For the IEEE 802.11 MAC protocol for wireless communication, which of the…
2016
For the IEEE 802.11 MAC protocol for wireless communication, which of the following statements is/are TRUE?
I. At least three non-overlapping channels are available for transmissions.
II. The RTS-CTS mechanism is used for collision detection.
III. Unicast frames are ACKed.
- A.
All I, II, and III
- B.
I and III only
- C.
II and III only
- D.
II only
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Correct answer: B
Answer: I and III are true; II is false.
I (At least three non-overlapping channels): True — In the 2.4 GHz band commonly used by 802.11b/g/n, there are at least three non-overlapping channels (typically channels 1, 6, and 11).
II (RTS–CTS for collision detection): False — RTS–CTS is a collision-avoidance mechanism used to mitigate hidden-node problems; it is not a collision-detection method.
III (Unicast frames are ACKed): True — Unicast MAC frames are acknowledged by the receiver using ACK frames to provide reliability at the MAC layer.
Therefore, the correct choice includes the statements that at least three non-overlapping channels are available (I) and that unicast frames are acknowledged (III).
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