Which of the following statements correctly describe the differences between half-duplex and full-duplex Ethernet? (Select two a

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问题 Which of the following statements correctly describe the differences between half-duplex and full-duplex Ethernet? (Select two answer choices.)

选项 A、Full-duplex Ethernet uses CSMA/CD to prevent collisions.
B、Half-duplex Ethernet uses a loopback circuit to detect collisions.
C、A full-duplex Ethernet card allows 20Mbps for data transmission.
D、Full-duplex Ethernet makes use of two pairs of wires for data.
E、An Ethernet hub can operate both half and full duplex simultaneously.

答案B,D

解析 Explanation:
Half-duplex Ethernet send and receives on the same line, so a loopback needs to be set to detect collisions. Alternatively, full-duple Ethernet doesn’t have to because it uses two pairs of wire, one to send and the other to receive. Collisions are not possible on full duplex Ethernet networks.

Incorrect Answers:
A. Full duplex uses both pairs of wires, so transmissions are sent on the first pair, and data that is received come in on the other pair. This prevents collisions.

C. Full duplex allows for data to be sent and received at the same time. It will not double the amount of bandwidth at any given time. The speed of the Ethernet link will remain at 10/100.

E. Hubs are shared devices and can only support one mode, unlike switches.
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