12.8.2 Module Quiz – WLAN Concepts (Answers)

12.8.2 Module Quiz – WLAN Concepts Answers

1. In the context of mobile devices, what does the term tethering involve?

  • connecting a mobile device to a USB port on a computer in order to charge the mobile device
  • connecting a mobile device to another mobile device or computer to share a network connection
  • connecting a mobile device to a 4G cellular network
  • connecting a mobile device to a hands-free headset

Explanation: Tethering allows a laptop or PC to use the Internet connection of a mobile device such as a cell phone, usually through a cellular data connection. This allows devices to connect to the Internet in locations where there is no Wi-Fi or cabled connection, but where there is still a cellular data connection.

2. Which feature of 802.11n wireless access points allows them to transmit data at faster speeds than previous versions of 802.11 Wi-Fi standards did?

  • SPS
  • WPS
  • MITM
  • MIMO

Explanation: Multiple-input multiple-output (MIMO) technology allows 802.11n devices to use multiple antennas in order to increase the available bandwidth for the wireless network. Single Point Setup (SPS) is a Cisco technology that makes AP deployment easier by supporting clustering from a single management interface. Wi-Fi Protected Setup (WPS) is used to simplify connecting clients to secure wireless networks. Man-in-the-middle (MITM) is a type of security attack where the attacker attempts to insert themselves into the middle of a data stream.

3. Which method of wireless authentication is currently considered to be the strongest?

  • open
  • WPA
  • WPA2
  • WEP
  • shared key

Explanation: WPA2 can use the AES encryption standard, which is currently the strongest method of encrypting wireless data.

4. Which parameter is commonly used to identify a wireless network name when a home wireless AP is being configured?

  • SSID
  • BESS
  • ad hoc
  • ESS

Explanation: The SSID is used to name a wireless network. This parameter is required in order for a wireless client to attach to a wireless AP.

5. Which characteristic describes a wireless client operating in active mode?

  • ability to dynamically change channels
  • must be configured for security before attaching to an AP
  • must know the SSID to connect to an AP
  • broadcasts probes that request the SSID

Explanation: A wireless client operating in active mode must know the name of the SSID. Probe requests are broadcast by a client across multiple channels and include the SSID name and supported standards. Active mode is used if an AP is configured to not broadcast beacon frames.

6. Which IEEE standard operates at wireless frequencies in both the 5 GHz and 2.4 GHz ranges?

  • 802.11a
  • 802.11g
  • 802.11b
  • 802.11n

Explanation: The 802.11n standard is backwards compatible with both the 802.11a and 802.11b standards and therefore operates at both 5 GHz and 2.4 GHz.

7. Which statement describes an autonomous access point?

  • It is a standalone access point.
  • It is managed by a WLAN controller.
  • It is server-dependent.
  • It is used for networks that require a large number of access points.

Explanation: An autonomous access point is used in environments that require a small number of access points. As network demands increase, more access points can be added to the environment with each access point acting independently of another. An autonomous access point can be configured using either a GUI or CLI.

8. Which two roles are typically performed by a wireless router that is used in a home or small business? (Choose two.)

  • Ethernet switch
  • RADIUS authentication server
  • repeater
  • WLAN controller
  • access point

Explanation: In addition to its roles as router, a typical SOHO wireless router acts as both a wireless access point and an Ethernet switch. RADIUS authentication is provided by an external server. A WLAN controller is used in enterprise deployments to manage groups of lightweight access points. A repeater is a device that enhances an incoming signal and retransmits it.

9. Which protocol and port numbers are used by both IPv4 and IPv6 CAPWAP tunnels? (Choose two.)

  • TCP
  • ICMP
  • UDP
  • 17 and 163
  • 5246 and 5247

Explanation: CAPWAP can operate either over IPv4 or IPv6 and can use UDP ports 5246 and 5247.

10. If three 802.11b access points need to be deployed in close proximity, which three frequency channels should be used? (Choose three.)

  • 8
  • 1
  • 3
  • 11
  • 6
  • 5

Explanation: In order to minimize interference, one of the three non-overlapping channels should be used in 2.4GHz Wi-Fi networks: 1, 6, or 11.

11. Which type of telecommunication technology is used to provide Internet access to vessels at sea?

  • satellite
  • cellular
  • WiMax
  • municipal WiFi

Explanation: Internet access by means of satellites is available across the world. Temporary installations, airplanes in flight, and naval vessels benefit from the use of satellite internet. Municipal Wi-Fi, WiMax, and cellular technology are not able to support the mobile requirements of naval vessels and airplanes in transit.

12. Which wireless network topology is being configured by a technician who is installing a keyboard, a mouse, and headphones, each of which uses Bluetooth?

  • hotspot
  • ad hoc mode
  • infrastructure mode
  • mixed mode

Explanation: Tethering enables a wireless device such as a phone to provide wireless Internet connectivity to other devices, thus creating a hotspot. Infrastructure mode is the type of wireless network that is created when an access point is being used. Mixed mode allows older wireless NICs to attach to an access point that can use a newer wireless standard.

