Which layer of the OSI model does the Ethernet MAC sublayer operate in?

The Ethernet MAC (Media Access Control) sublayer operates within the Data Link layer of the OSI model. This layer is responsible for node-to-node data transfer and handles access to the physical transmission medium. The MAC sublayer specifically manages how packets are placed on the network and the addressing and control of the data frames.

In the context of Ethernet, the MAC address is used to identify devices on the same network segment, allowing for the control of how frames are transmitted and ensuring that data is sent and received correctly between devices. By operating in the Data Link layer, the MAC sublayer plays a crucial role in coordinating access to the shared medium, which is essential for preventing collisions when multiple devices attempt to transmit over the same network segment.

The other layers listed, such as the Network layer, Physical layer, and Transport layer, serve different functions, including routing of packets, physical signaling, and end-to-end communication, respectively. However, they do not encompass the responsibilities of managing how data frames are transmitted over the Ethernet network, which is why the Data Link layer is the correct answer.