communication channel with no interference Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  17. Data Modulation (cont’d.) • Modem • Accomplishes translation • Converts digital to analog at the transmitting end • Converts analog to digital at the receiving end • Modulator/demodulator • Carrier wave • Combined with another analog signal (Information wave) to produce unique signal transmitted from one node to another • Preset properties (amplitude, frequency and phase) • Purpose • Convey information (messenger) Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  18. Data Modulation (cont’d.) • Information wave (data wave) • Added to carrier wave • Modifies one carrier wave property (amplitude, frequency or phase) • Frequency modulation (FM) • Carrier frequency modified • By application of data signal • Amplitude modulation (AM) • Carrier signal amplitude modified • By application of data signal Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  19. AM and FM Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  20. Simplex, Half-Duplex, and Duplex • Important data transmission characteristic • III) Signal Direction : direction in which the signals travel over the media • Simplex • Signal transmission: one direction • Like broadcast TV • Half-duplex transmission • Signal transmission: both directions but one at a time • One communication channel that maybe shared for multiple nodes to exchange information • Like walkie-talkie • Full-duplex (bidirectional) • Signals transmission: both directions simultaneously • Like telephone and on data networks • Multiple channels on the same medium Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  21. Figure 3-6 Simplex, half-duplex, and full duplex transmission • Channel • Distinct communication path between nodes • Separated physically (wires) or logically (multiplexing) • Full duplex advantage • Increases speed • Many network devices (modems & NICs) allow specifying half duplex or duplex Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  22. Multiplexing • Important data transmission characteristic • IV) Multiplexing • Technique that allows multiple signals to travel simultaneously over one medium • Takes place by logically separate the channel into subchannels • Subchannels • Logical multiple smaller channels • Multiplexing Devices: • Multiplexer (mux): A device that combines many channel signals at the transmission end • Demultiplexer (demux): A device that separates combined signals and regenerates them at the receiving end Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  23. Figure 3-7 Time division multiplexing • Multiplexing Types: • TDM (time division multiplexing) • Divides channel into multiple time intervals (slots) and assigns a separate time slot for each node on the network to carry data from that node. • Inefficient when some nodes rarely send data Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  24. Figure 3-8 Statistical multiplexing • Statistical multiplexing • Transmitter assigns slots to node according to priority, need depending on the network • More efficient than TDM  maximize available bandwidth Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  25. Figure 3-9 Frequency division multiplexing • FDM (frequency division multiplexing) • Unique frequency band for each communications subchannel • Signals modulated with different carrier frequencies, then multiplexed to simultaneously travel over a single channel • FDM implemented signals of above 3400 Hz • Two types • Cellular telephone transmission • DSL Internet access Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  26. Figure 3-10 Wavelength division multiplexing • WDM (wavelength division multiplexing) • One fiber-optic connection • Carries multiple light signals simultaneously20 millions • DWDM (dense wavelength division multiplexing) • Used on most modern fiber-optic networks • Extraordinary capacity Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  27. Important data transmission characteristics • V) Relationships between nodes • Point-to-point transmission: one transmitter and one receiver • Point-to-multipoint transmission: one transmitter and multiple receivers • Broadcast transmission • One transmitter and multiple, undefined receivers • Used on wired and wireless networks • Simple and quick • TV station • Nonbroadcast • One transmitter and multiple, defined receivers Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  28. Figure 3-11 Point-to-point versus broadcast transmission Relationships Between Nodes (cont’d.) Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  29. Important data transmission characteristics • V) Throughput • Measures amount of data transmitted during given time period • Capacity or bandwidth (technically different) • Quantity of bits transmitted per second (bps, Kbps, Mbps, Gbps, Tbps) • VI) Bandwidth (strict definition) • Measures difference between highest and lowest frequencies that medium can transmit • Range of frequencies • Measured in hertz (Hz) Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  30. Table 3-1 Throughput measures Throughput Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  31. Baseband and Broadband • Baseband transmission • Transmission form in which digital signals sent through direct current (DC) pulses applied to wire • Requires exclusive use of wire’s capacity • Transmit one signal (channel) at a time • One node transmit at a time • Example: Ethernet • Supports half-duplex mainly (nodes can send/receive on same wire but one at a time) • Broadband transmission • Transmission form in which signals modulated radiofrequency (RF) analog waves • Uses different frequency ranges • Does not encode information as digital pulses • Example: TV cable • More expensive and longer Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  32. Transmission Flaws • Noise • Any undesirable influence degrading or distorting signal, measured in decibels(dB) • Types of noise • EMI (electromagnetic interference) • Waves emanate from electrical devices or cables carrying electricity. • EMI/RFI (radiofrequency interference) • Cross talk • When a signal traveling on one wire or cable infringes on the signal traveling on adjacent wire or cable • NEXT (near end cross talk) • Potential cause: improper termination (damage wire insulation, untwisted wire) • Environmental influences • Heat Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  33. Figure 3-12 Cross talk between wires in a cable Transmission Flaws (cont’d.) Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  34. Transmission Flaws (cont’d.) • Attenuation • Loss of signal’s strength as it travels away from source • Signal boosting technology • Analog signals pass through amplifier (device increases voltage of a signal) • Noise also amplified • Regeneration • Digital signals retransmitted in original form • Repeater: device regenerating digital signals • Amplifiers and repeaters • OSI model Physical layer • Extend length of network Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  35. Transmission Flaws (cont’d.) • Latency • Delay between signal transmission and receipt • Causes • Cable length • Intervening connectivity device • RTT (round trip time) • Time for packet to go from sender to receiver, then back from receiver to sender • Measured in milliseconds • May cause network transmission errors Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  36. Common Media Characteristics • Selecting transmission media • Match networking needs with media characteristics • Physical media characteristics • Throughput • Cost • Size and scalability • Connectors • Noise immunity Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  37. Throughput • Most significant transmission method factor • Measures amount of data transmitted during given time period • Causes of limitations • Laws of physics (not faster than light) • Signaling and multiplexing techniques • Noise (more time and resources to compensate for noise) • Devices connected to transmission medium • Fiber-optic cables allows faster throughput • Compared to copper or wireless connections Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  38. Cost • Precise costs difficult to pinpoint • Media cost dependencies • Existing hardware, network size, labor costs • Variables influencing final cost • Installation cost • New infrastructure cost versus reuse • Maintenance and support costs • Cost of lower transmission rate affecting productivity • Cost of obsolescence Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  39. Noise Immunity • Noise distorts data signals • Distortion rate dependent upon transmission media • Fiber-optic: least susceptible to noise  it does not use electric current, but light waves, to conduct signals • Limit impact on network • Cable installation • Far away from powerful electromagnetic forces • Select media protecting signal from noise (cables ) • Antinoise algorithms (pipelines) Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  40. Size and Scalability • Three specifications • Maximum nodes per segment • Maximum segment length • Maximum network length • Depends on physical characteristics of wires and electrical characteristics of data transmission • Maximum nodes per segment dependency • Attenuation and latency • Maximum segment length dependency • Attenuation and latency plus segment type • Maximum distance a signal can travel and still be interpreted accurately Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  41. Size and Scalability (cont’d.) • Segment types • Populated: contains end nodes • Unpopulated(Link segment): No end nodes (routers) • Segment length limitation • After certain distance, signal loses strength • Cannot be accurately interpreted • Maximum network length dependency • Attenuation and latency plus segment type • Sum of the network’s segment length Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  42. Connectors and Media Converters • Connectors • Hardware connecting wire to network device • Specific to particular media type • Affect costs • Installing and maintaining network • Ease of adding new segments or nodes • Technical expertise required to maintain network • Media converter • Hardware enabling networks or segments running on different media to interconnect and exchange signals Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  43. Figure 3-15 Copper wire-to-fiber media converter Connectors and Media Converters (cont’d.) Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  44. Figure 3-16 Coaxial cable Coaxial Cable • Foundation for Ethernet network • Central metal core (often copper) • Surrounded by insulator, braided metal shielding (braiding or shield) and an outer cover (sheath or jacket) Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  45. Coaxial Cable • Central metal core • Carries electromagnetic signal • Insulator • Plastic material such as Polyvinyl Chloride (PVC) or Teflon to protect the core from the metal shield (avoid short circuit) • Braided metal shielding: • Shield (noise) and ground for signal • Sheath or jacket: • Made of PVC or fire-resistance plastic • Protects against physical damage Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  46. Coaxial Cable (cont’d.) • High noise resistance • Advantage over twisted pair cabling • Carry signals farther before amplifier required • Disadvantage over twisted pair cabling • More expensive more raw manufacture materials • Hundreds of specifications • RG (Radio Guide) specification number • Differences: shielding and conducting cores • Transmission characteristics(impedance, attenuation, throuhput) Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  47. Coaxial Cable (cont’d.) • Conducting core • American Wire Gauge (AWG) size • Larger AWG smaller diameter • Data networks usage • RG-6: Used in modern cable TV connections, most common • RG-8: Thicknet--obsolete • RG-58: Thinnet—also obsolete for data networks • RG-59: Used for short spans in modern cable TV connections Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  48. Coaxial Cable (cont’d.) • Connectors • F-type • BNC Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  49. Figure 3-17 F-type connector Figure 3-18 BNC Connector Coaxial Cable (cont’d.) Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

  50. Figure 3-19 Twisted pair cable Twisted Pair Cable • Most common today • Color-coded insulated copper wire pairs • 0.4 to 0.8 mm diameter • Every two wires twisted around each other • All pairs encased in a plastic sheath • Pair numbers depend on the cable type Notes on Network+ Guide to Networks, 5th Edition modified by Dr. Feda AlShahwan

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