Credits Copyright Wiley Copyright The Mc

Credits: Copyright © Wiley Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. Jozef Goetz, 2014 expanded by Jozef Goetz, 2014 1

• Identify the various guided transmission media • Twisted pair • Coaxial cable • Optical Fiber • Describe the various types of wireless transmission • Terrestrial Microwave • Satellite Microwave • Broadcast Radio • Infrared Jozef Goetz, 2014 2

Transmission medium and physical layer Transmission media are actually located below the physical layer and directly controlled by the physical layer We can say that transmission media belong to layer zero Jozef Goetz, 2014 3

Transmission medium and physical layer signals are transmitted from one device to another in the form of electromagnetic energy, which is propagated through transmission media. Jozef Goetz, 2014 4

Transmission medium Electromagnetic energy, a combination of electric and magnetic fields. n Each of the following constitutes a portion of the electromagnetic spectrum vibrating in relation to each other, includes: n n power, radio waves n n infrared light, visible light, ultra violet light, and X, gamma, and cosmic rays. Jozef Goetz, 2014 5

CONCEPTS AND TERMINOLOGY Data transmission occurs between transmitter and receiver over some transmission medium. Transmission Media Guided Media Unguided Media The electromagnetic waves are guided along a physical path. The electromagnetic waves are not guided. Examples: • twisted pair, • coaxial cable, and • optical fiber Examples: • propagation through air, • vacuum, and • sea water. Jozef Goetz, 2014 6

Figure Classes of transmission media Transport signals in the form of electric current. Jozef Goetz, 2014 7

Guided Media Twisted Pair Cable Coaxial Cable Fiber Optic Cable Jozef Goetz, 2014 8

TRANSMISSION MEDIA [1] Physical Description [2] Types [3] Transmission Characteristics [4] Applications Jozef Goetz, 2014 9

Twisted-pair cable insulator Jozef Goetz, 2014 conductor 10

TWISTED PAIR PHYSICAL DESCRIPTION • Consists of a twisted pair of two insulated copper wires. • A wire pair acts as a single communication link. • Typically 4 pairs, or 8 wires in a cable. • Over longer distances, cables may contain hundreds of pairs • Twisting tends to decrease the crosstalk and noise interference. Jozef Goetz, 2014 11

UTP (Unshielded Twisted-Pair) cables and STP (Shielded Twisted-Pair) cables Used by IBM, better prevention of noise and crosstalk n n Shielded twisted pair (STP) has metallic foil-like shield placed around wires Unshielded twisted pair (UTP) is twisted pair cable without outer shielding 12 Jozef Goetz, 2014

TWISTED PAIR TRANSMISSION CHARACTERISTICS [1] UTP (Unshielded Twisted Pair) Subject to external electromagnetic interference. [2] STP (Shielded Twisted Pair) Less susceptible (affected) to interference by shielding twisted pair with metallic braid. Jozef Goetz, 2014 13

Table: Categories of unshielded twisted-pair cables UTP 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 4 20 MHz 20 Mbps Digital LANs 5 100 MHz 100 Mbps Digital LANs 6 200 MHz 200 Mbps Digital LANs 7 600 MHz 600 Mbps Digital LANs Electric Industrial Association EIA-568 -A recognizes many categories of Jozef Goetz, 2014 UTP (unshielded twisted-pair cables ) cabling 14

Table Categories of unshielded twisted-pair cables Jozef Goetz, 2014 15

Impairment types Attenuation = means loss of energy Distortion means the signal changes its form or shape Noise is another cause of impairment Jozef Goetz, 2014 16

Attenuation = means loss of energy to overcome the resistance of the medium (converted to heat) We can use the decibel to measure the changes in the strength of a signal The decibel (d. B) measures the relative strength of 2 signals A = 10 log 10 (P 2/P 1) [d. B] where P 1 and P 2 are the powers of a signal at points 1 and 2, respectively. If A < 0 a signal is attenuated If A > 0 a signal is amplified Jozef Goetz, 2014 17

