data communication & networking csci...

1

Dr. Thomas HicksComputer Science Department

Trinity University 1

Data Communication

& Networking CSCI 3342

Must Consider Protocols

2

3

Protocols

http://www.networksorcery.com/enp/topic/ipsuite.htm

http://www.networksorcery.com/enp/Protocol.htm

http://www.networksorcery.com/

http://www.networksorcery.com/enp/topic/ipsuite.htm

http://www.networksorcery.com/enp/Protocol.htm

Guided & Unguided

Media

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5

Guided & Unguided Transmission Media

6

Guided & Unguided

Host-To-Network Layer Also Called

Link Layer

Computers Use Electromagnetic Signals To Represent Data

Signals Are Transmitted In The Form Of Electromagnetic

Energy!

Electromagnetic Signals Can Travel Through A Vacuum, Air,

Metals, Glass, Fiber, Plastic, Water, & Other Transmission

Media.

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ElectromagneticEnergy

8

Electromagnetic Energy

Power

Voice

Radio Waves

Infrared Light

Visible Light

9

ElectromagneticEnergy

ElectricalFields

MagneticFields

= +

Vibrating In Relation To Each Other

Ultraviolet Light

X Rays

Gamma Rays

Cosmic Rays

Electromagnetic Spectrum - 1

Power Voice Radio Waves

Infrared Light Visible Light Ultraviolet Light

X Rays Gamma Rays Cosmic Rays

Each Of These Forms Of Electromagnetic Energy Has It’s

Place In The Electromagnetic Spectrum.

10

Where Is Ethernet In

This Spectrum?

Electromagnetic Spectrum - 2

Not All Portions Of The Spectrum Have Been Harnessed For

Data Communications.

Voice-band Frequencies Most Often Use ?

Radio Frequencies Use?

Visible Light Frequencies Use ?

11

Metal Cables

Air

Fiber Optic

Straight Wiring

vs

Twisted Pair

12

In The Beginning- Flat Parallel Cable

Early Communication Was Done With Two Flat Parallel

Lines

Generally Encased In Plastic Insulation

Similar To The Electrical Lines In Your Homes.

Lots Of Noise – Limited Distance!

13

Not On The List In The Previous Slide! Not Used Today!

Unshielded Twisted-Pair Cable UTP

2 Medal Conductors – Usually Copper

Colored Plastic Outer Insulation

Most Common Type Of Telecommunication Medium Used

Today

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15

Shielded Twisted-Pair Cable STP

17

Same 16 Units

Of Noise On Top

Wire & 12 On

Bottom Wire

Twisted-Pair Frequency Range

Human Voice Has Frequency Range of 0 to 4 KHz.

Sampling Rate = 2 * Highest Frequency (4000 Hz)

Works Fine For Voice! Phone Company Has Used It For

Years!

Several Grades/Thicknesses

18

Shielded Foil Twisted-Pair (SFTP)

19

Metal Shield Helps Prevent Noise

Metal Shield Helps Avoid Cross-Talk – The

Undesired Effect Of One Channel On Another

Twisted Pairs Often Bundled!

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21

UTP Gage Makes Is The Difference!

UTP Performance

Wiring

Categories

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EIA Grading - UTP

23

Category 1 POTS Analog Voice, ISDN Interface

Door Bell – Not For Data

Category 2 IBM Token Ring – Some Analog Voice

Data <= 4 Mbps

Category 3 Voice/Data 10Base-T

Data <= 16 Mbps

Category 4 16 Mbps Token Ring

Data <= 20 Mbps

Category 5 100Base-T Ethernet

155 Mbps ATM – 1Gbps [4 pair]

Electronic Industries Association

EIA Grading For UTP (cont)

24

Category 5e Data <= 200 Mbps for 100 Meters

(enhanced) 155 Mbps ATM – Gigabit Ethernet [GE]

Category 6 Shielded Foil Twisted-Pair (SFTP)

Super-fast broadband applications

100BaseT, ATM & GE

Signal Rate Up To 200 MHz [4 Pairs]

Category 7 Gigabit Ethernet [GE] at 100 Meters

Super-fast broadband applications

Signal Rate Up To 600 MHz [4 Pairs]

“The Twist" isn't dead. In fact, the music keeps getting faster.

