Network Guide to Networks 5th Edition

1
Network Guide to Networks5th Edition

• Chapter 3
• Transmission Basics and Networking Media

Last modified 9-7-10
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

3
Transmission Basics

• Transmit
• Issue signals along network medium
• Transmission
• Process of transmitting
• Signal progress after transmitted
• Transceiver
• Transmit and receive signals

4
Analog and Digital Signaling

• Important data transmission characteristic
• Signaling type analog or digital
• Volt
• Electrical current pressure
• Electrical signal strength
• Directly proportional to voltage
• Signal voltage
• Signals
• Current, light pulses, electromagnetic waves

5

• Analog data signals
• Voltage varies continuously
• Properties
• Amplitude, frequency, wavelength, phase

6
Analog and Digital Signaling (contd.)

• Amplitude
• Analog waves 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

7

• Phase
• Waves progress over time in relationship to
  fixed point

8
Analog and Digital Signaling (contd.)

• 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
• Digital signals
• Pulses of voltages
• Positive voltage represents a 1
• Zero voltage represents a 0

9

• Binary system
• 1s and 0s represent information
• Bit (binary digit)
• Possible values 1 or 0
• Digital signal pulse

10

• 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 bits
  position)

11
Analog and Digital Signaling (contd.)

• 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

12
Binary to Decimal conversion

• Binary numbers are sometimes written prefixed
  with 0b
• 0b0001 08 04 02 11 1
• 0b1010 18 04 12 01 10
• 0b1011 18 04 12 11 11

13
Decimal to Binary

• 14 842 18 14 12 01 0b1110
• 3 21 08 04 12 11 0b0011
• 6 42 08 14 12 01 0b0110

14
Larger Values

• 128 1128 064 032 016 08 04 02
  01
• 128 0b10000000
• 162 128 32 2
• 162 1128 064 132 016 08 04 12
  01
• 162 0b10100010
• 0b11110000
• 1128 164 132 116 08 04 02 01 0
  
• 128 64 32 16 240

15
Binary on Quizzes

• Binary conversions are part of this course and
  will be on the quizzes and the final exam
• You can review the binary iClicker slides
• Samsclass.info
• Click on CNIT 106
• Click on Lecture Notes

16
iClicker Questions
17
When listening to music, I turn the volume knob
to make it louder. What property of the sound
has changed?

1. Amplitude
2. Phase
3. Frequency
4. Wavelength
5. More than one of the above

1 of 4
18
My guitar string is out of tune, so I turn the
tuning knob to adjust it. What property of the
sound has changed?

1. Amplitude
2. Phase
3. Frequency
4. None of the above
5. More than one of the above

2 of 4
19
What is the decimal form of the binary number
0b111?

1. 3
2. 4
3. 5
4. 7
5. Some other number

3 of 4
20
What is the binary form of the number 11?

1. 0b11
2. 0b111
3. 0b1111
4. 0b1001
5. 0b1011

4 of 4
21
Benefits of Digital Signaling

• 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

22
Data Modulation

• Data relies on digital transmission
• Network connection may handle only analog signals
• Modem
• Accomplishes translation
• Modulator/demodulator
• Data modulation
• Technology modifying analog signals
• Make data suitable for carrying over
  communication path

23
Data Modulation (contd.)

• Carrier wave
• Combined with another analog signal
• Produces unique signal
• Transmitted from one node to another
• Preset properties
• Purpose
• Convey information
• Information wave (data wave)
• Added to carrier wave
• Modifies one carrier wave property

24
Data Modulation (contd.)

• Frequency modulation (FM)
• Carrier frequency modified
• By application of data signal
• Amplitude modulation (AM)
• Carrier signal amplitude modified
• By application of data signal

25
AM and FM

• From link Ch 3a

26
Simplex, Half-Duplex, and Duplex

• Simplex
• Signal transmission one direction
• Like broadcast TV
• Half-duplex transmission
• Signal transmission both directions
• One at a time
• One communication channel
• Shared for multiple nodes to exchange information
• Full-duplex
• Signals transmission both directions
  simultaneously
• Used on data networks

27

• Channel
• Distinct communication path between nodes
• Separated physically or logically
• Full duplex advantage
• Increases speed

28
Multiplexing

• Multiplexing
• Multiple signals
• Travel simultaneously over one medium
• Subchannels
• Logical multiple smaller channels
• Multiplexer (mux)
• Combines many channel signals
• Demultiplexer (demux)
• Separates combined signals
• Regenerates them

29

• TDM (time division multiplexing)
• Divides channel into multiple time intervals

30

• Statistical multiplexing
• Transmitter assigns slots to nodes
• According to priority, need
• More efficient than TDM

31

• FDM (frequency division multiplexing)
• Unique frequency band for each communications
  subchannel
• Two types
• Cellular telephone transmission
• DSL Internet access

32

• WDM (wavelength division multiplexing)
• One fiber-optic connection
• Carries multiple light signals simultaneously
• DWDM (dense wavelength division multiplexing)
• Used on most modern fiber-optic networks
• Extraordinary capacity

33
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
• Nonbroadcast
• One transmitter and multiple, defined receivers

34
Relationships Between Nodes (contd.)
35
iClicker Questions
36
A radio dial is tuned to 510 KHz. What part of
the radio transmission is at that frequency?

