CCNA 1 v7.0 Modules 4 – 7 Exam Answers

CCNA 1 v7.0 Modules 4 – 7: Ethernet Concepts Exam Answers 2020

1. What is the purpose of the OSI physical layer?

controlling access to media
transmitting bits across the local media*
performing error detection on received frames
exchanging frames between nodes over physical network media

2. Why are two strands of fiber used for a single fiber optic connection?

The two strands allow the data to travel for longer distances without degrading.
They prevent crosstalk from causing interference on the connection.
They increase the speed at which the data can travel.
They allow for full-duplex connectivity.*

3. Which characteristic describes crosstalk?

the distortion of the network signal from fluorescent lighting
the distortion of the transmitted messages from signals carried in adjacent wires*
the weakening of the network signal over long cable lengths
the loss of wireless signal over excessive distance from the access point

4. Which procedure is used to reduce the effect of crosstalk in copper cables?

requiring proper grounding connections
twisting opposing circuit wire pairs together*
wrapping the bundle of wires with metallic shielding
designing a cable infrastructure to avoid crosstalk interference
avoiding sharp bends during installation

5. Match the situation with the appropriate use of network media.

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p5

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p5

6. A network administrator is measuring the transfer of bits across the company backbone for a mission critical financial application. The administrator notices that the network throughput appears lower than the bandwidth expected. Which three factors could influence the differences in throughput? (Choose three.)

the amount of traffic that is currently crossing the network*
the sophistication of the encapsulation method applied to the data
the type of traffic that is crossing the network*
the latency that is created by the number of network devices that the data is crossing*
the bandwidth of the WAN connection to the Internet
the reliability of the gigabit Ethernet infrastructure of the backbone

7. What are two characteristics of fiber-optic cable? (Choose two.)

It is not affected by EMI or RFI.*
Each pair of cables is wrapped in metallic foil.
It combines the technique of cancellation, shielding, and twisting to protect data.
It typically contains 4 pairs of fiber-optic wires.
It is more expensive than UTP cabling is.*

8. What is a primary role of the Physical layer in transmitting data on the network?

create the signals that represent the bits in each frame on to the media*
provide physical addressing to the devices
determine the path packets take through the network
control data access to the media

Explanation: The OSI physical layer provides the means to transport the bits that make up a frame across the network media. This layer accepts a complete frame from the data link layer and encodes it as a series of signals that are transmitted to the local media.

9. With the use of unshielded twisted-pair copper wire in a network, what causes crosstalk within the cable pairs?

the magnetic field around the adjacent pairs of wire*
the use of braided wire to shield the adjacent wire pairs
the reflection of the electrical wave back from the far end of the cable
the collision caused by two nodes trying to use the media simultaneously

Explanation: Crosstalk is a type of noise, or interference that occurs when signal transmission on one wire interferes with another wire. When current flows through a wire a magnetic field is produced. The produced magnetic field will interface the signal carried in the adjacent wire.

10. Refer to the graphic.

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p10

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p10

What type of cabling is shown?

STP
UTP
coax
fiber*

Explanation: Network cabling include different types of cables:
UTP cable consists of four pairs of color-coded wires that have been twisted together and then encased in a flexible plastic sheath.
STP cable uses four pairs of wires, each wrapped in a foil shield, which are then wrapped in an overall metallic braid or foil.
Coaxial cable uses a copper conductor and a layer of flexible plastic insulation surrounds the copper conductor.
Fiber cable is a flexible, extremely thin, transparent strand of glass surrounded by plastic insulation.

11. In addition to the cable length, what two factors could interfere with the communication carried over UTP cables? (Choose two.)

Crosstalk*
bandwidth
size of the network
signal modulation technique
electromagnetic interference*

Explanation: Copper media is widely used in network communications. However, copper media is limited by distance and signal interference. Data is transmitted on copper cables as electrical pulses. The electrical pulses are susceptible to interference from two sources:
Electromagnetic interference (EMI) or radio frequency interference (RFI) – EMI and RFI signals can distort and corrupt the data signals being carried by copper media.
Crosstalk – Crosstalk is a disturbance caused by the electric or magnetic fields of a signal on one wire interfering with the signal in an adjacent wire.

12. Refer to the graphic.

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p12

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p12

What type of cabling is shown?

STP
UTP*
coax
fiber

13. Which two devices commonly affect wireless networks? (Choose two.)

Blu-ray players
home theaters
cordless phones*
microwaves*
incandescent light bulbs
external hard drives

Explanation: Radio Frequency Interference (RFI) is the interference that is caused by radio transmitters and other devices that are transmitting in the same frequency.

