10. Physical Layer

Question 1

What connection must be established before any network communications can occur?

Answer 1

1. A physical connection to a local network

• It can be wired or wireless depending on the setup of the network

Question 2

What things that enables a device to connect to a network?

Answer 2

1. Network Interface Card ( NIC )

• Some device may have just one NIC, while others may have multiple NICs
• Not al physical connections ofter the same level of performance

Question 3

Where does the Physical Layer accepts the complete frame from?

Answer 3

1. Data Link Layer

• Then encodes it as a series of signals that are transmitted to the local media

Question 4

What layer is the last step in the encapsulation?

Answer 4

1. Physical Layer

Question 5

What does physical layer do?

Answer 5

1. Transport bits across the network media

Question 6

Who governed the TCP/IP standards?

Answer 6

1. IETF

Question 7

What organizations manages physical layer standards?

Answer 7

1. ISO
2. EIA/TIA
3. ITU-T
4. ANSI
5. IEEE

Question 8

List out the 3 functional areas for Physical Layer Standards

Answer 8

1. Physical Components
2. Encoding
3. Signaling

Question 9

What does encoding do?

Answer 9

1. Conversts the stram of bits into a format recognizable by the next device in the network path

• It provides predictable patterns that can be recognized by the next device

Question 10

List out the encoding methods

Answer 10

1. Manchester
2. 4B/5B
3. 8B/10B

Question 11

What does signaling do?

Answer 11

1. How the bit values, “1” and “0” are represented on the physical medium

• It can be vary based on the type of medium being used

Question 12

What is bandwidth?

Answer 12

1. The capacity at which a medium can carry data

Question 13

What components play a role in determining available bandwidth? ( 3 )

Answer 13

1. Physical media properties
2. Current technologies
3. Laws of Physics

Question 14

What does digital bandwidth measures?

Answer 14

1. The amount of data that can flow from one place to another in a given amount of time; how many bits can be transmitted in a second

Question 15

Explain latency

Answer 15

1. Amount of time ( delays ) for data to travel from one given point to another

Question 16

Explain Throughput

Answer 16

1. The measure of the transfer of bits across the media over a given period of time

• Rate at which data is successfully transferred from one location to another over a network within a specified time period.

Question 17

Explain Goodput and how to calculate it

Answer 17

1. The measure of usable data transferred over a given period of time
2. Goodput = Throughput - Traffic Overhead ( Latency )

Question 18

What is the most common type of cabling used in networks today?

Answer 18

1. Copper Cabling

Question 19

What is the advantages of Copper Cabling? ( 3 )

Answer 19

1. Not expensive
2. Easy to install
3. Low resistance to electrical current flow

Question 20

What is the limitataions of coper cabling?

Answer 20

1. Attenuation
   
   • The longer the electrical signals have to traverl, the weaker they get
2. Electromagnetic Interference ( EMI ) and Radio Frequency Interference ( RFI ) can distort and corrupt the data signals

Question 21

How to mitigate the limitations of copper cabling ? ( 3 )

Answer 21

1. Strict adherence to cable length limits will mitigate attenuation
2. Some kinds of copper cable mitigate EMI and RFI by using metallic sheilding and grounding
3. Some kinds of copper cable mitigate crosstalk by twisting opposing circult pair wires together

Question 22

List out the methods for copper cabling ( 3 )

Answer 22

1. Unshielded Twisted-Pair ( UTP )
2. Shielded Twisted-Pair ( STP )
3. Coaxial Cable

Question 23

What copper cabling methods is the most common networking media?