TWISTED PAIR TYPES Crosstalk (XT) is any phenomenon by which a signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel. Crosstalk is usually caused by undesired capacitive, inductive, or conductive coupling from one circuit, part of a circuit, or channel, to another. Near end crosstalk (NEXT) Interference between two pairs in a cable measured at the same end of the cable as the interfering transmitte Jozef Goetz, 2014 18

Unshielded Twisted Pair UTP n Why unshielded twisted pair wire is preferred in modern Ethernet network configurations: n n n It is cheaper than other types of cabling. It is easy to work with. It allows transmission rates that were impossible 10 years ago. Jozef Goetz, 2014 19

RJ Connectors n UTP uses registered jack (RJ) connectors n RJ-11 connects a phone to a phone jack n n Used with UTP cable similar to Category 1 cable and uses two pairs (four wires) RJ-22 used for handsets of older style telephones n RJ-45 is used in Ethernet data networks Uses four pairs of wires (eight wires) n Usually associated with Category 3 or higher UTP Jozef Goetz, 2014 wire n 20

Figure UTP connector is RJ 45 (Registered Jack) connector Eight-position, shielded modular connector. UTP connector is a keyed connector – inserted in only one way Jozef Goetz, 2014 21

Figure UTP performance increases with f above 100 KHz and gauge [gejdz] The attenuation is measured in decibels per mile Jozef Goetz, 2014 22

TWISTED PAIR APPLICATIONS By far the most common transmission medium for both analog and digital signals is twisted pair. Most commonly used medium in the telephone network and is the workhorse for communications within buildings (PBX). Twisted pair is only commonly used within a building for LAN. Data rates supported: 10 Mbps, 100 Mbps, even recently 1 Gbps. Jozef Goetz, 2014 23

TWISTED PAIR APPLICATIONS Used for both Digital and Analog transmission. For analog signals, amplifiers are required every 5 to 6 km. For digital transmission, repeaters are required every 2 km Jozef Goetz, 2014 24

Coaxial cable Jozef Goetz, 2014 25

COAXIAL CABLE PHYSICAL DESCRIPTION • Coaxial cables consists of two conductors: outer conductor, and inner conductor made of copper. • The dielectric material separates the inner from the outer conductor. • The outer conductor is covered with a plastic jacket/shield. n n Shield covered by PVC or Teflon-type covering frequently referred to as a plenum-rated coating n Jozef Goetz, 2014 Does not release toxic gases if it catches on fire 26

COAXIAL CABLE TYPES TWO TYPES: [1] Thinnet more flexible, lower bandwidth [2] Thicknet less flexible, higher bandwidth Jozef Goetz, 2014 27

Categories of coaxial cables Impedance Use RG-59 75 W Cable TV 50 W Thin Ethernet RG-11 Jozef Goetz, 2014 Category RG-58 RG – radio government rating 50 W Thick Ethernet 28

Thin Ethernet or Thinnet n A thin coaxial cable n 10 Base-2 n 10 mbps data rates for up to 200 meters Jozef Goetz, 2014 29

F-Connector n n Coaxial cable connector Commonly used in broadband home video applications, such as cable television Jozef Goetz, 2014 30

RG-59 n Coaxial cable is used for low-power video and audio transmission n n Connects DVD to TV, for example Can be used for data runs longer than 100 meters n UTP limited to 100 -meter data runs Jozef Goetz, 2014 31

RG-6 n n Used for cable TV inside house as well as from the external drop point into the house Also used in fast broadband Internet connections Jozef Goetz, 2014 32

Broadband over Power Line (BPL) n n IEEE 1901 standard Standard power grid and power cables carry electricity and data n Uses same cabling as the power in a house n Not available in the United States n Useful for rural areas and third-world areas Jozef Goetz, 2014 33

BNC connectors n Used with Thinnet cables (Thin Internet) to device computer to Ethernet used at the end to prevent the reflection of the signal Jozef Goetz, 2014 34

