Network+ Guide to Networks 6 th Edition Chapter 3 Transmission Basics and Networking - PowerPoint Presentation

Network+ Guide to Networks6th Edition Chapter 3Transmission Basics and Networking Media

ObjectivesExplain basic data transmission concepts, including full duplexing, attenuation, latency, and noise Describe the physical characteristics of coaxial cable, STP, UTP, and fiber-optic mediaCompare the benefits and limitations of different networking mediaExplain the principles behind and uses for serial cables Identify wiring standards and the best practices for cabling buildings and work areas Network+ Guide to Networks, 6 th Edition 2

Transmission BasicsTransmit Issue signals along network mediumTransmissionProcess of transmittingSignal progress after transmitting Transceiver Transmits and receives signals Network+ Guide to Networks, 6 th Edition 3

Analog and Digital SignalingImportant data transmission characteristic Signaling type: analog or digitalVoltElectrical current pressureElectrical signal strength Directly proportional to voltage Signal voltage Signals Current, light pulses, electromagnetic waves Network+ Guide to Networks, 6 th Edition 4

Analog and Digital Signaling (cont’d.) Analog data signalsVoltage varies continuouslyFundamental properties of analog signalsAmplitude Measure of strength at given point in time Frequency Number of times amplitude cycles over fixed time WavelengthDistance between one peak and the nextPhaseProgress of wave over time compared to a fixed point Network+ Guide to Networks, 6 th Edition 5

6 Figure 3-1 An example of an analog signal Network+ Guide to Networks, 6 th Edition Courtesy Course Technology/Cengage Learning

7 Figure 3-2 Waves with a 90 degree phase difference Network+ Guide to Networks, 6 th Edition Courtesy Course Technology/Cengage Learning

Analog and Digital Signaling (cont’d.)Analog signal benefit over digital More variableConvey greater subtleties with less energyDrawback of analog signalsVaried and imprecise voltage Susceptible to transmission flaws Digital signals Pulses of voltages Positive voltage represents a 1Zero voltage represents a 0 Network+ Guide to Networks, 6 th Edition 8

9 Figure 3-3 An example of a digital signal Network+ Guide to Networks, 6 th Edition Courtesy Course Technology/Cengage Learning Figure 3-4 Components of a byte Courtesy Course Technology/Cengage Learning

Analog and Digital Signaling (cont’d.)Convert byte to decimal number Determine value represented by each bitAdd valuesConvert decimal number to a byteReverse the process Convert between binary and decimal By hand or calculator Network+ Guide to Networks, 6 th Edition 10

Analog and Digital Signaling (cont’d.)Digital signal benefit over analog signal More reliableLess severe noise interferenceDigital signal drawbackMany pulses required to transmit same information Overhead Nondata information Required for proper signal routing and interpretation Example: network layer addressing information Network+ Guide to Networks, 6 th Edition 11

Data ModulationData relies on digital transmission Network connection may handle only analog signalsModemAccomplishes translationModulator/demodulator Data modulation Technology modifying analog signals Make data suitable for carrying over communication path Network+ Guide to Networks, 6 th Edition 12

Data Modulation (cont’d.)Carrier wave Combined with another analog signalProduces unique signalTransmitted from one node to anotherPreset properties Purpose: convey information Information wave (data wave) Added to carrier wave Modifies one carrier wave property Network+ Guide to Networks, 6 th Edition 13

Data Modulation (cont’d.)Frequency modulation Carrier frequency modified by application of data signalAmplitude modulationCarrier signal amplitude modified by application of data signalDigital subscriber line (DSL) Also makes use of modulation Network+ Guide to Networks, 6 th Edition 14

15 Network+ Guide to Networks, 6 th Edition Figure 3-5 A carrier wave modified through frequency modulation Courtesy Course Technology/Cengage Learning

Simplex, Half-Duplex, and DuplexSimplex Signals travel in one directionHalf-duplex transmissionSignals travel in both directionsOne at a time Shared communication channel Full-duplex Signals travel in both directions simultaneously Used on data networks Network+ Guide to Networks, 6 th Edition 16