25

Categories of unshielded twisted-pair cables

Category Bandwidth Data Rate Digital/Analog Use

1 very low < 100 kbps Analog Telephone

2 < 2 MHz 2 Mbps Analog/digital T-1 lines

3 16 MHz 10 Mbps Digital LANs





Prices

Continue To Change

26

Look Up 1000' Cat 6?

27

1000 ft Costs $69.99Unshielded Twisted-Pair Cable UTP

Internet Pricing Varies – Cat 6- Complete Cables

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http://www.qualitycables.com

UTP Cable With Boot

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Cat 5

http://www.fourpair.com

2014?

Price

Changes?

31

Cat 6


2014?

Price

Changes?

Cat 5-6Standards

32

33

UTP Ethernet Connections – Generally 8 Pin Cat 5

34

Ethernet Cables – 568A

Tools

35

36

Name The Tool!


37http://www.fourpair.com

Name The Tool!


Name The Tool!

42

http://deepsurplus.site.

yahoo.net/cateforrjrjr.html

Name The Tool!

43http://www.networkingsource.com/502030.html

Name The Tool!

44

http://www.networkingsource

.com/502030.html

Name The Tool!

http://www.networkingsource/

45

Name The Tool!

Coax

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Coaxial Cable - coax

47

Usually

Copper

Metal

Mesh

Coax Signal - RG Ratings

Coaxial Wire Categorized By Radio Government Ratings

Each Different Specs/Thicknesses etc.

48

RG-8 Thick Ethernet RG-58 Thin Ethernet

RG-9 Thick Ethernet RG-59 TV

RG-11 Thick Ethernet

Coax Signal - RG Ratings

Coax Carries Signals Of Higher Frequencies Than Twisted

Pair

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50

Category Impedance Use

RG-59 75 W Cable TV

RG-58 50 W Thin Ethernet

RG-11 50 W Thick Ethernet

Categories Of Coaxial Cable

51

Coaxial Performance

BNC

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53

BNC Connectors

Connectors

54

Coax

Connectors

There Area A

Variety Of Coax

Connectors

55

Fiber Optic

56

57

Fiber Optic Construction

Fiber Optic Cable

Single Strand

58

Fiber Optic Cable - Multi Strand

Made of Glass Or Plastic

Transmit Light Signals

# Fibers Vary – Often More Than One In The Cable

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Optical Fiber Cables

60

Optical Fiber Cables

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There Are Many

Ways To Connect

Cables

Fiber Optic Connectors

There Are Many

Different

Connector Types

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63



Connectors Must Be As Precise As The Cable Itself.

Metal Connectors Provide A Greater Degree Of Latitude

With Respect To Length. Fiber Connectors Must Be Ultra

Precise.

If Connectors Overly Tight Alter Angle Reflection.

If Connectors Have A Gap Dissipate Signal.

64

About Fiber Optic Communication

65

Light - 1

Light Travels 186,000 Miles/Second In A Vacuum.

The Speed Of Light Varies With The Density Of The

Medium.

Light Travels In A Straight Line As Long As It Is Moving

Through A Single Substance.

66

Light - 2

Assume That A Ray Of Light Travel From Air [Less Dense]

Into A Water [More Dense]

The Speed Changes Abruptly.

Refraction - The Change In The Light Angle

67

Light - 3


A Beam Traveling From Less Dense Into More Dense Is

Bent Toward The Vertical Axis.

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Vertical Axis

Angle Of Incidence

Angle Of Refraction

AI > AR

Light – 4

Angles Of Incidence/Refraction


A Beam Traveling From More Dense Into Less Dense Is

Bent Away From The Vertical Axis.

69

Vertical Axis

Angle Of Incidence

Angle Of Refraction

AR > AI

Light – 5

Critical Angle

At Some Point The Change In The Incidence Angle Results

In A Refracted Angle Of 90 Degrees. This Is Called The

Critical Angle.

70

Light – 6

Angle Of Reflection

When The Angle Of Incidence Is Greater Than The Critical

Angle, A Reflection Occurs.

71

Light No Longer Passes Into The Less Dense Medium

Why Fiber? Use A Glass Rod?

