CWS CWS WLAN Roaming and QoS Questions and Answers 2

Question 1

Which QoS mechanism in 802.11 replaces the legacy DCF for differentiated traffic handling?

Accepted Answer

EDCA (Enhanced Distributed Channel Access)

Answer

EDCA is the contention-based QoS mechanism introduced with 802.11e that provides differentiated channel access for four traffic categories.

Question 2

What roaming threshold metric do most enterprise WLAN controllers use to trigger a client roam?

Accepted Answer

RSSI below a configured dBm threshold

Answer

Enterprise controllers monitor client RSSI and trigger load-balancing or roam suggestions when signal drops below a configured threshold.

Question 3

In 802.11r, what is stored in the PMK-R0 key holder?

Accepted Answer

The top-level fast transition key derived from the master session key

Answer

PMK-R0 is the top-level key in the 802.11r key hierarchy, stored at the R0 Key Holder (typically the WLAN controller).

Question 4

Which TXOP parameter in WMM defines the maximum time a station may transmit after winning channel access?

Accepted Answer

TXOP Limit

Answer

The TXOP Limit sets the maximum duration a station can hold the channel and transmit a burst of frames after winning the contention.

Question 5

What is the primary benefit of deploying both 802.11k and 802.11v together in an enterprise WLAN?

Accepted Answer

Clients receive neighbor reports AND network-assisted roaming suggestions for seamless handoffs

Answer

802.11k provides neighbor lists and 802.11v enables the network to direct clients to better APs, together enabling intelligent, low-latency roaming.

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