CWNA 802.11 Standards & Protocol Architecture 2

Question 1

Which Wi-Fi generation corresponds to the 802.11ax standard?

Accepted Answer

Wi-Fi 6

Answer

802.11ax is branded as Wi-Fi 6 (and Wi-Fi 6E when extended to the 6 GHz band), introducing OFDMA and BSS Coloring.

Question 2

What does the term 'BSS Coloring' introduced in 802.11ax help achieve?

Accepted Answer

Reduce co-channel interference by tagging frames from different BSSs

Answer

BSS Coloring tags frames with a color identifier so devices can distinguish transmissions from overlapping BSSs and reduce unnecessary deferrals.

Question 3

What is the function of the DCF (Distributed Coordination Function) in 802.11?

Accepted Answer

Distributed contention-based channel access used by all stations

Answer

DCF is the fundamental contention-based channel access method in 802.11, using CSMA/CA for all stations to share the medium.

Question 4

Which 802.11 amendment first introduced Quality of Service (QoS) through the WMM (Wi-Fi Multimedia) specification?

Accepted Answer

802.11e

Answer

802.11e introduced the Enhanced Distributed Channel Access (EDCA) mechanism that became the basis for WMM QoS in Wi-Fi.

Question 5

What is the role of the DTIM (Delivery Traffic Indication Message) beacon field?

Accepted Answer

Signal sleeping clients that buffered multicast/broadcast frames are ready

Answer

DTIM beacons alert power-saving clients that multicast or broadcast frames are buffered at the AP and about to be sent.

CWNA - Wireless Network Administrator Practice Test