We could transmit through a high quality glass rod – Why

Use Fiber Optic Cable?

72

Doesn’t bend very well.

Easily broken..

Light – 7

Optical Fibers Use

Reflection To Guide Light

Through A Channel.

73

Fiber Optic Communication

An Optical Fiber is a waveguide for light that consists of :

Core : inner part where wave propagates

Cladding: outer part used to keep wave in core

Buffer: protective coating

Jacket: outer protective shield

74

Fiber Optic Communication

The Glass/Plastic Core Is Surrounded By Less Dense

Glass/Plastic Cladding.

The Idea Is For The Light To Reflect Off The Cladding &

Remain In The Fiber Channel.

Information Is Encoded On The Beam Of Light As A Series

Of On-Off Flashes That Represent 0’s & 1’s.

75

Fiber Optic Communication (cont)

Core Must Be Ultra-pure And Completely Regular In Shape

& Size. Chemical Differences & Irregularities Ruin

Reflections.

Outer Jacket – Teflon, Plastic, Metal Tubing, Metal Mesh,

etc. – Pros & Cons In Strength vs. Installation Ease.

76

Fiber Types

77

Sample Fiber Types

78

Fiber Type Core (microns) Cladding (microns)

62.5/125 62.5 125

50/125 50.0 125

100/140 100.0 140

8.3/125 8.3 125

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Type Core Cladding Mode

50/125 50 125 Multimode, graded-index

62.5/125 62.5 125 Multimode, graded-index

100/125 100 125 Multimode, graded-index

7/125 7 125 Single-mode

Fiber Types

80

Optical Fiber Performance

How LightTravels Through

Fiber

Propagation Modes81

82How Light Propagates/Travels Through Fiber

About Multimode Step-Index Fiber

Step-Index Fibers obtain their name from this abrupt change,

called the step change, in refractive index.

In Step-Index Multimode Fiber, Light Travels In A Straight

Line Until It Reaches The Interface Of The Core & The

Cladding. Then It Changes Abruptly.

Unfortunately Some Of The Beams Strike The Interface At

An Angle Smaller Than The Critical Angle & Are Lost.

This makes Multimode Fiber Inadequate For Precise

Applications!

Since Some Bounce More Than Others, The Sequence

Changes And Must Be Recombined!

83

About Multimode Graded-Index Fiber

In graded-index fibers, the refractive index of the core varies

gradually as a function of radial distance from the fiber

center.

Index Refers To Index Of Refraction.

Graded Fiber Refers To A Difference In Grades. Density

Highest At Core. Density Lowest At Interface.

A Horizontal Beam Straight Through The Core Would Be

The Only Straight Line.

Requires Careful Placement Of Receiver To Reconstruct

Signals Accurately.

The performance of multimode graded-index fibers is usually

superior to multimode step-index fibers.

84

About Single Mode Fiber

Graded Fiber Refers To A Difference In Grades. Density

Highest At Core. Density Lowest At Interface. Is Less Dense

Than Multimode!

Highly Focused Beam Of Light Limit Beams To Small Range

Of Angles – All Close To Horizontal!

Beams Do Not Have To Be Recombined!

85

Light Sources For Fiber Optic

The Fiber Optic Receiving Device Must Have A

Photosensitive Cell Called A Photodiode.

The Fiber Optic Light Source Can Be Light-Emitting Diode

(LED) Or An Injection Laser.

LED’s -Cheaper – Unfocused

Laser – More Expensive – Highly Focused

86

Fiber

Pros & Cons

87

Advantages Of Fiber Optic

Less Noise. Noise Is Not A Factor In Light.

External Light Only Possible

Interference – This Blocked By Outer

Jacket.

Less Signal Attenuation – Greater

Distance – Miles Without Regeneration.

Much Higher Bandwidth

88

Disadvantages Of Fiber Optic

Much More Expensive – Materials Instillation, etc.

Laser Light Source – Can Cost Thousands Of Dollars

Installation Requires Much More Training & Equipment

Fragile - Glass Is More Easily Broken Than Wire.

