Chapter 10 441u33

Chapter 10: Managing a Wireless LAN TRUE/FALSE 1. Almost all WLAN vendors provide utilities to assist in monitoring the wireless network. ANS: T

REF: 326

2. Acquiring data, such as error statistics and packets received, from each access point and each wireless device across the network is normally a quick and easy task. ANS: F

REF: 332

3. A wireless network is a static system. ANS: F

REF: 335

4. Antenna adjustment may require the existing antennas to be reoriented or placed on a pole or mast for better transmission and reception. ANS: T

REF: 339-340

5. Information security weaknesses can never be entirely eliminated. ANS: T

REF: 349

MULTIPLE CHOICE 1. In the Windows operating system, what window provides basic tools for monitoring a WLAN? a Wireless Adapter Information c Access Point Utilities . . b Wireless Network Connection Status d Network Monitor . .

ANS: B

REF: 327

2. It is important for wireless system s to maintain a(n) ____ log that contains a record of all problems, solutions, and configuration changes. a manual c network . . b event d AP . .

ANS: A

REF: 330

3. What tool(s) are used most often as “standard” network monitoring tools? a AP Monitor and Simple Network Management Protocol . b WLAN Logger and Remote Monitoring

. c Simple Network Management Protocol and Remote Monitoring . d All of the above .

ANS: C

REF: 332

4. The current version of SNMP (____) addresses security and remote configuration. a v1 c v3 . . b v2 d v4 . .

ANS: C

REF: 333

5. ____ is a nonvolatile storage chip used in computers and other devices. a Firmware c RMON . . b SNMP d EEPROM . .

ANS: D

REF: 335

6. When updating firmware in an enterprise-level access point, the Receiving AP must be able to hear the IP ____ issued by the Distribution AP. a multicast c broadcast . . b unicast d netcast . .

ANS: A

REF: 338

7. What is the last step in RF site tuning? a adjust channel settings . b documenting changes .

ANS: B

c . d .

modify throughput

c . d .

free space loss

validate coverage area

REF: 339

8. What is another name for propagation loss? a transmission loss . b effective loss .

signal loss

ANS: C

REF: 340

9. What information is required for a link budget? a power of the transmitter c . . b path length d . .

ANS: D

frequency of the link All of the above

REF: 340

10. For a proper WLAN performance, the link budget must be ____ dB. a greater than zero c greater than ten . . b greater than five d less than ten . .

ANS: A

REF: 341

11. Which type of RF loss is caused by the equipment itself, not external objects? a Refraction c Voltage Standing Wave Ratio . . b Scattering d Absorption . .

ANS: C

REF: 341

12. A ____ antenna is most typically used on a WLAN. a c sectorized . . b rod d beam steering . .

ANS: B

REF: 341

13. Most vendors illustrate their radiation patterns by splitting the three-dimensional donut into two perpendicular planes called ____ and elevation. a donut c plain . . b horizontal d azimuth . .

ANS: D

REF: 343

14. A(n) ____ amplifier boosts the RF signal before it is injected into the device that contains the antenna. a bidirectional c unidirectional . .

b pre-injection .

ANS: A

d .

internal

REF: 344

15. ____ attenuators are the only type permitted by the FCC for WLAN systems. a Variable-loss c Bidirectional . . b Fixed-loss d Unidirectional . .

ANS: B

REF: 345

16. A ____ limits the amplitude and disturbing interference voltages by channeling them to the ground. a RF attenuator c lightning arrestor . . b splitter d phase modulator . .

ANS: C

REF: 345

17. The first step in creating a security policy is ____. a risk assessment c impact analysis . . b security auditing d documentation . .

ANS: A

REF: 346

18. When conducting a security audit, ____ should determine vulnerabilities. a a highly-paid consultant . b a wireless system employed by the company . c a junior . d a team with diverse backgrounds .

ANS: D

REF: 348

19. Vulnerabilities that are ranked as ____ are events that would cause the organization to cease functioning or be seriously crippled in its capacity to perform. a major c significant . . b catastrophic d small impact . .