1. Modem
2. Carrier Wave
3. FM
4. AM
5. Simplex

1 of 4
37
On a telephone call, both people can talk at the
same time. What type of communication is that?

1. Simplex
2. Half-duplex
3. Full-duplex
4. Multiplexer
5. Demultiplexer

2 of 4
38
What type of transmission sends the largest
amount of data through a single fiber optic cable?

1. TDM
2. Statistical multiplexing
3. FDM
4. WDM
5. DWDM

3 of 4
39
What technique combines several signals so they
can be transmitted through a single cable?

1. Multiplexer
2. Demultiplexer
3. Point-to-point
4. Broadcast
5. Point-to-multipoint

4 of 4
40
Throughput and Bandwidth

• Throughput
• Measures amount of data transmitted during given
  time period
• Capacity or bandwidth
• Quantity of bits transmitted per second
• Bandwidth (strict definition)
• Measures difference between highest and lowest
  frequencies medium can transmit
• Range of frequencies
• Measured in hertz (Hz)

41
Throughput
42
Baseband and Broadband

• Baseband transmission
• Digital signals sent through direct current (DC)
  pulses applied to wire
• Requires exclusive use of wires capacity
• Transmit one signal (channel) at a time
• Example Ethernet
• Broadband transmission
• Signals modulated
• Radiofrequency (RF) analog waves
• Uses different frequency ranges
• Does not encode information as digital pulses

43
Transmission Flaws

• Noise
• Any undesirable influence degrading or distorting
  signal
• Types of noise
• EMI (electromagnetic interference)
• EMI/RFI (radiofrequency interference)
• Cross talk
• NEXT (near end cross talk)
• Potential cause improper termination
• Environmental influences
• Heat

44
Transmission Flaws (contd.)
45
Transmission Flaws (contd.)

• Attenuation
• Loss of signals strength as it travels away from
  source
• Signal boosting technology
• Analog signals pass through amplifier
• Noise also amplified
• Regeneration
• Digital signals retransmitted in original form
• Repeater device regenerating digital signals
• Amplifiers and repeaters
• OSI model Physical layer

46
Transmission Flaws (contd.)

• 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

47
Common Media Characteristics

• Selecting transmission media
• Match networking needs with media characteristics
• Physical media characteristics
• Throughput
• Cost
• Size and scalability
• Connectors
• Noise immunity

48
Throughput

• Most significant transmission method factor
• Causes of limitations
• Laws of physics
• Signaling and multiplexing techniques
• Noise
• Devices connected to transmission medium
• Fiber-optic cables allows faster throughput
• Compared to copper or wireless connections

49
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

50
Noise Immunity

• Noise distorts data signals
• Distortion rate dependent upon transmission media
• Fiber-optic least susceptible to noise
• Limit impact on network
• Cable installation
• Far away from powerful electromagnetic forces
• Select media protecting signal from noise
• Antinoise algorithms

51
Size and Scalability

• Three specifications
• Maximum nodes per segment
• Maximum segment length
• Maximum network length
• Maximum nodes per segment dependency
• Attenuation and latency
• Maximum segment length dependency
• Attenuation and latency plus segment type

52
Size and Scalability (contd.)

• Segment types
• Populated contains end nodes
• Unpopulated No end nodes
• Link segment
• Segment length limitation
• After certain distance, signal loses strength
• Cannot be accurately interpreted

53
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

54
Connectors and Media Converters (contd.)
55
iClicker Questions
56
A NIC is rated at 100 Mbps. What specification
has that value?

1. Throughput
2. Bandwidth
3. Baseband
4. Broadband
5. Noise

1 of 4
57
What technique sends data through a cable as DC
pulses.?

1. Throughput
2. Bandwidth
3. Baseband
4. Broadband
5. Noise

2 of 4
58
What problem is caused by attaching plugs
sloppily to an Ethernet cable?

1. EMI
2. NEXT
3. Attenuation
4. Regeneration
5. Latency

3 of 4
59
Which flaw is caused, in part, by the time it
takes the signal to pass through the cable?

