15) Deploying and Troubleshooting Wireless Flashcards
A small organization is securing their wireless network with Wi-Fi Protected Access 3 (WPA3) personal. What are some of the issues with this method of authentication? (Select all that apply.)
A. Group authentication
B. No accountability
C. SAE
D. PAKE
A. Group authentication
B. No accountability
One of the issues with WPA3, a personal mode of authentication, is group authentication because the administrator must configure the same secret on the access point and on each node that joins the network.
One of the issues with WPA3, a personal mode of authentication, is that there is no accountability for individual user actions as all users share the same credential.
Simultaneous Authentication of Equals (SAE) is a personal authentication mechanism for Wi-Fi networks introduced with WPA3 to address vulnerabilities in the WPA-PSK method.
Password Authenticated Key Exchange (PAKE) is another way to reference WPA3 Personal Authentication.
A wireless administrator is receiving reports that users cannot connect to the wireless network in certain areas of the building. What can the administrator use to locate dead zones?
A. Heat map
B. Site survey
C. DRS
D. Beacon
A. Heat Map
A heat map shows the signal strength within a particular channel obtained in different locations graphically and shows areas with a strong signal and warnings where signal strength drops off.
A site survey is a documentation about a location for the purposes of building an ideal wireless infrastructure; it often contains optimum locations for wireless antenna and access point placement.
Dynamic Rate Switching/Selection (DRS) in an access point determines an appropriate data rate based on the quality of the signal.
A beacon is a special management frame broadcast by the access point to advertise the wireless LAN. The beacon frame contains the SSID, supported data rates, and signaling, plus encryption/authentication requirements.
An administrator responsible for implementing network coverage in a historical monument cannot install cabling in many areas of the building. What are some ways the administrator can take advantage of wireless distribution systems (WDS) to help? (Select all that apply.)
A. To create a beacon
B. To create a BSA
C. To create an ESA
D. To create a bridge
C. To create an ESA
D. To create a bridge
The administrator can use WDS to create an extended service area (ESA). The administrator must set the APs to use the same channel, SSID, and security parameters.
The administrator can use WDS to bridge two separate cabled segments. When WDS is in bridge mode, the access points will not support wireless clients; they simply forward traffic between the cabled segments.
A beacon is a special management frame broadcast by access points to advertise a wireless LAN. The WDS may use a beacon, but this would not help with coverage in non-cabled areas.
When an administrator installs a single access point, it creates a basic service area (BSA). WDS is unnecessary in areas with only one access point.
An administrator wants the ability to centrally configure and manage access points (APs). What are some solutions the administrator could use for this? (Select all that apply.)
A. Hardware
B. Software
C. Fat AP
D. Wireless Mesh Network
A. Hardware
B. Software
The administrator could use a dedicated hardware device called a wireless LAN controller to centralize the management and monitoring of the APs on the network.
The administrator could use a software application, which the administrator can run on a server or workstation, to centralize the management of APs.
A fat AP is an AP whose firmware contains enough processing logic to be able to function autonomously and handle clients without the use of a wireless controller.
While Wireless Mesh Networks are not used to centrally configure APs, they are capable of discovering one another and peering, forming a Mesh Basic Service Set (MBSS).
An administrator is investigating issues with intermittent connectivity to the wireless network. The administrator has verified that the access point configurations are correct. However, the administrator suspects that there may be other issues causing the problem. What are some areas the administrator should investigate? (Select all that apply.)
A. Signal strength
B. Cabling
C. Interference
D. Power
A. Signal Strength
C. Interference
The administrator should investigate signal strength, or radiofrequency attenuation because as the distance from the antenna increases, the strength of the signal decreases in accordance with the inverse-square rule.
The administrator should investigate interference as interference sources collectively overlay a competing background signal, referred to as noise.
Cabling is not an issue as the client devices are connecting to the access points over the wireless network and not through a wired LAN.
Power would not be an issue because the connection is intermittent and a power issue would cause the access points to be down completely.
An administrator is configuring a wireless LAN (WLAN) extended service area. Which of the following will the administrator need to configure the same on each access point? (Select all that apply.)
