CYBR1-Domain 5.0 Review MC-Format (N10-008) (101)

Ralph is testing some newly installed twisted-pair cable runs on his network using a wiremap tester, and he has found one run that appears to have a cable break. However, the connectors at both ends are correctly installed, so the break must be somewhere inside the cable itself, which is nearly 100 meters long. Which of the following tools can Ralph use to determine the location of the cable break? (Choose all that apply.) A. Tone generator and locator B. Multimeter C. Time-domain reflectometer D. Cable certifier

C, D. A time-domain reflectometer (TDR) is a device that determines the length of a cable by transmitting a signal at one end and measuring how long it takes for a reflection of the signal to return from the other end. Using this information and the cable's nominal velocity of propagation (NVP)—a specification supplied by the cable manufacturer—the device can calculate the length of a cable run. In a cable with a break in its length, a TDR calculates the length of the cable up to the break. Cable certifiers typically have time-domain reflectometry capabilities integrated into the unit. A tone generator and locator or a multimeter cannot locate a cable break.

Alice is the network administrator of her company's network. The company has just moved into a building that has existing Category 6 (Cat 6) Unshielded Twisted Pair (UTP) cabling. However, none of the cable connections have been labeled, and Alice is trying to identify and document where each cable run starts and ends. Which tools can Alice use for this purpose? (Choose all that apply.) A. A packet sniffer B. A loopback adapter C. A tone generator and locator D. A wiremap tester

C, D. Alice can use a tone generator and locator or a wiremap tester to identify and test cable connections. By connecting the tone generator or the remote wiremap unit to one end of a cable run, she can use the locator or the master wiremap unit to find the other end. This can enable her to identify a starting point and an ending point for a cable run. A loopback adapter is used to test the transmission and reception capabilities of a port. A packet sniffer captures and analyzes network traffic; it cannot identify cables.

Ralph's company has expanded to include an additional building on the far end of the corporate campus, approximately 4 kilometers away from the building housing the datacenter. A single-mode fiber-optic cable connection has been installed between the new building \and the datacenter for a 1000Base-BX10 connection, but the cable is not yet connected to a transceiver at the datacenter end. Noticing that there is a 1000Base-SX transceiver module in the datacenter storeroom, Ralph is wondering if he could use this on the new cable run. Which of the following are reasons why this might not work? (Choose all that apply.) A. Transceiver mismatch B. Incorrect cable type C. Excessive cable length D. Wavelength mismatch

A, B, C, D. The 1000Base-SX standard calls for multimode cable with a maximum length of approximately 500 meters, while the new cable run is 4,000 meters and uses single-mode cable. The 1000Base-SX transceiver will also be incompatible with the 1000Base-BX10 transceiver at the other end. 1000Base-BX10 uses wavelengths from 1,300 to 1,600 nanometers (nm), whereas 1000Base-SX uses wavelengths of 770 to 860 nm.

Which of the following should a troubleshooter look for when a duplex mismatch is suspected on an Ethernet network? (Choose all that apply.) A. Collisions B. Runt frames C. CRC errors D. Failed ping tests

A, B, C. There should be no collisions at all on a full-duplex network, so collisions indicate that at least one side of the connection is trying to operate in half-duplex mode. Ethernet running over twisted-pair cable, in its original half-duplex mode, detects collisions by looking for data on the transmit and receive pins at the same time. In full-duplex mode, data is supposed to be transmitted and received at the same time. In a duplex mismatch, in which one side of a connection is configured to use full duplex and the other end is configured to use half duplex, the full-duplex communications originating from one side look like collisions to the half-duplex side. The half-duplex adapter transmits a jam signal as a result of each collision, which causes the full-duplex side to receive an incomplete or damaged frame, which are perceived as runts or through Cyclic Redundancy Check (CRC) errors. Both sides then start to retransmit frames in a continuing cycle, causing network performance to diminish. Ping tests do not detect a duplex mismatch, because ping only transmits a small amount of data in one direction at a time. The mismatch only becomes apparent when the systems transmit large amounts of data.

Which of the following statements about multitiered technical support organizations are true? (Choose all that apply.) A. Help calls are always escalated to second-tier technicians when they involve mission-critical network components such as routers. B. First-tier technicians generally handle desktop problems. C. Second-tier technicians are generally less experienced than first-tier technicians. D. First-tier technicians are generally less experienced than second-tier technicians.

A, B, D. First-tier technicians are generally less experienced than second-tier technicians. First-tier technicians are the first point of contact for users. They receive and prioritize help desk calls and escalate problems to second-tier technicians, if necessary. First-tier technicians generally handle individual desktop problems, whereas second-tier technicians troubleshoot mission-critical network components such as routers and switches.

Which of the following application layer protocols includes a program that enables a user to log on to a network device and execute commands on the remote system using a command-line interface? (Choose all that apply.) A. Telnet B. File Transfer Protocol (FTP) C. Simple Network Management Protocol (SNMP) D. Domain Name System (DNS) E. Nslookup

A, B. Both Telnet and FTP are protocols that include command-line client applications, with Telnet providing terminal emulation and FTP file transfer functionality. SNMP and DNS are both application layer protocols, but neither one includes a program. Nslookup has a command-line interface, but it executes commands on the local system, not a remote one.

Ed is trying to troubleshoot a problem that has caused a wired network connection to slow down noticeably. Which of the following wired network problems will cause a drastic slowdown of a network connection, without causing it to fail completely? (Choose all that apply.) A. Bottleneck B. Speed mismatch C. Duplex mismatch D. TX/RX reversal

A, C. A bottleneck is a component involved in a network connection that is not functioning correctly, causing a traffic slowdown that affects the entire network. A duplex mismatch occurs when one side of a connection is configured to use full duplex and the other end is configured to use half duplex. When this occurs, the full-duplex communications on the one side look like collisions to the half-duplex side. The half-duplex adapter transmits a jam signal as a result of each collision, which causes the full-duplex side to receive an incomplete frame. Both sides then start to retransmit frames in a continuing cycle, causing network performance to diminish drastically. A speed mismatch or a Transmit and Receive (TX/RX) reversal will stop network communication completely.

Which of the following statements about cable certifiers are true? (Choose all that apply.) A. A cable certifier eliminates the need for tools like tone generators and wiremap testers. B. Cable certifiers are the most inexpensive cable testing solution. C. Cable certifiers must be reconfigured whenever a new cable specification is standardized. D. Cable certifiers can only test copper-based cables.

A, C. Cable certifiers can detect all of the faults that tone generators and wiremap testers can detect, and they can do a great deal more, such as specify whether a cable run meets the performance specifications defined in a cable standard. When testing a new cable type, the specifications defined in the cable standard must be added to the device. Cable certifiers are far more expensive than most other cable testing solutions. Cable certifiers are available that support various cable media, including copper and fiber optic.

Which of the following are reasons for documenting a network problem or incident? (Choose all that apply.) A. Documentation makes it easier to escalate calls to senior technicians. B. Documentation makes it easier to prioritize administrative tasks. C. Documentation makes it easier to prioritize each help call. D. Documentation makes it easier to escalate calls to first-tier technicians.

A, C. When a network problem or incident is reported, documentation begins. Proper documentation makes it easier for a first-tier support technician to prioritize and to escalate the call to senior technicians, if necessary

Ralph is the administrator of his company's network. All of the users on the network are reporting that they are having difficulty connecting to a particular application server that is located on a perimeter network, on the other side of a router. The users are not having trouble connecting to local hosts. Which of the following troubleshooting tools can Ralph use to verify the network layer functionality of the application server and the router? (Choose all that apply.) A. ping B. route C. arp D. traceroute

A, D. Ralph can use the ping and traceroute tools to verify the network layer functionality of the application server and the router. The ping tool tests the network layer through the exchange of Internet Control Message Protocol (ICMP) Echo and Echo Reply messages. The traceroute tool can verify that there is a functioning path between the users' workstations and the application server. The route tool is used to administer the routing table on the local machine. The arp tool is used to view a computer's Internet Protocol to Media Access Control (IP to MAC) address resolution table stored in memory

On Monday morning, Alice arrives at work to find multiple email and telephone messages from users who are unable to access the Accounting department's file server. Which of the following are the best questions to ask during the beginning stage of the troubleshooting process? (Choose two.) A. What has changed since the users were last able to access the server? B. Are there any software updates that Alice should apply to the server? C. Has the server suffered a hard disk failure? D. Which users are reporting a problem, and where are they located?

