Question Banks 21-25 PDF

Question Bank 21: A Network Troubleshooting Methodology 1. Out of these three steps in the diagram, the majority of a troubleshooter's efforts are spent in which step? a. Problem report b. Problem diagnosis c. Problem resolution d. Documentation Answer: b. Problem diagnosis Explana...

Question Bank 21: A Network Troubleshooting Methodology 1. Out of these three steps in the diagram, the majority of a troubleshooter's efforts are spent in which step? a. Problem report b. Problem diagnosis c. Problem resolution d. Documentation Answer: b. Problem diagnosis Explanation: This figure depicts a simplified model of the troubleshooting steps previously described. This simplified model consists of three steps: 1. Problem report 2. Problem diagnosis 3. Problem resolution Of these three steps, the majority of a troubleshooter's efforts are spent in the problem diagnosis step. Documentation is an important step, but is normally accomplished via a fairly quick point and click interface. 2. Which Layer 1 troubleshooting issue can occur from not carefully ensuring compatibility with cable type and wavelength in use? a. Transceiver mismatch b. Crosstalk c. dB loss d. Opens and shorts Answer: a. Transceiver mismatch Explanation: Transceivers must be selected carefully to ensure compatibility with the cable type and wavelengths in use. 3. A first step in a structured troubleshooting methodology is which of these? a. Hypothesize the probable cause. b. Create an action plan. c. Create a post-mortem report. d. Define the problem. Answer: d. Define the problem. Explanation: Isolating or defining the problem would precede any of the other options. 4. Which of the following is a common OSI Layer 1 (physical layer) troubleshooting issue? (Choose two) a. Bad cables or connectors b. dB loss  c. Bad module d. Port configuration e. VLAN configuration Answer: a. Bad cables or connectors; b. dB loss Explanation: Bad cable or connectors and dB loss are OSI Layer 1 (physical layer) troubleshooting issues; Bad module, port configuration, and VLAN configuration are OSI Layer 2 (data link layer) troubleshooting issues. Bad cable or connectors and dB loss are OSI Layer 1 (physical layer) troubleshooting issues; Bad module, port configuration, and VLAN configuration are OSI Layer 2 (data link layer) troubleshooting issues. 5. Which of the following is a common wireless network troubleshooting issue? (Choose two.) a. Radio-frequency interference (RFI) b. Crosstalk c. Multiple paths of propagation d. Layer 2 loop e. Bad cables or connectors Answer: a. Radio-frequency interference (RFI); c. Multiple paths of propagation Explanation: Radio-frequency interference (RFI) and multiple paths of propagation are common wireless network troubleshooting issues. Crosstalk and bad cables or connectors are OSI Layer 1 (physical layer) troubleshooting issues, and Layer 2 loop is an OSI Layer 2 (data link layer) troubleshooting issue. 6. Which of the following comprise a simplified troubleshooting flow? (Choose three.) a. Problem resolution b. Problem monitoring c. Problem diagnosis d. Problem report Answers: a. Problem resolution; c. Problem diagnosis; d. Problem report Explanation: Identifying, fixing, and reporting the problem are often the three steps in a simplified troubleshoong flow. 7. What is it that occurs when an electronic signal creates an electromagnetic field around its conductors thus causing waveforms on a nearby analog connection. a. Distance limitations b. Transposed leads c. Crosstalk d. Bad cable placement Answer: c. Crosstalk Explanation: Crosstalk can occur when an analog connection creates an electromagnetic field around its conductors, inducing its waveforms on a nearby analog connection. This phenomenon is most commonly experienced in an analog phone call. Crosstalk can be minimized by using a higher category of cabling, because higher categories of cables better limit the radiation of electromagnetic waves. 8. What step is most likely to follow the “create an action plan” step in a structured troubleshooting methodology? a. Verify problem resolution b. Test the hypothesis c. Define the problem d. Hypothesize the possible cause Answer: a. Verify problem resolution Explanation: One of the final steps of a structured troubleshooting methodology would be to verify problem resolution. This would follow a creation and an implementation of an action plan. 9. Consider the following network diagram. Assume that both switches are capable of autonegotiating Ethernet speeds of 10, 100, and 1000 Mbps, but do not support MDIX. Which one of the following is most likely an issue in this topology? a. This network topology is fine and should work with no problems. b. No ping reply is being received between Client A and Server 1. c. The Ethernet switches have a TX cable that is too short. d. Switch SW1 is does not support frame relay. Answer: b. No ping reply is being received between Client A and Server 1. Explanation: In the topology the ports interconnecting the two switches do not support MDIX and are not using a crossover cable, which be necessary for Tx pins to be interconnected with the Rx pins. As a result, no communication is possible between the two switches or any devices connected through them. 10. Which networking troubleshooting methodology step would include coming up with a new theory or escalating the issue if the theory is not confirmed? a. Step 1: Identify the problem b. Step 4: Establish a plan of action to resolve the problem and identify potential effects c. Step 2: Establish a theory of probable cause d. Step 3: Test the theory to determine the cause Answer: d. Step 3: Test the theory to determine the cause Explanation: Step 3 is Test the theory to determine the cause. This step includes: If the theory is confirmed, determine the next steps to resolve the problem. If the theory is not confirmed, reestablish a new theory or escalate the issue to the next level. 