CWNP PW0-205 問題集

質問 1：
James is a sales associate for ABC Company. Sitting at his desk, James can use the wireless LAN with no problems. James takes his laptop downstairs to ABC Company Engineering department. James finds that he cannot connect to the Internet or the company intranet, but his wireless LAN card utilities shows that he is associated to the wireless network. Engineers are reporting no network connectivity problems over the wireless LAN. When using a protocol analyzer, what will you most likely find as the cause of the problem?
A. ABC Company administrator has configured different security mechanisms for the Sales and Engineering departments.
B. Someone has placed a rogue DHCP server on the Engineering network.
C. James has a static IP configured on his laptop, and he has now roamed across a layer 3 network boundary.
D. An ARP storm is consuming the wireless medium bandwidth making network connectivity almost impossible.
E. ABC Company administrator has configured protocol filters on the Engineering department access points.
正解：C

質問 2：
Which of the following IEEE 802.11 units has a 16-bit frame check sequence (FCS)?
A. 802.11g Announcement Traffic Indication Message (ATIM)
B. 802.11 MAC Protocol Data Unit (MPDU)
C. 802.11b Physical Layer Convergence Protocol (PLCP) header
D. 802.11a MPDU Frame Control field
E. 802.11 Wired Equivalent Privacy (WEP)
正解：C

質問 3：
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 MPDU frame FCS field is 4 bytes, while the MMPDU frame FCS field is 8 bytes.
B. An MMPDU header may only contain three address fields, but an MPDU may have four address fields.
C. 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.
D. The MMPDU frame body is limited to 200 bytes, whereas the MPDU frame body can carry up to 2312 bytes.
正解：B

質問 4：
While operating in DCF mode, stations and access points must use a backoff algorithm in order to arbitrate for medium access. During what specific period of time is the backoff timer decremented?
A. During the Contention-free Period
B. During a DCF Interframe Space
C. During the Defer Window
D. During any part of the Superframe
E. During the Contention Window
正解：E

質問 5：
Which of the following must be true before an 802.11 station may transmit a frame on the RF medium using DCF mode?
A. The station must have received a PS-Poll frame from the access point.
B. The Network Allocation Vector must be equal to zero.
C. A time period of at least PIFS must have passed.
D. All collision arbitration must be completed on the RF medium.
E. A time period of at least DIFS must have passed.
F. The Backoff Timer must be equal to zero.
正解：B,E,F

質問 6：
Which of the following parameters accurately describe the Beacon Interval field in the Beacon Management frame?
A. Indicates the exact time interval between beacon transmissions
B. Measured in time units of 1024 us
C. Value can range from 1 to 32,768
D. 4-octet length
E. Measured in time units of 1 us
F. Indicates the desired time interval between TBTTs
正解：B,F

質問 7：
ABC Company has hired you to troubleshoot an intermittent performance problem with their 802.11g wireless LAN. They have noticed that intermittently throughout a typical day, their wireless LAN latency increases enough to interrupt some mission critical applications.
ABC demands that you wait until after business hours to begin any troubleshooting that might cause service interruptions to the wireless network. Considering that ABC Company has no baseline analysis, what possible first step do you take toward troubleshooting ABC Company wireless network problem?
A. You perform a walk-through of ABC Company premises during business hours using a protocol analyzer looking for data frames with high Retry counts and MAC CRC Error counts.
B. You perform a walk-through of ABC Company's premises during business hours using a protocol analyzer looking for 802.11g Basic Service Sets that have both 802.11b and
802.11g stations associated. You then compare this information to where the latency is being experienced.
C. You install protocol analyzer probes near each access point in order to see if a large percentage of data frames are carrying their maximum payload over the next two days.
D. Using a protocol analyzer, you search for rogue access points that might be causing interference in the 2.4 GHz ISM band by emitting beacons.
E. After business hours, you enable the traffic generator function of a wireless protocol analyzer in order to simulate various high utilization conditions on the network while testing ABC Company applications.
F. After business hours, you search for wireless clients that are transmitting too many Probe Request frames and temporarily replace them as a troubleshooting measure.
正解：A,B,E