What statement about the IEEE 802.11-2016 QoS facility is true?

Question

Options

• A802.11 control frames are assigned to the 802.11 EF priority queue.
• BWhen the Voice queue has frames awaiting transmission, no data will be transmitted from the
• C802.11 QoS is achieved by giving high priority queues a statistical advantage at winning
• DFour 802.1p user priorities are mapped to eight 802.11 transmit queues.

• A
  4% (1)
• B
  4% (1)
• C
  75% (18)
• D
  17% (4)

Explanation

802.11 QoS is achieved by giving high priority queues a statistical advantage at winning contention. 802.11 QoS is based on the Enhanced Distributed Channel Access (EDCA) mechanism, which defines four access categories (ACs) for different types of traffic: Voice, Video, Best Effort, and Background. Each AC has its own transmit queue and contention parameters, such as Arbitration Interframe Space (AIFS), Contention Window (CW), and Transmission Opportunity (TXOP). These parameters determine how long a station has to wait before transmitting a frame and how long it can occupy the channel. Higher priority ACs have shorter AIFS, smaller CW, and longer TXOP, which means they have more chances to access the channel and send more data than lower priority ACs. However, this does not guarantee that higher priority ACs will always win the contention, as there is still a random backoff process involved. Therefore, 802.11 QoS is a statistical service that provides different levels of service quality based on traffic categories.

No community discussion yet for this question.