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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. More Questions: CCNA 1 v7 Modules 4 – 7 Exam Answers Please login or Register to submit your answer CCNA 1 v7.0 Modules 4 – 7: Ethernet Concepts Exam Answers 20201. What is the purpose of the OSI physical layer?controlling access to 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. 3. Which characteristic describes crosstalk?the distortion of the network signal from fluorescent lighting 4. Which procedure is used to reduce the effect of crosstalk in copper cables?requiring proper grounding connections 5. Match the situation with the appropriate use of network media.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* 7. What are two characteristics of fiber-optic cable? (Choose two.)It is not affected by EMI or RFI.* 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* 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* 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 What type of cabling is shown?STP Explanation: Network cabling include different types of cables: 11. In addition to the cable length, what two factors could interfere with the communication carried over UTP cables? (Choose two.)Crosstalk* 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: 12. Refer to the graphic.CCNA 1 v7.0 Modules 4 – 7 Exam Answers p12 What type of cabling is shown?STP 13. Which two devices commonly affect wireless networks? (Choose two.)Blu-ray players 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. 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* 16. What is contained in the trailer of a data-link frame?logical address 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. 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 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 20. Which media communication type does not require media arbitration in the data link layer?deterministic 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.* 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. 23. What are three ways that media access control is used in networking? (Choose three.)Ethernet utilizes
CSMA/CD.* 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. 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 Explanation: Layer 2 headers contain the following: 26. What type of communication rule would best describe CSMA/CD?access method* 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* 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: 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. 29. What is the auto-MDIX feature on a switch?the automatic configuration of an interface for 10/100/1000 Mb/s operation 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 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 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 32. What are two examples of the cut-through switching method? (Choose two.)store-and-forward 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 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 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 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.* 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 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* 39. Which switching method uses the CRC value in a frame?cut-through 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 Explanation: Important actions that a switch performs are as follows: 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.* 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.* 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 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 45. Refer to the exhibit.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. 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 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 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 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* 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* 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* 51. What OSI physical layer term describes the capacity at which a medium can carry data?Bandwidth* 52. What OSI physical layer term describes the capacity at which a medium can carry data?Bandwidth* 53. What OSI physical layer term describes the measure of the transfer of bits across a medium over a given period of time?Throughput* 54. What OSI physical layer term describes the amount of time, including delays, for data to travel from one point to another?Latency* 55. What OSI physical layer term describes the amount of time, including delays, for data to travel from one point to another?Latency* 56. What OSI physical layer term describes the measure of usable data transferred over a given period of time?Goodput* 57. What OSI physical layer term describes the physical medium which uses electrical pulses?copper cable* 58. What OSI physical layer term describes the physical medium that uses the propagation of light?fiber-optic cable* 59. What OSI physical layer term describes the physical medium for microwave transmissions?Air* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* 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.* Modules 4 – 7: Ethernet Concepts Exam Answers (Additional)1. What is the purpose of the OSI physical layer?controlling access to 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. 3. Which characteristic describes crosstalk?the distortion of the network signal from
