Appendix C 666 Your network has 10 computers that are networked together using 15. a Star topology. Which of the following is a possible point of failure for this topology, which could bring down the entire network? A. Cable B. Network card C. T-connector D. Hub Correct answer and explanation: D. Hub. In a Star topology, all computers are connected through one central hub. Computers are cabled to this hub, making it a centralized point where the network is connected. If the hub fails, the network would go down. Incorrect answers and explanations: A, B, and C. Answer A is incorrect because if a cable broke or failed in some way, it would only remove the computer connected to it from the network. Answer B is incorrect because a failed network card in a computer would only prevent that particular com- puter from being able to access the network. Answer C is incorrect because a T-connector is used to connect computers to a cable in a Bus topology. A Star topology is being used in this situation. ChApTEr 2: NETworK MEdIA You are the network administrator of a 10BaseT network. On the 1. weekend, when few people are working, you run 110 m of cable to a new server that is being used as a file server. The cable is installed in a new section of the building, where no cabling cur- rently exists. When you attempt to access files on the server, they are experiencing errors and corrupt data. Which of the following is most likely the cause of this problem? A. Bandwidth B. Attenuation C. Crosstalk from a neighboring cable D. CSMA/CD issues Correct answer and explanation: B. Attenuation. Attenuation occurs when data transmitted over media weakens over distance. The scenario states that the cable length is 110 m, which is 10 m longer than the maximum distance for 10BaseT. Incorrect answers and explanations: A, C, and D. Answer A is incorrect because bandwidth is a measurement of the amount of data that can be Appendix C 667 passed over a cable in a given amount of time. Answer C is incorrect because the cable is being installed in a section of the building where no other cabling currently exists. Crosstalk occurs when the electromagnetic field of one wire interferes with the transmission of another. Answer D is incorrect because Carrier Sense Multiple Access with Collision Detection (CSMA/CD) prevents devices from interfering with one another during transmission by detecting collisions of data. It is not a cause for data to weaken or to corrupted. Your company uses UTP cable for all of its network connections 2. including workstations and servers. The users have reported problems connecting to one of the most important servers on the network and you have been called in to look at it, due to a possible physical security breach by a former employee. While examining the server, you find that a small battery-powered motor has been placed and is running next to the server’s network connection. What is causing the network problem? A. Electromagnetic interference B. Static electricity C. Transceivers D. Unknown, but the motor is probably unrelated Correct answer and explanation: A. Electromagnetic interference (EMI) is a low voltage, low current, high-frequency signal that can interfere with the elec- tronic signals transmitted over cabling. The motor is powered by electromagnets whose presence can interfere with the flow of electrons along the UTP cable. Incorrect answers and explanations: B, C, and D. Answer B is incorrect because static electricity may cause damage to network cards and other elec- tronics but will not interfere with network traffic on a UTP cable. Answer C is incorrect because transceivers are the portion of a network interface that trans- mits and receives electrical signals across the transmission media. It is unlikely that this is a cause of the problem. Answer D is incorrect because the small motor is most likely to be the source of this interference. Anytime a UTP cable is near electromagnetic interference there will be communications problems. You are designing a new network and are concerned about interfer-3. ence from other wires. Which of the following is most susceptible to transmission errors due to crosstalk? A. Coaxial B. UTP C. STP D. Fiber optic Appendix C 668 Correct answer and explanation: B. UTP. Unshielded twisted-pair is most vulnerable to crosstalk. Crosstalk refers to the unwanted electrical fields induced by neighboring cables. These electrical fields generate false signals. Because the UTP cable is unshielded, it is more susceptible to transmission errors caused by crosstalk than any other given cable types. Incorrect answers and explanations: A, C, and D. Answer A is incorrect because the coaxial cable is shielded and is less prone to errors cause by