A, D. The first stage of the troubleshooting process calls for Alice to identify the problem by gathering information. Learning about who is reporting the problem and what has changed since the server was last accessible can provide Alice with information that could help her determine whether the problem is located in the users' workstations, somewhere in the network, or in the server itself. The other options are intended to test a theory about a probable cause, a troubleshooting stage that comes later.

Which of the following command-line utilities can run on Windows, Unix, or Linux systems? (Choose all that apply.) A. ping B. traceroute C. ifconfig D. iptables E. nslookup

A, E. The ping and nslookup utilities can both run on Windows, Unix, or Linux systems. The traceroute command runs only on Unix or Linux, although there is a Windows version called tracert. The ifconfig and iptables commands only exist on Unix and Linux systems.

Which of the following types of cables is used to connect a terminal to the console port of a router or switch? A. Rollover B. Straight through C. Crossover D. Plenum E. Shielded F. Tap

A. A rollover cable is a type of null modem cable, usually flat and light blue in color, with the pinouts reversed on either end, to enable a terminal to communicate with a router or switch through the device's dedicated console port. None of the other options are suitable for this purpose. A straight through cable is the standard network cable used to connect a computer to a switch. A crossover cable is designed to connect two network adapters directly. A plenum cable is a type of cable intended for use within air spaces and has an outer sheath that does not produce toxic fumes when it burns. A shielded cable is intended to protect signals from electromagnetic interference. A tap is a device used to branch a coaxial cable to two devices

Which of the following types of patch cables is used to connect a computer to a wall plate? A. Straight through B. Crossover C. Rollover D. Plenum

A. A straight through cable is the standard network patch cable used to connect a computer to a wall plate. A crossover cable is designed to connect two network adapters directly. A rollover cable is used to enable a terminal to communicate with a router or switch through the device's console port. A plenum cable is a type of cable intended for use within air spaces that has an outer sheath that does not produce toxic fumes when it burns.

Which of the following types of Unshielded Twisted Pair (UTP) wiring faults cannot be detected by a wiremap tester? A. Split pairs B. Open circuits C. Short circuits D. Transposed wires

A. A wiremap tester consists of a main unit that connects to all eight wires of a UTP cable at once and a loopback device that you connect to the other end, enabling you to test all of the wires at once. A wiremap tester can detect opens and shorts, as well as transposed wires. However, it cannot detect split pairs because, in that fault, the pins are properly connected.

Which of the following tools can you use to test the optical loss in a fiber-optic cable? A. An OLTS B. A TDR C. A tone generator and locator D. A wiremap tester

A. An optical loss test set (OLTS) identifies signal loss in fiber-optic cabling. A time-domain reflectometer (TDR) measures electrical signals in copper-based cabling, not light signals. Tone generator and locator tools and wiremap testers are used in copper-based cabling installations, not fiber-optic cabling.

Alice receives a call in which a user reports that he is unable to send print jobs to the network-attached workgroup printer near his desk. Which of the following tasks should Alice perform first? A. Reinstall the printer driver on the user's workstation. B. Test network connectivity to the printer using the ping utility. C. Examine the switches to which the user's workstation and the printer are connected. D. Check to see if there are printer firmware upgrades available.

A. Because the multiple problems seem to be unrelated, Alice should handle them individually by creating a separate trouble ticket for each one and prioritizing each one. None of the problems seem to be severe enough to warrant escalation, nor should it be necessary to replace the computer. While it would be possible to send a technician to address all of the problems at once, it would be more efficient to assign each its own priority and handle it like any other trouble call.

Which of the following command-line utilities enables you to view the Internet Protocol (IP) configuration on a Unix or Linux host? A. ifconfig B. nslookup C. ipconfig D. netstat E. iperf

A. On a Unix or Linux host, the ifconfig command displays the system's current IP configuration settings and parameters. ipconfig is a Windows command-line utility that performs the same basic function. The other options are command-line utilities that do not display IP configuration information.

Which of the following parameters enables you to specify the number of messages the ping tool transmits? A. -n B. -t C. -i D. -a

A. Running the ping tool with the -n parameter specifies the number of messages the tool should transmit with each execution. The -t parameter causes the ping tool to send messages to the target continuously until manually stopped. The -i parameter specifies the Time to-Live (TTL) value of the messages that ping transmits. The -a parameter resolves an Internet Protocol (IP) address specified as the target to a hostname.

A single Windows user suddenly cannot connect to any hosts on the network (local or remote). Alice interviews the user and finds out that he made some changes to his computer's Internet Protocol (IP) configuration properties. What should she do next? A. Run the ipconfig command to view the local configuration B. Check the Domain Name System (DNS) server to see if it is resolving IP hostnames C. Check the Windows Internet Name Service (WINS) server to see if it is resolving Network Basic Input/Output System (NetBIOS) names D. Verify that the router is functioning

A. Since only one user is reporting the problem, and he had admitted to making changes to his IP configuration, Alice should probably start by checking the configuration using the ipconfig command. If the router, DNS server, or WINS server were causing the problem, more than one user would be experiencing difficulties.

Alice has a network with a Domain Name System (DNS) server, a proxy server, and an Internet router. A user is complaining that she suddenly cannot connect to hosts on her own Local Area Network (LAN) and other internal LANs, and she cannot access hosts on the Internet. What is the likeliest problem? A. The user's local configuration B. The proxy server C. The DNS server D. The router

A. Since only one user is reporting the problem, the user's computer and its configuration are the likeliest suspect components. A DNS, proxy, or router problem would affect more than one user

Which of the following Windows command-line utilities produced the output shown here? Reply from 97.74.144.153: bytes=32 time=111ms TTL=53 Reply from 97.74.144.153: bytes=32 time=109ms TTL=53 Reply from 97.74.144.153: bytes=32 time=108ms TTL=53 Reply from 97.74.144.153: bytes=32 time=109ms TTL=53 Statistics for 97.74.144.153: Chapter 5 ■ Network Troubleshooting 217 Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 108ms, Maximum = 111ms, Average = 109ms A. ping B. tracert C. netstat D. arp E. hostname

A. The Windows ping utility functions by transmitting a series of Internet Control Message Protocol (ICMP) Echo Request messages to a specified destination. The destination system responds with ICMP Echo Reply messages that are listed in the output display. The tracert, netstat, arp, and hostname utilities are not capable of producing this output.

Ralph is testing a twisted-pair cable run using a tone generator and locator. When he applies the tone generator to one particular wire at one end of the cable, he fails to detect a tone at the other end. Which of the following faults has Ralph discovered? A. Open B. Short C. Split pair D. Crosstalk

A. The failure to detect a tone on a wire indicates that there is either a break in the wire somewhere inside the cable or a bad connection with the pin in one or both connectors. This condition is called an open circuit. A short is when a wire is connected to two or more pins at one end of the cable. A split pair is a connection in which two wires are incorrectly mapped in exactly the same way on both ends of the cable. Crosstalk is a type of interference caused by signals on one wire bleeding over to other wires.

Which of the following troubleshooting steps involves prioritizing trouble tickets based on the severity of the problem? A. Identify symptoms of the problem B. Establish a theory of probable cause C. Test the theory to determine cause D. Establish a plan of action to resolve the problem and identify potential effects E. Implement the solution or escalate as necessary F. Verify full system functionality and, if applicable, implement preventive measures G. Document findings, actions, and outcomes

A. The first step in troubleshooting is to identify the problem by establishing symptoms related to the network issue being reported. In this step, problems are typically reported as trouble tickets, which are prioritized based on the severity of the problem. You complete the other steps after the trouble ticket has been prioritized and is being investigated

Which of the following troubleshooting steps involves asking the user preliminary questions such as, "What were you doing when the problem occurred?" A. Identify the problem B. Establish a theory of probable cause C. Test the theory to determine cause D. Establish a plan of action to resolve the problem and identify potential effects E. Implement the solution or escalate as necessary F. Verify full system functionality and, if applicable, implement preventative measures G. Document findings, actions, and outcomes

A. The first step in troubleshooting is to identify the problem by establishing symptoms related to the network problem being reported. In this step, you ask the user many questions to identify and define the symptoms of the problem and prioritize the trouble ticket. Although you might continue to ask the user questions throughout the troubleshooting process, this is typically associated with the first step of the troubleshooting process.

