CWNA 2-1

1.

1 point

What statement about the IEEE 802.11e QoS facility is true?

When the Voice queue has frames awaiting transmission, no data will be transmitted from the Best Effort queue.

Four 802.1p user priorities are mapped to eight 802.11 transmit queues.

802.11 control frames are assigned to the 802.11 EF priority queue.

802.11 QoS is achieved by giving high priority queues a statistical advantage at winning contention.

To improve efficiency, Block Acknowledgments are required for Voice and Video WMM queues.

2.

1 point

In an 802.11n WLAN with a heterogeneous set of associated client devices including 802.11b, 11g, and 11n, what HT protection mode will the BSS use?

Mode 2: 20 MHz protection mode

Mode 0: No protection mode (Greenfield)

Mode 3: Non-HT mixed mode

Mode 1: Nonmember protection mode

3.

1 point

What term correctly completes the following sentence? In an IEEE 802.11 frame, the IP packet is considered by the MAC layer to be a(n) _________.

PLCP Protocol Data Unit (PPDU)

IP datagram

PLCP Service Data Unit (PSDU)

MAC Service Data Unit (MSDU)

MAC Protocol Data Unit (MPDU)

4.

1 point

Prior to association, what parameter can 802.11 client devices measure and use to select the optimal access point for association?

Retry rate of probe request and response frames

Signal strength of access point beacons received

Average round trip time to reach the IP router

Average round trip time to reach the Internet DNS server

Proximity to potential access points

5.

1 point

During the discovery and connectivity process, client and AP stations exchange information about their supported data rates. After the association, how do client
and AP stations select the supported data rate that will be used to send an 802.11 data frame?

The client and AP may use different transmit rates, but the AP determines the data rate that will be used by each client station in the BSS.

The client and AP may use different transmit rates, but the client determines the data rate that it will use and the data rate that the AP will use when communicating to the client.

The client and AP may use a different transmit rates, but the transmit rate is determined by the peer station, based on the peer's experience of the RF link.

During the association, the client and AP agree to use the same transmit rate, but either station can request a change at any time after the association.

The client and AP each choose the optimal data rate to use independently of one another, based on their own measurements related to the RF link.

6.

1 point

In an infrastructure Basic Service Set (BSS), how does the passive scanning process occur?

Client stations record information in the Probe Response frames for use in the association process.

Access points broadcast Beacons on a single channel for which they are programmed. Nearby client stations listen for Beacon frames and record information found in the Beacons for use in the association process.

Client stations broadcast Probe Request frames on all supported channels in the regulatory domain. Nearby access points respond with Probe Response frames.

Access points broadcast Beacons on all channels of each radio within the regulatory domain. Nearby client stations record information found in the Beacons for use in the association process.

Client stations broadcast Probe Request frames on the single channel for which they are programmed. Nearby access points respond on that channel with Probe Response frames. Client stations record information found in the Probe Response frames for use in the association process.

7.

1 point

As a station moves away from the access point to which it is associated, it changes its data rate from 600 Mbps to 540 Mbps and then to 450 Mbps.
What IEEE 802.11 term is used to describe this functionality?

Adaptive Rate Management

Rate Set Selectivity

Multirate Control

Modulation and Coding Selection

Dynamic Rate Switching

8.

1 point

What term correctly completes the following sentence? 802.11a/b/g used a mandatory 800ns guard interval. 802.11n introduced an optional short 400ns guard
interval. Guard intervals (GI) are necessary in OFDM to reduce the likelihood of interference between two consecutive ____________.

Frames

Bytes

Symbols

Bits

Packets

Segments

9.

1 point

What component of the 802.11 standard allows stations to reserve access to the RF medium for a specified period of time?

Short guard intervals

Probe Request frames

DTIM Interval

RTS or CTS frames

Listen Interval

10.

1 point

Which answer correctly completes the following sentence? The WMM certification, created by the Wi-Fi Alliance, is based on the ___________ coordination
function with support for ___________ QoS priority.

Dynamic, distributed

Hybrid, contention-based

Distributed, trigger-and-delivery

Enhanced, contention-free

Point, scheduled