17 Network+ Guide to Networks, 6 th Edition Figure 3-6 Simplex, half-duplex, and full-duplex transmission Courtesy Course Technology/Cengage Learning

Simplex, Half-Duplex, and Duplex (cont’d.)Channel Distinct communication path between nodesSeparated physically or logicallyFull duplex advantageIncreases speed of data travel Some modems and NICs allow specifying half- or full-duplex communication Modern NICs use full duplex by default Network+ Guide to Networks, 6 th Edition 18

MultiplexingMultiplexing Multiple signalsTravel simultaneously over one mediumSubchannels Logical multiple smaller channels Multiplexer (mux) Combines many channel signals Demultiplexer (demux)Separates combined signalsRegenerates them Network+ Guide to Networks, 6 th Edition 19

Multiplexing (cont’d.) Time division multiplexing (TDM)Divides channel into multiple time intervals Network+ Guide to Networks, 6 th Edition 20 Courtesy Course Technology/Cengage Learning Figure 3-7 Time division multiplexing

Multiplexing (cont’d.) Statistical multiplexingTransmitter assigns slots to nodesAccording to priority, needMore efficient than TDM Network+ Guide to Networks, 6 th Edition 21 Courtesy Course Technology/Cengage Learning Figure 3-8 Statistical multiplexing

Multiplexing (cont’d.) Frequency division multiplexing (FDM)Unique frequency band for each communications subchannelCellular telephone transmission DSL Internet access Network+ Guide to Networks, 6 th Edition 22 Courtesy Course Technology/Cengage Learning Figure 3-9 Frequency division multiplexing

Multiplexing (cont’d.) Wavelength division multiplexing (WDM)One fiber-optic connectionCarries multiple light signals simultaneously Network+ Guide to Networks, 6 th Edition 23 Courtesy Course Technology/Cengage Learning Figure 3-10 Wavelength division multiplexing

Multiplexing (cont’d.) Dense wavelength division multiplexing (DWDM)Used on most modern fiber-optic networksExtraordinary capacity Network+ Guide to Networks, 6 th Edition 24

Relationships Between NodesPoint-to-point transmission One transmitter and one receiverPoint-to-multipoint transmissionOne transmitter and multiple receiversBroadcast transmission One transmitter and multiple, undefined receivers Used on wired and wireless networks Simple and quick NonbroadcastOne transmitter and multiple, defined recipients Network+ Guide to Networks, 6 th Edition 25

Network+ Guide to Networks, 6 th Edition 26 Courtesy Course Technology/Cengage Learning Figure 3-11 Point-to-point versus broadcast transmission

Throughput and BandwidthThroughput Amount of data transmitted during given time periodAlso called capacity or bandwidthExpressed as bits transmitted per secondBandwidth (strict definition) Difference between highest and lowest frequencies medium can transmit Range of frequencies Measured in hertz (Hz) Network+ Guide to Networks, 6 th Edition 27

Network+ Guide to Networks, 6 th Edition 28 Courtesy Course Technology/Cengage Learning Table 3-1 Throughput measures

Baseband and Broadband Baseband transmissionDigital signals sent through direct current (DC) pulses applied to wireRequires exclusive use of wire’s capacity Transmit one signal (channel) at a time Example: Ethernet Broadband transmission Signals modulated as radio frequency (RF) analog wavesUses different frequency rangesDoes not encode information as digital pulses Network+ Guide to Networks, 6 th Edition 29

Transmission Flaws NoiseAny undesirable influence degrading or distorting signalTypes of noiseEMI (electromagnetic interference) Example: radio frequency interference Cross talk Signal on one wire infringes on adjacent wire signal Near end cross talk (NEXT) occurs near source Network+ Guide to Networks, 6 th Edition 30

Network+ Guide to Networks, 6 th Edition 31 Courtesy Course Technology/Cengage Learning Figure 3-12 Cross talk between wires in a cable

