PW0-250 - Certified Wireless Design Professional (CWDP)
Go back to CWNP - Certified Wireless Security Professional
Which definition correctly describes the "local MAC" variation of the centralized WLAN architecture?
All MAC functions are performed by the AP. A minimal subset of network control is offloaded to the WLAN controller along with management and monitoring functions.
Why does a frame transmitted at 1 Mbps have a greater usable range than the same frame transmitted at 54 Mbps?
Receiver sensitivity requirements are lower for frames transmitted with less complex modulation and coding.
You are site surveying a network for VoWiFi. You have positioned an AP for a manual survey and are moving away from the AP with a phone in Survey Mode in your hand and you are reading the RSSI value of the signal received from the AP. You have previously determined that the noise floor was approximately -94 dBm on this floor of the building. The phone's documentation does not specify a recommended RSSI or SNR value for best performance. Based on the information provided and the type of device (VoWiFi phone) you are deploying, what minimum RSSI should you plan for in all areas you are monitoring and where VoWiFi service is desired?
What is a radome?
A weatherproof piece of plastic covering an antenna or antenna system.
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?
Location-based services for wireless assets or RFID tags
Given: You are evaluating the theoretical and real-world RF gain benefits of transmit and receive features introduced by 802.11n with MIMO. This exercise allows you to quantify the feature's value in a real-world environment. What is the maximum theoretical signal gain of chip-based TxBF and MRC (as features) when compared to the same AP using only a single antenna for transmit and receive (effectively simulating a 1x1 chip)?
2 Rx or Tx chains = 3 dBi gain 3 Rx or Tx chains = approx 5 dBi gain 4 Rx or Tx chains = 6 dBi gain
Given: For this fill-in the blank question, each answer option contains an answer for the first and second blanks, separated by a dash "--". Choose the answer option that correctly fills in both blanks in the following sentence. A WLAN may use 802.11 admission control to ________, and admission control requirements are configured separately for each ________.
Regulate the available bandwidth resources -- Access Category
You are testing a VoWLAN deployment, and your communication measurements show a certain amount of lost packets. What would be an acceptable packet error rate value to still provide acceptable call quality?
No more than 1% PER max should be acceptable
You are working on a VoWLAN design with your customer's wired networking team. How many distinct priority levels do you expect for the voice applications?
1 priority level for voice RTP, 1 priority level for voice control and RTCP
After surveying for the ideal mounting locations for APs, you have been asked to compromise RF propagation optimization due to aesthetic concerns raised by your customer. In the end, you've decided to mount the APs in the ideal locations and paint the APs so they go unnoticed in the environment. What is a valid recommendation or consideration when painting APs? (Choose 2)
Do not paint the notification LEDs on the AP, but configure them to be dim or turned off altogether until troubleshooting is required.
Painting APs may void the product manufacturer's warranty.
What is the DSCP Per Hop Behavior equivalent classification of the 802.11e AC_VO priority level?
At a university, the WLAN has been successfully deployed for ubiquitous access for faculty, students, and guests. Many student computer labs are available throughout the campus with wired network connectivity, but there are also a few smaller lab areas and workstations where Ethernet cabling is not available. For student wireless use, the students must authenticate against RADIUS/Active Directory using PEAP. Also, the network administrators at this university would like administrative access to these workstations when they are not in use by students so that the administrators can manage group policies, update OS patches, and perform other routine software maintenance. What deployment options are available and recommended for both student use and remote administration of these workstations? (Choose 2)
Machine authentication accounts should be enabled to provide persistent machine network connectivity when student users are not associated.
These workstations should be Ethernet-connected to a wireless client bridge, which will maintain network connectivity independent of student connectivity status.
Given: Assume that music on hold (MOH) features are unicast only. What VoWiFi implementations require multicast packet delivery support by the WLAN infrastructure?
Push-to-Talk VoWiFi phones
Given: As the wireless network administrator for XYZ Company, you are planning to upgrade your aging wireless network infrastructure, as well as some clients, to support 802.11n. In your research, you have discovered that your new wireless client devices and infrastructure are 802.11n, WMM, and WMM-PS certified by the Wi-Fi Alliance. Some of your existing client devices are 802.11a/b/g devices that do not support WMM. Given this information, what scenario is possible when your company's employees begin using both types of client devices on the new WLAN?