ANS: B

REF: 349

20. ____ security protects the equipment and infrastructure itself, and has one primary goal: to prevent unauthorized s from reaching the equipment in order to use, steal, or vandalize it. a Physical c Hardware . . b Practical d Social . .

ANS: A

REF: 350

21. What technique(s) is/are most effective for defeating social engineering attacks? a physical and software security . b documentation . c education and policies . d undercover work by network s .

ANS: C

REF: 350

COMPLETION 1. In order to use SNMP, a software ____________________ is loaded onto each network device that will be managed using SNMP. ANS: agent REF: 332 2. ____________________ is software that is embedded into hardware to control the device. ANS: Firmware REF: 335 3. A(n) ____________________ antenna is typically used in outdoor areas. They are designed to be used in installations where aesthetics and high performance are key factors. ANS: REF: 342 4. The first step in the security policy cycle is to perform a(n) ____________________, which attempts to determine the nature of the risks to the organization’s assets.

ANS: risk assessment REF: 346 5. ____________________ engineering relies on tricking or deceiving someone to give a hacker access to a system. ANS: Social REF: 350 MATCHING Match each term with the correct statement below. a link budget f RF site tuning b Remote g effective receiving Monitoring sensibility c beam steering h software agent d firmware i attenuator e splitter .

1. software that is embedded into hardware to control the device 2. device that has a single input connector and multiple output connectors 3. part of SNMP that monitors network traffic and stores that information in its management information base 4. rough calculation of all known elements of the link to determine if the signal will have the proper strength when it reaches the other end of the link 5. device that decreases the RF signal 6. SNMP-based tool used to monitor LANs that are connected through a wide area network 7. attempting to readjust the settings of the AP after a firmware upgrade 8. decreases interference by attenuating unwanted sources of interference 9. antenna gain (dBi) less cable loss (dB) at the receiver and receiver sensitivity (dBm) 1. ANS: D

REF: 335

2. ANS: E

REF: 345

3. ANS: H

REF: 332

4. ANS: A

REF: 340

5. ANS: I

REF: 345

6. ANS: B

REF: 335

7. ANS: F

REF: 339

8. ANS: C

REF: 343

9. ANS: G

REF: 340

SHORT ANSWER 1. Many enterprise-level access points provide utilities that offer three types of information. What are they? ANS: The first is a record of events (usually called an event log), such as devices associating with the access point. The second type of information is statistics on wireless transmissions. The final type of information regards the connection to the wired Ethernet network. REF: 330 2. Although data from the access point and devices can be beneficial, there are drawbacks to relying solely on these sources of information. What are the drawbacks? ANS: Retention of data—Data gathered from the access point and devices is collected in real time, but there is not always the facility for creating a large repository for that data. Without the ability to retain the data it is difficult to establish a baseline. Data collection—Acquiring data from each access point and each wireless device across the network can be a labor and time-intensive task. Timeliness—Unless a person is constantly monitoring this data, it cannot be used to warn of an impending wireless issue. Rather, the data can only be used after a problem occurs when trying to identify what may have caused it. REF: 332 3. What is Remote Monitoring? ANS: Remote Monitoring (RMON) is an SNMP-based tool used to monitor LANs that are connected through a wide area network (WAN). RMON allows a remote network node to gather network data at almost any point on a LAN or a WAN. RMON uses SNMP but also incorporates a special database for remote monitoring that includes different groups of statistics. The statistics gathered can contain data measured for both the wired LAN and the wireless LAN interfaces. It can also compare these statistical samples to previously configured thresholds. If the monitored variable crosses a threshold, an event alarm can be generated. REF: 335 4. List and describe three RF tuning settings. ANS:

Adjust radio power levels on all access points—Because firmware upgrades may increase the RF coverage areas, it may be necessary to readdress the power settings on all APs. Adjust channel settings—It may be necessary to restore the channel settings to their original configuration. Once the original channel plan is restored, channels may be adjusted based on adjacent channels, cellular overlap, and adjusted radio power settings. Validate coverage area—As a part of the RF site tuning, it is important to re-determine the perimeter of each AP’s RF coverage area. Each AP should be measured independently of all other access points and then the overall coverage of the WLAN should be measured. During this process additional configuration adjustments may be required on different access points. Modify integrity and throughput—Once the RF coverage cells have been determined, throughput rates and proper cellular overlap may need to be determined and changes made as necessary. Document changes—Any changes should be clearly documented. The edited entries should include channel selection, power settings, firmware version, and modulation corrections. Additionally, maps should be created that offer a visual representation of the RF coverage cells and AP placement. REF: 339 5. A radio frequency link between the sender and receiver consists of three basic elements. What are they? ANS: Effective transmitting power—This is the transmitter power (measured in dBm) less any cable or connector loss (db) plus the antenna gain (dBi). Propagation loss—This is the free space loss (in dB). Effective receiving sensibility—The effective receiving sensibility is the antenna gain (dBi) less cable loss (dB) at the receiver and receiver sensitivity (dBm). REF: 340 6. There are several factors that may result in RF loss. What are they? ANS: Absorption—Certain types of materials can absorb the RF signal. Reflection—Instead of the signal being “soaked up” by absorption it is “bounced back” by reflection. Scattering—Scattering of the signal is caused by small objects or rough surfaces. Refraction—Refraction occurs when an RF signal moves from one medium to another of a different density; the signal actually bends instead of traveling in a straight line. Diffraction—Diffraction is caused by an object in the path of the transmission. Diffraction occurs when an object with rough surfaces is in the path of the RF signal and causes it to bend. Voltage Standing Wave Ratio—Unlike the previous examples in which external objects caused RF signal loss, Voltage Standing Wave Ratio (VSWR) is caused by the equipment itself. REF: 341 7. Describe a sectorized antenna. ANS: A sectorized antenna “cuts” the standard 360-degree pattern into four quarters. Each quarter has its own transmitter and antenna. In this way the radiation pattern can be specialized for North, South, East, and West transmissions, with additional power given to different quarters as necessary. REF: 342

8. What is an RF amplifier? ANS: An RF amplifier is a device that amplifies or increases the amplitude of an RF signal. The positive difference in amplitude between two signals is known as gain. Although gain can occur unintentionally when an RF signal bounces off an object and combines with the original signal to amplify it, more often it is necessary to “boost” a signal to compensate for loss of power. This loss may be the result of the distance between the AP and the wireless device, or it could be due to the length of cable from a wireless device to its antenna (as when an external antenna is attached to an AP). RF amplifiers can be of two types. A unidirectional amplifier increases the RF signal level before it is injected into the transmitting antenna. A bidirectional amplifier boosts the RF signal before it is injected into the device that contains the antenna. For a WLAN this would be the access point or wireless device. Most RF amplifiers for WLANs are bidirectional. REF: 344 9. What are the factors that should be considered in determining the relative value of assets? ANS: How critical is this asset to the goals of the organization? How much profit does it generate? How much revenue does it generate? What is the cost to replace it? How much does it cost to protect it? How difficult would it be to replace it? How quickly can it be replaced? What is the security impact if this asset is unavailable? REF: 347 10. When creating a functional (working) security policy, there are several elements that should be considered. Describe them. ANS: Baseline practices establish the benchmark for actions using the wireless network. Baseline practices may be different for different organizations due to the needs of the wireless network. Once baseline practices are identified they can be used for creating design and implementation practices. Design and implementation practices form the foundation of what conduct on the wireless LAN is acceptable. With a wireless security policy it is critical that monitoring, response, and reporting be clearly outlined. A security policy must specifically identify physical security. Physical security protects the equipment and infrastructure itself, and has one primary goal: to prevent unauthorized s from reaching the equipment in order to use, steal, or vandalize it. Physical security is a major challenge with wireless LANs because the RF signal cannot be contained within the four walls of a building. REF: 350