Certmaster Deploying and Troubleshooting Wireless Flashcards
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, D
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.
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, D
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 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 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.
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, D
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.
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, B, D
Co-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.
802.11 relies on a shared physical bus running at half-duplex. How does this standard manage contention?
A.CSMA/CA
B.ACK
C.RTS
D.CTS
A
802.11 uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) where clients avoid collisions by waiting until the channel is idle before sending.
An ACK is an acknowledgment. Under CSMA/CA, when a station receives a frame, it performs error checking. If the frame is intact, the station responds with an ACK.
An RTS is a Request to Send. 802.11 also defines a Virtual Carrier Sense flow control mechanism where a station broadcasts an (RTS) with the source and destination and the time required to transmit.
A CTS is a Clear To Send. When a station broadcasts RTS, the receiving station responds with a CTS and all other stations in range do not attempt to transmit within that period.
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
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.
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, B
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.
An administrator is configuring wireless coverage for a public library where visitors are not expected to have pre-existing accounts. What type of authentication should the administrator implement?
A.WPA3-Personal
B.Captive portal via HTTPS
C.WPA3-Enterprise
D.802.1X/EAP
B
In an environment such as a public library, where users don’t have pre-existing accounts, a captive portal can provide a convenient method for guest access. This authentication method redirects users to a web page for authentication before they can access the internet. Using HTTPS ensures that the interaction with the portal is encrypted and secure.
WPA3-Personal as a form of authentication would require all users to have a pre-shared key (PSK) to connect to the network, which is not practical for a public setting like a library.
WPA3-Enterprise, as a form of authentication, requires each user to have individual network credentials stored on a secure server. It is used primarily in business environments and is not suitable for a public setting like a library.
Similar to WPA3-Enterprise, this authentication method requires users to have individual network credentials. It’s typically used in enterprise environments and would not be practical for a public library.
Which of the following are formats for 2G cellular communications? (Select all that apply.)
A.EV-DO
B.GSM
C.CDMA
D.HSPA+
B, C
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.
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 are showing complete signal loss, 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, C, D
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 implementing encryption on the wireless network. What standard should the administrator implement?
A.TKIP
B.WPA
C.WEP
D.WPA2
D
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.
An administrator is tasked with centralizing the configuration and management of access points (APs) across a network. What types of solutions could the administrator employ that function as a Wireless LAN Controller (WLC)? (Select all that apply.)
A.Hardware
B.Software
C.Fat AP
D.Wireless Mesh Network
A, B
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).
What protocol can an administrator configure in a wireless mesh network (WMN) to allow the stations to perform path discovery and forwarding between peers?
A.MBSS
B.IBSS
C.HWMP
D.BSSID
C
The administrator can configure the Hybrid Wireless Mesh Protocol (HWMP), which is a routing protocol, to allow the mesh stations to perform path discovery and forwarding between peers.
Nodes, or mesh stations, in a wireless mesh network form a Mesh Basic Service Set (MBSS), when they are capable of discovering one another and peering.
An Independent Basic Service Set (IBSS) is a type of wireless network where connected devices communicate directly with each other instead of over an established medium such as an access point.
The Basic Service Set Identifier (BSSID) is the media access control (MAC) address of an access point supporting a basic service area.