A. BSSID
B. ESSID
C. BSS
D. Security information
B. ESSID
D. Security information
The administrator will need to configure the same Extended Service Set Identifier (ESSID) on each access point in the extended service area. The ESSID is the network name configured on multiple devices.
The administrator will need to configure the same security information on each access point in the extended service area.
The Basic Service Set Identifier (BSSID) is the media access control (MAC) address of an access point supporting a basic service area.
A Basic Service Set (BSS) is when an access point mediates communications between client devices and can also provide a bridge to a cabled network segment.
A library user connected their tablet to the library’s open access point. Which of the following items will NOT secure the open connection and protect the user’s communications?
A. Using a VPN
B. Using HTTPS
C. Using a screen protector
D. Enabling SSL/TLS
C. Using a screen protector
Using a screen protector on the tablet may protect the user’s tablet screen from others in the same location who may try to view it, but it will not secure the open wireless connection.
Using a virtual private network (VPN) will secure the open connection with an encrypted “tunnel” between the user’s computer and the VPN server.
Using only Hypertext Transfer Protocol Secure (HTTPS) connections will secure any confidential web data the user sends.
Enabling Secure Socket Layer/Transport Layer Security (SSL/TLS) for use with email, VoIP, IM, and file transfer services will secure that data from anyone who may be eavesdropping on the open access point.
A wireless administrator is troubleshooting dead zones in a building. Although the administrator used a heat map to determine the optimum position for access points (APs), some areas that should have coverage have very low signal strength which is unusable to clients. What should the administrator check? (Select all that apply.)
A. Throughput
B. Antenna placement
C. Antenna cable attenuation
D. EIRP
B. Antenna placement
C. Antenna cable attenuation
D EIRP
The administrator should check the antenna placement as incorrect antenna placement could cause or exacerbate attenuation and interference problems and cause issues with the signal strength.
The administrator should check for antenna cable attenuation which is signal loss caused by an external antenna connected to an access point over cabling.
The administrator should check Effective Isotropic Radiated Power (EIRP) which is the sum of transmit power, antenna cable/connector loss, and antenna gain and can affect wireless coverage.
Throughput is the amount of data transferred at the network layer, discarding overhead from layers 1 and 2, this would not be relevant to causing low signal strength.
An administrator is testing the signal strength in a concrete building and measures a 12 dB loss between the office where the access point is located and the office next door. What is the cause of the decibel loss?
A. Absorption
B. Refraction
C. Reflection
D. EMI
A. Absorption
Absorption is causing decibel loss. Absorption refers to the degree to which walls and windows will reduce signal strength when passing through construction materials.
Refraction is when a glass of water can cause radio waves to bend and take a different path to the receiver. This can also cause the data rate to drop.
Reflection/bounce (multipath interference) is when mirrors or shiny surfaces cause signals to reflect and introduce a variable delay which causes packet loss and the data rate to drop.
Electromagnetic interference (EMI) is the interference from a powerful radio or electromagnetic sources working in the same frequency band, such as a Bluetooth device, cordless phone, or microwave oven.
A wireless installer is networking a conference room with 9’ ceilings. What is the best type of antenna for wireless devices?
A. Vertical rod
B. Yagi
C. Parabolic/dish or grid
D, Polarization
A. Vertical Rod
The wireless devices should have vertical rod antennas which receive and send signals in all directions more-or-less equally and the installer should mount them on the ceiling for the best coverage, unless the ceiling is particularly high.
A Yagi antenna, which is a bar with fins, extends the wireless signal to a particular area. This antenna is focused in a single direction.
A parabolic/dish or grid antenna extends the wireless signal to a particular area. This antenna is focused in a single direction.
Polarization is not an antenna but refers to the orientation of the wave propagating from the antenna. To maximize signal strength, the transmission and reception antennas should normally use the same polarization.
An administrator is evaluating the wireless coverage in a conference hall. There are enough access points to provide for 25 clients per access point, but many users are finding the wireless network to be unresponsive and timing out requests. What could be causing this issue? (Select all that apply.)