13. Which type of wireless topology is created when two or more Basic Service Sets are interconnected by Ethernet?

  • BSS
  • ESS
  • ad hoc WLAN
  • WiFi Direct

Explanation: Wireless devices operate in either ad hoc or infrastructure modes. An ad hoc WLAN, also referred to as an independent basic service set (IBISS), operates on a peer-to-peer basis without a network. Infrastructure modes can consist of a single Basic Service Set (BSS) with an AP interconnecting associated stations, or an Extended Service Set (ESS), with two or more BSSes interconnected over a wire distribution system such as Ethernet. WiFi Direct is a compatibility certification unrelated to WLAN topologies.

14. What Wi-Fi management frame is regularly broadcast by APs to announce their presence?

  • association
  • beacon
  • probe
  • authentication

Explanation: Beacon frames are broadcast periodically by the AP to advertise its wireless networks to potential clients. Probing, association, and authentication frames are only sent when a client is associating to the AP.

15. An AP regularly broadcasts which type of management frame?

  • Authentication
  • Beacon
  • Probe request
  • Probe response

Explanation: Beacons are the only management frame that may regularly be broadcast by an AP. Probing, authentication, and association frames are used only during the association (or reassociation) process.

16. What type of wireless antenna is best suited for providing coverage in large open spaces, such as hallways or large conference rooms?

  • Directional
  • Omnidirectional
  • Parabolic dish
  • Yagi

Explanation: Omnidirectional antennas send the radio signals in a 360 degree pattern around the antenna. This provides coverage to devices situated anywhere around the access point. Dishes, directional, and Yagi antennas focus the radio signals in a single direction, making them less suitable for covering large, open areas.

17. Which wireless security method requires clients to manually identify the SSID to connect to the WLAN?

  • MAC Address Filtering
  • IP Address Filtering
  • SSID cloaking
  • SSID disclosing

Explanation: SSID cloaking is a weak security feature that is performed by APs and some wireless routers by allowing the SSID beacon frame to be disabled. Although clients have to manually identify the SSID to be connected to the network, the SSID can be easily discovered.

18. What are the two methods that a wireless client can use to discover an AP? (Choose two.)

  • Delivering a broadcast frame
  • Initiating a three-way handshake
  • Receiving a broadcast beacon frame probe response
  • Sending an ARP request
  • Transmitting a probe request

Explanation: Two methods can be used by a wireless device to discover and register with an access point: passive mode and active mode. In passive mode, the AP sends a broadcast beacon frame that contains the SSID and other wireless settings. In active mode, the wireless device must be manually configured for the SSID, and then the device broadcasts a probe request.

19. What type of wireless network topology would be used in a medium to large organization?

  • Ad hoc
  • Hotspot
  • Infrastructure
  • Mixed mode
  • Tethering

Explanation: Ad hoc mode (also known as independent basic service set or IBSS) is used in a peer-to-peer wireless network, such as when Bluetooth is used. A variation of the ad hoc topology exists when a smart phone or tablet with cellular data access is enabled to create a personal wireless hotspot. Mixed mode allows older wireless NICs to attach to an access point that can use a newer wireless standard.

20. What IEEE 802.11 wireless standards operate only in the 2.4 GHz range? (Choose two.)

  • 802.11a
  • 802.11b
  • 802.11g
  • 802.11n
  • 802.11ac
  • 802.11ad

Explanation: The 802.11a and 802.11ac standards operate only in the 5 GHZ range. The 802.11b and 802.11g standards operate only in the 2.4 GHz range. The 802.11n standard operates in both the 2.4 and 5 GHz ranges. The 802.11ad standard operates in the 2.4, 5, and 60 GHz ranges.

21. Which IEEE wireless standard is backward compatible with older wireless protocols and supports data rates up to 1.3 Gb/s?

  • 802.11
  • 802.11a
  • 802.11ac
  • 802.11g
  • 802.11n

Explanation: 802.11ac provides data rates up to 1.3 Gbps and is still backward compatible with 802.11a/b/g/n devices. 802.11g and 802.11n are older standards that cannot reach speeds over 1 Gbps.

22. In a 2.4 GHz wireless network, which three channels should be used to avoid interference from nearby wireless devices? (Choose three.)

  • 0
  • 1
  • 3
  • 6
  • 9
  • 11
  • 14

Explanation: Interference occurs when one signal overlaps a channel reserved for another signal, causing possible distortion. The best practice for 2.4 GHz WLANs that require multiple APs is to use the non-overlapping channels 1, 6, and 11. These are selected because they are 5 channels apart and therefore minimize the interference with adjacent channels.

23. Which authentication method is more secure but requires the services of a RADIUS server?

  • WEP Enterprise
  • WPA Personal
  • WPA Enterprise
  • WPA2 Personal

Explanation: WPA and WPA2 Personal are intended for home or small office networks where users authenticate using a pre-shared key (PSK). WPA and WPA2 Enterprise is intended for enterprise networks but requires a RADIUS authentication server which provides additional security. WEP Enterprise is not a valid option.

24. Which option correctly describes when an AP openly advertises its service by periodically sending broadcast beacon frames containing the SSID, supported standards, and security settings?

  • Active mode
  • Mixed mode
  • Open authentication mode
  • Passive mode

Explanation: When an access point is configured in passive mode, the SSID is broadcast so that the name of wireless network will appear in the listing of available networks for clients. Active is a mode used to configure an access point so that clients must know the SSID to connect to the access point. APs and wireless routers can operate in a mixed mode, meaning that that multiple wireless standards are supported. Open is an authentication mode for an access point that has no impact on the listing of available wireless networks for a client.

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