CWNP CWAP-404 問題集

質問 1：
As a WLAN consultant, you have been asked to troubleshoot a problem with a single wireless client station (Station-Z). Your customer informs you that other wireless client stations are not having problems with wireless connectivity, and that Station-Z is configured in the same manner as all other wireless client stations on the network. Station-Z is showing an unusually high retransmission count in its client utility statistics. Using a wireless protocol analyzer, where and how should you begin troubleshooting this problem? (Choose 2)
A. Position the analyzer near Station-Z. Analyze Station-Z's transmissions and acknowledgements.
Look for RF and obstacle-induced interference.
B. Position the analyzer near the access point. See if Station-Z's frames are reaching the access point and if so, analyze their signal strength.
C. Position the analyzer halfway between Station-Z and the access point. Analyze the data rate at which frames are sent and how long they take to be received.
D. Position the analyzer near Station-Z. Analyze the frames Station-Z is receiving, looking for delayed ACK frames.
E. Position the analyzer halfway between Station-Z and the access point. Measure the distance between Station-Z and the access point.
正解：A,B

質問 2：
What is indicated to a QoS AP when a QoS STA sets U-APSD Flag bits to 1 in (Re) Association frames?
A. Which user priorities require use of a TSPEC
B. Which user priorities are mapped to access categories
C. Which access categories are scheduled
D. Which access categories require admission control
E. Which access categories are both trigger-enabled and delivery-enabled
正解：E

質問 3：
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. The STA is transmitting data using more spatial streams than the potable analyzer can support
B. 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.
C. 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.
D. The portable analyzer is too close to the AP causing CCI, blinding the AP to the client's packets
正解：C
解説: (Topexam メンバーにのみ表示されます)

質問 4：
In what scenario is Open Authentication without encryption not allowed based on the 802.11 standard?
A. When operating a BSS in the 6 GHz band
B. When operating a BSS in FIPS mode
C. When operating a BS5 in the CBRS band
D. When operating a BSS in a government facility
正解：A
解説: (Topexam メンバーにのみ表示されます)

質問 5：
According to the IEEE 802.11 standard, what is one structural difference between a MAC Protocol Data Unit (MPDU) and a MAC Management Protocol Data Unit (MMPDU)?
A. The MMPDU frame body is limited to 300 bytes, whereas the MPDU frame body can carry up to
2304 bytes.
B. The MPDU frame's FCS field is 4 bytes, while the MMPDU frame's FCS field is 8 bytes.
C. Both the MPDU and MMPDU have a QoS Control (QC) field, but all bits of the MMPDU's QC field are always 0.
D. An MMPDU header may only contain three address fields, but an MPDU may have four address fields.
E. The MPDU header always places the BSSID in the first address field, but in the MMPDU the BSSID can be found in any of the address fields.
正解：D