What type of Media Access Control (MAC) system does Ethernet utilize?

Ethernet utilizes a contention-based Media Access Control (MAC) system, which is designed to handle multiple devices trying to access the same communication channel. In a contention-based system, devices on the network listen for a clear channel before transmitting data. This is commonly implemented using a protocol called Carrier Sense Multiple Access with Collision Detection (CSMA/CD).

When a device wants to send data, it first checks if the network is busy. If it senses that no other device is currently transmitting, it will proceed to send its data. However, since multiple devices can sense the channel at the same time, collisions may occur when two devices transmit simultaneously. The CSMA/CD protocol helps manage these collisions by having devices pause for a random amount of time before attempting to retransmit, thus minimizing repeated collisions.

This method contrasts sharply with token-based MAC systems, where a token circulates on the network, granting permission to transmit to only the device holding the token. Time Division and Frequency Division MAC systems are typically used in other networking technologies and are not characteristic of the Ethernet standard. Hence, the contention-based MAC system is the foundational access method in Ethernet networking, enabling efficient communication among devices.