Which feature identifies devices on a local network at layer 2?

The feature that identifies devices on a local network at layer 2 is MAC addressing. This is because the Media Access Control (MAC) address operates at the Data Link layer of the OSI model, which is layer 2. Each device on a local network is assigned a unique MAC address that identifies it on the network, enabling communication and data transfer between devices.

In contrast, IP addressing operates at layer 3 of the OSI model, which is responsible for routing packets across networks rather than within a local segment. Subnetting, which involves dividing a larger network into smaller, manageable segments, also relies on layer 3 IP addressing for efficient routing. Routing itself pertains to the process of directing network traffic between different networks, primarily functioning at layer 3 and thereby not focusing on local identification of devices. Thus, MAC addressing is specifically designed for layer 2 network identification, distinguishing it from the other options.