Transmission Flaws (cont’d.) AttenuationLoss of signal’s strength as it travels away from sourceSignal boosting technologyAnalog signals pass through amplifier Noise also amplified Regeneration Digital signals retransmitted in original form Repeater: device regenerating digital signalsAmplifiers and repeatersOSI model Physical layer Network+ Guide to Networks, 6 th Edition 32

Network+ Guide to Networks, 6 th Edition 33 Courtesy Course Technology/Cengage Learning Figure 3-14 A digital signal distorted by noise and then repeated Figure 3-13 An analog signal distorted by noise and then amplified Courtesy Course Technology/Cengage Learning

Transmission Flaws (cont’d.)LatencyDelay between signal transmission and receipt May cause network transmission errorsLatency causesCable lengthIntervening connectivity deviceRound trip time (RTT) Time for packet to go from sender to receiver, then back from receiver to sender Network+ Guide to Networks, 6 th Edition 34

Common Media CharacteristicsSelecting transmission media Match networking needs with media characteristicsPhysical media characteristics ThroughputCostNoise immunitySize and scalability Connectors and media converters Network+ Guide to Networks, 6 th Edition 35

ThroughputMost significant factor in choosing transmission methodCauses of throughput limitationsLaws of physicsSignaling and multiplexing techniques Noise Devices connected to transmission medium Fiber-optic cables allow faster throughput Compared to copper or wireless connections Network+ Guide to Networks, 6 th Edition 36

CostPrecise costs difficult to pinpointMedia cost dependencies Existing hardware, network size, labor costsVariables influencing final costInstallation costNew infrastructure cost versus reuseMaintenance and support costs Cost of lower transmission rate affecting productivity Cost of downtime Cost of obsolescence Network+ Guide to Networks, 6th Edition 37

Noise ImmunityNoise distorts data signals Distortion rate dependent upon transmission mediaFiber-optic: least susceptible to noiseLimit noise impact on networkCable installation Far away from powerful electromagnetic forces Select media protecting signal from noise Antinoise algorithms Network+ Guide to Networks, 6 th Edition 38

Size and ScalabilityThree specifications Maximum nodes per segmentMaximum segment lengthMaximum network lengthMaximum nodes per segment dependency Attenuation and latency Maximum segment length dependency Attenuation and latency plus segment type Network+ Guide to Networks, 6 th Edition 39

Size and Scalability (cont’d.)Segment types Populated: contains end nodesUnpopulated: no end nodesAlso called link segmentSegment length limitation After certain distance, signal loses strength Cannot be accurately interpreted Network+ Guide to Networks, 6 th Edition 40

Connectors and Media ConvertersConnectors Hardware connecting wire to network deviceSpecific to particular media typeAffect costsInstalling 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 Network+ Guide to Networks, 6 th Edition 41

Network+ Guide to Networks, 6 th Edition 42 Courtesy of Omnitron Systems Technology Figure 3-15 Copper wire-to-fiber media converter

Coaxial CableCentral metal core (often copper) surrounded by: InsulatorBraided metal shielding (braiding or shield)Outer cover (sheath or jacket) Network+ Guide to Networks, 6 th Edition 43 Figure 3-16 Coaxial cable Courtesy Course Technology/Cengage Learning

Coaxial Cable (cont’d.)High noise resistanceAdvantage over twisted pair cabling Carry signals farther before amplifier requiredDisadvantage over twisted pair cablingMore expensiveHundreds of specificationsRG specification number Differences: shielding and conducting cores Transmission characteristics Network+ Guide to Networks, 6 th Edition 44

Coaxial Cable (cont’d.)Conducting core American Wire Gauge (AWG) sizeLarger AWG size, smaller wire diameterData networks usageRG-6 RG-8 RG-58 RG-59 Network+ Guide to Networks, 6 th Edition 45

Network+ Guide to Networks, 6 th Edition 46 Courtesy of MCM Electronics, Inc. Figure 3-17 F-Type connector © Igor Smichkov/Shutterstock.com Figure 3-18 BNC connector

