CWT CWT Wireless Client Management & QoS 1 — Questions and Answers
Question 1: What is the 802.11 association process, and what is the correct sequence of steps for a client to join a BSS?
- Authentication → Association → DHCP
- DHCP → Authentication → Association
- Scanning → Authentication → Association (Correct answer)
- Association → Authentication → Scanning
Correct answer: Scanning → Authentication → Association
A Wi-Fi client first scans for networks, then authenticates with the AP, and finally completes the association process before exchanging data frames.
Question 2: What is 802.11r (Fast BSS Transition) and how does it benefit wireless clients?
- A standard for higher data rates on 5 GHz
- A roaming protocol that pre-authenticates clients with neighboring APs to reduce handoff latency (Correct answer)
- A power-saving protocol that turns off radios between beacons
- A security standard requiring WPA3 encryption
Correct answer: A roaming protocol that pre-authenticates clients with neighboring APs to reduce handoff latency
802.11r enables fast BSS transition by pre-authenticating clients with neighboring APs, significantly reducing the roaming handoff time to support real-time applications.
Question 3: What is the purpose of WMM (Wi-Fi Multimedia) in a wireless network?
- To increase the physical data rate of 802.11ac networks
- To provide Quality of Service by prioritizing traffic into four access categories (voice, video, best effort, background) (Correct answer)
- To encrypt multimedia streams using AES
- To allow APs to stream video directly to clients
Correct answer: To provide Quality of Service by prioritizing traffic into four access categories (voice, video, best effort, background)
WMM (based on 802.11e) defines four traffic access categories that prioritize voice and video packets over less time-sensitive data and background traffic.
Question 4: What is the difference between active and passive scanning by a wireless client?
- Active scanning transmits probe requests on each channel; passive scanning listens for beacon frames (Correct answer)
- Passive scanning is faster than active scanning
- Active scanning only works on 5 GHz; passive only works on 2.4 GHz
- There is no functional difference in the scan results
Correct answer: Active scanning transmits probe requests on each channel; passive scanning listens for beacon frames
In active scanning, clients broadcast probe requests and wait for probe responses, while passive scanning simply listens for AP beacon frames without transmitting.
Question 5: What is BSS coloring in 802.11ax (Wi-Fi 6) and how does it improve network efficiency?
- A visual scheme for color-coding SSIDs in management dashboards
- A mechanism that tags frames with a BSS identifier so devices can distinguish overlapping networks and reduce unnecessary deferrals (Correct answer)
- A channel bonding technique unique to 6 GHz
- An encryption color code used for WPA3 key exchange
Correct answer: A mechanism that tags frames with a BSS identifier so devices can distinguish overlapping networks and reduce unnecessary deferrals
BSS coloring assigns a color (numerical tag) to each BSS so that clients can recognize transmissions from overlapping networks and avoid deferring unnecessarily, improving spatial reuse.
Question 6: What does the term 'sticky client' describe in a Wi-Fi network, and what is the impact on performance?
- A client that caches too much local data
- A client that remains associated to a distant or weak AP instead of roaming to a stronger one nearby (Correct answer)
- A client configured with a static IP address
- A device that broadcasts excessive ARP requests
Correct answer: A client that remains associated to a distant or weak AP instead of roaming to a stronger one nearby
A sticky client holds onto its current AP association even when a closer AP offers a stronger signal, resulting in poor throughput and degraded experience.
CWT CWT Wireless Client Management & QoS 1
What is the 802.11 association process, and what is the correct sequence of steps for a client to join a BSS?