Alice is working the help desk when a user calls and reports that she is unable to connect to the Internet. Which of the following steps is the one Alice is least likely to perform first when troubleshooting the problem? A. Check the configuration of the router connecting the LAN to the Internet B. Ask the user if she can access resources on the local network C. Check to see if anyone else is experiencing the same problem D. Check the user's job title to see if she is an important person in the company

A. There are many possible causes for the problem that are more likely than a router configuration error, so this is not something Alice would check first. Asking if the user can access the local network attempts to isolate the problem. If she cannot, the problem could be in her computer; if she can, then the problem lies somewhere in the Internet access infrastructure. If other users are experiencing the problem, then the issue should receive a higher priority, and Alice knows that the problem does not lie in the user's computer. While it might not be the first thing she checks, it is a political reality that higher ranking users often get preferential treatment.

Alice has recently installed some new computers onto her Gigabit Ethernet network. To ensure the best possible network performance, she has configured the network adapters in the new computers to run at 1 Gbps speed and use full-duplex communication. Once the computers are in service, however, Alice begins getting reports of extremely poor network performance on those machines. She tries running some ping tests and does not see any problem. She calls in a consultant to perform a packet analysis, and the consultant detects large numbers of packet collisions, late collisions, Cyclic Redundancy Check (CRC) errors, and runt frames. Which of the following could conceivably be the problem? A. Duplex mismatch B. TX/RX reversal C. Incorrect cable type D. Damaged cables

A. There should be no collisions on a full-duplex network, so the problem is clearly related to the duplexing of the communications. Ethernet running over twisted-pair cable, in its original half-duplex mode, detects collisions by looking for data on the Transmit and Receive (TX/RX) pins at the same time. In full-duplex mode, data is supposed to be transmitted and received at the same time. When one side of a connection is configured to use full duplex, as Alice's new computers are, and the other end is configured to use half duplex (as the switches must be), the full-duplex communications on the one side look like collisions to the half-duplex side. The half-duplex adapter transmits a jam signal as a result of each collision, which causes the full-duplex side to receive an incomplete frame. Both sides then start to retransmit frames in a continuing cycle, causing network performance to diminish drastically. The ping tests do not detect a problem, because ping only transmits a small amount of data in one direction at a time. The other options would likely cause the ping tests to fail as well. The solution to the problem is to configure all of the devices to autonegotiate their speed and duplex modes.

Which of the following Windows command-line utilities produced the output shown here? Server: trv213.pljd.net Address: 203.186.120.114 Non-authoritative answer: Name: microsoft.com Addresses: 104.43.195.251 23.100.122.175 23.96.52.53 191.239.213.197 104.40.211.35 A. nslookup B. pathping C. netstat D. route

A. nslookup is a command-line utility that generates Domain Name System (DNS) resource record requests and sends them to a specific DNS server. The output shown here first specifies the name and address of the DNS server to which the request was sent, and then the response to the request, containing the name to be resolved and the Internet Protocol (IP) addresses contained in the server's resource record for that name. The pathping, netstat, and route utilities cannot perform DNS queries.

Ralph has to spend the day completing a twisted-pair cable installation in his office. Contractors have already pulled the cables through the walls and ceilings. Ralph only has to attach connectors to the ends of the cables, both internal cable runs and patch cables. Which of the following tools will Ralph need? (Choose all that apply.) A. Telepole B. Crimper C. Punchdown tool D. Pigtail splicer

B, C. A crimper is a plier-like tool that cable installers use to attach RJ45 connectors to patch cables. A punchdown tool is a tool that cable installers use to attach keystone connectors to cable ends, for use in wall plates and patch panels. A telepole is a device used to run cables through walls, floors, and ceilings, but since the cable runs have already been pulled, Ralph will not need this tool. A pigtail splicer is a tool used only in fiber-optic cable installations.

After experiencing some problems with devices connected to the company's fiber-optic network, Alice brings in a contractor to test the fiber-optic cable runs. The contractor detects a significant amount of decibel (dB) loss in some of the cable runs, which could be the source of the problems. Which of the following are possible causes of the decibel loss? (Choose all that apply.) A. Electromagnetic interference B. Dirty optical cables C. Excessive cable length D. Signal crosstalk

B, C. Dirt on fiber-optic cable connectors can reduce the strength of the signal, resulting in decibel loss. Excessive cable length can result in greater attenuation and weaker signals due to the decibel loss. Electromagnetic interference and signal crosstalk are both factors that can affect copper cable transmissions, but not fiber optic.

Ed is trying to troubleshoot a problem with his wired network, and his research has led him to a list of possible network faults. The list is rather old, however, and Ed is wondering if some of the problems are relevant. Which of the following wired network problems no longer occur with modern Gigabit Ethernet switches and network adapters in their default configurations? (Choose all that apply.) A. Bottleneck B. Speed mismatch C. Duplex mismatch) D. Transmit and Receive (TX/RX reversal

B, C. The Gigabit Ethernet standards call for switches and network adapters to support auto negotiation by default, which enables devices to communicate and select the best network speed and duplex mode available to them both. Therefore, speed mismatches and duplex mismatches no longer occur unless someone modifies the speed or duplex settings to incompatible values on one or both devices.

Ed is trying to troubleshoot a problem that has caused a wired network connection to fail completely. Which of the following wired network problems will cause a complete failure of a network connection? (Choose all that apply.) A. Bottleneck B. Speed mismatch C. Duplex mismatch D. TX/RX reversal E. Bad switch port

B, D, E. A speed mismatch on a wired network only occurs when two devices are configured to use a specific transmission speed and those speeds are different. In that case, network communication stops. For network communication to occur on a twisted-pair network, transmit (TX) pins must be connected to receive (RX) pins. If the connections are reversed, no communication occurs. If the switch port to which a computer is connected is bad, there will be no network communication. Bottlenecks and duplex mismatches will slow down network communications, but they will not stop them completely.

Which of the following tools can you use to create your own twisted pair patch cables? (Choose all that apply.) A. Punchdown tool B. Crimper C. Pliers D. Wire stripper

B, D. A crimper is a device used for attaching connectors to patch cables. A wire stripper, while not essential to the process, can simplify the task of preparing the cable. A punchdown tool is used for attaching keystone connectors to cable ends, for use in wall plates and patch panels. A standard set of pliers is not used in the process of attaching connectors.

Which of the following tools might you use when connecting internal twisted-pair cable runs to the keystone connectors that snap into wall plates? (Choose all that apply.) A. A crimper B. A punchdown tool C. A pigtail splicer D. A wire stripper E. A fusion splicer

B, D. The punchdown tool is critical to this operation. In one motion, the tool strips the insulation off of the wire, presses it down into the connector, and cuts off the excess at the end. A wire stripper simplifies the task of preparing the cable for the connection process. A crimper is used only for attaching connectors to patch cables. Pigtail splicers and fusion splicers are used only on fiber-optic networks.

Which of the following statements about prioritizing help calls are true? (Choose all that apply.) A. Individual desktop problems take precedence over problems with shared resources. B. Problems with shared resources take precedence over individual desktop problems. C. Departmental problems take precedence over networkwide problems. D. Networkwide problems take precedence over departmental problems.

B, D. When establishing priorities, networkwide problems take precedence over departmental problems, and problems with shared resources take precedence over individual desktop problems

A. There should be no collisions on a full-duplex network, so the problem is clearly related to the duplexing of the communications. Ethernet running over twisted-pair cable, in its original half-duplex mode, detects collisions by looking for data on the Transmit and Receive (TX/RX) pins at the same time. In full-duplex mode, data is supposed to be transmitted and received at the same time. When one side of a connection is configured to use full duplex, as Alice's new computers are, and the other end is configured to use half duplex (as the switches must be), the full-duplex communications on the one side look like collisions to the half-duplex side. The half-duplex adapter transmits a jam signal as a result of each collision, which causes the full-duplex side to receive an incomplete frame. Both sides then start to retransmit frames in a continuing cycle, causing network performance to diminish drastically. The ping tests do not detect a problem, because ping only transmits a small amount of data in one direction at a time. The other options would likely cause the ping tests to fail as well. The solution to the problem is to configure all of the devices to autonegotiate their speed and duplex modes.

B, E. One possible cause of the problem is that the DNS process on the remote server is corrupted or not running. Another possible cause is that there is a firewall blocking access to the server's Unshielded Twisted Pair (UTP) port 53. Both of these would render the port unreachable. The Transmission Control Protocol/Internet Protocol (TCP/IP) client on the server is operating, as verified by the ping utility. This means that the IP host configurations on Ralph's computer and on the DNS server are both functioning. The router does not need to be running DNS to forward datagrams.

