Chapter 9 - 802.11 MAC

Which of the following statements regarding the four MAC address fields in the 802.11 MAC header are accurate? (Choose all that apply.) A. Address 2 is always the transmitter address (TA). B. Address 3 is always the transmitter address (TA). C. Address 1 is always the basic service set identifier (BSSID). D. Address 1 is always the receiver address (RA). E. Address 3 is always the basic service set identifier (BSSID). F. Address 2 is always the receiver address (RA).

A. Address 2 is always the transmitter address (TA). D. Address 1 is always the receiver address (RA).

The presence of what type of transmissions can trigger the protection mechanism within an ERP basic service set? (Choose all that apply.) A. Association of an HR-DSSS client B. Association of an ERP-OFDM client C. HR-DSSS beacon frame D. ERP beacon frame with the NonERP_Present bit set to 1 E. Association of an FHSS client

A. Association of an HR-DSSS client C. HR-DSSS beacon frame D. ERP beacon frame with the NonERP_Present bit set to 1

Which of the following information is included in a probe response frame? (Choose all that apply.) A. Channel information B. Supported data rates C. Basic data rates D. SSID E. Traffic indication map

A. Channel information B. Supported data rates C. Basic data rates D. SSID

Which of these 802.11 data frames carry an MSDU payload? (Choose all that apply.) A. Non-QoS data frame B. QoS data frame C. Null frame D. QoS null frame

A. Non-QoS data frame B. QoS data frame

The WLAN help desk gets a call that suddenly all the legacy 802.11b wireless barcode scanners cannot connect to any of the 802.11n APs. However, all the 802.11g/n clients can still connect. What are the possible causes of this problem? (Choose all that apply.) A. The WLAN administrator disabled the 1, 2, 5.5, and 11 Mbps data rates. B. The WLAN administrator disabled the 6 and 9 Mbps data rates. C. The WLAN administrator enabled the 6 and 9 Mbps data rates as basic rates. D. The WLAN administrator configured all the APs on channel 6.

A. The WLAN administrator disabled the 1, 2, 5.5, and 11 Mbps data rates. C. The WLAN administrator enabled the 6 and 9 Mbps data rates as basic rates.

What would cause an 802.11 station to retransmit a unicast frame? (Choose all that apply.) A. The transmitted unicast frame was corrupted. B. The ACK frame from the receiver was corrupted. C. The receiver's buffer was full. D. The transmitting station's buffer was full.

A. The transmitted unicast frame was corrupted. B. The ACK frame from the receiver was corrupted.

Which of the following statements about scanning are true? (Choose all that apply.) A. There are two types of scanning: passive and active. B. Stations must transmit probe requests in order to learn about local APs. C. The 802.11 standard allows APs to ignore probe requests for security reasons. D. It is common for stations to continue to send probe requests after being associated to an AP.

A. There are two types of scanning: passive and active. D. It is common for stations to continue to send probe requests after being associated to an AP.

What can you conclude about this frame based on the frame capture graphic shown? (Choose all that apply.) A. This is a unicast frame. B. This is a multicast frame. C. This is a broadcast frame. D. This a transmission between a mesh point AP and a mesh portal AP. E. This frame is encrypted. F. The frame check sequence (FCS) of the previous attempt of the same frame failed at the receiving station.

A. This is a unicast frame. F. The frame check sequence (FCS) of the previous attempt of the same frame failed at the receiving station.

WLAN users have recently complained about gaps in audio and problems with the push-to-talk capabilities with the ACME Company's VoWiFi phones. What could be the cause of this problem? A. A misconfigured TIM setting B. A misconfigured DTIM setting C. A misconfigured ATIM setting D. A misconfigured BTIM setting

B. A misconfigured DTIM setting

What are some examples of how an 802.11 action frame can be used? (Choose all that apply.) A. An action frame can function as a probe request. B. An action frame can function as a neighbor report request. C. An action frame can function as a probe response. D. An action frame can function as a channel switch announcement. E. An action frame can function as a beacon.

B. An action frame can function as a neighbor report request. D. An action frame can function as a channel switch announcement.

Given that an 802.11 MAC header can have as many as four MAC addresses, which types of addresses are not found in an 802.3 MAC header? (Choose all that apply.) A. SA B. BSSID C. DA D. RA E. TA

B. BSSID D. RA E. TA

If a station is in power-save mode, how does it know that the AP has buffered unicast frames waiting for it? A. By examining the PS-Poll frame B. By examining the TIM field C. When it receives an ATIM D. When the Power Management bit is set to 1 E. By examining the DTIM interval

B. By examining the TIM field

How does a client station indicate that it is using power-save mode? A. It transmits a frame to the AP with the Sleep field set to 1. B. It transmits a frame to the AP with the Power Management field set to 1. C. Using DTIM, the AP determines when the client station uses power-save mode. D. It does not need to, because power-save mode is the default.

B. It transmits a frame to the AP with the Power Management field set to 1.

When a client station is first powered on, what is the order of frames generated by the client station and AP? A. Probe request/response, association request/response, authentication request/response B. Probe request/response, authentication request/response, association request/response C. Association request/response, authentication request/response, probe request/response D. Authentication request/response, association request/response, probe request/response

B. Probe request/response, authentication request/response, association request/response

Which of the following 802.11 frames carry an MSDU payload that may eventually be transferred by the integration service into an 802.3 Ethernet frame? A. 802.11 management frames B. 802.11 control frames C. 802.11 data frames D. 802.11 action frames E. 802.11 association frames

C. 802.11 data frames

Which of the following contains only LLC data and the IP packet but does not include any layer 2 802.11 data? A. MPDU B. PPDU C. PSDU D. MSDU E. MMPDU

D. MSDU

When a station sends an RTS, the Duration/ID field notifies the other stations that they must set their NAV timers to which of the following values? A. 213 microseconds B. The time necessary to transmit the Data and ACK frames C. The time necessary to transmit the CTS frame D. The time necessary to transmit the CTS, Data, and ACK frames

D. The time necessary to transmit the CTS, Data, and ACK frames

Based on the 802.11 frame capture shown here, which type of networking communication is occurring? A. AP to client station B. Client station to server C. Client station to AP D. Server to client station E. AP to AP

E. AP to AP

When is an 802.11ac AP transmitting on 5 GHz required by the IEEE 802.11-2016 standard to respond to probe request frames from nearby client stations? (Choose all that apply.) A. When the probe request frames contain a null SSID value B. When the probe request client is also an 802.11ac radio C. When the probe request is encrypted D. When the probe request has the Power Management bit set to 1 E. When the probe request frames contain the correct SSID value

A. When the probe request frames contain a null SSID value E. When the probe request frames contain the correct SSID value

Which of the following statements are true about beacon management frames? (Choose all that apply.) A. Beacons can be disabled to hide the network from intruders. B. Time-stamp information is used by the clients to synchronize their clocks. C. In a BSS, clients share the responsibility of transmitting the beacons. D. Beacons can contain vendor-proprietary information.

B. Time-stamp information is used by the clients to synchronize their clocks. D. Beacons can contain vendor-proprietary information.