CWNA-106 Certified Wireless Network Administrator Questions and Answers

Itemized list of equipment, licenses, and support contracts required for the facility

RF heat map illustrating coverage and signal quality for each frequency band

Documentation proving proper entry of wall material types into the site survey software

Documentation noting where each access point will be placed and how it will be mounted

Documentation noting how each WLAN user group will authenticate to the network

dBm

W

dB

mW

VSWR

VHT TXOP power save allows stations to enter sleep mode and legacy Power Save does not.

VHT TXOP power save uses the partial AID in the preamble to allow clients to identify frames targeted for them.

Legacy Power Save mode was removed in the 802.11ac amendment.

VHT TXOP power save allows the WLAN transceiver to disable more components when in a low power state.

The power output from the radio into the RF cable

The power output from the radio after cable losses

The highest RF signal strength that is transmitted from a given antenna

Reflected power due to an impedance mismatch in the signal path

Power supplied from the transmission line to the antenna input

RF pre-deployment planning and post-deployment reporting of access point locations on a floor plan

Performance and security monitoring of WLAN controllers with alarms and notifications for administrative staff

Radio management, fast roaming, key caching, and other centralized control plane operations

Centralized bridging of guest data traffic and application of firewall and QoS policies to data

Management of WLAN controller configuration and provisioning of firmware updates

Generating, encrypting, and decrypting 802.11 frames and collecting RF radio data.

Use of the latest 802.11ac equipment

Business justification

User productivity impact

Antenna types

Defining RF channels for use

256-QAM

Distributed Coordination Function (DCF)

Phase Shift Keying (PSK)

Transmit Power Control (TPC)

Radio Resource Management (RRM)

Dynamic Frequency Selection (DFS)

During the association, the client and AP agree to use the same transmit rate, but either station can request a change at any time after the association.

The client and AP each choose the optimal data rate to use independently of one another, based on their own measurements related to the RF link.

The client and AP may use different transmit rates, but the AP determines the data rate that will be used by each client station in the BSS.

The client and AP may use different transmit rates, but the client determines the data rate that it will use and the data rate that the AP will use when communicating to the client.

The client and AP may use a different transmit rates, but the transmit rate is determined by the peer station, based on the peer’s experience of the RF link.

Fresnel Zone size

Maximum input power

Beamwidth

Impedance

VSWR Ratio

Verify that RF signals from XYZ Company’s APs are not penetrating outside the perimeter of the building.

Determine how much signal strength is passing between floors.

Locate wiring closets on each floor occupied by XYZ Company.

Identify security best practice violations on neighboring WLANs.

Verify that XYZ Company’s APs are not directly above or below APs on adjacent floors.

HR/DSSS (802.11b)

OFDM (802.11a)

ERP (802.11g)

HT (802.11n)

CCK (802.11b)

VHT (802.11ac)

Access points broadcast Beacons on all channels of each radio within the regulatory domain. Nearby client stations record information found in the Beacons for use in the association process.

Client stations broadcast Probe Request frames on all supported channels in the regulatory domain. Nearby access points respond with Probe Response frames. Client stations record information in the Probe Response frames for use in the association process.

Client stations broadcast Probe Request frames on the single channel for which they are programmed. Nearby access points respond on that channel with Probe Response frames. Client stations record information found in the Probe Response frames for use in the association process.

Access points broadcast Beacons on a single channel for which they are programmed. Nearby client stations listen for Beacon frames and record information found in the Beacons for use in the association process.

CCMP, TKIP

802.1X/EAP, WEP

TLS, SSL

CCKM, WEP

RC5, RC4

Client stations would see two different sets of AP capabilities as they roam between APs with the same BSSID.

The added range of 802.11n APs would cause additional co-channel interference.

The additional beacon material in 802.11n beacons would confuse 802.11b/g client stations.

Beacons from 802.11n APs use 40 MHz channels, while beacons from 802.11g APs use 20 MHz channels.

MU-MIMO

Inverse square law

Path spread phenomenon

Fresnel zone thinning

Ohm’s law

9 Mbps

11 Mbps

12 Mbps

54 Mbps

65 Mbps

130 Mbps

Alternates between awake and dozing, depending on its need to transmit and receive information

Enters a low-power radio state until it receives a WMM PS-Poll frame from the AP

Experiences higher throughput and lower latency than when operating in Active mode

Powers down a subset of MIMO radio chains and transmits information at a slower data rate

Buffers frames destined to the low-power AP until the AP wakes its radio and begins beaconing again

Performing protocol analysis with a single wireless adapter that is scanning all channels in use

Testing a constant conversation or handset tone while roaming from area to area, or performing an active survey

Configuring DSCP-to-802.11e QoS maps on the handset for each access category.