Performance and battery life will be inconsistent between WMM-PS and non-WMM-PS client devices when used with applications that support WMM-PS.
You told your customer that multipath fading may be mitigated simply by moving one or both of the receiver's antennas a little bit, usually by one to four wavelengths away from its original position. Your customer is prepared to make the change, but does not know the wavelength for 802.11a. What is the approximate wavelength of an 802.11a radio wave?
5.5 cm (2.16 inches)
Multicast video applications typically require special treatment on the Wi-Fi network due to the nature of multicast traffic. Many vendors implement proprietary multicast-to-unicast conversion for this reason. Which of the following is NOT a valid reason for special unicast conversion of downlink multicast traffic?
Multicast traffic must always be transmitted via omnidirectional antennas.
When performing an indoor predictive site survey to make the WLAN planning and design cycle more efficient, what is a best practice for configuration of the simulated APs in the predictive modeling software?
If dynamic RRM will be used, AP transmit power should be set to an estimated average level of the expected client devices, such as 25 mW.
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?
Given: A WLAN controller is connected to ABC Company's core layer 3 Ethernet switch with an IEEE 802.1Q trunk connection. The WLAN controller's native VLAN is VLAN 6 and its IP address is 10.0.14.2 /24. Lightweight APs supporting centralized forwarding are connected to the network on VLANs 7, 8, and 9, and they each build a layer 3 tunnel back to the WLAN controller's IP address. The dynamically assigned IP addresses received by each AP from a DHCP server will be ________________.
Associated with the VLAN on which they are connected.
What is the purpose of Friis transmission equation [(LdB) = 20 log(d) + 20 log (f) - 27.55 ]?
Calculate RF path loss in free space
An associated STA detects a new BSS with the same SSID as the STA's current BSS. The new BSS uses a different IP subnet than the current BSS. If the STA is configured to use 802.1X/EAP preauthentication, what is likely to occur?
The STA will attempt to preauthenticate, but fail because the new BSS uses a different data-link broadcast domain.
What is the purpose of DHCP Option 43, and how is it used with WLANs?
It supports vendor-specific IP address attributes for node discovery purposes. APs use Option 43 with vendor class identifiers to obtain the IP address of a centralized WLAN controller.
As an implementation engineer, you have just received initial design specs from a network designer for your dual-band 802.11n deployment. The network design documents prescribe the following data rate configuration for the 2.4 GHz radio: Basic Rates -- 5.5, 6, 11, 12 Mbps Supported Rates --9, 18, 24, 36, 48, and 54 Mbps as well as MCS 0-15 What will result from this design strategy?
HR/DSSS (802.11b) stations will not be able to associate to the service set.
You are on site, planning a network at a freight shipping company on a busy harbor. Since the preliminary WLAN design specifies support for the 5 GHz spectrum, you would like to test for radar pulses to determine if DFS channels should be supported at this facility. As a part of your spectral survey with a laptop-based analyzer, you include DFS testing to identify the presence of radar. This is done by manually observing Real-time FFT, Duty Cycle, and Active Devices charts of the spectrum analyzer software. What potential drawback is present with this DFS test method? (Choose 3)
Many WLAN products that support DFS channels report several false positives. Ideally, the actual WLAN equipment used in the deployment should be used to test for DFS.
Some sources of 5 GHz radar, such as military ships, are mobile in nature. A longer, automated test setup should be used to identify the presence or absence of radar.
Manual identification of radar pulses using spectrum analysis charts can be very difficult due to radar's low amplitude at the Wi-Fi receiver.
In a centralized WLAN architecture, what new problem may arise when you change the data forwarding model from centralized to distributed? (Choose 2)
APs that were designed for a centralized forwarding model may not support all features in distributed forwarding mode.
The Ethernet switch ports to which APs are connected may need to be reconfigured to support VLAN tagging and QoS at the network edge.