14. Which two statements describe the services provided by the data link layer? (Choose two.)

It defines the end-to-end delivery addressing scheme.
It maintains the path between the source and destination devices during the data transmission.
It manages the access of frames to the network media.*
It provides reliable delivery through link establishment and flow control.
It ensures that application data will be transmitted according to the prioritization.
It packages various Layer 3 PDUs into a frame format that is compatible with the network interface.*

Explanation: The data link layer is divided into two sub layers, namely Logical Link Control (LLC) and Media Access Control (MAC). LLC forms a frame from the network layer PDU into a format that conforms to the requirements of the network interface and media. A network layer PDU might be for IPv4 or IPv6. The MAC sub layer defines the media access processes performed by the hardware. It manages the frame access to the network media according to the physical signaling requirements (copper cable, fiber optic, wireless, etc.)

15. What is the function of the CRC value that is found in the FCS field of a frame?

to verify the integrity of the received frame*
to verify the physical address in the frame
to verify the logical address in the frame
to compute the checksum header for the data field in the frame

16. What is contained in the trailer of a data-link frame?

logical address
physical address
data
error detection*

17. Which statement describes a characteristic of the frame header fields of the data link layer?

They all include the flow control and logical connection fields.
Ethernet frame header fields contain Layer 3 source and destination addresses.
They vary depending on protocols.*
They include information on user applications.

Explanation: All data link layer protocols encapsulate the Layer 3 PDU within the data field of the frame. However, the structure of the frame and the fields that are contained in the header vary according to the protocol. Different data link layer protocols may use different fields, like priority/quality of service, logical connection control, physical link control, flow control, and congestion control.

18. A network team is comparing physical WAN topologies for connecting remote sites to a headquarters building. Which topology provides high availability and connects some, but not all, remote sites?

mesh
partial mesh*
hub and spoke
point-to-point

Explanation: Partial mesh topologies provide high availability by interconnecting multiple remote sites, but do not require a connection between all remote sites. A mesh topology requires point-to-point links with every system being connected to every other system. A point-to-point topology is where each device is connected to one other device. A hub and spoke uses a central device in a star topology that connects to other point-to-point devices.

19. Which two fields or features does Ethernet examine to determine if a received frame is passed to the data link layer or discarded by the NIC? (Choose two.)

auto-MDIX
CEF
Frame Check Sequence*
minimum frame size*
source MAC address

20. Which media communication type does not require media arbitration in the data link layer?

deterministic
half-duplex
full-duplex*
controlled access

Explanation: Half-duplex communication occurs when both devices can both transmit and receive on the medium but cannot do so simultaneously. Full-duplex communication occurs when both devices can transmit and receive on the medium at the same time and therefore does not require media arbitration. Half-duplex communication is typically contention-based, whereas controlled (deterministic) access is applied in technologies where devices take turns to access the medium.

21. Which statement describes an extended star topology?

End devices connect to a central intermediate device, which in turn connects to other central intermediate devices.*
End devices are connected together by a bus and each bus connects to a central intermediate device.
Each end system is connected to its respective neighbor via an intermediate device.
All end and intermediate devices are connected in a chain to each other.

Explanation: In an extended star topology, central intermediate devices interconnect other star topologies.

22. What is a characteristic of the LLC sublayer?

It provides the logical addressing required that identifies the device.
It provides delimitation of data according to the physical signaling requirements of the medium.
It places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media.*
It defines software processes that provide services to the physical layer.

23. What are three ways that media access control is used in networking? (Choose three.)

Ethernet utilizes CSMA/CD.*
Media access control provides placement of data frames onto the media.*
Contention-based access is also known as deterministic.
802.11 utilizes CSMA/CD.
Data link layer protocols define the rules for access to different media.*
Networks with controlled access have reduced performance due to data collisions.

24. During the encapsulation process, what occurs at the data link layer for a PC connected to an Ethernet network?

An IP address is added.
The logical address is added.
The physical address is added.*
The process port number is added.

Explanation: The Ethernet frame includes the source and destination physical address. The trailer includes a CRC value in the Frame Check Sequence field to allow the receiving device to determine if the frame has been changed (has errors) during the transmission.

25. What three items are contained in an Ethernet header and trailer? (Choose three.)

source IP address
source MAC address*
destination IP address
destination MAC address*
error-checking information*

Explanation: Layer 2 headers contain the following:
Frame start and stop indicator flags at the beginning and end of a frame
Addressing – for Ethernet networks this part of the header contains source and destination MAC addresses
Type field to indicate what Layer 3 protocol is being used
Error detection to determine if the frame arrived without error

26. What type of communication rule would best describe CSMA/CD?

access method*
flow control
message encapsulation
message encoding

Explanation: Carrier sense multiple access collision detection (CSMA/CD) is the access method used with Ethernet. The access method rule of communication dictates how a network device is able to place a signal on the carrier. CSMA/CD dictates those rules on an Ethernet network and CSMA/CA dictates those rules on an 802.11 wireless LAN.

