PW0-250 Online Practice Questions and Answers

When a WLAN controller transmits an Ethernet frame that has an IEEE 802.11 frame as its payload to a lightweight AP, what type of QoS marks can be applied to the Ethernet frame and/or its payload? (Choose 3)

A. IEEE 802.1Q PCP marks in the Ethernet frame header

B. User Priority marks in the IEEE 802.11 frame header

C. Throughput subscription marks in the Ethernet frame header

D. MPLS tags from the Label Edge Router (LER)

E. DSCP marks to the ToS bits in the encapsulating IP packet header

F. RSVP tag if RTP is the payload of the IEEE 802.11 frame

Your customer location is equipped with DAS, originally deployed to relay a GSM signal indoors and provide 802.11 data coverage to static stations. What type of wireless application would be least likely to be supported by this RF distribution model?

A. On-demand video streaming over wireless

B. Data connection with frequent roaming

C. Location-based services for wireless assets or RFID tags

D. VoWLAN if the codec is G.729.

E. FTP over implicit TLS/SSL

Given: The 802.11n APs you have selected for your public access deployment support many of the PHY and MAC enhancements offered by the 802.11n standard. The AP is single-band (2.4 GHz) and only allows 20 MHz channels. The WLAN radio in the AP is a 3x3 802.11n chip that supports two spatial streams.

What is the maximum MCS rate that could be supported by this AP?

A. 54 Mbps

B. 65 Mbps

C. 108 Mbps

D. 144 Mbps

E. 150 Mbps

F. 300 Mbps

You are tasked with designing the WLAN to accommodate certain high density areas on your university campus where users are highly transient (frequently come and go). With a limited DHCP pool size (subnet mask = 255.255.252.0) for this WLAN subnet, you want to ensure that your DHCP addresses are used efficiently and are not exhausted, which would prevent new client associations. The DHCP server is a Windows Server 2008 machine. Your design task is to determine the best configuration to allow as many users as possible while avoiding WLAN service interruptions and also to use the available addresses as efficiently as possible.

What setting would be most effective at achieving this design task?

A. Set the RTS threshold to 2346 bytes

B. Set the inactive wireless client timeout (client age-out) to 5 minutes

C. Set the maximum client limit per radio to 64

D. Set the DHCP lease for this pool to 20 minutes

E. Enable WLAN Controller DHCP relay

F. Enable mandatory admission control

G. Set the AES rekey interval to 5 minutes

H. Set the 802.1X re-authentication timer to 10 minutes

What is a radome?

A. A type of semi-circular ceiling found in atriums and that is a heavy cause of RF reflection.

B. A weatherproof piece of plastic covering an antenna or antenna system.

C. The unit used to measure the signal reflected backward by the end of a cable.

D. A piece of metal positioned behind APs mounted on outdoor poles, designed to limit the butterfly effect.

E. The unwanted signal coverage provided by either side or back lobes in directional antennas.

Why does a frame transmitted at 1 Mbps have a greater usable range than the same frame transmitted at 54 Mbps?

A. Free space path loss causes greater signal dispersion for higher rate transmissions.

B. Receiver sensitivity requirements are lower for frames transmitted with less complex modulation and coding.

C. To improve reliability, 802.11 STAs increase transmit power as the signaling rate decreases.

D. Lower data rate RF transmissions travel at higher speeds and are less likely to experience collisions.

E. Frames sent at higher data rates are also sent at higher power levels and are therefore more prone to collisions and multipath.

Assume that your network operates in a regulatory domain that allows use of UNII-1, UNII-2, UNII- 2e, UNII-3, and the 5.8 GHz ISM band for indoor Wi-Fi. In your upcoming 802.11n deployment, you would like to take advantage of the performance improvements that result from channel bonding. However, after extensive testing, you have determined that your mission-critical WLAN should not use channels requiring DFS support.

Given those two criteria (enable channel bonding and disable DFS channels), in the 5 GHz spectrum, how many non-overlapping channels will your system be able to use?

A. 2

B. 3

C. 4

D. 6

E. 11

When preparing a floor plan graphic for use in predictive and manual site surveying, what calibration method will lead to the most accurate and reliable RF data?

A. Use the known size of a small object, such as a ceiling tile, and use a single instance of this object (e.g. a single ceiling tile) to scale the floor plan.

B. Measure the width of an actual office doorway with a tape measure and use this value to calibrate against a doorway graphic.

C. Use the longest available measurement (like a straight exterior wall) to calibrate the graphic's scale.

D. Calibrate the ceiling height of the floor plan first, then the survey software should be able to auto-calibrate the X and Y planes of the graphic.

E. With properly formatted .bmp and .png graphics, the site survey software should be able to extract the scale directly from the graphic data during import.

Given: In a site survey deliverable report, you are expected to explain the spectrum measurements taken at the customer's site. The exhibit shows a representative sample capture of the RF environment at one of the customer sites.

What best explains the data presented in this exhibit?

A. The Real Time FFT chart shows a high noise floor across the entire 2.4 GHz band.

B. Channel 1 is being heavily utilized by Wi-Fi and channel 11 also has some moderate Wi-Fi activity.

C. As indicated by the data in the Active Devices list, the spectrum analysis chipset is also reporting 802.11 information.

D. Although some access points are present in a nearby area, they are not being heavily used.

During a post-deployment verification, you are requested to troubleshoot an area where users are experiencing poor throughput. They are using data communication only, mainly from laptops. You captured the frame displayed in the exhibit from the location where problems are reported. This frame is typical of those that were captured by the analyzer.

What does this frame reveal about the RF network in this area?

A. One station seems to be streaming video, thus may have reserved significant bandwidth via admission control

B. Contention Free is in place in this network, which may starve some non-QoS stations from access

C. Multipath or excessive collisions seem to be an issue in this area

D. The AP seems to be too far to provide enough coverage to this area

E. Stations are using null data frames as protection mechanisms to reserve the medium

F. The station that sent this frame is causing a DoS attack by using extended Duration values