Twisted Pair CableColor-coded insulated copper wire pairs 0.4 to 0.8 mm diameterEncased in a plastic sheath Network+ Guide to Networks, 6 th Edition 47 Courtesy Course Technology/Cengage Learning Figure 3-19 Twisted pair cable

Twisted Pair Cable (cont’d.)More wire pair twists per foot More resistance to cross talkHigher-qualityMore expensiveTwist ratio Twists per meter or foot High twist ratio Greater attenuation Network+ Guide to Networks, 6 th Edition 48

Twisted Pair Cable (cont’d.)Hundreds of different designs Twist ratio, number of wire pairs, copper grade, shielding type, shielding materials1 to 4200 wire pairs possibleWiring standard specificationTIA/EIA 568 Most common twisted pair types Category (cat) 3, 5, 5e, 6, 6a, 7 CAT 5 or higher used in modern LANs Network+ Guide to Networks, 6 th Edition 49

Twisted Pair Cable (cont’d.)Advantages Relatively inexpensiveFlexibleEasy installationSpans significant distance before requiring repeater Accommodates several different topologies Two categories Shielded twisted pair (STP) Unshielded twisted pair (UTP) Network+ Guide to Networks, 6 th Edition 50

STP (Shielded Twisted Pair)Individually insulated Surrounded by metallic substance shielding (foil)Barrier to external electromagnetic forcesContains electrical energy of signals insideMay be grounded Network+ Guide to Networks, 6 th Edition 51 Figure 3-20 STP cable Courtesy Course Technology/Cengage Learning

UTP (Unshielded Twisted Pair)One or more insulated wire pairs Encased in plastic sheathNo additional shieldingLess expensive, less noise resistance Network+ Guide to Networks, 6 th Edition 52 Courtesy Course Technology/Cengage Learning Figure 3-21 U TP cable

Comparing STP and UTPThroughputSTP and UTP can transmit the same rates CostSTP and UTP varyConnectorSTP and UTP use Registered Jack 45Telephone connections use Registered Jack 11 Network+ Guide to Networks, 6 th Edition 53

Comparing STP and UTP (cont’d.)Noise immunity STP more noise resistantSize and scalabilityMaximum segment length for both: 100 meters Network+ Guide to Networks, 6 th Edition 54

Terminating Twisted Pair Cable Patch cableRelatively short cableConnectors at both endsProper cable termination techniques Basic requirement for two nodes to communicate Poor terminations: Lead to loss or noise TIA/EIA standardsTIA/EIA 568ATIA/EIA 568B Network+ Guide to Networks, 6 th Edition 55

Network+ Guide to Networks, 6 th Edition 56 Courtesy Course Technology/Cengage Learning Figure 3-24 TIA/EIA 568A standard terminations Courtesy Course Technology/Cengage Learning Figure 3-25 TIA/EIA 568B standard terminations

Terminating Twisted Pair Cable (cont’d.) Straight-through cableTerminate RJ-45 plugs at both ends identicallyCrossover cableTransmit and receive wires on one end reversed Network+ Guide to Networks, 6 th Edition 57 Figure 3-26 RJ-45 terminations on a crossover cable Courtesy Course Technology/Cengage Learning

Terminating Twisted Pair Cable (cont’d.)Termination tools Wire cutterWire stripperCrimping toolAfter making cables: Verify data transmit and receive Network+ Guide to Networks, 6 th Edition 58

Fiber-Optic Cable Fiber-optic cable (fiber)One or more glass or plastic fibers at its center (core)Data transmissionPulsing light sent from laser or light-emitting diode (LED) through central fibers Cladding Layer of glass or plastic surrounding fibers Different density from glass or plastic in strands Reflects light back to coreAllows fiber to bend Network+ Guide to Networks, 6 th Edition 59