COAXIAL CABLE TRANSMISSION CHARACTERISTICS Used for both Digital and Analog transmission. Using FDM (Frequency-division multiplexing), a coaxial cable can carry over 10, 000 voice channels simultaneously. [1] Freq. characteristics – needs the frequent use of repeaters [2] Can be used for higher data rates. [3] Higher bandwidth (analog up to 500 MHz). [4] Less vulnerable to crosstalk & interference. Jozef Goetz, 2014 35

Figure Coaxial cable performance needs the frequent use of repeaters Jozef Goetz, 2014 36

COAXIAL CABLE APPLICATIONS • most versatile transmission medium and • widespread use in a wide variety of apps. The most important of these are: [1] Television distribution [2] Long distance telephone transmission [3] Short run computer system links [4] Local area networks (LAN) Jozef Goetz, 2014 37

OPTICAL FIBER TRANSMISSION CHARACTERISTICS • Optical fibers have greater information capacity than metallic cables. • Optical fibers use light instead of electricity to transmit information. Jozef Goetz, 2014 38

Concept of bending of light ray the light bends along the interface the ray reflects and travels again in the denser substance cladding (covering layer) is less dense glass or plastic • Optical fibers use the concept of total internal reflection Jozef Goetz, 2014 39

OPTICAL FIBER PHYSICAL DESCRIPTION • An optical fiber has a cylindrical shape with three concentric section: Core, Cladding, and Jacket. • Core & Cladding have different optical properties. • Optical fibers use the concept of total internal reflection n Light is dispersed on numerous paths as it travels through the core and is reflected back n Cladding used to line the core and focus the light back onto it Jozef Goetz, 2014 40

Fiber-Optic Cabling n n Transmits digital signals using light impulses rather than electricity Immune to Electro. Magnetic Interference (EMI) and Radio Frequency Interference (RFI) Works by allowing light impulses to be carried through either a glass or plastic core Is single-mode fiber (SMF) or multimode fiber (MMF) Jozef Goetz, 2014 41

Propagation modes propagation of different beams is almost identical (horizontal) multiple beams from light source move via the core in different path Jozef Goetz, 2014 42

Modes the index of refraction is related to density of the core is constant and suddenly degreases at the edge density of the core is highest at the center and degreases gradually to its lowest at the ed propagation of different beams is almost identical (horizontal) Jozef Goetz, 2014 43

Fiber types Multimode Fiber: Provides high bandwidth at high speeds over medium distances (up to about 3, 000 feet) Single Mode Fiber - SMF n n A very high-speed, long-distance fiber-optic cable Consists of one or two strands of fiberglass that carries the signals Lasers are primary light sources Spans very long distances because it can transmit data 50 times farther than multimode fiber at a faster rate numbers in micrometers 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 Single-mode 7/125 Jozef Goetz, 2014 44

Fiber construction the jacket made of PVC or Teflon Jozef Goetz, 2014 45

Fiber-optic Cable Connectors n n SC: Are latched – secure and prevent from falling out Work with single-mode and multimode optical fibers Last for around 1, 000 matings – good for 1000 connections/disconnections SC - Subscriber Connector (in TV) Jozef Goetz, 2014 ST: n n One of the most widely used fiber-optic connectors Uses a BNC style attachment ST – Straight-Tip (in network) new the same size as RJ 45 46

n Fiber-Optic Small Form Factor - SFF Connector Allows more fiber optic terminations in the same amount of space than its standard sized counterparts: 1/3 the size of SC and ST n Two most common versions: n n Mechanical Transfer Registered Jack (MT-RJ or MTRJ) Local Connector (LC) Jozef Goetz, 2014 47

Fiber-Optic Local Connector (LC) n n Newer style of SFF fiber optic connector Popular for use with Fibre-Channel (FC) adapters Used for fast storage area networks and Gigabit Ethernet adapters Similar +’s as MT-RJ and SFF but are easier to terminate and uses a ceramic insert Jozef Goetz, 2014 48

Optical fiber performance • flatter than in case of twisted and coaxial ones • need 10 times less repeaters Jozef Goetz, 2014 49