1. EMI
2. Attenuation
3. Regeneration
4. Latency
5. Media converter

4 of 4
60
Coaxial Cable

• Central metal core (often copper)
• Surrounded by insulator
• Braided metal shielding (braiding or shield)
• Outer cover (sheath or jacket)

61
Coaxial Cable (contd.)

• High noise resistance
• Advantage over twisted pair cabling
• Carry signals farther before amplifier required
• Disadvantage over twisted pair cabling
• More expensive
• Hundreds of specifications
• RG specification number
• Differences shielding and conducting cores
• Transmission characteristics

62
Coaxial Cable (contd.)

• Conducting core
• American Wire Gauge (AWG) size
• Data networks usage
• RG-6 Used in modern cable TV connections, most
  common
• RG-8 Thicknet--obsolete
• RG-58 Thinnetalso obsolete for data networks
• RG-59 Used for short spans in modern cable TV
  connections

63
Coaxial Cable (contd.)
64
Twisted Pair Cable

• Color-coded insulated copper wire pairs
• 0.4 to 0.8 mm diameter
• Encased in a plastic sheath

65
Twisted Pair Cable (contd.)

• More wire pair twists per foot
• More resistance to cross talk
• Higher-quality
• More expensive
• Twist ratio
• Twists per meter or foot
• High twist ratio
• Greater attenuation

66
Twisted Pair Cable (contd.)

• Hundreds of different designs
• Dependencies
• Twist ratio, number of wire pairs, copper grade,
  shielding type, shielding materials
• 1 to 4200 wire pairs possible
• Wiring standard specification
• TIA/EIA 568
• Twisted pair wiring types
• Cat (category) 3, 4, 5, 5e, 6, and 6e, Cat 7
• CAT 5 most often used in modern LANs

67
Twisted Pair Cable (contd.)

• Advantages
• Relatively inexpensive
• Flexible
• Easy installation
• Spans significant distance before requiring
  repeater
• Accommodates several different topologies
• Handles current faster networking transmission
  rates
• Two categories
• STP (shielded twisted pair)
• UTP (unshielded twisted pair)

68
STP (Shielded Twisted Pair)

• Individually insulated
• Surrounded by metallic substance shielding (foil)
• Barrier to external electromagnetic forces
• Contains electrical energy of signals inside
• May be grounded

69
UTP (Unshielded Twisted Pair)

• One or more insulated wire pairs
• Encased in plastic sheath
• No additional shielding
• Less expensive, less noise resistance

70
UTP (Unshielded Twisted Pair) (contd.)

• EIA/TIA standards
• Cat 3 (Category 3)
• Cat 4 (Category 4)
• Cat 5 (Category 5)
• Cat 5e (Enhanced Category 5)
• Cat 6 (Category 6)
• Cat 6e (Enhanced Category 6)
• Cat 7 (Category 7)

71
UTP (Unshielded Twisted Pair) (contd.)
72
Comparing STP and UTP

• Throughput
• STP and UTP transmit the same rates
• Cost
• STP and UTP vary
• Noise immunity
• STP more noise resistant
• UTP subject to techniques to offset noise
• Size and scalability
• STP and UTP maximum segment length
• 100 meters

73
Comparing STP and UTP (contd.)

• Connector
• STP and UTP use RJ-45 (Registered Jack 45)
• Telephone connections use RJ-11 (Registered Jack
  11)

74
Terminating Twisted Pair Cable

• Patch cable
• Relatively short cable
• Connectors at both ends
• Proper cable termination techniques
• Basic requirement for two nodes to communicate
• Poor terminations
• Lead to loss or noise
• TIA/EIA standards
• TIA/EIA 568A
• TIA/EIA 568B

75
(No Transcript)
76

• Straight-through cable
• Terminate RJ-45 plugs at both ends identically
• Crossover cable
• Transmit and receive wires on one end reversed

77
Terminating Twisted Pair Cable (contd.)

• Termination tools
• Wire cutter
• Wire stripper
• Crimping tool

78
Terminating Twisted Pair Cable (contd.)

• After making cables
• Verify data transmit and receive

79
iClicker Questions
80
Which type of cable is the most expensive?

1. Coaxial
2. STP
3. UTP
4. Straight-through
5. Crossover

1 of 4
81
Which type of cable has the most noise resistance?

1. Coaxial
2. STP
3. UTP
4. Straight-through
5. Crossover

2 of 4
82
What type of cable is the cheapest and most
common?

1. Coaxial
2. STP
3. UTP
4. Crossover

3 of 4
83
Which type of cable can be used to connect two
computers together without using any other
connectivity devices?