11. Which of the following is a common OSI Layer 3 (network layer) troubleshooting issue? (Choose two) a. Mismatched maximum transmission unit (MTU) for IP packets b. Distance limitations exceeded c. Incorrect subnet mask d. Crosstalk e. Layer 2 loop Answer: a. Mismatched maximum transmission unit (MTU) for IP packets; c. Incorrect subnet mask Explanation: Mismatched maximum transmission unit (MTU) for IP and incorrect subnet mask are OSI Layer 3 (physical layer) troubleshooting issues. Distance limitations exceeded and crosstalk are OSI Layer 1 (physical layer) troubleshooting issues, and Layer 2 loop is an OSI Layer 2 (data link layer) troubleshooting issue. 12. After fixing an issue, full system functionality and implemented preventive measures. What should you do next? a. Question the obvious and duplicate the problem b. Create a differential backup plan c. Document findings, actions, outcomes, and lessons learned d. Gather information and create a baseline Answer: c. Document findings, actions, outcomes, and lessons learned Explanation: After implementing preventive measures (Step 6),complete the final step (Step 7) by documenting findings, actions, outcomes, and lessons learned 13. A switch has been analyzed and found to be creating switching loops. What configuration item should be checked to discover if this can be easily fixed? a. CDP b. LACP c. STP d. Ethernet Answer: c. STP Explanation: The Spanning Tree Protocol (STP) is the primary protocol that is used to resolve Layer 2 loops on an Ethernet network. 14. When you are troubleshooting a network problem, what is one of the first steps you should take in the process? a. Establish a theory of probable cause. b. Determine if anything has changed. c. Gather information.  d. Approach multiple problems. Answer: c. Gather information. Explanation: Because a typical problem report lacks sufficient information to give a troubleshooter insight into a problem’s underlying cause, the troubleshooter should gather additional information, perhaps by using network maintenance tools or by interviewing impacted users. 15. Though all of these can collect packet information, which of the following is an example of a protocol analyzer? a. Nmap b. Sniffer c. Wireshark d. Nessus Answer: c. Wiershark Explanation: Wireshark is an example of a protocol analyzer that is free and easy to use. The others do detect various kinds of information, but don’t offer complete analysis. Question Bank 22: Troubleshoot Common Cabling Problems 1. Which function of a multimeter is used to measure the resistance of a cable? a. Ohmmeter b. Voltmeter c. Ammeter d. Continuity checker Answer: a. Ohmmeter Explanation: Ohm is a measurement of the resistance of a cable. An ohmmeter is used to measure the specific resistance. 2. What type of cable must be used in order to provide low voltage power to network devices using their network connection? a. Cat 5e or greater b. Cat 3 or greater c. Cat 5 or greater d. Cat 4 or greater Answer: a. In order to use PoE, your physical media must be Cat 5e or higher. Explanation: a. Cat 5e or greater 3. From a cable tester analysis, which one of the following is an indication of a miswire or fault on a CAT5 cable? a. Pins 1 and 2 are showing up as transmitting signals b. Pins 2 and 3 are wired together. c. Pins 3 and 6 are showing up as receiving signals  d. Pins 7 and 8 don’t show as connected. Answer: b. Pins 2 and 3 are wired together. Explanation: Pin 2 is a transmisison pin and pin 3 is a receiving pin. The signals would never make it to the other receiving computer. 4. What issue for fiber optic media could be critical if not addressed? a. Incorrect pin outs b. Dirty optical media c. EMI d. dB loss Answer: b. Dirty optical media Explanation: You need to ensure that you do not allow dirt to enter the cable or cable connectors when you are working with fiber optics. 5. If a second machine was not available to test a cable before shipping it with the intended machine, what device permits communication with itself in order to test its ability to send and receive traffic? a. Cable tester b. Loopback plug c. Cable crimper d. Fusion splicer e. Tone generator Answer: b. Loopback plug Explanation: A loopback plug takes its sent signals and loops them into the receive wire and is a simple method of testing a network device’s ability to send and receive traffic. 