89

Transmission

90

2 Classes Of Transmission Media

91

Guilded

MediaUnguilded

Media

Coaxial

Cable

Twisted Pair

Cable Fiber-Optic

Cable

Radio Wave

93

Unguilded Media

94

Troposphere – The Portion Of The

Earth’s Atmosphere Extending Out

About 30 Miles

What We Think Of As Air

Where Clouds, Wind, Weather Appear

Jet Travel

96

Ionosphere – The Portion Between The Troposphere

And Outer Space.

Contains Free Electrically Charged Particle

Troposphere

Ionosphere

About Very Low Frequency

Propagation

97

Very Low Frequency – VLF

About Surface Propagation - 1

Very Low Frequency – Propagated As Surface Waves

Through Air & Sea Water.

Radio Waves Travel Through The

Portion Of The Atmosphere

Hugging The Earth

Follows Curvature Of Earth

Greater The Transmit Power,

The Greater The Distance

98

Very Low Frequency – VLF


Does Not Suffer Much Attenuation. [Loss Of Energy]

High Levels Of Atmospheric

Noise [Heat & Electricity]

Used For Long Range Radio

Navigation

Used For Submarine Communication

3 KHz 30 KHz Frequency Range

99

About Low Frequency

Propagation

100

Low Frequency – LF


Very Low Frequency – Propagated As Surface Waves

Through Air

Radio Waves Travel Through The

Portion Of The Atmosphere

Hugging The Earth

Follows Curvature Of Earth

Greater The Transmit Power,

The Greater The Distance

101

Low Frequency – LF


Attenuation/Absorption Is Greater In Daylight.

High Levels Of Atmospheric

Noise [Heat & Electricity]

Used For Long Range Navigation

Used Radio Beacons & Navigational

Locators.

30 KHz 300 KHz Frequency Range

102

About MiddleFrequency

Propagation

103

Middle Frequency – MF

About Tropospheric Propagation - 1

Middle Frequency – Propagated (1) By Line Of Sight From

Antenna To Antenna

Limited By Curvature Of Earth

Middle Frequency –

Propagated (2) By Broadcast

Into Troposphere At Angle

Where Reflected Back Down

To Earth’s Surface

Greater Distance Than Line Of Sight

104



These Frequencies Absorbed By Ionosphere

Distance You Can Cover Is Limited To

The Angle At Which You Can Reflect

Without Entering Ionosphere

Attenuation/Absorption Is Greater

In Daylight.

Most Often Use Line Of Sight To

Reduce Absorption & Increase

Control

105



Used AM Radio, Maritime Radio,

Radio Direction Finding (RDF) &

Emergency Frequencies

300 KHz 3 MHz

Frequency Range

106

About HighFrequency

Propagation

107

High Frequency – HF

About Ionospheric Propagation - 1

High Frequency – Propagated By Higher Frequency

Radio Waves Radiated Into The Ionosphere

Where They Are Reflected Back To

Earth

Density Difference Between

Ionosphere & Troposphere

Cause Signal To Speed Up

Then Bounce Back To Earth

Allows Greater Distance

With Lower Power Output 108

High Frequency – HF

About Ionospheric Propagation - 2

Used Amateur Radio (HAM), Citizen’s Band (CB)

Radio, International Broadcasting,

Military Communication, Long

Distance Aircraft, Long Distance

Ship, Telephone, Telegraph,

Facsimile

3 MHz 30 MHz Frequency Range

109

About VeryHigh Frequency

Propagation

110

Very High Frequency – VHF

About Line-Of-Sight Propagation - 1

Very High Frequency – Transmitted Directly From Antenna

To Antenna

Antenna Must Be Directional

(Facing Each Other)

Antenna Must Be Tall

Enough Or Close Enough

To Avoid Curvature & Terrain

Limitations

Tricky – Radio Transmissions

Can Not Be Focused 111

Very High Frequency – VHF


Radio Waves Can Reflect Off Surface Of Earth Or Parts

Of Atmosphere

These Can Arrive Out Of

Order & Distort Signal.

