Chapter 5 and 6 Wireless

D. 360 Omnidirectional antennas have a horizontal beamwidth of 360°. The vertical beamwidth will vary depending on the design and the gain of the antenna.

1. Omnidirectional antennas have a horizontal beamwidth of __________ degrees. A. 90 B. 180 C. 270 D. 360

B. Passive scanning When a wireless client device listens for beacons, it is performing passive scanning. Active scanning is sending a probe request. Authentication occurs after the probe phase. Power save puts the device into a low power state.

1. When a WLAN device listens for beacon frames, it is participating in which phase? A. Power save B. Passive scanning C. Active scanning D. Authentication

B. Roaming Moving throughout a location will cause a wireless client to roam from one access point to another. As part of the roaming process a client sometimes, but not always, needs to reauthenticate.

10. The process in which a WLAN client connection moves from one access point to another is called __________. A. Reauthentication B. Roaming C. Rebuilding D. Roving

C. Cable D. Connector Cables and connectors can both result in a loss of signal strength. Antennas and amplifiers will add gain or increase signal strength. A transmitter outputs an absolute amount of power.

10. Which can cause a loss of signal strength? (Choose two.) A. Antenna B. Amplifier C. Cable D. Connector E. Transmitter

A. One 802.11g access points require only one antenna to function. Systems that support antenna diversity will require two antennas to correctly operate.

11. An IEEE 802.11g access point requires a minimum of how many antennas to move data? A. One B. Two C. Four D. Six

A. SSID C. Channel To successfully set up an ad hoc network, a user must know two parameters: the SSID and the RF channel it will be operating on. The BSSID is automatically generated in an ad hoc network. The BSSID is the MAC address of an AP radio; APs are not used in ad hoc networks. Protection mode does not apply to the situation.

11. In order to set up an ad hoc network, a user must know which two parameters? (Choose two.) A. SSID B. BSSID C. Channel D. MAC address E. Protection mode

B. Antenna diversity 802.11a access points can use antenna diversity. Gain and polarization are considered RF concepts.

12. 802.11a access points support which antenna technology to help reduce the effects of multipath? A. Adjustable gain B. Antenna diversity C. Adjustable polarization D. Antenna multiplexing

B. Two Open system authentication uses two frames. The first frame is from the client to the access point, and the second frame is from the access point back to the client. Shared-key authentication uses four frames.

12. The open system authentication process uses how many frames? A. One B. Two C. Three D. Four

C. ERP protection In 802.11b/g/n and mixed mode environments, throughput will be affected because of ERP protection mechanisms. Association and authentication are normal frames exchanged and do not affect throughput. HT protection mode is for 802.11n.

13. You are a help desk support technician at a retail department store, and you receive a call from a manager in the administrative offices. He complains that the performance of his 802.11g/n notebook computer decreases several times throughout the day. Upon visiting the customer, you realize several people are performing inventory using 802.11b barcode scanners in the adjacent room. What is most likely the cause of the poor performance for the manager's notebook computer? A. Association B. Authentication C. ERP protection D. HT protection

A. 32 characters maximum C. Is case sensitive An SSID has a maximum of 32 characters or octets. SSIDs are case sensitive.

14. Which items describe a service set identifier (SSID)? (Choose two.) A. 32 characters maximum B. 64 characters maximum C. Is case sensitive D. Is not case sensitive

C. Wind Of the answers listed, wind would have the biggest impact on a WLAN system. Rain, snow, and hail do not affect wireless transmission unless the weather is severe. In this case, the collection of the elements may have an impact on the WLAN signal transmitted or received.

14. Which weather element would commonly have an effect on a WLAN system? A. Rain B. Snow C. Wind D. Hail

A. AP radio The BSSID is the unique identifying MAC address of the access point's radio network adapter. This abbreviation is sometimes confused with SSID, which is a network name. The other MAC addresses are used in networking but are not representative of the BSSID.

15. A basic service set identifier (BSSID) is the unique identifying MAC address of the __________. A. AP radio B. AP Ethernet port C. Router D. Client

C. 50 WLAN cables and devices are rated at 50 ohms impedance. Cable and satellite television is rated at 75 ohms.

15. Wireless network cables and devices have impedance (AC resistance) of __________ ohms. A. 10 B. 25 C. 50 D. 75

B. 7 The curvature of the earth or earth bulge will have an impact on a WLAN signal after seven miles. If the signal needs to travel farther than seven miles, the antenna will have to be installed in a higher location.