6. During installation, a fiber cable was twisted and bent beyond its specifications and an OTDR confirmed a break in the cable. Which of the following might be able to salvage the installation? a. Multimeter b. Fusion splicer c. Fiber transceiver d. TDR Answer: b. Fusion splicer 7. A fiber cable connection needs to be measured to troubleshoot a failure to meet attenuation specifications. Which one of the following tools can be used to do that? a. Optical Time Domain Reflectometer b. Loopback test c. Tone Generator d. Multimeter Answer: a. Optical Time Domain Reflectometer Explanation: The Optical Time Domain Reflectometer can determine distance to a point of failure in addition to indicating a failure to deliver an optical signal a specified distance. A loopback plug can determine if an interface is working, but cannot verify whether a cable is the problem. A Tone Generator and multi-meter are for electrically conductive media. 8. The building inspector has arrived and has noted an issue with the type of CAT5 cable installed in the space above the ceiling. Which of the following criteria is he concerned with? a. UTP rated b. Rollover rated c. Plenum rated d. Riser rated Answer: c. Plenum rated; d. Riser rated Explanation: To mitigate the concern of pumping poisonous gas throughout a building’s heating, ventilation, and air conditioning (HVAC) system, plenum rated cabling can be used. The outer insulator of a plenum twisted-pair cable is not only fire retardant; some plenum cabling uses a fluorinated ethylene polymer (FEP) or a low-smoke polyvinyl chloride (PVC) to minimize dangerous fumes. Cables that run through risers should also be fire-proof to prevent the flame from traveling up the cable. 9. To connect a router to a user’s console port, a crossover cable has been connected from the user to a patch panel, which is mapped via a straight cable to the console port of the router. What is to be expected from this connection? a. The user will need to create console port settings to connect b. The user will not need to create console port setting to connect c. The user will not be able connect at all. d. The user will need to use a normal Ethernet port on the user’s machine directly to the console port of the router and bypass the patch panel. Answer: c. The user will not be able connect at all. Explanation: A console connection requires a console cable, not a crossover cable. However, if the user wanted to telnet/SSH into the router via the Ethernet port on the router, a crossover cable from the user’s Ethernet port would work. 10. Which of the following terms are directly related to the weakening or loss of a signal as it travels further down the network medium (Choose two)? a. Attenuation b. Throughput c. OTDR d. Interference e. Decibel (dB) loss Answer: a. Attenuation; e. Decibel (dB) loss Explanation: Attenuation is the weakening of a signal as a result of distance between two devices on a network medium. Attenuation is measured in decibels (dB). dB loss is also more prone to happen as the signal needs to go farther and farther in the media. 11. A 568A connection on one end of a CAT5 cable has been created. The other end is a 568B connection. Which of the following will this cable be useful for? (Choose all that apply) a. Connecting two non MDIX switches b. A PC to non MDIX Switch network access c. A PC to Router direct Ethernet connection d. A router to switch Ethernet connection e. A router to router Ethernet connection Answers: a. Connecting two non MDIX switches; c. A PC to Router direct Ethernet connection; e. A router to router Ethernet connection Explanation: This is a crossover cable being used to connect devices with similar pinouts. Disimilar pinouts would need a straight cable. That makes Answers ‘a’ and ‘e’ correct. Answer:‘c’ is also correct because the router is essentially just another machine connected to a switch as has the same pinouts as the PC. 12. You need to connect two older switches together that do not have auto- MDIX ports. What should you use? a. Console cable b. Crossover cable c. PoE cable d. Loopback adapter Answer: b. Crossover cable Explanation: Auto-MDIX technology on newer devices permits the port to adjust to the type of cable that is connected. Before this technology, we had to use a crossover cable to connect like devices. For example, to connect two switches together we would need a crossover cable. 13. A technician is asked to redo the patch panel’s wiring to accommodate a new patch panel for a working CAT6 wiring in an existing building. Which of the following would be a tool that could save her the most time? a. Tone generator b. A crimper c. A TDR d. Continuity tester Answer: a. Tone generator Explanation: With existing wiring, the biggest time drain is trying to determine which cables are coming out of the wall from various other locations. If the patch panel is to be set up in an organized way, a tone generator helps quickly identify which cable in a bunch is the right one for a particular end station to be mapped to a specific port on the patch panel block. 14. What kind of tool is used to connect the individual conductors of a cable to a 66 or 110 block? a. Compression tool b. AMP tool c. Punch-down tool d. Crimper Answer: c. Punch-down tool Explanation: A punch-down tool is used to connect the individual conductors of a cable to a 66 or 110 block. In some cases, these blocks will also be connected via an RJ-21 amphenol connector, but these would not be the connection of individual conductors (25, 50, 100 pair). 