TRANSMISSION CHARACTERSTICS OF GUIDED MEDIA Jozef Goetz, 2014 50

OPTICAL FIBER APPLICATIONS One of the most significant technological breakthroughs in data transmission was the development of practical fiber optic communications systems. Five most important apps for optical fiber: [1] Metropolitan trunks (12 km in length) [2] Rural exchange trunks (40 160 km in length) [3] Subscriber loops [4] Long-haul trunks (1500 km in length) Jozef Goetz, 2014 51

+’s n [1] Greater capacity >> 10 Gbps / per single fiber n n n n n transfer data at a rate of 1600 Gbps with WDM [2] Smaller size and lighter weight. [3] Lower attenuation. [4] Electromagnetic isolation. [5] Less repeaters. [6] Higher bandwidth [7] Resistance to corrosive materials [8] Immune to EMI and RFI [9] Can transmit up to 40 kilometers, about 25 52 miles, in a single hop Jozef Goetz, 2014

-’s n n [1] unidirectional [2] high cost n n More expensive than twisted-pair [3] installation/maintenance need expertise n n Troubleshooting equipment is expensive More difficult to troubleshoot Jozef Goetz, 2014 53

WIRELESS TRANSMISSION For unguided media, transmission and reception are achieved by means of an antenna. For transmission, the antenna radiates electromagnetic energy into the medium (air). For reception, the antenna picks up electromagnetic energy from the surrounding medium. Jozef Goetz, 2014 54

Electromagnetic spectrum for wireless communication • Transport waves without using a physical conductor 1. Radio Waves 3 KHz – 1 GHz 2. Microwaves 1 GHz – 400 GHz 3. Infrared 400 GHz – 400 THz Jozef Goetz, 2014 55

Wireless transmission waves Jozef Goetz, 2014 56

Radio propagation methods • follow the curvature of the planet • the greater the power, the greater the distance • very high f signals are transmitted in straight lines • directly from antenna to antenna • antennas must be directional, facing each other • , tall and close enough • wave radiate upward into the ionosphere • where they are reflected back to the earth • greater the distances with lower power output Jozef Goetz, 2014 57

Bands Band Range Propagation Application VLF 3– 30 KHz Ground Long-range radio navigation LF 30– 300 KHz Ground Radio beacons and navigational locators MF 300 KHz– 3 MHz Sky AM radio HF 3– 30 MHz Sky Citizens band (CB), ship/aircraft communication VHF 30– 300 MHz Sky and line-of-sight VHF TV, FM radio UHF 300 MHz– 3 GHz Line-of-sight UHF 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 Jozef Goetz, 2014 58

WIRELESS TRANSMISSION There are two types of configuration: [1] directional focused electromagnetic beam [2] omnidirectional Jozef Goetz, 2014 59

Omnidirectional antennas • Radiates the signal outward equally in all directions. • They are shaped like a tall pole and have their highest sensitivity in horizontal direction. • They are used to cover large areas where the exact location of the receiver is unknown. • Power is radiated and weakens proportionally to the expanding surface of the sphere. • Different antennas have different energy dispersion patterns Jozef Goetz, 2014 60

Applications: Radio waves are used for multicast communications (one sender, many receiver), such as • radio AM, FM • television UHF, VHF, • paging systems. Jozef Goetz, 2014 61

Unidirectional antennas [1] Most common type of microwave antenna is the parabolic “dish”. Typical size: 3 m in diameter. [2] Antenna is fixed rigidly and focuses a narrow beam to achieve a line-of-sight transmission to the receiving antenna. Jozef Goetz, 2014 62

Applications: Microwaves are used for unicast communication such as • cellular telephones, • satellite networks, and • wireless LANs. Jozef Goetz, 2014 63

MICROWAVE APPLICATIONS Three most important applications: [1] Used for both voice and television transmission [2] Long haul telecommunications services [3] Point-to-Point data links between buildings Jozef Goetz, 2014 64