Answer 23

1. Unshielded Twisted Pair ( UTP )

• Interconnects hosts with intermediary network devices

Question 24

What does UTP terminated with ? ( What type of connectors )

Answer 24

1. RJ-45

Question 25

List out the 3 key characteristics of UTP

Answer 25

1. The outer jacket protects the copper wires from physical damage 2. Twisted pairs protect the signal from interference 3. Color-coded plastic insulation electrically isolates the wires from each other and identifies each pair

Question 26

List out 3 comparison between STP and UTP

Answer 26

1. Better noise protection than UTP 2. More expensive than UTP 3. Harder to install than UTP * Interconnects hosts with intermediary network devices

Question 27

What does STP terminated with ? ( What type of connectors )

Answer 27

1. RJ-45

Question 28

List out the 4 key characteristics of STP

Answer 28

1. The outer jacket protects the copper wires from physical damage 2. Braided or Foil Sheild provides EMI/RFI protection 3. Foil shield for each pair of each wires provides EMI/RFI protection 4. Color-coded plastic insulation electrically isolates the wires from each other and identifies each pair

Question 29

List out the 4 key characteristics of Coasial Cable

Answer 29

1. Outer Cable Jacket to prevent minor physical damage 2. A woven copper braid, or metallic foil, acts as the second wire in the circuit and as a shield for the inner conductor 3. A layer of flexible plastic insulation 4. A copper conductor is used to transmit the electronic signals

Question 30

List out the connectors for Coaxial Connectors

Answer 30

1. BNC 2. N type 3. F type * Coaxial can be used in Wireless Installations ( Antennas ) or Cable internet installations

Question 31

What does UTP relies to limit crosstalk?

Answer 31

1. Cancellation - Each wire in a pair of wires uses opposite polarity. One wire is negative, the other wire is positive. They are twisted together and the magnetic fields effectively cancel each other and outside EMI/RFI 2. Variation in twists per foot in each wire - Each wire is twisted a different amount, which helps prevent crosstalk amongst the wires in the cable

Question 32

What is the standards for UTP? Who created the standards?

Answer 32

1. TIA/EIA - 568 Standards 2. TIA/EIA

Question 33

What are the TIA/EIA - 568 Standards standardizes elements?

Answer 33

1. Cable Types 2. Cable Lengths 3. Connectors 4. Cable Termination 5. Testing Methods

Question 34

Who established the electrical standards for copper cabling?

Answer 34

1. IEEE

Question 35

List out the examples for Electrical Standards ( 3 )

Answer 35

1. Category 3 2. Category 5 and 5e 3. Category 6

Question 36

List out all the cable colors for copper cable

Answer 36

1. Green 2. Green White 3. Brown 4. Brown White 5. Blue 6. Blue White 7. Orange 8. Orange White

Question 37

List out the cables allocation difference between Copper Straight-Through and Crossover

Answer 37

1. Straight Through - Pair 2 ( Orange ) 2. Crossover - Pair 3 ( Green ) * Slide 25

Question 38

What is the standard for Copper Straight Through ?

Answer 38

1. Both ends T568A or T568B * Host to Network Device

Question 39

What is the standard for Copper Crossover ?

Answer 39

1. One end with T568A, while other end with T568B * Host-to-host, Switch-to-switch, router-to-router

Question 40

Why is Fiber-Optic Cabling not as common as UTP?

Answer 40

1. Because the expense involved * It is ideal for some networking scenarios

Question 41

What is the advantages of Fiber-Optic Cabling? ( 2 )

Answer 41

1. Transmits data over longer distances at higher bandwidth than any other networking media 2. Less susceptible to attenuation, and completely immune to EMI/RFI

Question 42

What is Fiber-Optic Cabling made of?

Answer 42

1. Flexible, extremely thin strands of very pure glass

Question 43

How does Fiber-Optic Cabling encodes bits as pulses of light? ( 2 )

Answer 43

1. Uses a laser 2. LED to encode bits as pulses of light * It acts as a wave guide to transmit light betwen the two ends with minimal signal loss

Question 44

List out the 2 types of Fiber Media

Answer 44

1. Single-Mode Fiber 2. Multimode Fiber

Question 45

What is the description for Single-Mode Fiber? ( 3 )

Answer 45

1. Very small core 2. Uses expensive lasers 3. Long distance applicators

Question 46

What is the description for Multimode Fiber? ( 3 )

Answer 46

1. Larger Core 2. Uses less expensive LEDs 3. LED's transmit ar different angles 4. Up to 10 Gbps over 550 meters

Question 47

What does dispersion refers to?

