Cisco CCNA mock exam questions sample test – Question 216

.Which media access control method is used by Ethernet technology to minimize collisions in the network?

A. CSMA/CD
B. token passing
C. back-on algorithm
D. full-duplex


Correct Answer: A

Explanation:
Carrier Sense Multiple Access – Collision Detection (CSMA/CD) is used by Ethernet technology to minimize collisions in the network. The CSMA/CD method uses a back-off algorithm
to calculate random time for retransmission after a collision. When two stations start transmitting at the same time, their signals will collide. The CSMA/CD method detects the
collision, and both stations hold the retransmission for a certain amount of time that is determined by the back-off algorithm. This is an effort to help ensure that the retransmitted
frames do not collide.
Token passing is used by the token-ring network topology to control communication on the network.
Full-duplex is the Ethernet communication mode that allows workstation to send and receive simultaneously. With the use of full-duplex, the bandwidth of the station can effectively be
doubled. Hubs are not capable of handling full-duplex communication. You need dedicated switch ports to allow full-duplex communication.
The back-on algorithm is an invalid option. There is no such contention method.
Objective:
LAN Switching Fundamentals
Sub-Objective:
Describe and verify switching concepts
References:
Cisco Documentation > Internetworking Technology Handbook > Ethernet Technologies