MICROWAVE TRANSMISSION CHARACTERISTICS • The potential data rate depends directly on the frequency used. • The higher the frequency used, the higher the potential bandwidth and higher the potential data rate. • Common frequencies used: 2 to 40 GHz. Repeater spacing: 10 to 100 km is typical. Major Problem: rainfall [attenuation] Jozef Goetz, 2014 65

SATELLITE MICROWAVE PHYSICAL DESCRIPTION A communication satellite is a microwave relay station It is used to link two or more ground-based microwave transmitters/receivers. The satellite receives transmission on one frequency band (uplink), amplifies or repeats the signal, and transmits it on another frequency (downlink). Jozef Goetz, 2014 66

SATELLITE MICROWAVE SATELLITE COMMUNICATIONS CONFIG. There are two common configuration for satellite communication Jozef Goetz, 2014 67

SATELLITE MICROWAVE APPLICATIONS The most important applications for satellites: [1] Television distribution [2] Long-distance telephone transmission [3] Private business networks Jozef Goetz, 2014 68

SATELLITE MICROWAVE TRANSMISSION CHARACTERISTICS The optimum frequency range for satellite transmission is in the range of 1 to 10 GHz. Because of the long distances involved, there is a long propagation delay of 250 ms [round trip]. The delay is notable in ordinary telephone conversations. Also it causes problems with error control and flow control. Jozef Goetz, 2014 69

SATELLITE MICROWAVE VSAT - Very Small Aperture Terminal Jozef Goetz, 2014 70

INFRARED Infrared communications is achieved using transceivers that modulate noncoherent infrared light. Transmission Characteristics [1] Doesn’t penetrate walls. [2] No licensing is required. The most important applications for infrared: [1] Remote controls [2] Laptops [3] Wireless printers Jozef Goetz, 2014 71

Note: Infrared signals can be used for short-range communication in a closed area using line-ofsight propagation. • a data rate of 75 Kbps for a distance up to 8 m • recent standard a data rate of 4 Mbps • f = 300 GHz – 400 THz (1 mm – 770 nm) Jozef Goetz, 2014 72

Summary Radio waves are used for multicast communications, such as radio and television, and paging systems. Microwaves are used for unicast communication such as cellular telephones, satellite networks, and wireless LANs. Infrared signals can be used for short-range communication in a closed area using line-of-sight propagation. Jozef Goetz, 2014 73

Installing Wiring Distributions p. 67 -71 n Many components involved in wiring a computer network n n n Cables and connectors Cross connects Patch panels Jacks Devices connectors go into More Jozef Goetz, 2014 74

n n Vertical and Horizontal Cross-Connects Cross-connect is a location within a cabling system where all wires come together Cables that run from communications closets to wall outlets are horizontal connect cables n Vertical connect cables are backbone cables that n n connect equipment rooms, telecommunications rooms, and Jozef Goetz, 2014 75

Vertical and Horizontal Cross-Connects n Patch cable is any cable that has a connector on both ends and n is used to connect a network device to a network device, a wall jack to a network device, or a network device to a patch panel Jozef Goetz, 2014 76

Patch Panels n n Rack or wall-mounted structures that house cable connections Types of patch panels n n 66 block 110 block Demarc/demarc extension Smart jack Jozef Goetz, 2014 77

Front and Back View of Small Patch Panel Jozef Goetz, 2014 78

66 Block n n n Unsuited for network communications speeds faster than 10 mbps Considered legacy 25 pair capacity Jozef Goetz, 2014 79

MDF and IDF n Main Distribution Frame (MDF) n n n A wiring point generally used as a reference point for network and telephone lines Installed in building as part of prewiring process Intermediate Distribution Frame (IDF) n n Located in an equipment or telecommunications room Connected to MDF by a backbone cable Jozef Goetz, 2014 80

110 Block n n Use for computer networking One side has RJ-11 jacks (for phone connections) or RJ-45 jacks (for network connections) Jozef Goetz, 2014 81

Demarc/Demarc Extension n Demarc (demarcation point) is last point of responsibility of the service provider n n Is often at the MDF in a large building Demarc extension is length of copper or fiber that begins after the demarc but does not reach all the way up to your office n Most often used when the external service enters your building somewhere other than the MDF Jozef Goetz, 2014 82