Which of the following utilities can you use to view resource record information on a particular Domain Name System (DNS) server? (Choose all that apply.) A. netstat B. nslookup C. nbtstat D. arp E. dig

B, E. nslookup and dig are both command-line utilities that you can direct to a specific DNS server and then generate queries that display resource record information the program retrieves from the server. netstat displays information about networking protocols, whereas nbtstat displays information derived from the system's Network Basic Input/ Output System (NetBIOS) over Transmission Control Protocol/Internet Protocol (TCP/IP) implementation. arp is a tool that you can use to display and manage a system's Address Resolution Protocol (ARP) table entries. netstat, nbtstat, and arp are not able to display resource record information.

Ralph is a new hire for a consulting firm that frequently performs cable installations. He is trying to learn more about the tools needed to install internal cable runs. To that end, which of the following statements about cable crimpers has Ralph found to be true? A. Cable installers use a crimper to attach keystone connectors to lengths of bulk cable. B. Cable installers use a crimper to attach RJ45 connectors to lengths of bulk cable. C. You need to purchase a separate crimper for each type of cable to which you want to attach connectors. D. Making your own patch cables by applying connectors yourself is always more economical than buying prefabricated patch cables.

B. A crimper is a plier-like device that cable installers use to create patch cables by attaching RJ45 connectors to lengths of bulk cable. Installers use a punchdown tool, not a crimper, to attach a cable end to a keystone connector. It is not always necessary to purchase a crimper for each cable type. Some crimpers are designed for a single cable/connector combination, but there are many that have replaceable bits, supporting a variety of cables and connectors. Making patch cables yourself can represent a false economy. Buying bulk cable and connectors and making patch cables yourself can conceivably be cheaper than purchasing prefabricated cables. However, when you factor in the time needed to attach the connectors, the learning curve required to attach the connectors correctly, and the failure rate requiring the re-application of connectors, it might be more economical to purchase prefabricated patch cables in quantity instead.

Ed is a first-tier support technician. He receives the help calls listed here. His job is to prioritize them based on their severity. Which of the following should be the problem that receives the lowest priority? A. A problem with an order entry or customer service call center resource that affects an entire department, with multiple Local Area Networks (LANs) B. A fatal error that causes a single computer to fail C. A problem with a mission-critical backbone router that affects an entire network D. A problem with an application server that affects a single LAN

B. A problem that affects the entire network should be given highest priority. This includes a mission-critical backbone router. Problems that affect multiple LANs or an entire department are generally given the next highest priority. An application problem that affects a shared application server on a LAN should be given the next highest priority. A problem with a single user's computer should be given the lowest priority if the other problems have been reported.

A routine test of a newly installed twisted-pair cable run with a wiremap tester indicates that there is a short circuit on one of the wires. Which of the following procedures might possibly correct the fault? A. Use a different pinout on both ends of the cable B. Replace the connectors at both ends of the cable run C. Move the cable away from any potential sources of electromagnetic interference D. Use a higher grade of Unshielded Twisted Pair (UTP) cable

B. A short circuit is a wiring fault indicating that a pin at one end of a cable run is connected to two pins at the other end. To correct the problem, you must replace the connector with the faulty wiring. None of the other suggestions are solutions for a wiring fault.

Ralph is testing a twisted-pair cable run using a tone generator and locator. When he appliesthe tone generator to a particular pin at one end of the cable, he detects a tone on two pins at the other end. Which of the following faults has Ralph discovered? A. Open B. Short C. Split pair D. Crosstalk

B. A short is when a wire is connected to two or more pins at one end of the cable or when the conductors of two or more wires are touching inside the cable. This would cause a tone applied to a single pin at one end to be heard on multiple pins at the other end. An open circuit would manifest as a failure to detect a tone on a wire, indicating that there is either a break in the wire somewhere inside the cable or a bad connection with the pin in one or both connectors. A split pair is a connection in which two wires are incorrectly mapped in exactly the same way on both ends of the cable. Crosstalk is a type of interference caused by signals on one wire bleeding over to other wires.

Ralph's company has engaged a firm of wiring contractors to install some new fiber-optic cable runs. Before the cables are connected to any devices, Ralph wants to confirm that they have been installed to proper specifications. He brings in a contractor from another firm to test the cable runs. To test each cable run, the contractor connects a light source to one end of the cable and a measuring device to the other end. Which of the following is the correct name for this testing device? A. Optical power meter B. OLTS C. OTDR D. Multimeter

B. An optical loss test set (OLTS) is the term for the combination of an optical light source and an optical power meter. The optical power meter by itself cannot be used to test the cable runs when there are no devices connected to them. An Optical Time Domain Reflectometer (OTDR) is a device for measuring the lengths and other characteristics of fiber-optic cables. A multimeter is a device for measuring the electric current on a copper cable.

Ed has discovered that some of the twisted-pair cable runs on his newly installed Ethernet network are well over 100 meters long. Which of the following problems is his network likely to experience due to cable segments that are greater than the specified length? A. Jitter B. Attenuation C. Crosstalk D. EMI

B. Attenuation is the weakening of a signal as it travels long distances, whether on a wired or wireless medium. The longer the transmission distance, the more the signal weakens. Cable length specifications are designed in part to prevent signals from attenuating to the point at which they are unviable. Jitter, crosstalk, and electromagnetic interference (EMI) are all conditions that can affect the performance of a wired network, but they are not directly related to the length of the cable.

Which of the following cable installation tools is likely to be the most expensive? A. A crimper B. A cable certifier C. A punchdown tool D. A wiremap tester

B. Crimpers and punchdown tools are relatively simple and inexpensive mechanical devices that cable installers use to connect bulk cable to connectors. A wiremap tester is an electronic device for cable testing, but it is still relatively simple. A cable certifier is a complex electronic device that can perform a battery of tests on a cable run, confirm that the cable conforms to the required wiring standards, and maintain records of the testing procedure. Cable certifiers are by far the most expensive of the devices listed.

In the standard troubleshooting methodology, which of the following steps appears last, but must actually be practiced throughout the troubleshooting process? A. Test the theory to determine cause B. Document findings, actions, and outcomes C. Verify full system functionality and, if applicable, implement preventive measures D. Implement the solution or escalate as necessary E. Establish a plan of action to resolve the problem and identify potential effects F. Establish a theory of probable cause G. Identify the problem

B. Documenting everything you discover and everything you do is a crucial part of the troubleshooting method that must begin before you take any other action whatsoever. However, it appears as the last step in the troubleshooting methodology

Users are having trouble connecting to Internet hosts. Alice suspects that there is a problem with the Domain Name System (DNS) server, and she wants to verify this. Which of the following steps can she take to determine whether the DNS server is resolving Internet hostnames? A. Issue the ipconfig command from a local workstation B. Try to connect to a host using the IP address instead of the hostname C. Ping the DNS server to see if it is functioning D. Use the tracert command to test the functionality of the DNS server

B. If Alice suspects that a DNS server is not resolving hostnames, she should try connecting to a remote host using the Internet Protocol (IP) address instead of the name. If she can connect, she knows that all internal Local Area Network (LAN) components and the Internet gateway are functioning, and the remote host is functioning. The problem most likely lies within the DNS server itself. If Alice cannot connect to a remote host using the IP address, the problem is not the DNS server. She would need to do more testing to isolate the problem device and the affected area. ipconfig is a workstation command that enables you to verify the local IP configuration; it is not used to test a DNS server's functionality. Using the ping command will only tell you whether the computer hosting the DNS service is functioning at the network layer of the Open Systems Interconnection (OSI) model; it will not test the DNS service functionality. The tracert (or traceroute) command is used to identify the hop-by-hop path taken to reach a destination; it does not allow you to test functionality above the network layer of the OSI model.

You have a problem with a server or other network component that prevents many users from working. What type of problem is this? A. A networkwide problem B. A shared resource problem C. A systemwide problem D. A user application problem

B. If a problem lies within a specific server or other network component that prevents many users from working, it is a shared resource problem. A problem that lies within resources that provide services to the entire network is a networkwide problem. Systemwide problems put a specific computer out of commission, preventing a user from getting any work done. An application problem is a problem that affects only a single user's access to a device or application.

