With regard to Ethernet media access methods, which of the following are true? (Choose all that apply.)

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问题 With regard to Ethernet media access methods, which of the following are true?
(Choose all that apply.)

选项 A、A device waits for an electronic signal before transmitting.
B、A device listens and waits until the media is not busy before transmitting.
C、All devices on an Ethernet segment see data that passes on the network medium.
D、Only the sender and the receiver devices see data that passes on the network medium.
E、Ethernet networks allow you to configured devises with higher transmission priority.

答案B,C

解析 Explanation:
Ethernet uses the CSMA/CD access method.
CSMA/CD logic helps prevent collisions and also defines how to act when a collision does occur. The CSMA/CD algorithm words like this:
1. A device with a frame to send listens until the Ethernet is not busy.
2. When the Ethernet is not busy, the sender begins sending the frame.
3. The sender listens to make sure that no collision occurred.
4. Once the senders hear the collision, they each send a jamming signal, to ensure that all stations recognize the collision.
5. After the jamming is complete, each sender randomizes a timer and waits that long.
6 When each timer expires, the process starts over with Step 1.
So, all devices on the Ethernet need to use CSMA/CD to avoid collisions and to recover when inadvertent collisions occur.
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