CWT CWT Wireless Client Management & QoS 2 — Questions and Answers
Question 1: What is DSCP marking and how is it used to preserve QoS across a wireless and wired network?
- A method of physically labeling Ethernet cables by priority
- A per-packet tagging mechanism in the IP header that indicates traffic priority for QoS treatment across network devices (Correct answer)
- A Wi-Fi-only signaling method that does not translate to wired networks
- An encryption method used in WPA2-Enterprise
Correct answer: A per-packet tagging mechanism in the IP header that indicates traffic priority for QoS treatment across network devices
DSCP (Differentiated Services Code Point) marks IP packets with a priority value that routers, switches, and wireless controllers use to apply consistent QoS treatment end-to-end.
Question 2: What is the purpose of band steering in a dual-band wireless network?
- Steering all clients to use only WPA3 authentication
- Encouraging capable clients to connect on the less congested 5 GHz band instead of the 2.4 GHz band (Correct answer)
- Physically redirecting antenna beams toward clients
- Assigning static channels to specific client devices
Correct answer: Encouraging capable clients to connect on the less congested 5 GHz band instead of the 2.4 GHz band
Band steering uses RSSI thresholds and probe response manipulation to guide dual-band capable clients to the typically faster and less congested 5 GHz band.
Question 3: A VoIP call over Wi-Fi requires low latency and low jitter. Which WMM access category should voice traffic be mapped to?
- AC_BK (Background)
- AC_BE (Best Effort)
- AC_VI (Video)
- AC_VO (Voice) (Correct answer)
Correct answer: AC_VO (Voice)
VoIP traffic should be mapped to the AC_VO (Voice) WMM access category, which has the highest priority and shortest contention windows for minimum latency.
Question 4: What is the 802.11k standard and how does it assist with client roaming?
- It defines WPA3 security requirements for enterprise networks
- It provides clients with a neighbor report of nearby APs so they can make faster, more informed roaming decisions (Correct answer)
- It enables mesh backhaul between access points
- It specifies power-save mechanisms for battery-powered devices
Correct answer: It provides clients with a neighbor report of nearby APs so they can make faster, more informed roaming decisions
802.11k (Radio Resource Management) allows APs to provide clients with neighbor reports listing nearby APs, reducing the scan time needed before a roaming decision.
Question 5: What is the role of a wireless LAN controller (WLC) in managing client associations in a centralized deployment?
- The WLC assigns IP addresses directly to all wireless clients
- The WLC centralizes AP configuration, enforces policies, and can manage load balancing and roaming decisions across all APs (Correct answer)
- The WLC replaces the DHCP server in all enterprise networks
- The WLC only manages security certificates and has no role in client association
Correct answer: The WLC centralizes AP configuration, enforces policies, and can manage load balancing and roaming decisions across all APs
A WLC centralizes management of lightweight APs, enabling consistent policy enforcement, coordinated roaming, and load balancing across the entire wireless infrastructure.
Question 6: What is airtime fairness and how does it improve the performance of mixed-speed wireless networks?
- Equally splitting data throughput among all clients regardless of signal quality
- Allocating equal transmission time to each client so that slow legacy clients don't monopolize the wireless medium (Correct answer)
- Ensuring all clients connect at the same data rate by limiting faster clients
- A feature that equally shares encryption keys among clients
Correct answer: Allocating equal transmission time to each client so that slow legacy clients don't monopolize the wireless medium
Airtime fairness gives each client an equal share of transmission time rather than equal data throughput, preventing slower legacy clients from disproportionately occupying the channel.
CWT CWT Wireless Client Management & QoS 2
What is DSCP marking and how is it used to preserve QoS across a wireless and wired network?