A user reports that she cannot connect to a server on her network. Ed wants to identify the scope of the problem, so he tries to reproduce the problem on the user's computer. The problem still remains. No other users are reporting this problem. What is the next logical step that Ed should perform to identify the affected area? A. Verify that the local router is forwarding traffic. B. Try performing the same task on another computer attached to the same segment. C. Verify that the server is configured properly. D. Verify that the switch the client is connected to is functioning.

B. In this scenario, only one user is reporting a problem. Therefore, the likeliest next step is to perform the same task on another computer attached to the same segment. If Ed can perform the task successfully, the problem most likely lies within the user's computer or the connection to the switch. Since no other users are reporting the same problem, the server and switches on the network are probably up and functioning. Checking the router is not necessary since the user and server are on the same network.

Which of the following command-line utilities is capable of performing the same basic function as traceroute or tracert? A. ping B. pathping C. netstat D. route

B. Like traceroute and tracert, pathping is capable of generating a list of the routers that packets pass through on the way to a specific destination system. pathping also displays the percentage of lost packets for each hop, which traceroute and tracert cannot do. The ping, netstat, and route utilities are not capable of displaying route traces.

Under which of the following conditions is a cable installer required to use plenum cable? A. When cables run close to sources of electromagnetic interference (EMI) B. When cables are running through building air flow spaces C. When data and voice traffic will be running over the same cable D. When cables are running through areas of low temperature

B. Plenum cable is a type of cable intended for use within building air spaces (called plenums) that has an outer sheath that is more resistant to high temperatures and does not produce toxic fumes when it burns. The use of plenum cable has no effect on EMI or the type of traffic on the cable, nor is it required for low temperature areas.

Ralph is working on a new twisted-pair network cable installation on which the individual cable runs were not properly labeled as they were pulled. Ralph now has to trace each of the cable ends in the office area to the correct cable end in the data center and label them correctly. Which of the following tools should Ralph use to locate the correct cable in a bundle of unlabeled cable ends? A. Cable certifier B. Tone generator and locator C. OTDR D. Multimeter

B. Ralph can use a tone generator and locator to locate the correct cable associated with each office connection. By connecting the tone generator to one end of a cable run, he can use the locator to find the other end. A cable certifier identifies a variety of cable performance characteristics, typically including cabling length, signal attenuation, and crosstalk. An Optical Time Domain Reflectometer (OTDR) is a device for measuring the lengths and other characteristics of fiber-optic cables. A multimeter is a device for measuring the electric current on a copper cable.

Ralph is the network administrator of his company's network. He has had three users call the help desk to report that they are having problems connecting to the local application server. Comparing their stories, Ralph suspects that their Transmission Control Protocol (TCP) connections are being dropped. The users are not having problems connecting to any other hosts on the network. To troubleshoot this problem, Ralph decides to use a protocol analyzer. He wants to store and view only the traffic relating to the hosts and server that are having problems. How can Ralph do this? A. Configure a display filter B. Configure a capture filter C. Set a trap on the analyzer D. Configure both a capture filter and a display filter

B. Ralph wants to store and view only the traffic relating to the hosts that are experiencing problems. The best way to do this is to set a capture filter. Capture filters determine what is stored in the buffer. Display filters only determine what is displayed from the contents of the buffer. You do not set a trap on an analyzer—you set traps on Simple Network Management Protocol (SNMP) agents. Also, there is no need to configure both a capture filter and a display filter. If you set a capture filter that blocks all other traffic from entering the buffer, the display filter would be redundant.

Which of the following parameters causes the ping tool to transmit messages continually until manually halted? A. -n B. -t C. -i D. -a

B. Running the ping tool with the -t parameter causes it to send messages to the target continuously until it is manually stopped. The -n parameter specifies the number of messages the ping tool should transmit. The -i parameter specifies the time-to-live (TTL) value of the messages ping transmits. The -a parameter resolves an Internet Protocol (IP) address specify as the target to a hostname.

Which of the following Windows command-line utilities produced the output shown here? 1 <1 ms <1 ms <1 ms RT-N86U [192.168.2.99] 2 3 ms 5 ms 4 ms 192.168.3.1 3 25 ms 30 ms 17 ms 10.172.1.1 4 20 ms 19 ms 29 ms gateway-BE1-EBlocal.eh.lpod.net [207.44.123.89] 5 26 ms 29 ms 29 ms gateway-be1-abn2abn2.ab.lpod.net [207.44.127.49] 6 * * * Request timed out. 7 111 ms 108 ms 109 ms be38.trmc0215-01.ars.mgmt.hox3.kkg [184.168.0.69] 8 108 ms 107 ms 108 ms be38.trmc0215-01.ars.mgmt.hox3.kkg [184.168.0.69] 9 106 ms 109 ms 108 ms ip-216-69-188-102.ip.srvr.net [216.69.188.102] 10 106 ms 108 ms 99 ms p3nlh153.shr.prod.phx3.srvr.net [97.74.144.153] A. ping B. tracert C. netstat D. arp E. hostname

B. The Windows tracert utility functions by transmitting a series of Internet Control Message Protocol (ICMP) Echo Request messages to a specified destination with incrementing Time to Live (TTL) values. Each successive message reaches one hop farther on the route to the destination before timing out. The tracert display therefore lists the names and addresses of the routers that packets must traverse to reach the destination. The ping, netstat, arp, and hostname utilities are not capable of producing this output.

Which of the following Windows commands enables you to delete the entire ARP cache? A. arp -c * B. arp -d * C. arp -a D. arp -s

B. The arp -d command is for deleting cache entries, and by running it with the asterisk wildcard, the command deletes all of the entries in the cache. The arp -a command displays the entries in the ARP table stored in its cache, and the arp -s command is for adding entries. The arp -c * command is not a valid option.

Which of the following commands displays the routing table on the local computer? A. arp -r B. netstat -r C. ifconfig -r D. telnet -r

B. The netstat utility can display the routing table, along with other types of network traffic and port information. The arp utility is for adding addresses to the Address Resolution Protocol (ARP) cache; it cannot display the routing table. The ifconfig command displays Transmission Control Protocol/Internet Protocol (TCP/IP) configuration information on Unix and Linux systems; it cannot display the routing table. Telnet is a terminal emulation program; it cannot display the routing table.

Which of the following command-line utilities enables you to generate Domain Name System (DNS) request messages? A. ifconfig B. nslookup C. nbtstat D. netstat E. iperf

B. The nslookup tool enables you to generate DNS request messages from the command line and send them to a specific DNS server. The other options listed are not DNS utilities.

In which troubleshooting step do you try to duplicate a network problem to logically and methodically eliminate elements that are not the source of the problem? A. Identify the problem. B. Establish a theory of probable cause. C. Test the theory to determine cause. D. Establish a plan of action to resolve the problem and identify potential effects. E. Implement the solution or escalate as necessary. F. Verify full system functionality and, if applicable, implement preventative measures. G. Document findings, actions, and outcomes.

B. The second step in troubleshooting is to attempt to duplicate a problem and develop a theory of its probable cause. As you troubleshoot a problem, you then test your theory to confirm your findings. You complete the other troubleshooting steps after the specific cause has been identified

Which of the following troubleshooting tools can test cabling for length, attenuation, near-end crosstalk (NEXT), equal level far-end crosstalk (ELFEXT), propagation delay, delay skew, and return loss? A. Wiremap tester B. Cable certifier C. Time-domain reflectometer (TDR) D. Optical loss test set (OLTS) E. Spectrum analyzer

B. You can use a cable certifier to identify a variety of cable performance characteristics, typically including cabling lengths, signal attenuation, crosstalk, propagation delay, delay skew, and return loss, in addition to providing all the functionality of a wiremap tester. The other tools listed are dedicated to a single testing modality and do not test for crosstalk.

While performing a protocol analysis, Alice notes that there are many Internet Control Message Protocol (ICMP) packets in her captured traffic samples. She attributes these to her frequent use of Transmission Control Protocol/Internet Protocol (TCP/IP) troubleshooting tools. Which of the following utilities are used to test network layer characteristics of a host using ICMP messages? (Choose all that apply.) A. ipconfig B. netstat C. ping D. tracert

C, D. ping and tracert are both utilities that test network layer characteristics using ICMP messages. ping tests the network layer functionality of the host, and traceroute displays the path to the host through the internetwork. ipconfig and netstat do not use ICMP messages.