A. CCI
B. ACI
C. Overcapacity
D. Bandwidth saturation
A. CCI
B. ACI
D. Bandwidth saturation
O-channel interference (CCI) could be causing this issue. It occurs when multiple access points use the same channel, and it reduces the opportunities for devices to transmit.
Adjacent channel interference (ACI) could be causing this issue. It occurs when access points use different but overlapping channels and it raises noise levels.
Bandwidth saturation could be causing this issue. Wireless is a broadcast medium and all clients share the available bandwidth so if one client is a bandwidth hog the others may not get a reliable connection.
Overcapacity would not be an issue as a maximum of 30 clients per access point is the rule of thumb and in this case, there are only 25 clients per access point.
Which of the following are formats for 2G cellular communications? (Select all that apply.)
A. EV-DO
B GSM
C. CDMA
D. HSPA+
B. GSM
C. CDMA
Global System for Mobile Communication (GSM) is a format for 2G and a standard for cellular radio communications and data transfer.
Code Division Multiple Access (CDMA) is a format for 2G and means that each subscriber uses a code to key the modulation of their signal and the receiver uses this “key” to extract the subscriber’s traffic from the radio channel.
CDMA2000/Evolution Data Optimized (EV-DO) are the main 3G standards deployed by CDMA network providers.
Evolved High-Speed Packet Access (HSPA+) is a 3G standard developed via several iterations from the Universal Mobile Telecommunications System (UMTS) used on GSM networks.
An administrator is implementing encryption on the wireless network. What standard should the administrator implement?
A. TKIP
B. WPA
C. WEP
D. WPA2
D. WPA2
The administrator should implement Wi-Fi Protected Access 2 (WPA2) which provides authenticated encryption and makes replay attacks harder.
Temporal Key Integrity Protocol (TKIP) is not a wireless encryption standard. It is a protocol used by WPA to try to mitigate the various attacks against WEP.
The administrator should not implement Wi-Fi Protected Access (WPA) which was supposed to fix critical vulnerabilities in the earlier wired equivalent privacy (WEP) standard but is not secure enough for continued use.
The administrator should not implement the wired equivalent privacy (WEP) standard which threat actors can exploit with replay attacks that aim to recover the encryption key.
What standards are most wireless LANs based on?
A. 802.11
B. Wi-Fi 5
C. MU-MIMO
D. Cellular radio
A. 802.11
Most wireless LANs (WLANs) are based on the IEEE 802.11 standards which define the physical layer media by which data encodes into a radio carrier signal by using a modulation scheme.
Wi-Fi 5 works only in the 5 GHz band although it can use the 2.4 GHz band for legacy standards (802.11g/n) in mixed mode.
Multiuser MIMO (MU-MIMO) is the use of spatial multiplexing to connect multiple MU-MIMO-capable stations simultaneously, providing the stations are not on the same directional path.
Cellular radio is mobile telephony standards divided into 2G (GSM; up to about 14 Kbps), 2.5G (GPRS, HSCSD, and EDGE; up to about 48 Kbps), and 3G (WCDMA; up to about 2 Mbps).
The IEEE 802.11 standards use two frequency bands. Which of the following statements regarding the frequency bands are true? (Select all that apply.)
A. The 2.4 GHz band is ideal for providing the longest signal range
B. The 5 GHz band is ideal for providing the longest signal range
C. The 2.4 GHz band supports a high number of individual channels
D. The 5 GHz band supports a high number of individual channels
A. The 2.4 GHz band is ideal fo providing th longest signal range
D. The 5 GHz band supports a high number of individual channels
The 2.4 GHz band is better at propagating through solid surfaces, making it ideal for providing the longest signal range.
The 5 GHz band supports more individual channels and suffers less from congestion and interference, meaning it supports higher data rates at shorter ranges.
5 GHz is less effective at penetrating solid surfaces and so does not support the maximum ranges achieved with 2.4 GHz standards.
The 2.4 GHz band does not support a high number of individual channels and is often congested, both with other Wi-Fi networks and other types of wireless technology.
