Which device is primarily used to connect multiple devices within a LAN and forwards frames based on MAC addresses?

• A. Router
• B. Switch
• C. Bridge
• D. Hub

Answer: (B)

A switch is used to connect multiple devices within a LAN and forwards frames based on MAC addresses. It learns the MAC addresses of devices by inspecting the source address of frames that arrive on each port and builds a MAC address table. When a frame with a known destination MAC arrives, the switch sends it only to the port associated with that MAC, which keeps traffic confined to the correct path and reduces collisions. If the destination MAC isn’t yet in the table, the switch floods the frame to all ports so the destination can respond and the switch can learn its location. This MAC-based forwarding is what makes switching efficient for single-LAN networks. In contrast, a hub blindly repeats signals to all ports, a bridge is an older, simpler form of the same idea with fewer ports, and a router routes between different networks using IP addresses rather than MAC addresses.