27. Which three basic parts are common to all frame types supported by the data link layer? (Choose three.)

header*
type field
MTU size
Data*
Tráiler*
CRC value

Explanation: The data link protocol is responsible for NIC-to-NIC communications within the same network. Although there are many different data link layer protocols that describe data link layer frames, each frame type has three basic parts:
Header
Data
Trailer

28. Which statement is true about the CSMA/CD access method that is used in Ethernet?

When a device hears a carrier signal and transmits, a collision cannot occur.
A jamming signal causes only devices that caused the collision to execute a backoff algorithm.
All network devices must listen before transmitting.*
Devices involved in a collision get priority to transmit after the backoff period.

29. What is the auto-MDIX feature on a switch?

the automatic configuration of an interface for 10/100/1000 Mb/s operation
the automatic configuration of an interface for a straight-through or a crossover Ethernet cable connection*
the automatic configuration of full-duplex operation over a single Ethernet copper or optical cable
the ability to turn a switch interface on or off accordingly if an active connection is detected

Explanation: The auto-MDIX enables a switch to use a crossover or a straight-through Ethernet cable to connect to a device regardless of the device on the other end of the connection.

30. Refer to the exhibit.

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p30

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p30

What is the destination MAC address of the Ethernet frame as it leaves the web server if the final destination is PC1?

00-60-2F-3A-07-AA
00-60-2F-3A-07-BB
00-60-2F-3A-07-CC*
00-60-2F-3A-07-DD

Explanation: The destination MAC address is used for local delivery of Ethernet frames. The MAC (Layer 2) address changes at each network segment along the path. As the frame leaves the web server, it will be delivered by using the MAC address of the default gateway.

31. A Layer 2 switch is used to switch incoming frames from a 1000BASE-T port to a port connected to a 100Base-T network. Which method of memory buffering would work best for this task?

port-based buffering
level 1 cache buffering
shared memory buffering*
fixed configuration buffering

32. What are two examples of the cut-through switching method? (Choose two.)

store-and-forward switching
fast-forward switching*
CRC switching
fragment-free switching*
QOS switching

33. Which frame forwarding method receives the entire frame and performs a CRC check to detect errors before forwarding the frame?

cut-through switching
store-and-forward switching*
fragment-free switching
fast-forward switching

Explanation: Fast-forward and fragment-free switching are variations of cut-through switching, which begins to forward the frame before the entire frame is received.

34. What is the purpose of the FCS field in a frame?

to obtain the MAC address of the sending node
to verify the logical address of the sending node
to compute the CRC header for the data field
to determine if errors occurred in the transmission and reception*

Explanation: The FCS field in a frame is used to detect any errors in the transmission and receipt of a frame. This is done by comparing the CRC value within the frame against a computed CRC value of the frame. If the two values do not match, then the frame is discarded.

35. Which switching method has the lowest level of latency?

cut-through
store-and-forward
fragment-free
fast-forward*

Explanation: Fast-forward switching begins to forward a frame after reading the destination MAC address, resulting in the lowest latency. Fragment-free reads the first 64 bytes before forwarding. Store-and-forward has the highest latency because it reads the entire frame before beginning to forward it. Both fragment-free and fast-forward are types of cut-through switching.

36. A network administrator is connecting two modern switches using a straight-through cable. The switches are new and have never been configured. Which three statements are correct about the final result of the connection? (Choose three.)

The link between the switches will work at the fastest speed that is supported by both switches.*
The link between switches will work as full-duplex.*
If both switches support different speeds, they will each work at their own fastest speed.
The auto-MDIX feature will configure the interfaces eliminating the need for a crossover cable.*
The connection will not be possible unless the administrator changes the cable to a crossover cable.
The duplex capability has to be manually configured because it cannot be negotiated.

Explanation: Modern switches can negotiate to work in full-duplex mode if both switches are capable. They will negotiate to work using the fastest possible speed and the auto-MDIX feature is enabled by default, so a cable change is not needed.

37. Which advantage does the store-and-forward switching method have compared with the cut-through switching method?

collision detecting
frame error checking*
faster frame forwarding
frame forwarding using IPv4 Layer 3 and 4 information

Explanation: A switch using the store-and-forward switching method performs an error check on an incoming frame by comparing the FCS value against its own FCS calculations after the entire frame is received. In comparison, a switch using the cut-through switching method makes quick forwarding decisions and starts the forwarding process without waiting for the entire frame to be received. Thus a switch using cut-through switching may send invalid frames to the network. The performance of store-and-forward switching is slower compared to cut-through switching performance. Collision detection is monitored by the sending device. Store-and-forward switching does not use IPv4 Layer 3 and 4 information for its forwarding decisions.

38. When the store-and-forward method of switching is in use, what part of the Ethernet frame is used to perform an error check?

CRC in the tráiler*
source MAC address in the header
destination MAC address in the header
protocol type in the header

39. Which switching method uses the CRC value in a frame?

cut-through
fast-forward
fragment-free
store-and-forward*

Explanation: When the store-and-forward switching method is used, the switch receives the complete frame before forwarding it on to the destination. The cyclic redundancy check (CRC) part of the trailer is used to determine if the frame has been modified during transit.​​ In contrast, a cut-through switch forwards the frame once the destination Layer 2 address is read. Two types of cut-through switching methods are fast-forward and fragment-free.

