CISCOCCNA认证考试640-810题库原题9

　　a. half-duplex ethernet operates in a shared collision domain.

　　b. half-duplex ethernet operates in a private collision domain.

　　c. half-duplex ethernet has higher effective throughput.

　　d. half-duplex ethernet has lower effective throughput.

　　e. half-duplex ethernet operates in a private broadcast domain.

　　answer: a d

　　explanation:

　　a single device could not be sending a frame and receiving a frame at the same time because it would mean that a collision was occurring. so, devices simply chose not to send a frame while receiving a frame. that logic is called half-duplex logic.

　　ethernet switches allow multiple frames to be sent over different ports at the same time. additionally, if only one device is connected to a switch port, there is never a possibility that a collision could occur. so, lan switches with only one device cabled to each port of the switch allow the use of full-duplex operation. full

　　duplex means that an ethernet card can send and receive concurrently.