Fiber-Optic Cable (cont’d.)Plastic buffer outside cladding Protects cladding and coreOpaque to absorb escaping lightSurrounded by Kevlar (polymeric fiber) strands Plastic sheath covers Kevlar strands Network+ Guide to Networks, 6 th Edition 60 Figure 3-30 A fiber-optic cable Courtesy of Optical Cable Corporation

Fiber-Optic Cable (cont’d.)Different varieties Based on intended use and manufacturer Network+ Guide to Networks, 6 th Edition 61 Figure 3-31 Zipcord fiber-optic patch cable Courtesy Course Technology/Cengage Learning

Fiber-Optic Cable (cont’d.)Benefits over copper cabling Extremely high throughputVery high noise resistanceExcellent securityAble to carry signals for longer distancesIndustry standard for high-speed networkingDrawbacks More expensive than twisted pair cable Requires special equipment to splice Network+ Guide to Networks, 6 th Edition62

SMF (Single-Mode Fiber)Consists of narrow core (8-10 microns in diameter) Laser-generated light travels over one pathLittle reflectionLight does not disperse as signal travelsCan carry signals many miles: Before repeating required Rarely used for shorter connections Due to cost Network+ Guide to Networks, 6 th Edition 63

MMF (Multimode Fiber)Contains core with larger diameter than single-mode fiber Common sizes: 50 or 62.5 micronsLaser or LED generated light pulses travel at different anglesGreater attenuation than single-mode fiberCommon uses Cables connecting router to a switch Cables connecting server on network backbone Network+ Guide to Networks, 6 th Edition 64

Fiber-Optic ConvertersRequired to connect multimode fiber networks to single-mode fiber networks Also fiber- and copper-based parts of a networkNetwork+ Guide to Networks, 6th Edition 65 Figure 3-38 Single-mode to multimode converter Courtesy Omnitron Systems Technology

Serial CablesData transmission stylePulses issued sequentially, not simultaneously Serial transmission methodRS-232Uses DB-9, DB-25, and RJ-45 connectors Network+ Guide to Networks, 6 th Edition 66

Structured CablingCable plantHardware that makes up the enterprise cabling system Cabling standardTIA/EIA’s joint 568 Commercial Building Wiring StandardAlso known as structured cablingBased on hierarchical design Network+ Guide to Networks, 6 th Edition 67

Network+ Guide to Networks, 6th Edition 68 Figure 3-42 TIA/EIA structured cabling in an enterprise Courtesy Course Technology/Cengage Learning

Structured Cabling (cont’d.)Components Entrance facilitiesMDF (main distribution frame)Cross-connect facilitiesIDF (intermediate distribution frame) Backbone wiring Telecommunications closet Horizontal wiring Work area Network+ Guide to Networks, 6 th Edition 69

Structured Cabling (cont’d.) Network+ Guide to Networks, 6 th Edition 70 Table 3-2 TIA/EIA specifications for backbone cabling Courtesy Course Technology/Cengage Learning

Best Practices for Cable Installation and ManagementChoosing correct cabling Follow manufacturers’ installation guidelinesFollow TIA/EIA standardsNetwork problemsOften traced to poor cable installation techniquesInstallation tips to prevent Physical layer failures See Pages 121-122 in the text Network+ Guide to Networks, 6 th Edition 71

SummaryInformation transmission methods AnalogDigitalMultiplexing allows multiple signals to travel simultaneously over one mediumFull and half-duplex specifies whether signals can travel in both directions or one direction at a time Noise distorts both analog and digital signals Attenuation L oss of signal as it travels Network+ Guide to Networks, 6 th Edition 72

Summary (cont’d.)Coaxial cable composed of core, insulator, shielding, sheath Types of twisted pair cableShielded and unshieldedFiber-optic cable transmits data through light passing through the central fibers Network+ Guide to Networks, 6 th Edition 73

Summary (cont’d.)Fiber-optic cable categories Single and multimode fiberSerial communication often used for short connections between devicesStructured cabling standard provides wiring guidelines Network+ Guide to Networks, 6 th Edition 74