40. What are two actions performed by a Cisco switch? (Choose two.)

building a routing table that is based on the first IP address in the frame header
using the source MAC addresses of frames to build and maintain a MAC address table*
forwarding frames with unknown destination IP addresses to the default gateway
utilizing the MAC address table to forward frames via the destination MAC address*
examining the destination MAC address to add new entries to the MAC address table

Explanation: Important actions that a switch performs are as follows:
When a frame comes in, the switch examines the Layer 2 source address to build and maintain the Layer 2 MAC address table.
It examines the Layer 2 destination address to determine how to forward the frame. When the destination address is in the MAC address table, then the frame is sent out a particular port. When the address is unknown, the frame is sent to all ports that have devices connected to that network.

41. Which two statements describe features or functions of the logical link control sublayer in Ethernet standards? (Choose two.)

Logical link control is implemented in software.*
Logical link control is specified in the IEEE 802.3 standard.
The LLC sublayer adds a header and a trailer to the data.
The data link layer uses LLC to communicate with the upper layers of the protocol suite.*
The LLC sublayer is responsible for the placement and retrieval of frames on and off the media.

Explanation: Logical link control is implemented in software and enables the data link layer to communicate with the upper layers of the protocol suite. Logical link control is specified in the IEEE 802.2 standard. IEEE 802.3 is a suite of standards that define the different Ethernet types. The MAC (Media Access Control) sublayer is responsible for the placement and retrieval of frames on and off the media. The MAC sublayer is also responsible for adding a header and a trailer to the network layer protocol data unit (PDU).

42. What is the auto-MDIX feature?

It enables a device to automatically configure an interface to use a straight-through or a crossover cable.*
It enables a device to automatically configure the duplex settings of a segment.
It enables a device to automatically configure the speed of its interface.
It enables a switch to dynamically select the forwarding method.

43. What is one advantage of using the cut-through switching method instead of the store-and-forward switching method?

has a positive impact on bandwidth by dropping most of the invalid frames
makes a fast forwarding decision based on the source MAC address of the frame
has a lower latency appropriate for high-performance computing applications​*
provides the flexibility to support any mix of Ethernet speeds

Explanation: Cut-through switching provides lower latency switching for high-performance computing (HPC) applications. Cut-through switching allows more invalid frames to cross the network than store-and-forward switching. The cut-through switching method can make a forwarding decision as soon as it looks up the destination MAC address of the frame.

44. Which is a multicast MAC address?

FF-FF-FF-FF-FF-FF
5C-26-0A-4B-19-3E
01-00-5E-00-00-03*
00-26-0F-4B-00-3E

45. Refer to the exhibit.

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p45

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p45

What is wrong with the displayed termination?

The woven copper braid should not have been removed.
The wrong type of connector is being used.
The untwisted length of each wire is too long.*
The wires are too thick for the connector that is used.

Explanation: When a cable to an RJ-45 connector is terminated, it is important to ensure that the untwisted wires are not too long and that the flexible plastic sheath surrounding the wires is crimped down and not the bare wires. None of the colored wires should be visible from the bottom of the jack.

46. Refer to the exhibit.

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p46

CCNA 1 v7.0 Modules 4 – 7 Exam Answers p46

The PC is connected to the console port of the switch. All the other connections are made through FastEthernet links. Which types of UTP cables can be used to connect the devices?​

1 – rollover, 2 – crossover, 3 – straight-through
1 – rollover, 2 – straight-through, 3 – crossover*
1 – crossover, 2 – straight-through, 3 – rollover
1 – crossover, 2 – rollover, 3 – straight-through

Explanation: A straight-through cable is commonly used to interconnect a host to a switch and a switch to a router. A crossover cable is used to interconnect similar devices together like switch to a switch, a host to a host, or a router to a router. If a switch has the MDIX capability, a crossover could be used to connect the switch to the router; however, that option is not available. A rollover cable is used to connect to a router or switch console port.

47. Open the PT Activity. Perform the tasks in the activity instructions and then answer the question.
Which port does Switch0 use to send frames to the host with the IPv4 address 10.1.1.5?

Fa0/1
Fa0/5
Fa0/9
Fa0/11*

Explanation: Issuing the command ipconfig /all from the PC0 command prompt displays the IPv4 address and MAC address. When the IPv4 address 10.1.1.5 is pinged from PC0, the switch stores the source MAC address (from PC0) along with the port to which PC0 is connected. When the destination reply is received, the switch takes the destination MAC address and compares to MAC addresses stored in the MAC address table. Issuing the show mac-address-table on the PC0 Terminal application displays two dynamic MAC address entries. The MAC address and port entry that does not belong to PC0 must be the MAC address and port of the destination with the IPv4 address 10.1.1.5.