15. What is the name of the tool is used to find a specific wire from one location to another remote location (another office)? a. Butt set  b. AMP tool c. Punch-down tool d. Toner probe Answer: d. Toner probe Explanation: A toner probe is used to find a specific wire from one location to another remote location; typically, this remote location is another office in the same building (or close). It does this by connecting to one end and transmitting an audible tone, which is then found on the other side with a receiving probe. 16. When working with copper cabling (as opposed to fiber optic), a ________ can check the continuity, voltage, and current flow. a. loopback plug b. protocol analyzer c. toner probe d. multimeter Answer: d. multimeter Explanation: When working with copper cabling (as opposed to fiber-optic cabling), a multimeter can check a variety of a cable's electrical characteristics. These characteristics include resistance (in ohms), current (in amps), and voltage (in volts). 17. Imagine that you have been troubleshooting a network cable (either copper or fiber optic), and you determine that there is a break in the cable. What would you use to identify exactly where the break exists? a. Throughput tester b. Punch-down tool c. Toner probe d. Time domain reflectometer Answer: d. Time domain reflectometer Explanation: Identifying exactly where the break exists in a long length of cable can be problematic. TDRs send a signal down a cable. When the signal encounters a cable fault, a portion of the signal reflects back to the source. Based on the speed of electricity, or light in the medium and the amount of time required for the reflected electric signal or light to be returned to the source, a TDR or an OTDR can mathematically determine where the cable fault lies. 18. What can a throughput tester be used for? a. Locate faults in a cable b. Identifies which pair of wires connects back to an end user's location c. Observes how a network performs under a heavy load d. Prevents static discharge from damaging other components Answer: c. Observes how a network performs under a heavy load Explanation: In addition to computing the throughput under varying conditions, throughput testers are specifically valuable for analyzing a network that is under a heavy load. A throughput tester is a network appliance, typically has multiple network interfaces and can generate high volumes of random data. 19. What are the two primary functions of a Bit-error rate tester BERT? a. Pattern generator b. Error detector c. Throughput measurement d. Cable certification Answer: a. Pattern generator; b. Error detector Explanation: A bit-error rate tester (BERT) tests the functionality of a circuit by generating test patterns and measuring the error rate of the pattern when it is received on the other side of the circuit. Commonly, these are used along with loopback plugs so that the same device can both generate traffic and error check. However, they can also be used as a pair with one on each side of a circuit, with one acting as a pattern generator and the other acting as an error detector. 20. Which device is used by a technician needing to check a voice line, commonly by connecting directly into the line at a distribution point? a. BERT b. Toner c. Butt set d. TDR Answer: c. Butt set Explanation: A butt set is a used by technicians to test voice lines; this is typically done my tapping into the line at a distribution point (for instance, IDF, MDF, pole). 21. A(n) ________ is a broken strand of copper that prevents current from flowing through a circuit. (Select the best Answer.) a. open b. short c. tap d. break Answer: a. open Explanation: An open is a broken strand of copper that prevents current from flowing through a circuit. A short occurs when two copper connectors touch each other. A tap is used when connecting off of an existing circuit to make a new connection. 22. Two adjacent switches need to be connected. One of them has MDIX technology. The other one does not. What are some issues that might come up in trying to connect them? a. Both switches will need MDIX.  b. They need a crossover over cable c. The switch with MDIX will automatically adjust to the cable d. They will need a straight cable e. The duplex/speed setting needs to be verified Answer: b. They need a crossover over cable; e. The duplex/speed setting needs to be verified Explanation: The Medium Dependent Interface Crossover (MDIX) feature is implemented on most modern Ethernet switches to provide a workaround for incorrect cables being used for connectivity. As long as one switch has MDIX, the cable Tx/Rx adjustment will be made automatically. However, if one switch does not use MDIX, it will need its port settings checked to match the duplex/speed settings of the other switch. 