Answer 47

1. The spreading out of a light pulse over tim.

Question 48

List out the 4 types of industry for Fiber-Optic Cabling

Answer 48

1. Enterprise Networks 2. Fiber-to-the-Home 3. Long-Haul Networks 4. Submarine Cable Network

Question 49

What does Enterprise Networks used for?

Answer 49

1. Backbone cabling applcations and interconnection infrastructure devices

Question 50

What does Fiber-to-the-Home ( FTTH ) ?

Answer 50

1. Used to provide always-on broadband services to homes and small businesses

Question 51

What does Long-Haul Networks used for?

Answer 51

1. Used by service provides to connect countries and cities

Question 52

What does Submarine Cable Networks used to?

Answer 52

1. Used to provide reliable high-speed, high-capacity solutions capable of surviving in harsh undersea environment at up to transoceanic distances

Question 53

What is the bandwidth between UTP cabling and Fibe-Optic Cabling?

Answer 53

1. UTP Cabling ( 10 Mb/s - 10 GB/s ) 2. Fiber-Optic Cabling ( 10Mb/s - 100 CB/s )

Question 54

What is the distance between UTP cabling and Fiber-Optic Cabling?

Answer 54

1. UTP , Relatively Short ( 1 - 100 meters ) 2. Fiber-Optic Cabling , Relatively Long ( 1 - 100,000 meters )

Question 55

What is immune to EMI and RFI UTP cabling or Fiber-Optic Cabling?

Answer 55

1. Fiber-Optic Cabling

Question 56

What is immune to Immunity to electrical hazards UTP cabling or Fiber-Optic Cabling?

Answer 56

1. Fiber-Optic Cabling

Question 57

What has the highest media and connector costs?

Answer 57

1. Fiber-Optic Cabling

Question 58

What has the highest installation skills required?

Answer 58

1. Fiber-Optic Cabling

Question 59

What is the highest Safety Precautions?

Answer 59

1. Fiber-Optic Cabling

Question 60

List out the limitations of wireless media

Answer 60

1. Coverage Area - Effective coverage can be significantly impacted by the physical characteristics of the deployment location 2. Interference - Wireless is susceptible to interference and can be disrupted by many comon devices 3. Security - Wireless communication coverage requires no access to a physical strand of media, so anyone can gain access to the transmission 4. Shared Medium - WLANs operate in half-duplex, which means only onw device can send or receive at a time. Many users accessing the WLAN simultaneously results in reduced bandwidth for each user.

Question 61

What does Wireless Media carries?

Answer 61

1. Carries electromagnetic signals representing binary digits using radio or microwave frequencies 2. This provides the greatest mobility option 3. Wireless connection numbers continue to increase

Question 62

What organizations cover both the data link and physical layer for wireless data communications?

Answer 62

1. IEEE 2. Telecommunications

Question 63

List out the specifications that physical layer dictate

Answer 63

1. Data to radio signal encoding methods 2. Frequency and power of transmission 3. Signal reception and decoding requirements 4. Antenna design and construction

Question 64

List out the wireless standards ( 4 )

Answer 64

1. Wi-Fi ( IEEE 802.11 ) - Wireless LAN ( WLAN ) technology 2. Bluetooth ( IEEE 802.15 ) - Wireless Personal Area network ( WPAN ) standard 3. WiMax ( IEEE 802.16 ) - Uses a point-to-multipoint topology to provide broadband wireless access 4. Zigbee ( IEEE 802.15.4 ) - Low data-rate, low power-consumption communications, primarily for Internet of Things ( IoT ) applications

Question 65

List out the required devices for Wireless LAN ( WLAN ) ( 2 )

Answer 65

1. Wireless Access Point ( AP ) - Concentrate wireless signals from users and connect to the existing copper-based network infrastructure 2. Wireless NIC Adapters - Provide wireless communications capability to network hosts

Question 66

What must be considered when purchasing WLAN equipment?

Answer 66

1. Compatibility 2. Interoperability