48. What does the term “attenuation” mean in data communication?

loss of signal strength as distance increases*
time for a signal to reach its destination
leakage of signals from one cable pair to another
strengthening of a signal by a networking device

Explanation: Data is transmitted on copper cables as electrical pulses. A detector in the network interface of a destination device must receive a signal that can be successfully decoded to match the signal sent. However, the farther the signal travels, the more it deteriorates. This is referred to as signal attenuation.

49. What makes fiber preferable to copper cabling for interconnecting buildings? (Choose three.)

greater distances per cable run*
lower installation cost
limited susceptibility to EMI/RFI*
durable connections
greater bandwidth potential*
easily terminated

Explanation: Optical fiber cable transmits data over longer distances and at higher bandwidths than any other networking media. Unlike copper wires, fiber-optic cable can transmit signals with less attenuation and is completely immune to EMI and RFI.

50. What OSI physical layer term describes the process by which one wave modifies another wave?

Modulation*
IEEE
EIA/TIA
air

51. What OSI physical layer term describes the capacity at which a medium can carry data?

Bandwidth*
IEEE
EIA/TIA
air

52. What OSI physical layer term describes the capacity at which a medium can carry data?

Bandwidth*
throughput
latency
goodput

53. What OSI physical layer term describes the measure of the transfer of bits across a medium over a given period of time?

Throughput*
bandwidth
latency
goodput

54. What OSI physical layer term describes the amount of time, including delays, for data to travel from one point to another?

Latency*
bandwidth
throughput
goodput

55. What OSI physical layer term describes the amount of time, including delays, for data to travel from one point to another?

Latency*
fiber-optic cable
air
copper cable

56. What OSI physical layer term describes the measure of usable data transferred over a given period of time?

Goodput*
fiber-optic cable
air
copper cable

57. What OSI physical layer term describes the physical medium which uses electrical pulses?

copper cable*
fiber-optic cable
air
goodput

58. What OSI physical layer term describes the physical medium that uses the propagation of light?

fiber-optic cable*
goodput
latency
throughput

59. What OSI physical layer term describes the physical medium for microwave transmissions?

Air*
goodput
latency
throughput

60. Which two functions are performed at the MAC sublayer of the OSI data link layer? (Choose two.)

Implements a trailer to detect transmission errors.*
Controls the NIC responsible for sending and receiving data on the physical medium.*
Places information in the frame that identifies which network layer protocol is being used for the frame.
Adds Layer 2 control information to network protocol data.
Enables IPv4 and IPv6 to utilize the same network interface and media.

61. Which two functions are performed at the LLC sublayer of the OSI data link layer? (Choose two.)

Enables IPv4 and IPv6 to utilize the same network interface and media.*
Places information in the frame that identifies which network layer protocol is being used for the frame.*
Integrates various physical technologies.
Implements a process to delimit fields within a Layer 2 frame.
Controls the NIC responsible for sending and receiving data on the physical medium.

62. Which two functions are performed at the MAC sublayer of the OSI data link layer? (Choose two.)

Provides a mechanism to allow multiple devices to communicate over a shared medium.*
Controls the NIC responsible for sending and receiving data on the physical medium.*
Places information in the frame that identifies which network layer protocol is being used for the frame.
Adds Layer 2 control information to network protocol data.
Communicates between the networking software at the upper layers and the device hardware at the lower layers.

63. Which two functions are performed at the MAC sublayer of the OSI data link layer? (Choose two.)

Controls the NIC responsible for sending and receiving data on the physical medium.*
Integrates various physical technologies.*
Communicates between the networking software at the upper layers and the device hardware at the lower layers.
Adds Layer 2 control information to network protocol data.
Places information in the frame that identifies which network layer protocol is being used for the frame.

64. Which two functions are performed at the LLC sublayer of the OSI data link layer? (Choose two.)

Adds Layer 2 control information to network protocol data.*
Places information in the frame that identifies which network layer protocol is being used for the frame.*
Performs data encapsulation.
Controls the NIC responsible for sending and receiving data on the physical medium.
Integrates various physical technologies.

65. Which two functions are performed at the MAC sublayer of the OSI data link layer? (Choose two.)

Provides synchronization between source and target nodes.*
Integrates various physical technologies.*
Communicates between the networking software at the upper layers and the device hardware at the lower layers.
Adds Layer 2 control information to network protocol data.
Enables IPv4 and IPv6 to utilize the same network interface and media.

66. Which two functions are performed at the LLC sublayer of the OSI data link layer? (Choose two.)

Adds Layer 2 control information to network protocol data.*
Enables IPv4 and IPv6 to utilize the same network interface and media.*
Provides data link layer addressing.
Implements a trailer to detect transmission errors.
Provides synchronization between source and target nodes.

