CWS CWS Wireless Client Devices 2 — Questions and Answers
Question 1: Which Wi-Fi client power-saving mechanism allows an access point to buffer frames for a sleeping client and deliver them upon request?
- Active Mode (AM)
- Legacy Power Save (PS-Poll) (Correct answer)
- WMM-Power Save (U-APSD)
- Target Wake Time (TWT)
Correct answer: Legacy Power Save (PS-Poll)
Legacy Power Save uses PS-Poll frames to request buffered unicast data from the AP after waking.
Question 2: A wireless client associates but cannot obtain an IP address. The most likely Layer 2 issue to investigate first is:
- Incorrect SSID passphrase
- 4-Way Handshake failure (Correct answer)
- DHCP server misconfiguration
- Incorrect DNS suffix
Correct answer: 4-Way Handshake failure
A failed 4-Way Handshake prevents successful association completion, blocking all traffic including DHCP.
Question 3: What is the primary purpose of the 802.11 Probe Request frame sent by a wireless client?
- To authenticate with an AP
- To actively discover available BSSs (Correct answer)
- To request an IP address
- To negotiate QoS parameters
Correct answer: To actively discover available BSSs
Probe Requests are sent by clients to actively scan for SSIDs and gather AP capability information.
Question 4: Which client device setting controls how aggressively the client roams away from an AP with a degrading signal?
- Transmit power level
- Roaming aggressiveness / sensitivity (Correct answer)
- Channel bandwidth
- Short guard interval toggle
Correct answer: Roaming aggressiveness / sensitivity
Roaming aggressiveness (or sensitivity) determines the RSSI threshold at which a client will scan and reassociate to a better AP.
Question 5: A dual-band 802.11ac client is connected to a 2.4 GHz radio. What feature could the AP use to encourage the client to use the 5 GHz band?
- Band steering (Correct answer)
- MU-MIMO
- OFDMA
- Beamforming
Correct answer: Band steering
Band steering techniques (e.g., delaying Probe Responses on 2.4 GHz) encourage capable clients to associate on 5 GHz.
Question 6: Which frame type does a wireless client transmit to gracefully disconnect from an AP?
- Disassociation frame (Correct answer)
- Deauthentication frame
- Null data frame with power management bit set
- RTS frame
Correct answer: Disassociation frame
A Disassociation frame is sent by the client to terminate the association while keeping the authentication state.
Question 7: What does the term 'sticky client' describe in a Wi-Fi environment?
- A client that frequently changes SSIDs
- A client that remains associated to a far or weak AP instead of roaming to a closer one (Correct answer)
- A client using MFP (Management Frame Protection)
- A client that only supports 2.4 GHz
Correct answer: A client that remains associated to a far or weak AP instead of roaming to a closer one
A sticky client fails to roam to a closer or stronger AP, degrading its own throughput and potentially affecting channel airtime.
CWS CWS Wireless Client Devices 2
Which Wi-Fi client power-saving mechanism allows an access point to buffer frames for a sleeping client and deliver them upon request?