CWS CWS Wireless Client Devices 4 — Questions and Answers
Question 1: Which 802.11ax (Wi-Fi 6) feature allows an AP to schedule specific wake times for client devices, significantly improving battery life for IoT clients?
- MU-MIMO
- OFDMA
- Target Wake Time (TWT) (Correct answer)
- BSS Coloring
Correct answer: Target Wake Time (TWT)
TWT allows devices to negotiate scheduled sleep and wake intervals with the AP, dramatically reducing power consumption.
Question 2: A wireless client NIC supports 2×2:2 MIMO. What does the last number '2' indicate?
- Maximum MCS index
- Number of spatial streams (Correct answer)
- Number of antennas
- Channel bandwidth in tens of MHz
Correct answer: Number of spatial streams
In the TxR:S notation, S (the last number) represents the number of supported spatial streams.
Question 3: Which client capability allows it to receive data from multiple APs simultaneously in an 802.11 network (multi-link operation)?
- 802.11r Fast BSS Transition
- 802.11ax OFDMA
- 802.11be Multi-Link Operation (MLO) (Correct answer)
- 802.11k Neighbor Reports
Correct answer: 802.11be Multi-Link Operation (MLO)
MLO, introduced in 802.11be (Wi-Fi 7), allows a client to simultaneously transmit and receive across multiple frequency bands or channels.
Question 4: When a client performs an 802.11r Fast BSS Transition, what is the primary benefit compared to a standard reassociation?
- Higher data rates after roaming
- Reduced roaming latency by pre-establishing keys at the target AP (Correct answer)
- Elimination of the need for WPA2
- Support for legacy WEP clients
Correct answer: Reduced roaming latency by pre-establishing keys at the target AP
802.11r pre-authenticates and pre-derives keys at the target AP, reducing roam time from hundreds of milliseconds to tens.
Question 5: A client device supports WPA3-Enterprise 192-bit mode. Which cipher suite does this mandate?
- AES-128-CCM
- TKIP
- GCMP-256 with SHA-384 (Correct answer)
- WEP-104
Correct answer: GCMP-256 with SHA-384
WPA3-Enterprise 192-bit security mode requires GCMP-256 encryption and SHA-384 for HMAC, aligned with CNSA suite requirements.
Question 6: What information does a wireless client obtain from an 802.11k Neighbor Report?
- The AP's IP address and DHCP server location
- A list of nearby APs with channel and BSSID information to assist roaming decisions (Correct answer)
- The current channel utilization percentage
- The RADIUS server address
Correct answer: A list of nearby APs with channel and BSSID information to assist roaming decisions
802.11k Neighbor Reports give clients a list of candidate APs (BSSID, channel, RSSI) so they can roam without performing a full scan.
Question 7: Which wireless client behavior is described as 'transmit power control' (TPC)?
- The client adjusting its output power based on AP instructions or distance to reduce interference (Correct answer)
- The client boosting power to maximum when RSSI drops below -70 dBm
- The AP controlling which channel the client uses
- The client selecting the highest MCS rate automatically
Correct answer: The client adjusting its output power based on AP instructions or distance to reduce interference
TPC allows clients to reduce transmit power based on AP feedback, minimizing co-channel interference with neighboring cells.
CWS CWS Wireless Client Devices 4
Which 802.11ax (Wi-Fi 6) feature allows an AP to schedule specific wake times for client devices, significantly improving battery life for IoT clients?