67. Which two functions are performed at the MAC sublayer of the OSI data link layer? (Choose two.)

Implements a trailer to detect transmission errors.*
Provides synchronization between source and target nodes.*
Places information in the frame that identifies which network layer protocol is being used for the frame.
Enables IPv4 and IPv6 to utilize the same network interface and media.
Adds Layer 2 control information to network protocol data.

68. Which two functions are performed at the LLC sublayer of the OSI data link layer? (Choose two.)

Enables IPv4 and IPv6 to utilize the same network interface and media.*
Adds Layer 2 control information to network protocol data.*
Integrates various physical technologies.
Implements a trailer to detect transmission errors.
Provides synchronization between source and target nodes.

69. Which two functions are performed at the MAC sublayer of the OSI data link layer? (Choose two.)

Provides a mechanism to allow multiple devices to communicate over a shared medium.*
Controls the NIC responsible for sending and receiving data on the physical medium.*
Places information in the frame that identifies which network layer protocol is being used for the frame.
Adds Layer 2 control information to network protocol data.
Enables IPv4 and IPv6 to utilize the same network interface and media.

70. What action will occur if a switch receives a frame and does have the source MAC address in the MAC table?

The switch refreshes the timer on that entry.*
The switch shares the MAC address table entry with any connected switches.
The switch does not forward the frame.
The switch sends the frame to a connected router because the destination MAC address is not local.

71. What action will occur if a switch receives a frame with the destination MAC address FF:FF:FF:FF:FF:FF?

The switch forwards it out all ports except the ingress port.*
The switch shares the MAC address table entry with any connected switches.
The switch does not forward the frame.
The switch sends the frame to a connected router because the destination MAC address is not local.

72. What action will occur if a host receives a frame with a destination MAC address it does not recognize?

The host will discard the frame.*
The host sends the frame to the switch to update the MAC address table.
The host forwards the frame to the router.
The host forwards the frame to all other hosts.

73. What action will occur if a switch receives a frame with the destination MAC address 01:00:5E:00:00:D9?

The switch forwards it out all ports except the ingress port.*
The switch does not forward the frame.
The switch sends the frame to a connected router because the destination MAC address is not local.
The switch shares the MAC address table entry with any connected switches.

74. What action will occur if a host receives a frame with a destination MAC address of FF:FF:FF:FF:FF:FF?

The host will process the frame.*
The host forwards the frame to the router.
The host sends the frame to the switch to update the MAC address table.
The host forwards the frame to all other hosts.

75. What action will occur if a switch receives a frame and does have the source MAC address in the MAC table?

The switch refreshes the timer on that entry.*
The switch adds it to its MAC address table associated with the port number.
The switch forwards the frame to the associated port.
The switch sends the frame to a connected router because the destination MAC address is not local.

76. What action will occur if a host receives a frame with a destination MAC address of FF:FF:FF:FF:FF:FF?

The host will process the frame.*
The host returns the frame to the switch.
The host replies to the switch with its own IP address.
The host forwards the frame to all other hosts.

77. What action will occur if a switch receives a frame and does have the source MAC address in the MAC table?

The switch refreshes the timer on that entry.*
The switch shares the MAC address table entry with any connected switches.
The switch does not forward the frame.
The switch adds it to its MAC address table associated with the port number.

78. What action will occur if a host receives a frame with a destination MAC address it does not recognize?

The host will discard the frame.*
The host replies to the switch with its own IP address.
The host forwards the frame to all other hosts.
The host returns the frame to the switch.

79. What action will occur if a switch receives a frame with the destination MAC address FF:FF:FF:FF:FF:FF?

The switch forwards it out all ports except the ingress port.*
The switch refreshes the timer on that entry.
The switch does not forward the frame.
The switch sends the frame to a connected router because the destination MAC address is not local.

Modules 4 – 7: Ethernet Concepts Exam Answers (Additional)

1. What is the purpose of the OSI physical layer?

controlling access to media
transmitting bits across the local media*
performing error detection on received frames
exchanging frames between nodes over physical network media

2. Why are two strands of fiber used for a single fiber optic connection?

The two strands allow the data to travel for longer distances without degrading.
They prevent crosstalk from causing interference on the connection.
They increase the speed at which the data can travel.
They allow for full-duplex connectivity.*

3. Which characteristic describes crosstalk?

the distortion of the network signal from fluorescent lighting
the distortion of the transmitted messages from signals carried in adjacent wires*
the weakening of the network signal over long cable lengths
the loss of wireless signal over excessive distance from the access point

4. Which procedure is used to reduce the effect of crosstalk in copper cables?

requiring proper grounding connections
twisting opposing circuit wire pairs together*
wrapping the bundle of wires with metallic shielding
designing a cable infrastructure to avoid crosstalk interference
avoiding sharp bends during installation

5. Which type of UTP cable is used to connect a PC to a switch port?

console
rollover
crossover
straight-through*

6. What is the definition of bandwidth?

the measure of the transfer of bits across the media over a given period of time
the speed at which bits travel on the network
the amount of data that can flow from one place to another in a given amount of time*
the measure of usable data transferred over a given period of time