Which of the following devices is not one of the tools generally used by a data networking cable installer? A. Tone generator and locator B. Wiremap tester C. Butt set D. Cable certifier

C. A butt set is a one-piece telephone handset with alligator clips that enables its operator to connect to a telephone line anywhere that the cables are accessible. They are used by telephone cable technicians, but generally not by installers of network data cables. The other options are all standard tools used by data networking cable installers.

Ed is a first-tier support technician. He receives the help calls listed here. His job is to prioritize them based on their severity. Which of the following should be the problem that receives the highest priority? A. A problem with an order entry or customer service call center resource that affects an entire department, with multiple Local Area Networks (LANs) B. A fatal error that causes a single computer to fail C. A problem with a mission-critical backbone router that affects an entire network D. A problem with an application server that affects a single LAN

C. A problem that affects the entire network should be given highest priority. This includes a mission-critical backbone router. Problems that affect multiple LANs or an entire department are generally given the next highest priority. An application problem that affects a shared application server on a LAN should be given the next highest priority. A problem with a single user's computer should be given the lowest priority if the other problems have been reported.

Which of the following troubleshooting tools enables you to copy all of the packets transmitted over a network to a buffer, interpret the protocols used in the packets, and display the output? A. Event Viewer B. Traffic monitor C. Protocol analyzer D. Management console

C. A protocol analyzer copies all network traffic, interprets the protocol headers and fields, and displays the output. The Event Viewer displays system, application, and security event logs on a single computer. There is no network troubleshooting tool called a traffic monitor. A management console is a remote monitoring and management device that queries Simple Network Management Protocol (SNMP) agents.

Ralph is using a tone generator and locator to test some newly installed twisted-pair cable runs on his network. Which of the following cable faults will he be unable to detect? A. Open B. Short C. Split pair D. Transposed pairs

C. A split pair is a connection in which two wires are incorrectly mapped in exactly the same way on both ends of the cable. Each pin on one end of the cable is correctly wired to the corresponding pin at the other end, but the wires inside the cable used to make the connections are incorrect. In a properly wired connection, each twisted pair should contain a signal wire and a ground wire. In a split pair, it is possible to have two signal wires twisted together as a pair. This can generate excessive amounts of crosstalk, corrupting both of the signals involved. Because all of the pins are connected properly, a tone generator and locator cannot detect this fault. An open circuit would manifest as a failure to detect a tone on a wire, indicating that there is either a break in the wire somewhere inside the cable or a bad connection with the pin in one or both connectors. A short is when a wire is connected to two or more pins at one end of the cable or when the conductors of two or more wires are touching inside the cable. Transposed pairs is a fault in which both of the wires in a pair are connected to the wrong pins at one end of the cable. All three of these faults are detectable with a tone generator and locator.

Which of the following cable faults increases a twisted-pair cable's susceptibility to crosstalk? A. Open B. Short C. Split pair D. Transposed pairs

C. A split pair is a connection in which two wires are incorrectly mapped in exactly the same way on both ends of the cable. Each pin on one end of the cable is correctly wired to the corresponding pin at the other end, but the wires inside the cable used to make the connections are incorrect. In a properly wired connection, each twisted pair should contain a signal wire and a ground wire. In a split pair, it is possible to have two signal wires twisted together as a pair. This can generate excessive amounts of crosstalk, corrupting both of the signals involved. Open circuits, shorts, and transposed pairs interfere with cable performance but do not make it more susceptible to crosstalk.

Ed is experiencing poor network performance on some new twisted-pair cable runs. After ruling out all other causes, he tests the cables with a tone generator and locator and finds no faults. Finally, he examines the cable connectors more closely and finds that, while the pins at one end of the cable are correctly connected to their corresponding pins at the other end, in some cases there are two solid color wires twisted together in a pair. Which of the following types of faults has Ed discovered? A. Open circuit B. Short circuit C. Split pairs D. Transposed wires

C. A split pair is a connection in which two wires are incorrectly mapped in exactly the same way on both ends of the cable. In a properly wired connection, each twisted pair should contain a colored signal wire and a striped ground wire. In a split pair, it is possible to have two signal wires twisted together as a pair. This can generate excessive amounts of crosstalk, corrupting both of the signals involved. Because all of the pins are connected properly, a tone generator and locator cannot detect this fault. An open circuit would manifest as a failure to detect a tone on a wire, indicating that there is either a break in the wire or a bad connection in one or both connectors. A short is when a wire is connected to two or more pins or when the conductors of two or more wires are touching. Transposed pairs is a fault in which both of the wires in a pair are connected to the wrong pins at one end of the cable. All three of these faults are detectable with a tone generator and locator

Which of the following is considered a systemwide error? A. A problem with an order entry or customer service call center resource B. A problem with a router that affects only one Local Area Network (LAN) C. A fatal error that causes a single computer to fail D. A problem with an email server that affects all network users

C. A systemwide error is a problem that renders an individual user's system (computer) completely unusable. All the other problems listed would affect more than one system or user

When troubleshooting, you begin by taking steps to identify the problem. After you do this, which of the following steps should you perform next? A. Implement the solution B. Establish a plan of action C. Establish a theory of probable cause D. Verify full system functionality

C. After identifying the problem, the next step is to establish a theory for the probable cause of the problem. After that, you can test your theory, establish a plan of action, implement a solution, verify the functionality of the system, and document the entire process.

Which step of the troubleshooting model involves replacing components until a faulty hardware device is identified? A. Duplicate the problem B. Gather information C. Test the theory to determine the cause D. Establish a plan of action to resolve the problem E. Verify full system functionality F. Document findings, actions, and outcomes

C. After you have established a theory of probable cause, you can try to test the theory by replacing hardware components one by one until you find the faulty device.

Alice takes a call from a user who is unable to send email to a colleague in one of the company's branch offices. Alice begins by having the user try to send emails to different people at the branch office, to people in the local office, and to people on the Internet. She then checks the user's Internet Protocol (IP) configuration settings, the computer's Local Area Network (LAN) communication, and the cable connection to the network. Which of the following approaches is Alice using to troubleshoot the problem? A. OSI bottom-to-top B. Divide and conquer C. OSI top-to-bottom D. Question the obvious

C. Alice is using a top-to-bottom approach, based on the Open Systems Interconnection (OSI) reference model. She begins at the top of the model (the application layer) by checking the system's email capabilities, and then proceeds downwards to check the computer's IP configuration (at the network layer), the local network connectivity (the data link layer), and the computer's cables (the physical layer). A bottom-to-top approach would begin with the cables. The divide-and-conquer approach and questioning the obvious would not involve the steps Alice took in the order that she took them.

Ralph is a new hire working on a network that uses Category 5 (Cat 5) Unshielded Twisted Pair (UTP) cable, which was installed several years ago. Over time, some of the paper labels that the original cable installers used to identify the wall plates and patch panel connectors have worn away or fallen off. As a result, Ralph has quite a few cable runs that he is unable to identify. After checking with his supervisor, Ralph discovers that the company has no cable testing equipment and is unwilling to hire a consultant just to identify cable runs. What is the most inexpensive tool Ralph can use to associate unlabeled wall plates with the correct patch panel ports? A. A wiremap tester B. A cable certifier C. A tone generator and locator D. A time-domain reflectometer (TDR)

C. All of the suggested tools are capable of associating wall plates with the correct patch panel ports, but the tone generator and locator is by far the most inexpensive solution.

Which of the following terms describes the progressive weakening of transmitted signals as they travel along a network medium? A. Absorption B. Latency C. Attenuation D. Crosstalk

C. Attenuation is the weakening of a signal as it travels long distances, whether on a wired or wireless medium. The longer the transmission distance, the more the signal weakens. Absorption is the tendency of a wireless signal to change as it passes through different materials. Latency is a measurement of the time it takes for a signal to travel from its source to its destination. Crosstalk is a type of interference that occurs on wired networks when a signal bleeds over to an adjacent wire.

Ralph is a first-tier technician working the help desk. A user calls in, saying that when she turned her computer on that morning, nothing appeared on the screen. Which of the following should be Ralph's first question to the user? A. What is your computer's IP address? B. Have you applied the latest system updates? C. Are the computer and monitor plugged in to AC power? D. Has anyone else been using your computer?

C. In troubleshooting, one of the first steps in the process of identifying the problem is to question the obvious, such as whether the computer is plugged in or switched on. It would be unlikely that the user would know her computer's IP address or what updates had been installed when the screen is blank. Questioning whether other people have used the computer might come up later, but it will be little help at this stage of the troubleshooting process.