16. The curvature of the earth will have an impact on the WLAN signal after how many miles? A. 2 B. 7 C. 10 D. 25

B. Independent A network consisting only of wireless client stations is an independent basic service set (IBSS). Other terms for this type of network are ad hoc and peer-to-peer. Infrastructure mode is a term used with a basic service set that consists of a single access point. Active and passive are scanning modes in which wireless devices connect to a wireless network.

16. When an IEEE 802.11g WLAN consists only of wireless client stations, the network is operating as which type of basic service set? A. Active B. Independent C. Passive D. Infrastructure

A. Semidirectional A patch antenna provides semidirectional coverage. The amount of coverage depends on the design and gain of the antenna. Parabolic dishes are highly directional.

17. A patch antenna is an example of which type of antenna? A. Semidirectional B. Omnidirectional C. Highly directional D. Dipole-directional

C. 32 An SSID can be a maximum of 32 characters or octets and is also case-sensitive.

6. A service set identifier (SSID) has a maximum limit of how many characters or octets? A. 8 B. 16 C. 32 D. 128

A. Active Active gain requires an external power source to provide an increase in signal strength. An amplifier is an example of a device that uses active gain. Antennas provide an increase in strength by using passive gain.

6. Powered amplifiers provide an increase in signal strength by using __________ gain. A. Active B. Passive C. Positive D. Maximum

C. Active mode Because the computer is almost always plugged into an AC power source, it is unnecessary to have the device perform power save functions. Therefore, active mode (sometimes referred to as continuous aware mode) is the best solution. Power save mode would work well for a device that is on battery power and will help extend the battery life. Association and passive mode do not pertain to power save.

17. You are a technical support engineer and provide help desk support for the network in a manufacturing company. You receive a call from the sales manager who wants to know how power save operations should be set up on her notebook computer to optimize the system performance. The notebook computer is plugged into an AC power source and rarely used on battery. Which mode would you recommend her to set on the wireless adapter? A. Power save mode B. Association mode C. Active mode D. Passive mode

A. One or more An ESS, as stated in the IEEE 802.11 standard, is one or more interconnected basic service sets.

18. According to the IEEE 802.11 standard, an extended service set (ESS) consists of how many interconnected basic service sets? A. One or more B. Two or more C. Three or more D. Four or more

B. Horizontal The horizontal RF radiation pattern of an antenna is displayed using an azimuth chart. The vertical radiation pattern is displayed using an elevation chart.

18. An azimuth chart shows which RF radiation pattern? A. Vertical B. Horizontal C. Positive D. Negative

D. 60 It is recommended that at least 60 percent of the Fresnel zone be free of obstruction in order to have acceptable RF line of sight. Up to 40 percent of the zone can be blocked by obstructions without affecting the signal.

19. A point-to-point wireless link requires what percent of the Fresnel zone to be clear in order to be considered to have an acceptable RF line of sight? A. 0 B. 20 C. 40 D. 60

A. Authentication In order for a wireless client to become part of a basic service set, it must first authenticate and then associate. The distribution system is the network in which the access point is physically connected. Deauthentication and reauthentication occur when a client either logs off the wireless network or roams from one access point to another.

19. The IEEE 802.11 association process happens after which phase? A. Authentication B. Distribution C. Deauthentication D. Reauthentication

B. Passive Antennas provide an increase in RF coverage by means of passive gain. Passive gain occurs when isotropic RF energy is focused into a specific radiation pattern. Active gain requires the use of an external power source.

2. Antennas provide an increase in RF coverage by using gain. A. Active B. Passive C. Positive D. Maximum

C. Dynamic rate switching Dynamic rate switching (also called dynamic rate selection) allows a WLAN device to adjust data rates based on received signal. Dynamic frequency selection allows an access point to pick the best frequency to operate on based on the environment. Transmit power control automatically adjusts output power. Transmit save mode does not exist.

2. You are a sales engineer connected to an IEEE 802.11ac access point with a mobile computer. As you move away from the access point, the connection speed slows to the next lowest supported data rate. The change in data rate is described by which term? A. Dynamic frequency selection B. Transmit power control C. Dynamic rate switching D. Transmit save mode

B. At least one A BSS consists of only one access point. An IBSS has zero access points. A network with more than one access point would be considered an ESS.

