CWAP-403 Online Practice Questions and Answers

You have installed a new 802.11ac WLAN configured with 80 MHz channels. Users in one area are complaining about poor performance. This area is currently served by a single AP. You take a spectrum analysis capture in the poor performing area. While examining the waterfall plot you notice the airtime utilization is higher on the first 20 MHz of the 80 MHz channel when compared to the rest of the channel. What do you conclude?

A. The AP is misconfigured and needs to be reconfigured to 80MHz operation

B. RRM is enabled and has dynamically picked a 20 MHz channel

C. The first 20 MHz is the AP's primary channel and higher airtime utilization on the primary channel is normal when an AP Is configured for 80 MHz operation

D. Non Wi-Fi interference is preventing the APs 80 MHz operation

What is the function of the PMD sub-layer?

A. Converts 1s and 0s given to it by the PLCP sub-layer into the appropriate RF signals

B. Provides framing

C. Adds a PHY preamble and header to a PSDU

D. Performs A-MPDU

You're the WLAN administrator for a large retailer based at the HQ in New York. The London-based office has been complaining about WLAN disconnections around lunch time each day. You suspect this might be interference from the staff microwave, how might you test your theory from the New York office?

A. Access the microwave remotely and run a diagnostic check

B. Ask a local member of staff to take some pictures of the microwave, including some close-ups of the door seal so that you can access it

C. Place one of the London APs into spectrum analyzer mode and monitor the situation over lunch time

D. Ask a local member of staff to change the frequency of the microwave and see if the disconnections stop

Using a portable analyzer you perform a packet capture next to a client STA and you can see that the STA is associated to a BSS. You observe the STA sending packets to the AP and the AP sending packets to the STA. Less the 2% of all packets are retransmissions. You move to capture packets by the AP and, while the retry rate is still very low, you now only see unidirectional traffic from the AP to the client. How do you explain this behavior?

A. There is a transmit power mismatch between the client and the AP and while the client can hear the Aps traffic,the AP cannot hear the client.

B. The portable analyzer has a lower receive sensitivity than the AP and while it can't capture the packets from the client STA, the AP can receive them OK.

C. The STA is transmitting data using more spatial streams than the potable analyzer can support

D. The portable analyzer is too close to the AP causing CCI, blinding the AP to the client's packets

Given: The Frame Check Sequence (FCS) is a 32 CRC used for error detection. The CRC is calculated over what?

A. Frame Body only

B. Mac Header and Frame Body only

C. PHY Header, MAC Header and Frame Body

D. PHY Header and MAC Header only

Where, in a protocol analyzer, would you find an indication that a frame was transmitted as part of an AMPDU?

A. The HT Operation Element

B. A-MPDU flag in the HT Control Field

C. A-MPDU flag in the Frame Control Field

D. The Aggregation flag in the Radio Tap Header

Which piece of information Is not transmitted in an HT PDDU header?

A. Number of Spatial Streams

B. PPDU length

C. Channel number

D. MCS index

Which one of the statements regarding the Frame Control field in an 802.11 MAC header is true?

A. Only Control frames have a Frame Control field

B. The Frame Control field contains three sub-fields and eight one-bit flags

C. The Frame Control field is used to communicate the duration value

D. The Frame Control field is always set to 0

802.11k Neighbor Requests and Neighbor Reports are sent in what type of Management Frames?

A. RRM

B. Action

C. Beacon

D. Reassociation Request and Reassociation Response

You are troubleshooting a client that is experiencing slow WLAN performance. As part of the troubleshooting activity, you start a packet capture on your laptop close to the client device. While analyzing the packets, you suspect that you have not captured all packets transmitted by the client. By analyzing the trace file, how can you confirm if you have missing packets?

A. Look for gaps in the sequence number in MAC header

B. Protocol Analyzers show the number of missing packets in their statistics view

C. Retransmission are an indication of missing packets

D. The missing packets will be shown as CRC errored packets