Smart Jack n n Also called a Network Interface Device (NID) owned by the Public Switched Telephone Network (PSTN) A special network interface often used between the service provider’s network and the internal network Service provider may install a NID that has power and can be looped for testing purposes Jozef Goetz, 2014 83

Verifying Correct Wiring Installation n What can go wrong? n n n Copper cables placed too close to a magnetic source Cable jackets ripped off when pulling cable Cables cut wrong and extended beyond the maximum length for their type Fiber optic cables handled roughly or poorly installed Test, test, and test again Jozef Goetz, 2014 84

Wiring Best Practices n Install more cables than necessary n n If a cable goes bad in the future, an extra cable can take the place of the bad cable Keep detailed records Jozef Goetz, 2014 85

Verifying Proper Wiring Termination n n Inspect the installation Verify that all wires are terminated properly in the right order Fiber-optic termination requires specialized and expensive equipment and training Terminate new connections using the appropriate tools Jozef Goetz, 2014 86

Wireless Media n Defined by the IEEE 802. 11 standards n n 802. 11 a 802. 11 b 802. 11 g 802. 11 n Jozef Goetz, 2014 87

IEEE 802. 11 n n Most prominent standard for wireless LANs Addresses: n n n n Distance Speed Latency Frequency Channels Channel Bonding MIMO Jozef Goetz, 2014 88

802. 11 a n n n Theoretical maximum throughput is 54 mbps; realistically more like 22 mbps Maximum indoor distance is ~50 feet or 15 meters Maximum outdoor distance is ~100 feet or 30 meters Uses the 5 GHz radio frequency range 8 non-overlapping channels Jozef Goetz, 2014 89

802. 11 b n n n Theoretical throughput of up to 11 mbps; realistically more like 2. 5 mbps Maximum indoor range or distance is ~150 feet or 45 meters Maximum outdoor range is ~300 feet or 90 meters Uses the 2. 4 GHz radio frequency range 3 non-overlapping channels: 1, 6, and 11. Jozef Goetz, 2014 90

802. 11 g n n Uses the same frequency range and same channels as 802. 11 b Has same distance capabilities as 802. 11 b Theoretical throughput is 54 mbps; realistic throughput is ~22 mbps Fully backwards compatible with 802. 11 b Jozef Goetz, 2014 91

802. 11 n n n Uses 5 GHz and 2. 4 GHz frequency ranges Theoretical throughput is 300 to 600 mbps; realistically between 100 and 200 mbps Maximum indoor distance is ~229 feet or 70 meters Maximum outdoor distance is 820 feet or 250 meters Uses channel bonding, where two or more adjacent channels are linked together Jozef Goetz, 2014 92

Comparison of 802. 11 http: //www. jpelectron. com/sample/Info%20 and%20 Documents/Wirel ess%20 Technology%20 Comparison%20 Chart/ Jozef Goetz, 2014 93

Tying It All Together n n Important to know what types of media connect to specific devices and in which order Connecting the wrong type of media to a device, or connecting media in the wrong place, prevents network communication Jozef Goetz, 2014 94

Cable Summary n • n n Common cabling is shielded twisted-pair (STP) or unshielded twisted-pair (UTP). Common grades of twisted pair wires used in LANs are CAT 5, CAT 5 e, and CAT 6 Some cabling is susceptible to EMI (electromagnetic interference) and interference. Fiber optic cabling transmits digital signals using light impulses and is immune to EMI and RFI. Jozef Goetz, 2014 95

Summary (Continued) n n Fiber-optic cabling is Single-Mode Fiber (SMF) or Multimode Fiber (MMF). Patch panels are rack- or wall-mounted structures that house cable connections. Types of patch panels include 66 block, 110 block, demarc/demarc extension, and smart jack. Wireless standards are 802. 11 a, 802. 11 b, 802. 11 g, and 802. 11 n. Jozef Goetz, 2014 96