7. Which statement correctly describes frame encoding?

It uses the characteristic of one wave to modify another wave.
It transmits data signals along with a clock signal which occurs at evenly spaced time durations.
It generates the electrical, optical, or wireless signals that represent the binary numbers of the frame.
It converts bits into a predefined code in order to provide a predictable pattern to help distinguish data bits from control bits.*

8. What is a characteristic of UTP cabling?

Cancellation*
cladding
immunity to electrical hazards
woven copper braid or metallic foil

9. A wireless LAN is being deployed inside the new one room office that is occupied by the park ranger. The office is located at the highest part of the national park. After network testing is complete, the technicians report that the wireless LAN signal is occasionally affected by some type of interference. What are two possible causes of the signal distortion? (Choose two.)

the microwave oven*
the large number of trees that surround the office
the cellular phones that are used by the employees*
the elevated location where the wireless LAN was installed
the number of wireless devices that are used in the wireless LAN

10. What is indicated by the term throughput?

the guaranteed data transfer rate offered by an ISP
the capacity of a particular medium to carry data
the measure of the usable data transferred across the media
the measure of the bits transferred across the media over a given period of time*
the time it takes for a message to get from sender to receiver

11. What is one advantage of using fiber optic cabling rather than copper cabling?

It is usually cheaper than copper cabling.
It is able to be installed around sharp bends.
It is easier to terminate and install than copper cabling.
It is able to carry signals much farther than copper cabling.*

12. Which standards organization oversees development of wireless LAN standards?

IANA
IEEE*
ISO
TIA

13. A network administrator is designing a new network infrastructure that includes both wired and wireless connectivity. Under which situation would a wireless connection be recommended?

The end-user device only has an Ethernet NIC.
The end-user device requires a dedicated connection because of performance requirements.
The end-user device needs mobility when connecting to the network.*
The end-user device area has a high concentration of RFI.

14. A network administrator is troubleshooting connectivity issues on a server. Using a tester, the administrator notices that the signals generated by the server NIC are distorted and not usable. In which layer of the OSI model is the error categorized?

presentation layer
network layer
physical layer*
data link layer

15. What type of cable is used to connect a workstation serial port to a Cisco router console port?

crossover
rollover*
straight-through
coaxial

16. What is the binary representation for the decimal number 173?

10100111
10100101
10101101*
10110101

17. Given the binary address of 11101100 00010001 00001100 00001010, which address does this represent in dotted decimal format?

234.17.10.9
234.16.12.10
236.17.12.6
236.17.12.10*

18. How many binary bits exist within an IPv6 address?

32
48
64
128*
256

19. What is the binary equivalent of the decimal number 232?

11101000*
11000110
10011000
11110010

20. Which two statements are correct about IPv4 and IPv6 addresses? (Choose two.)

IPv6 addresses are represented by hexadecimal numbers.*
IPv4 addresses are represented by hexadecimal numbers.
IPv6 addresses are 32 bits in length.
IPv4 addresses are 32 bits in length.*
IPv4 addresses are 128 bits in length.
IPv6 addresses are 64 bits in length.

21. Which IPv4 address format was created for ease of use by people and is expressed as 201.192.1.14?

binary
dotted decimal*
hexadecimal
ASCII

22. What is the dotted decimal representation of the IPv4 address 11001011.00000000.01110001.11010011?

192.0.2.199
198.51.100.201
203.0.113.211*
209.165.201.223

23. What is the decimal equivalent of the binary number 10010101?

149*
157
168
192

24. What is the decimal equivalent of the hex number 0x3F?

63*
77
87
93

25. What is the dotted decimal representation of the IPv4 address which is represented as the binary string 00001010.01100100.00010101.00000001?

10.100.21.1*
10.10.20.1
100.10.11.1
100.21.10.1

26. What is the decimal equivalent of 0xC9?

185
200
201*
199

27. Which is a valid hexadecimal number?

F*
g
h
j

28. What is the binary representation of 0xCA?

10111010
11010101
11001010*
11011010

29. How many bits are in an IPv4 address?

32*
64
128
256

30. What identifier is used at the data link layer to uniquely identify an Ethernet device?

IP address
MAC address*
sequence number
TCP port number
UDP port number

31. Which two engineering organizations define open standards and protocols that apply to the data link layer? (Choose two.)

International Organization for Standardization (ISO)*
Internet Assigned Numbers Authority (IANA)
International Telecommunication Union (ITU)*
Electronic Industries Alliance (EIA)
Internet Society (ISOC)

32. Which layer of the OSI model is responsible for specifying the encapsulation method used for specific types of media?

application
transport
data link*
physical

33. What is true concerning physical and logical topologies?

The logical topology is always the same as the physical topology.
Physical topologies are concerned with how a network transfers frames.
Physical topologies display the IP addressing scheme of each network.
Logical topologies refer to how a network transfers data between devices.*

34. What type of physical topology can be created by connecting all Ethernet cables to a central device?

bus
ring
star*
mesh

35. A technician has been asked to develop a physical topology for a network that provides a high level of redundancy. Which physical topology requires that every node is attached to every other node on the network?

bus
hierarchical
mesh*
ring
star

36. Which statement describes the half-duplex mode of data transmission?

Data that is transmitted over the network can only flow in one direction.
Data that is transmitted over the network flows in one direction at a time.*
Data that is transmitted over the network flows in one direction to many different destinations simultaneously.
Data that is transmitted over the network flows in both directions at the same time.