cross- talk. Answer C is incorrect because STP (shielded twisted-pair) is shielded, and thereby is also more protected against crosstalk. Answer D is incorrect because the fiber-optic cable works on light signals and is not affected by either electrical or magnetic signals. You are designing a new network for a grocery store. Cabling will 4. have to run along the ceiling, where there are a significant num- ber of florescent lights. You are concerned about interference from these lights. Which of the following cable types could be used, which would not be susceptible to this type of interference? A. Coaxial B. UTP C. STP D. Fiber optic Correct answer and explanation: D. Fiber optic. Fiber-optic cabling is the only type of cabling that is immune to electromagnetic interference. Fiber- optic cable carries digital data signals in the form of modulated pulses of light, which isn’t effected by EMI. Incorrect answers and explanations: A, B, and C. Answers A, B, and C are incorrect because each of these use copper wiring that is susceptible to EMI. Your network uses vampire taps and AUI connectors to access data 5. from the network cable. Which of the following cabling types is being used? A. Thinnet B. Thicknet C. STP D. Fiber optic Correct answer and explanation: B. Thicknet. Thicknet is a term for cabling used in 10Base5 networks. Thicknet coaxial cable can transfer data over longer distances than the 10Base2 Thinnet cable and requires vampire Appendix C 669 taps to connect to the network interface card with the adapter unit interface (AUI) connector. Thicknet is not a common cabling type and is only used in backbones. Incorrect answers and explanations: A, C, and D. Answer A is incorrect because the Thinnet is a 10Base2 cable. Answer C is incorrect because STP is a twisted-pair cable that uses an RJ-45 connector and not a vampire tap or AUI connector. Answer D is also incorrect because fiber-optic cable doesn’t use vampire taps or AUI connectors. You are designing a 10Base2 network. In creating this network, 6. what distance limitation will you be facing when installing the cabling? A. 100 m B. 185 m C. 500 m D. 2 km Correct answer and explanation: B. 185. 10Base2 (Thinnet) has a distance limitation of 185 m. 10Base5 (Thicknet) has a distance limitation of 500 m, and 10BaseT has a distance limitation of 100 m. Incorrect answers and explanations: A, C, and D. Answer A is incorrect because 100 m is a limitation for 10BaseT. Answer C is incorrect because 500 m is a distance limitation for 10Base5 networks. Answer D is incorrect because 2 km is a distance limitation for fiber-optic cable. Examine the illustration shown in the following Figure 2.12.7. FIGurE 2.12 Appendix C 670 Your network is a 10Base2 network, and it uses these connectors to attach to the network. Which of the following types of connectors is being used? A. RJ-11 B. DIX C. BNC Barrel Connector D. BNC T-connector Correct answer and explanation: D. BNC T-connector. The connector shown in the illustration is a BNC T-connector, which is circular and T-shaped. It is used to connect workstations to a 10Base2 (Thinnet) network. Incorrect answers and explanations: A, B, and C. Answer A is incorrect because an RJ-11 connector is used to connect devices to a telephone line and is a small square-shaped connector with a locking clip and several wire places inside the connector itself. Answer B is incorrect because a DIX con- nector is D-shaped and has 15 pins. Answer D is incorrect because a BNC barrel connector is round or barrel-shaped. You have been hired by a small company to cable its network. The 8. company has offices in two buildings that are 300 m apart. Both of the offices have about 15 computers and the numbers are expected to grow in near future. All of the computers are within 90 m of one another. You need to decide on the cabling that will be used both in the individual buildings, and which will be used to connect the buildings LANs together. Which of the following will you do? A. Use UTP cabling in each of the buildings, and connect the two buildings together using 10BaseT cabling. B. Use fiber-optic cabling in each of the buildings, and connect the two buildings together using 10Base2 cabling. C. Use 10BaseT cabling in each of the buildings, and connect the two buildings together using 10Base5 cabling. D. Use 100BaseFX cabling in each of the buildings, and connect the two buildings together using 10BaseT cabling. Correct answer and explanation: C. Use 10BaseT cabling in each of the buildings and connect the two buildings together using 10Base5 cabling. The two offices can be connected using thick coaxial cable (10Base5), which can transfer data up to 500 m. 10BaseT can be used within the buildings because