20. A basic service set (BSS) consists of how many access points? A. Zero B. At least one C. At least two D. At least four

A. 0 An IBSS uses no access points and is also known as peer-to-peer or ad hoc networking. A BSS uses one access point.

3. An independent basic service set (IBSS) consists of how many access points? A. 0 B. 1 C. 2 D. 4

A. Parallel Horizontal beamwidth is parallel to the earth's surface. This is based on how the E-field propagates away from the antenna element. Vertical beamwidth is perpendicular to the earth's surface.

3. Horizontal beamwidth is __________ to the earth's surface. A. Parallel B. Perpendicular C. Positive D. Negative

B. Two An IEEE 802.11a or IEEE 802.11b/g access point will require two antennas for diversity. Although there are two antennas, a single input/single output access point will have only one radio. The access point provides additional intelligence to determine which antenna to use. Other WLAN technologies, such as IEEE 802.11ac MIMO, may use multiple antennas.

4. IEEE 802.11a/b/g access points require __________ antennas on each radio for diversity functionality. A. One B. Two C. Three D. Six

C. 802.11a client devices If a device is part of a peer-to-peer network, it will connect to other like devices. An access point and a wireless switch are both infrastructure networking devices and will be part of either a BSS or ESS.

4. WLAN devices in an 802.11a peer-to-peer network will connect to which device(s)? A. An access point B. 802.11g client devices C. 802.11a client devices D. A wireless switch

A. Data rate decreases The data rate decreases as a WLAN device moves away from an access point. The data rates increase as a WLAN device moves closer to one access point. The output power does not change based on the location of the wireless device in the radio range of the access point.

5. As a device moves away from an access point, which of the following is true regarding dynamic rate switching? A. Data rate decreases B. Output power decreases C. Data rate increases D. Output power increases

B. Lightning arrestor A lightning arrestor is used to protect a WLAN system from an indirect lightning strike. A lightning arrestor will direct transient or induced electrical current to earth ground as a result of a lightning strike.

5. What device is used to shunt transient current to ground in the event of an indirect lightning strike? A. Lightning striker B. Lightning arrestor C. Lightning prevention D. Lightning breaker

C. Long-range Highly directional antennas are typically used for long-range point-to-point connectivity, such as bridge links. Omnidirectional antennas are used as part of an access point system or to provide point-to-multipoint links.

7. Highly directional antennas are typically used for __________ connectivity. A. Short-range B. Omnidirectional C. Long-range D. Dipole

B. Mismatched SSID If access points on the same DS are set with different SSIDs, the client will lose the connection while roaming unless all SSIDs are set in the client utility. The channel is set by the access point, and the BSSID is the MAC address of the AP radio.

7. You are a technical support engineer and receive a call from a customer regarding a problem with their wireless network connection. The building has an ESS network with five 802.11ac access points. The customer claims that when they move from their office to a conference room using the 802.11ac network they lose their connection and cannot connect to the access point in the conference room. Which is the most likely cause for this user to lose their connection when they roam on the wireless network? A. Different RF channel B. Mismatched SSID C. Different BSSID D. Mismatched association

C. Management Beacons are management frames and are used in the passive scanning process. Data frames carry data payload. Control frames reserve the medium and acknowledgment frames. Detail frames do not exist.

8. A beacon frame advertises information about the wireless network. A beacon frame is what type of frame? A. Data B. Control C. Management D. Detail

A. Polarization Changing the orientation of a device or antenna will change the polarization and affect the received signal strength. The signal strength may either increase or decrease depending on how the polarization is changed from the original position. Wavelength, frequency, and phase are characteristics of RF.

8. You are a network engineer troubleshooting a WLAN weak signal complaint. While moving a handheld WLAN device, you notice that the signal strength increases when the device is moved from a horizontal to a vertical position. This is because the __________ is changing. A. Polarization B. Wavelength C. Frequency D. Diffusion

B. Authenticate, associate The client must authenticate to an access point before it can associate. After both authentication and association have been completed, the client is considered to be part of the BSS.

9. In order for a wireless client to become completely part of the basic service set, it must first __________ and then __________. A. Associate, authenticate B. Authenticate, associate C. Deauthenticate, authenticate D. Disassociate, authenticate

A. Point-to-point C. Point-to-multipoint Point-to-point and point-to-multipoint both require RF line of sight to be able to effectively communicate. Scattering, reflection, and refraction are all behaviors of RF.

9. RF line of sight is required for which type of IEEE 802.11 WLAN installation? (Choose two.) A. Point-to-point B. Scattered C. Point-to-multipoint D. Reflected E. Refracted