1. Coaxial
2. STP
3. UTP
4. Straight-through
5. Crossover

4 of 4
84
Fiber-Optic Cable

• Fiber-optic cable (fiber)
• One (or several) glass or plastic fibers at its
  center (core)
• Data transmission
• Pulsing light sent from laser
• LED (light-emitting diode) through central fibers
• Cladding
• Layer of glass or plastic surrounding fibers
• Different density from glass or plastic in
  strands
• Reflects light back to core
• Allows fiber to bend

85
Fiber-Optic Cable (contd.)

• Plastic buffer
• Outside cladding
• Protects cladding and core
• Opaque
• Absorbs any escaping light
• Kevlar strands (polymeric fiber) surround plastic
  buffer
• Plastic sheath covers Kevlar strands

86

• Different varieties
• Based on intended use and manufacturer
• Two categories
• Single-mode
• Multimode

87
SMF (Single-Mode Fiber)

• Uses narrow core (lt 10 microns in diameter)
• Laser generated light travels over one path
• Little reflection
• Light does not disperse
• Accommodates
• Highest bandwidths, longest distances
• Connects carriers two facilities
• Costs prohibit typical LANs, WANs use

88
SMF (Single-Mode Fiber) (contd.)
89
MMF (Multimode Fiber)

• Uses core with larger diameter than single-mode
  fiber
• Common size 62.5 microns
• Laser or LED generated light pulses travel at
  different angles
• Common uses
• Cables connecting router to a switch
• Cables connecting server on network backbone

90
MMF (Multimode Fiber) (contd.)
91
MMF (Multimode Fiber) (contd.)

• Benefits
• Extremely high throughput
• Very high resistance to noise
• Excellent security
• Ability to carry signals for much longer
  distances before requiring repeaters than copper
  cable
• Industry standard for high-speed networking
• Drawback
• More expensive than twisted pair cable
• Requires special equipment to splice

92
MMF (Multimode Fiber) (contd.)

• Throughput
• Reliable transmission rates
• Can reach 100 gigabits (or 100,000 megabits) per
  second per channel (but only for singlemode, not
  multimode)
• Cost
• Most expensive transmission medium
• Connectors
• ST (straight tip)
• SC (subscriber connector or standard connector)
• LC (local connector)
• MT-RJ (mechanical transfer registered jack)

93
MMF (Multimode Fiber) (contd.)

• Noise immunity
• Unaffected by EMI
• Size and scalability
• Segment lengths vary
• 150 to 40,000 meters
• Due primarily to optical loss

94
(No Transcript)
95
DTE (Data Terminal Equipment) and DCE (Data
Circuit-Terminating Equipment) Connector Cables

• DTE (data terminal equipment)
• Any end-user device
• DCE (data circuit-terminating equipment)
• Device that processes signals
• Supplies synchronization clock signal

96
DTE and DCE Connector Cables (contd.)

• DTE and DCE connections
• Serial
• Pulses flow along single transmission line
• Sequentially
• Serial cable
• Carries serial transmissions

97
DTE and DCE Connector Cables (contd.)
98
DTE and DCE Connector Cables (contd.)

• RS-232 (Recommended Standard 232)
• EIA/TIA standard
• Physical layer specification
• Signal voltage, timing, compatible interface
  characteristics
• Connector types
• RJ-45 connectors, DB-9 connectors, DB-25
  connectors
• RS-232 used between PC and router today
• RS-232 connections
• Straight-through, crossover, rollover

99
Structured Cabling

• Cable plant
• Hardware making up enterprise-wide cabling system
• Standard
• TIA/EIA joint 568 Commercial Building Wiring
  Standard

100
(No Transcript)
101
(No Transcript)
102
Structured Cabling (contd.)

• Components
• Entrance facilities
• MDF (main distribution frame)
• Cross-connect facilities
• IDF (intermediate distribution frame)
• Backbone wiring
• Telecommunications closet
• Horizontal wiring
• Work area

103
(No Transcript)
104
Structured Cabling (contd.)
105
(No Transcript)
106
Best Practices for Cable Installation and
Management

• Choosing correct cabling
• Follow manufacturers installation guidelines
• Follow TIA/EIA standards
• Network problems
• Often traced to poor cable installation
  techniques
• Installation tips to prevent Physical layer
  failures

107
iClicker Questions
108
Which type of cable has the highest throughput
and range?

1. Singlemode fiber optics
2. Multimode fiber optics
3. Coaxial
4. Twisted Pair
5. RS-232

1 of 4
109
Which type of cable uses a core less than 10
microns in diameter?

1. Singlemode fiber optics
2. Multimode fiber optics
3. Coaxial
4. Twisted Pair
5. RS-232

2 of 4
110
What type of cable connects a router to a PC,
using a DB-9 connector?

1. Singlemode fiber optics
2. Multiemode fiber optics
3. DTE
4. DCE
5. RS-232

3 of 4
111
Which type of cable supplies a synchronization
clock signal?

1. Singlemode fiber optics
2. Multiemode fiber optics
3. DTE
4. DCE
5. RS-232

4 of 4