Second Exam PDF

**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 s...

**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 **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 - **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 **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 **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** **13. Which two devices commonly affect wireless networks? (Choose two.)** - Blu-ray players - home theaters - **cordless phones** - **microwaves** - incandescent light bulbs - external hard drives **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.** **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 **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 **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 **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. **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. **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** **26. What type of communication rule would best describe CSMA/CD?** - **access method** - flow control - message encapsulation - message encoding **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** - **trailer** - CRC value **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 **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 **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** **35. Which switching method has the lowest level of latency?** - cut-through - store-and-forward - fragment-free - **fast-forward** **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. **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 **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 trailer** - 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** **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 **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. **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 **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 **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 **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 **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 **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 **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.)** - 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. - **Controls the NIC responsible for sending and receiving data on the physical medium.** - **Implements a trailer to detect transmission errors.** - Enables IPv4 and IPv6 to utilize the same network interface and media. **60.1 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. **60.2 Which two functions are performed at the MAC sublayer of the OSI data link layer? (Choose two.)** - Enables IPv4 and IPv6 to utilize the same network interface and media. - **Provides synchronization between source and target nodes.** - **Implements a trailer to detect transmission errors.** - 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. **60.3 Which two functions are performed at the MAC 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.** - Communicates between the networking software at the upper layers and the device hardware at the lower layers. - **Provides synchronization between source and target nodes.** **60.4 Which two functions are performed at the MAC sublayer of the OSI data link layer? (Choose two.)** - Places information in the frame that identifies which network layer protocol is being used for the frame. - **Integrates various physical technologies.** - Adds Layer 2 control information to network protocol data. - **Controls the NIC responsible for sending and receiving data on the physical medium.** - Communicates between the networking software at the upper layers and the device hardware at the lower layers. **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. **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 **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 **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. **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. **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. **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. Which type of UTP cable is used to connect a PC to a switch port?** - console - rollover - crossover - **straight-through**