Which statement best describes devices that can perform both Layer 2 and Layer 3 functions?

• A. Some devices can perform both Layer 2 and Layer 3 functions.
• B. Only routers can perform Layer 2 and Layer 3.
• C. Only switches can perform Layer 2 and Layer 3.
• D. No devices can perform both.

Answer: (A)

The idea being tested is that networking devices can combine Layer 2 switching and Layer 3 routing functionalities in one device. In practice, some devices are designed to handle both levels: a Layer 3 switch, for example, can forward frames within a local network using MAC addresses (Layer 2) and also route traffic between VLANs (Layer 3). Routers can often perform some Layer 2 tasks like bridging or switching local frames as well, while switches can include routing capabilities for inter-VLAN communication. So it’s accurate to say that some devices can perform both Layer 2 and Layer 3 functions.

The other statements are too absolute or incorrect: not only routers can do both, since switches with routing features can too; not only switches can do both, since routers can sometimes handle Layer 2 tasks as well; and no devices can perform both is false because multilayer devices exist.