Answer

A network switch is a Data Link-layer device that connects devices within a LAN and forwards Ethernet frames based on MAC addresses.

Working

A switch learns the source MAC address of incoming frames and associates it with the receiving port in its MAC/forwarding table. When a frame arrives, it checks the destination MAC address:

• If the destination is known, it forwards the frame only through the appropriate port.
• If unknown, it floods the frame within the relevant LAN/VLAN.

Advantages

Switches reduce unnecessary traffic and allow multiple devices to communicate simultaneously using separate switch ports.

Exam-ready: A switch is a multiport Data Link-layer device that forwards frames using MAC addresses.