Delays in the transmission of data packets over a network can result in temporary service interruptions, dropouts, or even data loss. Which of the following terms is used to describe these delays? A. Crosstalk B. Electromagnetic interference (EMI) C. Jitter D. Attenuation

C. Jitter is defined as delays in the transmission of individual network packets. For audio or video transmissions, jitter can result in dropped words or frames. For data file transmissions, jitter can require retransmission of packets.

Alice's company has moved to a building that was prewired for twisted-pair Ethernet. However, since installing the company's Gigabit Ethernet equipment using the existing cable runs, performance has been poor. After performing some packet captures and analyzing the traffic samples, Alice discovers that there are a great many Ethernet frames being retransmitted. Next, she examines the cable runs in the drop ceilings. They do not appear to be overly long, and they do not appear to run near any major sources of electromagnetic interference. Which of the following could be the problem? A. Some of the cable runs are using T568A pinouts and some are using T568B. B. The cables only have two wire pairs connected, instead of four. C. The existing cable is not rated for use with Gigabit Ethernet. D. There are mismatched transceivers at the cable ends.

C. Of the options provided, the only possible source of the problem is that the cable runs are using a cable type not rated for Gigabit Ethernet. Some older buildings might still have Category 3 cable installed, which was used in the original twisted-pair Ethernet specification. Cat 3 is unsuitable for use with Gigabit Ethernet in many ways and can result in the poor performance that Alice is experiencing. A cable installation with runs wired using different pinout standards will not affect performance as long as each run uses the same pinouts at both ends. Gigabit Ethernet will not function at all if only two wire pairs are connected. The transceivers are located in the equipment that Alice's company brought from the old location, so they are not mismatched.

Which of the following Windows command-line utilities produced the output shown here? Active Connections Proto Local Address Foreign Address State TCP 127.0.0.1:5327 CM412:49770 ESTABLISHED TCP 127.0.0.1:49770 CM412:5327 ESTABLISHED TCP 127.0.0.1:52114 CM412:52115 ESTABLISHED TCP 192.168.2.24:2869 RT-M96U:42173 ESTABLISHED TCP 192.168.2.24:2869 RT-M96U:44356 ESTABLISHED TCP 192.168.2.24:51386 autodiscover:https ESTABLISHED TCP 192.168.2.24:51486 autodiscover:https ESTABLISHED TCP 192.168.2.24:51535 108-174-11-1:https ESTABLISHED TCP 192.168.2.24:51578 aki-cache:http TIME_WAIT TCP 192.168.2.24:51579 ia3s43-in-f142:http TIME_WAIT TCP 192.168.2.24:51591 208:https TIME_WAIT TCP 192.168.2.24:51592 208:https TIME_WAIT TCP 192.168.2.24:51593 198.8.20.212:https TIME_WAIT A. ping B. tracert C. netstat D. arp E. hostname

C. Running the Windows netstat utility with no parameters generates a list of the workstation's active connections. The ping, tracert, arp, and hostname utilities are not capable of producing this output.

Which of the following parameters enables you to specify the Time to Live (TTL) value of the messages that ping transmits? A. -n B. -t C. -i D. -a

C. Running the ping tool with the -i parameter specifies the TTL value of the messages that ping transmits. The -t parameter causes the ping tool to send messages to the target continuously until it is manually stopped. The -n parameter specifies the number of messages the ping tool should transmit. The -a parameter resolves an Internet Protocol (IP) address specified as the target to a hostname.

Ralph wants to use Power over Ethernet (PoE) to supply power to security cameras located throughout his company's datacenter. The Ethernet network is currently running at Gigabit Ethernet speed, but Ralph is planning to downgrade the camera connections to 100Base-TX, because that standard has two wire pairs free for the transmission of power. Which of the following statements about Ralph's plan is true? A. Ralph's planning is correct; only 10Base-T and 100Base-TX support PoE. B. Ralph's plan will not work because 100Base-TX is not compatible with PoE. C. Ralph's plan will work, but it is not necessary to downgrade the connections to 100Base-TX. D. Ralph's plan will not work, because PoE cannot supply enough power for the cameras.

C. The Alternative B PoE variant can use the spare wire pairs in a Category 5 (Cat 5) or better 10Base-T or 100Base-TX cable to supply power to connected devices. The Alternative A and 4PPoE variants cannot use the spare wire pair in this manner; they supply power using the wire pairs that carry data at the same time. For Gigabit Ethernet or faster installations, Alternative B is capable of using the data wire pairs.

Which of the following commands enables you to view the Address Resolution Protocol (ARP) table stored in memory? A. arp -c B. arp -d C. arp -a D. arp -s

C. The arp -a command displays the entries in the ARP table stored in its cache. The arp -d command is for deleting entries, and the arp -s command is for adding entries. The arp -c command is not a valid option.

Which of the following indicators can you use to determine whether an adapter is connected to a functioning hub or switch? A. Speed Light-Emitting Diode (LED) B. Collision LED C. Link pulse LED D. Status LED

C. The link pulse LED indicates the adapter is connected to a functioning hub or switch. The speed LED specifies the data rate of the link. The collision LED lights up when collisions occur. There is no status LED on a network interface adapter.

What is the name for a device that determines the length of a cable by transmitting a signal at one end and measuring how long it takes for a reflection of the signal to return from the other end? A. Fox and hound tester B. Wiremap tester C. Time-domain reflectometer D. Voltage event recorder E. Butt set F. Spectrum analyzer

C. The technique that provides this capability is called time-domain reflectometry (TDR). The tester transmits a signal over the cable and measures how long it takes for a reflection of the signal to return from the other end. Using this information and the cable's nominal velocity of propagation (NVP)—a specification supplied by the cable manufacturer— the device can calculate the length of a cable run. The other devices listed do not work in this way

Which TCP/IP utility should you use to most easily identify a malfunctioning router on your network? A. ifconfig B. ping C. traceroute D. netstat

C. The traceroute (or tracert) utility can locate a malfunctioning router by using an Echo Request messages with incrementing Time to Live (TTL) values. ifconfig is a network configuration utility for Unix and Linux systems; ping can test connectivity to another Transmission Control Protocol/Internet Protocol (TCP/IP) system, but it cannot locate a malfunctioning router; and netstat displays information about network connections and traffic but cannot locate a malfunctioning router

Which of the following are not general troubleshooting steps? (Choose all that apply.) A. Identify the problem B. Establish a theory of probable cause C. Test the theory to determine cause D. Verify that the client's Internet Protocol (IP) configuration is correct E. Establish a plan of action to resolve the problem and identify potential effects F. Verify that the router is forwarding. G. Implement the solution or escalate as necessary H. Verify full system functionality and, if applicable, implement preventive measures I. Document findings, actions, and outcomes

D, F. Verifying that a router is functioning and forwarding traffic and verifying that a client's IP configuration is correct are not considered general troubleshooting steps. You might perform these two steps as a subset of general troubleshooting steps.

Alice has been told by a consultant that the newly installed twisted-pair cable runs on her network might have split pairs. Which of the following cable testing tools can she use to detect split pairs? A. Tone generator and locator B. Wiremap tester C. Multimeter D. Cable certifier

D. A split pair is a connection in which two wires are incorrectly mapped in exactly the same way on both ends of the cable. Each pin on one end of the cable is correctly wired to the corresponding pin at the other end, but the wires inside the cable used to make the connections are incorrect. In a properly wired connection, each twisted pair should contain a signal wire and a ground wire. In a split pair, it is possible to have two signal wires twisted together as a pair. This can generate excessive amounts of crosstalk, corrupting both of the signals involved. Because all of the pins are connected properly, a tone generator and locator cannot detect this fault, and neither can a wiremap tester or a multimeter. However, a cable certifier is a highly sophisticated electronic device that can detect all types of cable faults, including split pairs, as well as measure cable performance characteristics.