fluorescent lighting 4. Which procedure is used to reduce the effect of crosstalk in copper cables?requiring proper grounding connections 5. Which type of UTP cable is used to connect a PC to a switch port?console 6. What is the definition of bandwidth?the measure of the transfer of bits across the media over a given period of time 7. Which statement correctly describes frame encoding?It uses the characteristic of one wave to modify another wave. 8. What is a characteristic of UTP cabling?Cancellation* 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* 10. What is indicated by the term throughput?the guaranteed data transfer rate offered by an ISP 11. What is one advantage of using fiber optic cabling rather than copper cabling?It is usually cheaper than copper cabling. 12. Which standards organization oversees development of wireless LAN standards?IANA 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. 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 15. What type of cable is used to connect a workstation serial port to a Cisco router console port?crossover 16. What is the binary representation for the decimal number 173?10100111 17. Given the binary address of 11101100 00010001 00001100 00001010, which address does this represent in dotted decimal format?234.17.10.9 18. How many binary bits exist within an IPv6 address?32 19. What is the binary equivalent of the decimal number 232?11101000* 20. Which two statements are correct about IPv4 and IPv6 addresses? (Choose two.)IPv6 addresses are represented by
hexadecimal numbers.* 21. Which IPv4 address format was created for ease of use by people and is expressed as 201.192.1.14?binary 22. What is the dotted decimal representation of the IPv4 address 11001011.00000000.01110001.11010011?192.0.2.199 23. What is the decimal equivalent of the binary number 10010101?149* 24. What is the decimal equivalent of the hex number 0x3F?63* 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* 26. What is the decimal equivalent of 0xC9?185 27. Which is a valid hexadecimal number?F* 28. What is the binary representation of 0xCA?10111010 29. How many bits are in an IPv4 address?32* 30. What identifier is used at the data link layer to uniquely identify an Ethernet device?IP address 31. Which two engineering organizations define open standards and protocols that apply to the data link layer? (Choose two.)International Organization for Standardization (ISO)* 32. Which layer of the OSI model is responsible for specifying the encapsulation method used for specific types of media?application 33. What is true concerning physical and logical topologies?The logical topology is always the same as the physical topology. 34. What type of physical topology can be created by connecting all Ethernet cables to a central device?bus 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 36. Which statement describes the half-duplex mode of data transmission?Data that is transmitted over the network can only flow in one direction. 37. Which is a function of the Logical Link Control (LLC) sublayer?to define the media access processes that are performed by the hardware 38. Which data link layer media access control method does Ethernet use?CSMA/CD* 39. What are the two sublayers of the OSI model data link layer? (Choose two.)internet 40. What method is used to manage contention-based access on a wireless network?CSMA/CD 41. What are two services performed by the data link layer of the OSI model? (Choose two.)It
encrypts data packets. 42. What does a router do after de-encapsulating a received frame?determines the best path* 43. What attribute of a NIC would place it at the data link layer of the OSI model?attached Ethernet cable 44. Although CSMA/CD is still a feature of Ethernet, why is it no longer necessary?the virtually unlimited availability of IPv6 addresses 45. Which network device makes forwarding decisions based on the destination MAC address that is contained in the frame?repeater 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 47. Which function or operation is performed by the LLC sublayer?It performs data encapsulation. 48. Which statement is true about MAC addresses?MAC
addresses are implemented by software. 49. What happens to runt frames received by a Cisco Ethernet switch?The frame is dropped.* 50. What are the two sizes (minimum and maximum) of an Ethernet frame? (Choose two.)56 bytes 51. What addressing information is recorded by a switch to build its MAC address table?the destination Layer 3 address of incoming packets 52. Which two characteristics describe Ethernet technology? (Choose two.)It is supported by IEEE 802.3 standards.* 53. What statement describes a characteristic of MAC addresses?They must be globally unique.* 54. What is the special value assigned to the first 24 bits of a multicast MAC address?01-5E-00 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.* 56. What is auto-MDIX?a type of Cisco switch 57. Which two functions or operations are performed by the MAC sublayer? (Choose two.)It is responsible for Media Access Control.* 58. What type of address is 01-00-5E-0A-00-02?an address that reaches every host inside a local subnet What is the purpose of the OSI physical?The role of the OSI Physical layer is to encode the binary digits that represent Data Link layer frames into signals and to transmit and receive these signals across the physical media - copper wires, optical fiber, and wireless - that connect network devices.
What is OSI physical layer?The physical layer is the first and lowest layer of the Open System Interconnection Model (OSI Model.) The physical layer (also known as layer 1) deals with bit-level transmission between different devices and supports electrical or mechanical interfaces connecting to the physical medium for synchronized communication.
Which definition best describes the function of the physical layer?What best describes the purpose of the physical layer? D. The chief purpose of the physical layer is to define the functional specifications for links between end systems and the electrical, optical and radio signals that carry data. Reliability, path selection and media access are the tasks of other layers.
What OSI physical layer term describes the measure of usable data transferred?What OSI physical layer term describes the measure of the transfer of bits across a medium over a given period of time? throughput.
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