In the 802.11 frame, the value used to record the network allocation vector (NAV) is?

Question

Options

• AFrame Control
• BDuration
• Caddress bits
• DSequence Control Bits

• A
  2% (1)
• B
  72% (33)
• C
  9% (4)
• D
  17% (8)

Explanation

Option B is correct because the Duration field in the 802.11 frame header carries the NAV value, expressed in microseconds. The NAV is a virtual carrier-sensing mechanism that informs neighboring stations how long the wireless medium will be occupied, allowing them to defer transmission without physically monitoring the channel.

Frame Control (A) contains metadata about the frame itself - its type, subtype, and protocol flags - and has nothing to do with medium reservation timing. The address fields (C) hold MAC addresses for source, destination, BSSID, and relay purposes, not timing values. Sequence Control (D) manages frame ordering and fragmentation reassembly, which is unrelated to channel access timing.

Memory tip: "Duration" answers the question "how long?" - and the NAV is precisely a timer telling stations how long to stay off the medium. If you associate Duration with "duration of channel occupation," the link to NAV becomes natural.

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