12.5-6_Channel Management

Question 1

Wireless LAN devices have transmitters and receivers tuned to specific frequencies of radio waves to communicate. A common practice is for frequencies to be allocated as___. Such ***are then split into smaller ranges called ___.

Answer 1

ranges
channels

Question 2

Frequency Channel Saturation
This is a modulation technique designed to spread a signal over a larger frequency band. Spread spectrum techniques were developed during war time to make it more difficult for enemies to intercept or jam a communication signal.

Answer 2

Direct-Sequence Spread Spectrum (DSSS)

Question 3

Frequency Channel Saturation
__: This relies on spread spectrum methods to communicate. It transmits radio signals by rapidly switching a carrier signal among many frequency channels.

Answer 3

Frequency-Hopping Spread Spectrum (FHSS)
With the FHSS, the sender and receiver must be synchronized to “know” which channel to jump to

Question 4

Frequency Channel Saturation
__: This is a subset of frequency division multiplexing in which a single channel uses multiple sub-channels on adjacent frequencies.

Answer 4

Orthogonal Frequency-Division Multiplexing (OFDM)

Question 5

Sub-channels in an OFDM system are precisely _____to one another which allow the sub-channels to overlap without interfering

Answer 5

orthogonal

Question 6

The new 802.11ax uses a variation of OFDM called ____

Answer 6

Orthogonal frequency-division multiaccess (OFDMA).

Question 7

A best practice for WLANs requiring multiple APs is to use __ channels.

Answer 7

non-overlapping

Question 8

When planning the location of APs, the ___ is important

Answer 8

approximate circular coverage area

Question 9

Plan a WLAN Deployment
If APs are to use existing wiring or if there are locations where APs cannot be placed, note these locations on the ___

Answer 9

map

Question 10

Plan a WLAN Deployment
Note all potential sources of___which can include microwave ovens, wireless video cameras, fluorescent lights, motion detectors, or any other device that uses the 2.4 GHz range.

Answer 10

interference

Question 11

Plan a WLAN Deployment
Position APs ___ (below/ above) obstructions.

Answer 11

above

Question 12

Plan a WLAN Deployment
Position APs _____(horizontally/ vertically) near the ceiling in the center of each coverage area, if possible.

Answer 12

vertically

Question 13

Plan a WLAN Deployment
Position APs in locations where__are expected to be. For example, conference rooms are typically a better location for APs than a hallway.

Answer 13

users

Question 14

Plan a WLAN Deployment
If an IEEE 802.11 network has been configured for mixed mode, the wireless clients may experience __than normal speeds in order to support the older wireless standards.

Answer 14

slower

Question 15

Wireless networks are specifically susceptible to several threats, including:
__: Wireless data should be encrypted to prevent it from being read by eavesdroppers.

Answer 15

Interception of data

Question 16

Wireless networks are specifically susceptible to several threats, including:
__: Unauthorized users attempting to access network resources can be deterred through effective authentication techniques.

Answer 16

Wireless Intruders

Question 17

Wireless networks are specifically susceptible to several threats, including:
__: Access to WLAN services can be compromised either accidentally or maliciously. Various solutions exist depending on the source of the DoS attack.

Answer 17

Denial of Service (DoS) Attacks

Question 18

Wireless networks are specifically susceptible to several threats, including:
___: Unauthorized APs installed by a well-intentioned user or for malicious purposes can be detected using management software.

Answer 18

Rogue APs

Question 19

Wireless DoS attacks can be the result of:

__: Configuration errors can disable the WLAN. For instance, an administrator could accidently alter a configuration and disable the network, or an intruder with administrator privileges could intentionally disable a WLAN.

Answer 19

Improperly configured devices

Question 20

Wireless DoS attacks can be the result of:

___: Their goal is to disable the wireless network completely or to the point where no legitimate device can access the medium.

Answer 20

A malicious user intentionally interfering with the wireless communication

Question 21

Wireless DoS attacks can be the result of:
___: WLANs are prone to interference from other wireless devices including microwave ovens, cordless phones, baby monitors, and more, as shown in the figure.

Answer 21

Accidental interference

Question 22

The ___ (2.4 GHz/ 5GHZ) band is more prone to interference than the___ (2.4 GHz/ 5GHZ) band.

Answer 22

2.4 GHZ
5 GHZ

Question 23

A___ is an AP or wireless router that has been connected to a corporate network without explicit authorization and against corporate policy

Answer 23

rogue AP

Question 24

TRUE OR FALSE
Anyone with access to the premises can install (maliciously or non-maliciously) an inexpensive wireless router that can potentially allow access to a secure network resource.

Answer 24

True

Question 25

True or False
A personal network hotspot could also be used as a rogue AP.

Answer 25

True

For example, a user with secure network access enables their authorized Windows host to become a Wi-Fi AP. Doing so circumvents the security measures and other unauthorized devices can now access network resources as a shared device.

Question 26

To prevent the installation of rogue APs, organizations must configure WLCs with___, as shown in the figure, and use monitoring software to actively monitor the radio spectrum for unauthorized APs.

Answer 26

rogue AP policies

Question 27

To minimize the risk of a DoS attack due to improperly configured devices and malicious attacks, harden all devices, keep ___ secure, create backups, and ensure that all configuration changes are incorporated off-hours.

Answer 27

passwords

Question 28

In a___ attack, the hacker is positioned in between two legitimate entities in order to read or modify the data that passes between the two parties.

Answer 28

man-in-the-middle (MITM)

Question 29

A popular wireless MITM attack is called the “___” attack, where an attacker introduces a rogue AP and configures it with the same SSID as a legitimate AP. Locations offering free Wi-Fi, such as airports, cafes, and restaurants, are particularly popular spots for this type of attack due to the open authentication.

Answer 29

evil twin AP

Question 30

Defeating an attack like an MITM attack depends on the ___of the WLAN infrastructure and the___ in monitoring activity on the network.

Answer 30

sophistication
vigilance