23. Using a networking model approach (OSI or TCP/IP)...a potential Layer 1 problem appears to be broken strands of copper in a cable, preventing a flow through a circuit. What type of Layer 1 problem is this? a. Open circuit b. Splitting pairs in a cable c. dB loss d. Cable placement Answer: a. Open circuit Explanation: An open circuit is a disconnected strand of copper that prevents current from flowing. On the other hand, a short occurs when two copper connectors touch each other, resulting in current flowing through that short rather than the attached electrical circuit (because the short has lower resistance). BONUS QUESTIONS: 24. Which of the following might be an indication of a crosstalk or EMI issue? a. Excessive jitter and/or delay b. Packets being resent by the source c. The issues disappear with a different cable d. All of the above Answer: d. All of the above Explanation: Any of these could indicate a crosstalk issue, but they are exclusive to crosstalk since other causes can be contributing. 25. When analyzing the end of a CAT5 cable at the connector, you notice that the strands of wire are hanging outside the connector, not inside the insulator, and the insulation is not crimped even though the wire map shows connectivity. Even with a good pinout indicated, which of the following is still a potential problem? a. There could be an open short b. The connector will not fit into the transceiver c. The throughput could be significantly less than the capacity by a factor of as much as 90% d. It looks bad but no other issue would surface Answer: c. The throughput could be significantly less than the capacity by a factor of as much as 90% Explanation: When the two machines perform a test to agree on the transmission speed, they will discover that the cable does not support more than 10 Mbps. This is due to the lack of twisting for more than ½ inch in conjunction with near end /far end crosstalk. 26. You have a link between two network devices that is not able to transmit at the full bandwidth of its capacity. What would most likely be the cause of this problem? a. Incorrect pinout b. Bad ports c. Duplex mismatch d. Failed NIC card Answer: c. Duplex mismatch Explanation: Duplex mismatches can cause links between devices to run inefficiently. A most common scenario is that one device is operating in half duplex while the other operates in full duplex. You can check this setting in Windows 10 for a NIC card for example. Open Device Manager and right-click on the suspect network adapter. Select Properties and then Speed & Duplex and look at the Value setting. Question Bank 23 Network Software Tools and Commands 1. How many ICMP messages are sent by default when using the ping command on a Windows machine? a. 5 b. 4 c. 1 d. 10 Answer: b. 4 Explanation: By default, Windows sends four ICMP messages to the destination host. 2. The ________ command can display a PC's current IP routing table. a. iproute b. router c. netroute d. route print Answer: d. route print Explanation: iproute, router, netroute are not valid commands. 3. Consider the following output: C:\> arp -a Interface: 172.16.202.128 --- 0xb Internet Address Physical Address Type 172.16.202.22 00-50-56-fd-65-2c dynamic 172.16.202.255 ff-ff-ff-ff-ff-ff static 224.0.0.22 01-00-5e-00-00-16 static  224.0.0.252 01-00-5e-00-00-fc static 255.255.255.255 ff-ff-ff-ff-ff-ff static What is the MAC address corresponding to the IP address of 172.16.202.22? a. ff-ff-ff-ff-ff-ff b. 00-50-56-fd-65-2c c. 01-00-5e-00-00-16 d. 01-00-5e-00-00-fc Answer: b. 00-50-56-fd-65-2c Explanation: The arp command permits you to see the IP-address-to-MAC-address mappings. You can read them from left to right. 4. Which PC command line ARP option is used to display current ARP entries in a host's ARP table? a. -a b. -d c. -s d. -n Answer: a. -a Explanation: Only the -a option is used to display the current ARP entries in a UNIX host's ARP table. 5. What Windows PC ‘ipconfig’ command option displays the IP address of the DNS server? a. No option is needed because the ipconfig displays DNS server information by default. b. /full c. /fqdn d. /all Answer: d. /all Explanation: Use the /all switch to learn many additional details about the IP configuration. This includes the DNS details. 6. The ________ command can be used to display information about current sessions, including source and destination IP addresses and port numbers. a. networkstat b. netstat c. ntstat d. ipstatus Answer: b. netstat 7. What multi-purpose protocol is used by the ping command? a. IGMP b. PIM c. ICMP  d. RTP Answer: c. ICMP Explanation: The ping command uses ICMP which is also used for Traceroute and other purposes including DHCP offers and APIPA. 8. What command is used to view the route table of a Windows device? a. show config b. show interface c. route print d. show tcpdump Answer: c. route print Explanation: The route print command is used to view the routing table configuration of a Windows PC. 9. Which command on a Windows or Linux host generates information about each router hop along the path from a source to a destination? a. ping -t b. tracert c. ping -r d. traceroute Answer: d. traceroute Explanation: Use traceroute in UNIX in order to follow the hop-by-hop path a packet takes. 10. What Linux command produced the following output? (Some output omitted...) ;; global options: +cmd ;; Got Answer: ;; ->>HEADER