it supports distances of 100 m. Incorrect answers and explanations: A, B, and D. Answer A is incorrect because 10BaseT has a distance limitation of 100 m. This means that the Appendix C 671 two buildings can’t be connected together. Answer B is incorrect because 10Base2 has a distance limitation of 185 m, which is too short for the two buildings. Answer D is also incorrect because 10BaseT has a distance limita- tion of 100 m. Your network uses 100BaseFX so that data can be transferred at 9. higher speeds and up to distances of 400 m. During transmission, data can travel in both directions, but only in one direction at a given time. Which of the following transmission methods is used? A. Simplex B. FireWire C. Half-Duplex D. Full-Duplex Correct answer and explanation: C. Half-Duplex. 100BaseFX is an Ether- net standard that uses fiber optic cabling. It can transmit data at speeds of 100 Mbps but if communication is half-duplex, it can transmit data across cable segments that are up to 400 m in length. If full-duplex is used, then it can transmit data up to 2 km. Because data travels both ways on the medium but in only one direction at a time, half-duplex is being described. Incorrect answers and explanations: A, B, and D. Answer A is incorrect because simplex refers to data moving in a single direction. Answer B is incorrect because FireWire is a proprietary name for IEEE1394, which is an external bus that supports fast data transfer rates of 400 Mbps and 800 Mbps. Answer D is incorrect because full-duplex refers to data traveling in both directions simultaneously. Examine the illustration shown in the following Figure 2.13.10. Your network uses UTP cabling in a Star topology. Which of the follow- ing types of connectors is being used? FIGurE 2.13 Appendix C 672 A. RJ-45 B. BNC C. ST D. SC Correct answer and explanation: A. RJ-45. The illustration shows an RJ-45 connector. This type of connector is used in unshielded twisted-pair (UTP) cabling and commonly used for networks that use a Star topology. An RJ-45 cable has eight pins and is rectangular in shape with a plastic lock on one side. Incorrect answers and explanations: B, C, and D. Answer B is incorrect because a BNC Barrel connector is round or barrel-shaped, whereas a BNC T-connector is circular and T-shaped. Neither of these types of connectors is used on with UTP. Answers C and D are incorrect because both ST and SC connectors are used with fiber-optic cabling. You are the Network+ technician assigned to an enterprise net-11. work looking to install a high-speed backbone. You want to imple- ment Gigabit Ethernet. Which connectors could you use in such a network? (Choose one) A. RJ-11 B. RG 58 C. SC D. BNC Correct answer: C Incorrect answers and explanations: A, B, and D. The RJ-11 connector is used for voice connections. RG 58 connectors are used with coaxial cabling, and BNC connectors are used with coaxial cable. As a network technician for 123 LLC, you are asked by your CIO 12. about the access method of Gigabit Ethernet. Which of the follow- ing access methods does Gigabit Ethernet use? A. FDDI B. CSMA/CD C. CSMA/CA D. Token passing Correct answer and explanation: B. CSMA/CD. Gigabit Ethernet has evolved from Ethernet that uses the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access method. Appendix C 673 Incorrect answers and explanations: A, C, and D: FDDI is a technology used to create high-speed backbone connections and uses token passing – it’s not an access method. CSMA/CA is primarily used for wireless technologies. Token passing is another access method, used with Token Ring networks and FDDI. A new technician for 123 Corp plans out the maximum length of 13. a Gigabit Ethernet segment using MMF optic cable is. What is the correct distance? (Choose only one) A. 100 m B. 125 m C. 550 m D. 10 km Correct answer and explanation: C. Gigabit Ethernet support distances of 550 m for multimode fiber links. Incorrect answers and explanations: A, B, and D – all are of the wrong length. You are the network engineer assigned to implement a new 14. 