37. Which is a function of the Logical Link Control (LLC) sublayer?

to define the media access processes that are performed by the hardware
to provide data link layer addressing
to identify which network layer protocol is being used*
to accept segments and package them into data units that are called packets

38. Which data link layer media access control method does Ethernet use?

CSMA/CD*
determinism
turn taking
token passing

39. What are the two sublayers of the OSI model data link layer? (Choose two.)

internet
physical
LLC*
transport
MAC*
network access

40. What method is used to manage contention-based access on a wireless network?

CSMA/CD
priority ordering
CSMA/CA*
token passing

41. What are two services performed by the data link layer of the OSI model? (Choose two.)

It encrypts data packets.
It determines the path to forward packets.
It accepts Layer 3 packets and encapsulates them into frames.*
It provides media access control and performs error detection.*
It monitors the Layer 2 communication by building a MAC address table.

42. What does a router do after de-encapsulating a received frame?

determines the best path*
de-encapsulates the frame
re-encapsulates the packet into a new frame
forwards the new frame onto the network medium

43. What attribute of a NIC would place it at the data link layer of the OSI model?

attached Ethernet cable
IP address
MAC address*
RJ-45 port
TCP/IP protocol stack

44. Although CSMA/CD is still a feature of Ethernet, why is it no longer necessary?

the virtually unlimited availability of IPv6 addresses
the use of CSMA/CA
the use of full-duplex capable Layer 2 switches*
the development of half-duplex switch operation
the use of Gigabit Ethernet speeds

45. Which network device makes forwarding decisions based on the destination MAC address that is contained in the frame?

repeater
hub
switch*
router

46. Which network device has the primary function to send data to a specific destination based on the information found in the MAC address table?

hub
router
switch*
modem

47. Which function or operation is performed by the LLC sublayer?

It performs data encapsulation.
It communicates with upper protocol layers.*
It is responsible for media access control.
It adds a header and trailer to a packet to form an OSI Layer 2 PDU.

48. Which statement is true about MAC addresses?

MAC addresses are implemented by software.
A NIC only needs a MAC address if connected to a WAN.
The first three bytes are used by the vendor assigned OUI.*
The ISO is responsible for MAC addresses regulations.

49. What happens to runt frames received by a Cisco Ethernet switch?

The frame is dropped.*
The frame is returned to the originating network device.
The frame is broadcast to all other devices on the same network.
The frame is sent to the default gateway.

50. What are the two sizes (minimum and maximum) of an Ethernet frame? (Choose two.)

56 bytes
64 bytes*
128 bytes
1024 bytes
1518 bytes*

51. What addressing information is recorded by a switch to build its MAC address table?

the destination Layer 3 address of incoming packets
the destination Layer 2 address of outgoing frames
the source Layer 3 address of outgoing packets
the source Layer 2 address of incoming frames*

52. Which two characteristics describe Ethernet technology? (Choose two.)

It is supported by IEEE 802.3 standards.*
It is supported by IEEE 802.5 standards.
It typically uses an average of 16 Mb/s for data transfer rates.
It uses the CSMA/CD access control method.*
It uses a ring topology.

53. What statement describes a characteristic of MAC addresses?

They must be globally unique.*
They are only routable within the private network.
They are added as part of a Layer 3 PDU.
They have a 32-bit binary value.

54. What is the special value assigned to the first 24 bits of a multicast MAC address?

01-5E-00
FF-00-5E
FF-FF-FF
01-00-5E*

55. What will a host on an Ethernet network do if it receives a frame with a destination MAC address that does not match its own MAC address?

It will discard the frame.*
It will forward the frame to the next host.
It will remove the frame from the media.
It will strip off the data-link frame to check the destination IP address.

56. What is auto-MDIX?

a type of Cisco switch
an Ethernet connector type
a type of port on a Cisco switch
a feature that detects Ethernet cable typ​e*

57. Which two functions or operations are performed by the MAC sublayer? (Choose two.)

It is responsible for Media Access Control.*
It performs the function of NIC driver software.
It adds a header and trailer to form an OSI Layer 2 PDU.*
It handles communication between upper and lower layers.
It adds control information to network protocol layer data.

58. What type of address is 01-00-5E-0A-00-02?

an address that reaches every host inside a local subnet
an address that reaches one specific host
an address that reaches every host in the network
an address that reaches a specific group of hosts*

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