Verifying the VHT functionality to handle the call volume incurred by a single VoIP phone call.

What data cabling is currently installed in the rooms and throughout the hotel?

How much RF loss do you expect between hotel rooms?

Who installed your existing wired network?

What types of applications will be used by the hotel staff?

On what frequency do the microwave ovens operate in the hotel suites?

Application Layer protocol availability analysis results

Layer 4 protocol availability analysis results

Capacity analysis results

WAN interface analysis results

Distributed Radiation

Active Amplification

Beam Compression

Passive Gain

RF Flooding

An impedance mismatch in the RF cables and connectors

Reflected direct current (DC) voltage on the main RF signal line

Attenuation of the RF signal as it travels along the main signal path

Crosstalk (inductance) between adjacent RF conductors

Mounting a lightning arrestor to a grounding rod

Mounting an omnidirectional antenna to a mast

Mounting an RF amplifier to a dipole antenna

Mounting a PoE injector to a perforated radome

Mounting an access point to a site survey tripod

Dynamic Rate Switching

Multirate Control

Modulation and Coding Selection

Rate Set Selectivity

Adaptive Rate Management

Any 802.11 protocol analyzer can see the SSID in clear text in frames other than Beacons and Probe Response frames. This negates any security benefit of trying to hide the SSID in Beacons and Probe Response frames.

This security practice prevents manufacturers’ client utilities from detecting the SSID. As a result, the SSID cannot be obtained by attackers, except through social engineering, guessing, or use of a WIPS.

Although it does not benefit the security posture, hiding the SSID in Beacons and Probe Response frames can be helpful for preventing some users (such as guests) from attempting to connect to the corporate network.

Any tenants in the same building using advanced penetration testing tools will be able to obtain the SSID by exploiting WPA EAPOL-Key exchanges. This poses an additional risk of exposing the WPA key.

To improve security by hiding the SSID, the AP and client stations must both be configured to remove the SSID from association request and response frames. Most WLAN products support this.

Up to 30 watts of power may be provided through an Ethernet cable.

By using CAT3 cabling, you can increase the maximum draw available to the PD.

When using CAT5 cabling, you decrease the maximum draw available to the PD.

Only endpoint PSEs are supported.

Only midspan PSEs are supported.

Client devices ignore the TIM field and automatically send PS-Poll frames after every beacon.

After each beacon, the AP attempts to empty its frame buffer by sending Wake-on-WLAN frames to wake each dozing client.

Request-to-Send and Clear-to-Send frame exchanges are used to trigger the delivery of buffered data.

The Beacon interval is changed from the default 100 time units to 10 or less time units.

Clients send null data frames to the AP and switch the power management bit from 1 to 0 to receive queued data.

Stations send a CTS-to-self frame to the AP with a very long duration period so they can receive all of their buffered data at once.

Fade Margin is an additional pad of signal strength designed into the RF system to compensate for unpredictable signal fading.

The Fade Margin of a long-distance radio link should be equivalent to the receiver’s antenna gain.

A Fade Margin is unnecessary on a long-distance RF link if more than 80% of the first Fresnel zone is clear of obstructions.

The Fade Margin is a measurement of signal loss through free space, and is a function of frequency and distance.

14 channels are available worldwide.

11 channels are available worldwide.

Regulatory domains worldwide require DFS and TPC in all these channels.

DFS may be required in some regulatory domains on some channels.

802.11 channels are separated by 5 Mhz

All ports on the Ethernet switch will be supporting Class 3 PoE powered devices.

Some APs are connected to a PoE switch and are also receiving power from an AC outlet.

The Ethernet switch uplink ports are not connected to an 802.3-2012, Clause 33-compliant core or distribution Ethernet switch.

A gigabit Ethernet switch port supporting an 802.11a/g AP auto-negotiates to 100 Mbps.

The installation team is not informed that PoE support will reduce the recommended maximum UTP cabling length from 100m to 50m.

Increase in downlink (transmitted by AP) frame retries

High retransmission count for a subset of client stations

Use of frame fragmentation with fragment bursts

Excessive use of null data frames

Duration values vary widely in each data frame

802.11ad compatibility

TPC support

Impedance in Ohms

Elevation Beamwidth

Return Loss Rating

Operating Frequencies

Coverage analysis to verify appropriate coverage and roaming boundaries

Spectrum analysis to locate and identify RF interference sources

Frequency-band hopping analysis to detect improper RF channel implementations

Protocol analysis to discover channel use on neighboring APs

Application analysis with an active phone call on a VoWiFi handset