When you troubleshoot a network problem, it is possible to introduce another problem while attempting to fix the original one. In which step of the troubleshooting process should you be aware of the residual effects that changes might have on the network? A. Identify the problem B. Establish a theory of probable cause C. Test the theory to determine cause D. Establish a plan of action to resolve the problem E. Implement the solution or escalate as necessary F. Verify full system functionality G. Document findings, actions, and outcomes

D. After you identify a problem and establish and test a theory of its probable cause, you must create a plan of action to resolve the problem and identify any potential effects (positive or negative) your solution might have. Then, you implement your solution, test the results, and finish documenting the incident

Which of the following troubleshooting tools is not used to test copper cabling installations? A. Wiremap tester B. Multimeter C. Tone generator and locator D. OTDR

D. An Optical Time Domain Reflectometer (OTDR) is a device that transmits light pulses over a fiber-optic network and measures the time interval and strength of the returning pulse, to measure the length of the cable run. An OTDR can be used to locate fiber-optic cable breaks, as well as characterize a cable run's reflectance, optical return loss, and other characteristics. Multimeters, tone generators, and wiremap testers are all devices that work only with copper networks.

Which of the following is a networkwide problem? A. A problem with an order entry or customer service call center resource B. A fatal error that causes a single computer to fail C. A problem with an application server that affects a single Local Area Network (LAN) D. A problem with a router that connects an entire network to the Internet

D. Any problem that affects all the users on the network is a networkwide problem and should be given the highest priority. An example of this would be a problem with an Internet router. All other problems listed do not affect the entire network.

Which step of the troubleshooting model involves identifying whether hardware or software has been recently installed or reconfigured? A. Identify symptoms B. Establish a theory of probable cause C. Establish a plan of action to resolve the problem and identify potential effects D. Determine if anything has changed. E. Test the theory to determine cause F. Document findings, actions, and outcomes

D. During the troubleshooting process, you must establish whether anything has changed. This typically involves asking the user whether any new or existing hardware or software has been installed or reconfigured.

Ed has discovered that some of the twisted-pair cables on his newly installed network are running right alongside fluorescent light fixtures in the drop ceiling. Which of the following problems is the network likely to experience due to the cables' proximity to the fixtures? A. Jitter B. Attenuation C. Crosstalk D. EMI

D. Fluorescent light fixtures and other devices in an office environment can generate magnetic fields, resulting in electromagnetic interference (EMI). When a copper-based cable runs too near to such a device, the magnetic fields can generate an electric current on the cable that interferes with the signals exchanged by network devices. Jitter, crosstalk, and attenuation are all conditions that can affect the performance of a wired network, but they are not directly related to the cables' proximity to light fixtures.

Ralph is a first-tier technician working the help desk. After identifying a network problem submitted by multiple users, Ralph comes up with a theory specifying a possible source of the problem and sets about testing his theory. Unfortunately, testing indicates that Ralph's theory is wrong; the source he suspected is not the cause of the problem. Which of the following should not be the next step in Ralph's troubleshooting process? A. Reinterview the users to gather more information about the problem B. Escalate the problem to a second-tier technician C. Repeat the process of establishing a theory of probable cause D. Begin replacing components that might contribute to the problem

D. Replacing components by guesswork could resolve the problem through chance, but it would more likely be a waste of time and hardware. When Ralph's first theory is disproven, the next logical step would be to devise another theory. This could conceivably involve reinterviewing the users or escalating the issue to a senior technician. If the theory had been confirmed, the next step would be to devise a plan of action to resolve the problem

Which of the following Windows command-line utilities produced the output shown here? Interface: 192.168.2.24 --- 0x2 internet Address Physical Address Type 192.168.2.2 d4-ae-52-bf-c3-2d dynamic 192.168.2.20 00-26-c7-7e-00-e0 dynamic 216 Chapter 5 ■ Network Troubleshooting 192.168.2.22 00-90-a9-a2-43-8f dynamic 192.168.2.27 1c-c1-de-ca-1f-12 dynamic 192.168.2.28 30-f7-72-38-e9-1d dynamic 192.168.2.255 ff-ff-ff-ff-ff-ff static 224.0.0.22 01-00-5e-00-00-16 static 224.0.0.251 01-00-5e-00-00-fb static 224.0.0.252 01-00-5e-00-00-fc static 224.0.0.253 01-00-5e-00-00-fd static 239.255.255.250 01-00-5e-7f-ff-fa static 255.255.255.255 ff-ff-ff-ff-ff-ff static A. ping B. tracert C. netstat D. arp E. hostname

D. Running the arp utility with the -a parameter on a Windows system displays the contents of the Address Resolution Protocol (ARP) cache. The cache contains records of the Internet Protocol (IP) addresses on the network that arp has resolved into Media Access Control (MAC) addresses. The ping, tracert, netstat, and hostname utilities are not capable of producing this output.

Which of the following devices is an essential tool for technicians working on telephone cables but is not needed for data networking cable installations? A. Tone generator and locator B. Wiremap tester C. Cable certifier D. Butt set

D. Telephone cable technicians have their own specialized tools, such as the butt set, a one-piece telephone handset with alligator clips that enables its operator to connect to a line anywhere that the cables are accessible

Which of the following Windows tools uses Internet Control Message Protocol (ICMP) messages and manipulates IPv4 time-to-live values to illustrate the route packets take through an internetwork? A. ping B. netstat C. route D. tracert E. nslookup F. hostname

D. The Windows tracert tool transmits a series of ICMP messages with incrementing Time to Live (TTL) values, which identify each router on the path that the packets take through the network. Ping uses ICMP, but it does not manipulate TTL values. Netstat, Route, Nslookup, and Hostname do not use ICMP messages, nor do they manipulate TTL values when performing their normal functions.

After connecting a tone generator to the green wire at one end of a twisted-pair cable run, Ralph proceeds to the other end of the cable and touches the locator to each of the eight pins in turn. The green wire and the green striped wire both produce a tone. What type of wiring fault has Ralph discovered? A. Split pair B. Far end crosstalk C. Transposed wires D. Short circuit E. Delay skew

D. The first and most essential test that installers must perform on every cable run is a continuity test, which ensures that each wire on both ends of the cable is connected to the correct pin and only the correct pin. If a pin on one end of a cable run is connected to two or more pins on the other end, the cable has a short circuit.

Which of the following command-line utilities can only run on Unix and Linux systems? A. ping B. ipconfig C. tracert D. ifconfig E. netstat

D. The ifconfig command runs only on Unix and Linux systems. The ping and netstat utilities run on Windows, Unix, or Linux systems. The ipconfig and tracert commands run only on Windows, although there is a Unix/Linux version of tracert called traceroute.

Ralph has been advised to check his Linux web servers for open ports that attackers might be able to use to penetrate the servers' security. Which of the following utilities can Ralph use to do this? A. tcpdump B. dig C. iptables D. nmap E. iperf

D. The nmap utility is capable of scanning a system for open ports that might be a security hazard. The tcpdump, dig, iptables, and iperf utilities cannot do this

Which of the following protocols does the ping program never use to carry its messages? A. Ethernet B. ICMP C. IP D. UDP E. TCP

E. All Windows ping transactions use Internet Control Message Protocol (ICMP) messages. ICMP messages are encapsulated directly within Internet Protocol (IP) datagrams; they do not use transport layer protocols, such as User Datagram Protocol (UDP). Ping transactions to destinations on the local network are encapsulated within Ethernet frames. On Unix and Linux, ping uses UDP, which is also encapsulated in IP datagrams.

Which of the following is not a tool that runs only on Unix or Linux systems? A. tcpdump B. dig C. iptables D. ifconfig E. route

E. Of the utilities listed, tcpdump, dig, iptables, and ifconfig are all tools that run on Unix or Linux systems only. The route utility runs on both Unix or Linux and Windows.

In which troubleshooting step is a trouble ticket created? A. Establish a theory of probable cause B. Verify full system functionality and, if applicable, implement preventive measures C. Implement the solution or escalate as necessary D. Test the theory to determine cause E. Identify the problem F. Document findings, actions, and outcomes G. Establish a plan of action to resolve the problem and identify potential effects

E. The first step in troubleshooting involves identifying the problem and creating a trouble ticket. You complete the other troubleshooting steps after the trouble ticket has been prioritized.

In which troubleshooting step do you create a record of your activities and inform the user of what happened and why? A. Identify the problem B. Establish a theory of probable cause C. Test the theory to determine cause D. Establish a plan of action to resolve the problem and identify potential effects E. Implement the solution or escalate as necessary F. Verify full system functionality and, if applicable, implement preventive measures G. Document findings, actions, and outcomes

G. The last step of the troubleshooting process is to document the solution and explain to the user what happened and why. In reality, documentation should begin when the problem is reported, and the documentation should be updated throughout the troubleshooting process.