Chapter 12

Question 1

Which of the following can cause roaming problems? (Choose Two)

Answer 1

A) Too little cell coverage overlap

B) Too much cell coverage overlap

Question 2

What is the most common way to overcome multipath in an indoor environment?

Answer 2

Diversity Antenna Systems

Question 3

Several users are complaining that their VoWiFi phones keep losing connectivity. The WLAN administrator notices that the frame transmissions of the VoWiFi phones are corrupted when listened to with a protocol analyzer near the access point, but are not corrupted when listened to with the protocol analyzer near the VoWiFi phone. What is the most likely cause of this problem?

Answer 3

Mismatched power settings

Question 4

What variables might affect range in an 802.11 WLAN? (Choose Three)

Answer 4

A) Antenna gain
B) Physical environment
C) Transmission power

Question 5

The “near / far” problem is normally addressed by the CSMA/CA process.

Answer 5

True

Question 6

Why would a WLAN network administrator consider disabling the two lowest rates on an 802.11b/g access point? (Choose Two)

Answer 6

A) Medium contention

B) Hidden node

Question 7

Which type of interference is caused by multipath?

Answer 7

Intersymbol interference

Question 8

This type of architecture has zero handoff time and all access points have the same BSSID

Answer 8

Single-channel Architecture

Question 9

In a multiple channel architecture (MCA) design, what is the greatest number of nonoverlapping channels that can be deployed in the 2.4 GHz ISM band? (In the United States)

Answer 9

3

Question 10

What can be done to fix the hidden node problem? (Choose Three)

Answer 10

A) Move the hidden node station
B) Remove the obstacle
C) Increase power on all client stations

Question 11

Data environments can typically handle a higher level of layer 2 retransmissions then VOIP networks.

Answer 11

True

Question 12

Which tool is normally used to discover sources of RF interference?

Answer 12

Spectrum Analyzer

Question 13

What are some of the negative effects of layer 2 retransmissions? (Choose Three)

Answer 13

A) Increased latency
B) Excessive MAC sublayer overhead
C) Jitter

Question 14

Which of these weather conditions is a concern when deploying a long-distance point-to-point bridge link?

Answer 14

A) Wind
B) Rain
C) Fog
D) Changes in air temperature
*** All of the above***

Question 15

A single user is complaining that her VoWiFi phone has choppy audio. The WLAN administrator notices that the user’s MAC address has a retry rate of 25 percent when observed with a protocol analyzer. However, all the other users have a retry rate of about 5 percent when also observed with the protocol analyzer. What is the most likely cause of this problem?

Answer 15

Hidden node

Question 16

Based on RSSI metrics, concentric zones of variable data rate coverage exist around an access point due to the upshifting and downshifting of client stations between data rates. What is the correct name of this process, according to the IEEE 802.11-2007 standard?

Answer 16

Dynamic rate switching

Question 17

If the access points transmit on the same frequency channel in a multi-channel (MCA) architecture, what type of interference is caused by overlapping coverage cells?

Answer 17

Co-channel interference

Question 18

What scenarios might result in a hidden node problem? (Choose Three)

Answer 18

A) Distributed antenna system
B) Too large coverage cell
C) Physical obstruction

Question 19

Which WLAN architecture can use the 40 MHz OFDM channel capabilities of an 802.11n access point in the 2.4 GHz ISM band using a single channel blanket?

Answer 19

Single channel architecture

Question 20

What type of solution may be deployed to provide continuous connectivity when a client station roams across layer 3 boundaries?

Answer 20

Mobile IP solution

Question 21

What type of interference is caused by overlapping coverage cells with overlapping frequencies?

Answer 21

Adjacent cell interference

Question 22

What are some problems that can occur when an access point is transmitting at full power? (Choose Three)

Answer 22

A) Hidden node
B) Mismatched power between the AP and the clients
C) Co-channel interference

Question 23

Layer 2 retransmissions occur when frames become corrupted. What are some of the causes of layer 2 retries? (Choose Four)

Answer 23

A) RF interference
B) Low SNR
C) Multipath
D) Adjacent cell interference (Adjacent Channel Interference)

Question 24

What variables might affect range in an 802.11 WLAN?

Answer 24

A) Wavelength
B) Free space path loss
C) Brick walls
D) Trees
***All of the above***

Question 25

What is the primary method of increasing capacity in a multi-channel architecture 802.11 WLAN?

Answer 25

Cell sizing