Used VHF Television [Channels 2-13],

FM Radio, & Aircraft AM Radio

30 MHz 300 MHz Frequency Range

112

About UltraHigh Frequency

Propagation

113

Ultra High Frequency – UHF


Ultra High Frequency – Transmitted Directly From Antenna

To Antenna

Antenna Must Be Directional

(Facing Each Other)

Antenna Must Be Tall

Enough Or Close Enough

To Avoid Curvature & Terrain

Limitations

Tricky – Radio Transmissions

Can Not Be Focused 114

Ultra High Frequency – UHF


Radio Waves Can Reflect Off Surface Of Earth Or

Parts Of Atmosphere.

Used UHF Television[Channels 14-69],

Mobile Telephone, Cellular Radio,

Paging & Microwave Links

300 MHz 3 GHz

Frequency Range

115

About SuperHigh Frequency

Propagation

116

Super High Frequency – SHF

Line-Of-Sight / Space Propagation - 1

Mostly Line-Of-Sight & Some Space Propagation

117



Super High Frequency – (1) Transmitted Microwave Line-

Of-Sight or (2) Transmitted VIA Satellite [SPACE]-

A Broadcast Signal Is Received

By An Orbiting Satellite; The

Satellite Re-broadcasts The

Signal Back To Earth

Line-Of-Sight Off Satellite

118



Used Terrestrial Microwave,

Satellite Microwave, & Radar

Communication

3 GHz 30 GHz

Frequency Range

119

About ExtremelyHigh Frequency

Propagation

120

Extremely High Frequency – EHF

About Space Propagation - 1

Extremely High Frequency – Transmitted VIA Satellite

[SPACE]

A Broadcast Signal Is Received

By An Orbiting Satellite; The

Satellite Re-broadcasts The

Signal Back To Earth

Line-Of-Sight Off Satellite

121

Extremely High Frequency – EHF

About Space Propagation - 2

Microwave Used In Scientific

Applications & Research

Radar, Satellite, &

Experimental Communications

30 GHz 300 GHz

Frequency Range

122

Propagation

Summary

123

124

Band Range Propagation Application

VLF 3–30 KHz Ground Long-range radio navigation

LF 30–300 KHz GroundRadio beacons and

navigational locators

MF 300 KHz–3 MHz Sky AM radio

HF 3–30 MHz SkyCitizens band (CB),

ship/aircraft communication

VHF 30–300 MHzSky and

line-of-sight

VHF TV,

FM radio

UHF 300 MHz–3 GHz Line-of-sightUHF TV, cellular phones,

paging, satellite

SHF 3–30 GHz Line-of-sight Satellite communication

EHF 30–300 GHz Line-of-sight Long-range radio navigation

OmnidirectionalAntenna

125

126

Omnidirectional Antenna

Terrestrial

Microwave

127

Terrestrial Microwave

Microwaves Do Not Follow The

Curvature Of The Earth – Require

Line-Of-Sight Transmission &

Reception Equipment

Antenna’s Mounted On High

Towers, Mountain Tops, etc.

Two Frequencies Required –

Up/Down

Each Frequency Requires

Transmitter & Receiver128

Terrestrial Microwave (cont)

Receiver & Transmitter For Both Frequencies Are Often

Combined Into Same Piece Of Hardware Today

A System Of Repeaters Extend Distance By

Echoing/Amplifying Signal

Original Or Different Frequency Allowed!

129

Microwave

Antenna

130

Types Of Antenna Used For Terrestrial Microwave - 1

Parabolic Dish Antenna – Every Line Parallel To The Line

Of Symmetry Bounces Off The Dish Into The Focus

Extends The Range As Opposed To A Single Receiver.

131

Types Of Antenna Used For Terrestrial Microwave - 2

Horn Antenna – Transmissions Are Broadcast Up The Stem

& Deflected Out In A Narrow Beam.

Likewise Beams are Caught In The Horn And Reflected

Down The Stem.

132

Satellite Communication

133

Satellite Communication

Satellite Communication Is Like The Line-Of-Sight

Microwave Communication – One Of The Stations Is A

Satellite Orbiting The Earth.

The Satellite Acts As A Super High Antenna – The

Curvature Of The Earth Limitation Is Greatly Reduced.

134

Satellite Communication (cont)

Span Continents With Single Bounce!

Adds Communication Capability To Any Location On Earth.

Satellites Expensive – Leasing Time/Frequencies Is

Relatively Cheap

135

GeosynchronousSatellites

136

Geosynchronous Satellites

Line-Of-Sight Requires Sending & Receiving Units Be

Locked Onto Each Other At All Times.