100 Mbps network connection. You need to select the correct cabling, as well as the correct standard. From the selections below, choose which 100 Mbps networking standard makes use of only two pairs of a Category 5 UTP cable. A. 10BaseT B. 100BaseFL C. 100BaseTX D. 100BroadT4 Correct answer and explanation: C. 100BaseTX uses two UTP pairs (four wires) in a Category 5 UTP cable. Incorrect answers and explanations: A, B, and D. Answer A is incorrect because 10BaseT requires Category 3 UTP and only operates at 10 Mbps. Answer B is incorrect because 100BaseFL doesn’t exist; it’s really 10BaseFL and it requires 10 Mbps fiber-optic cable. Answer D is incorrect because 100BoardT4 is not a legitimate networking standard. You work as a network technician for 123 LLC. You need to check 15. the electrical signals being sent from the NIC port out on the cable. Which device would you use to complete this test? (Choose one.) A. A wire map B. A fox and hound Appendix C 674 C. A crossover cable D. A hardware loopback Correct answer and explanation: D. A hardware loopback checks outgoing signals of a device. All other devices are not going to be able to provide that same type of test. ChApTEr 3: NETworK dEvICES Cables from workstations are connected to a central network con-1. nectivity device that takes data from one port and resends it to all of the other ports. In doing so, the data is regenerated so it is as strong as when it was originally sent. Which of the following devices is being used? A. Active hub B. Passive hub C. Switching hub D. Switch Correct answer and explanation: A. Active hub. An active hub will take data sent to it and resend it to all ports on the hub. An active hub also works as a repeater for all data received on its ports, as the signal is regenerated before it is transmitted on all ports of the hub. Incorrect answers and explanations: B, C, and D. Answer B is incorrect because the function of a passive hub is simply to receive data from one port of the hub and send it out to the other ports. It does not regenerate the data. Answers C and D are incorrect because a switch or switching hub will take the data sent to it on one port and then send it to a specific port that will send the data only to the destination computer or device. Your network consists of a single large LAN that is in a Star topol-2. ogy configuration. You have found that there are a significant num- ber of collisions occurring on the network and want to segment it into two smaller LANs. Which of the following devices will you use to segment this network, allowing each LAN to communicate with the other? A. NIC B. MAU C. Bridge D. Repeater Appendix C 675 Correct answer and explanation: C. Bridge. A bridge is a network connec- tivity device that connects two different networks and makes them appear to be one network, and allows a larger LAN to be segmented into two smaller halves. The bridge filters local traffic between the two networks and copies all other traffic to the other side of the bridge. Incorrect answers and explanations: A, B, and D. Answer A is incorrect because a NIC is simply a network interface card, which is installed on a PC or other network device, to allow it to communicate on the network. Answer B is incorrect because a MAU is a device that multiple workstations are connected to communicate on a Token Ring network. Answer D is incorrect because a repeater is used to connect segments of cable and repeat the data it receives so that it won’t weaken along the cable. You want to get Internet access for a computer that is used by the 3. IT staff to download drivers and updated software from the Inter- net. Because of the amount of data that is going to be downloaded, you want to use the fastest possible method of downloading data. Which of the following will you use? A. Analog modem with dial-up access to an ISP B. ISDN Digital Subscriber Line C. Consumer Digital Subscriber Line D. Very High Digital Subscriber Line Correct answer and explanation: D. Very High Digital Subscriber Line. A Very High Digital Subscriber Line has a downstream speed of 12.9 to 52.8 Mbps, and an upstream speed of 1.5 to 2.3 Mbps. Of the choices offered, this is the fastest choice for accessing the Internet. Incorrect answers and explanations: A, B, and C. Answer A is incorrect because an analog modem with dial-up access is limited to a maximum speed of 56 Kbps. Answer B is incorrect because an ISDN Digital Subscriber Line has a maximum speed of 128 Kbps. Answer D is incorrect because a Consumer Digital Subscriber Line has a maximum speed of 1 Mbps. You are fixing a faulty network card and find that it is unable to 4. send or receive data. You believe the transceiver has failed. Which type of transceiver is built into the network interface card? A. External B. Onboard C. RG 58 D. BNC . network. Answer B is incorrect because a failed network card in a computer would only prevent that particular com- puter from being able to access the network. Answer C is incorrect because a T-connector. transfer data over longer distances than the 10Base2 Thinnet cable and requires vampire Appendix C 669 taps to connect to the network interface card with the adapter unit interface (AUI) connector small company to cable its network. The 8. company has offices in two buildings that are 300 m apart. Both of the offices have about 15 computers and the numbers are expected to grow in near