Satellites Must Travel At Exactly The Same Speed As

Earth’s Rotation.

Because Speed Is Based

On Distance From Planet,

Only One One Orbit Is

Geosynchronous – 22,000

Miles From Earth Surface.

100% Coverage – At Least 3 Satellites 120 Degrees.137

Geosynchronous Satellites (cont)

Satellite Frequencies In Gigahertz Range.

Send Over One Band – Receive Over Another Band

Uplink – Up From Earth

To Satellite

Downlink – Down From

Satellite To Earth

138

Frequency Bands For Satellite Communications

139

Ka 17.7 – 21 GHz 27.5 – 31 GHz

Ku 11.7 – 12.2 GHz 14 - 14.5 GHz

C 3.7 – 4.2 GHz 5.925 –6.425 GHz

Band Downlink Uplink

Microwave UseIn Cell Phones

140

Cellular Telephone

Designed To Provide

Stable Communication

Between One Or

More Mobile Uses

Service Provider Must

Be Able To Locate &

Track A Caller

Service Provider Must

Be Able to Transfer Caller

As He/She Moves Into

New Call Area 141

Cellular Telephone (cont)

142

Cell Call

Made

Caller

Moves

To

Cell

Border

Call

Handed

Off

About Cellular Telephone

832 Carriers!

Band = 25MHz = 25,000 KHz

Carrier Frequencies = 30KHz

25,000 KHz / 30 KHz = 833 Carriers Per Band

Each Cell Phone – 1 Carrier Up & 1 Carrier Down

833 Carriers / 2 Carriers = 416 Channels Per Band

2 Bands = 832 Channels Available

143

About Cellular Telephone

832 Carriers!

2 Bands = 832 Channels Available

Some Channels Used For Controls

To Prevent Interference, Adjacent Cells Can Not Use The

Same Channels

Each Cell Normally Has Access To

Only 40 Channels

MTSO – Mobile Telephone

Switching Office

144

Microwave UseIn Wireless LANs

145

Inferared

146

Infrared

Short Range Communication

High Frequencies

Can't Penetrate Walls

Sun's Waves Interfere With It

Remotes! Wireless Keyboards! Wireless Mice!

147

Impairment

Revisited

148

Transmission Impairment

149

Attenuation

Attenuation – Loss Of Energy

When A Signal Is Transmitted Across A Medium, It Loses

Some Of Its Signal Strength Overcoming The Resistance Of

The Line.

150

Attenuation (cont)

Attenuation – Loss Of Energy

Why An Electrical Line Gets Warm Or Hot After Time.

Amplifiers Are Used To Amplify/Regenerate The Signal

151

Distortion

Distortion Means The Signal Changes Shape.

152

Noise

Noise

Thermal Noise – Random Electron Motion

Induced Noise – From Appliances

Cross Talk – One Wire Interfering With Another

Impulse Noise – Short High Energy Spike – Lightning,

Power Generators, etc.

153

Summary

154

155

Radio waves are used

for multicast

communications, such as

radio and television, and

paging systems.

Note:

156

Microwaves are used for

unicast communication such

as cellular telephones,

satellite networks, and

wireless LANs.

Note:

157

Infrared signals can be

used for short-range

communication in a closed

area using line-of-sight

propagation such as remote

controls.

Note:

The Network Administrator Must

Consider Many Things

158

When Comparing Media You Should Consider The Following

Cost : Materials + Installation

Speed : Maximum Number Bits/Second

Attenuation – Tendency Of Signal To Become

Weak/Distorted Over Distance

Electromagnetic Interference (EMI) – Susceptibility Of

Medium To External Magnetic Energy Interference. (Snow :

Video & Static : Audio)

Security – Protection Against Eavesdropping

159

160

Data Communications & Networking

CSCI 3342

Dr. Thomas E. HicksComputer Science Department

Trinity University

Textbook: Computer Networks

By Andrew Tanenbaum

Textbook: Data Communications & Networking

By Behrouz Forouzan

Special Thanks To WCB/McGraw-Hill For Providing

Graphics For

Many Text Book Figures For Use In This Presentation.

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