Which device forwards frames within a LAN based on MAC addresses?

Which device forwards frames within a LAN based on MAC addresses?

• A. Hub broadcasts all frames to every port with no filtering.
• B. Router connects networks and routes traffic.
• C. Switch forwards frames within a LAN based on MAC addresses.
• D. Bridge filters packets using VLANs.

Answer: (C)

Frames on a LAN are delivered using MAC addresses. A switch learns which MAC addresses can be reached via which ports by inspecting the source address of arriving frames, building a MAC address table that maps each MAC to a specific port. When a frame arrives with a destination MAC that’s in the table, the switch forwards it only to the corresponding port, keeping other ports quiet. If the destination isn’t yet known, the switch floods the frame to all ports in the LAN to learn where the destination resides. This MAC-based forwarding is what makes a switch the device that efficiently moves frames within a single LAN. Hubs don’t filter at all; they broadcast every frame to all ports. Routers operate at the network layer and move traffic between different networks, not within the same LAN based on MACs. Bridges can forward based on MAC addresses too, but modern networks rely on switches for this function, and switches add VLAN functionality to segment networks.

Frames on a LAN are delivered using MAC addresses. A switch learns which MAC addresses can be reached via which ports by inspecting the source address of arriving frames, building a MAC address table that maps each MAC to a specific port. When a frame arrives with a destination MAC that’s in the table, the switch forwards it only to the corresponding port, keeping other ports quiet. If the destination isn’t yet known, the switch floods the frame to all ports in the LAN to learn where the destination resides. This MAC-based forwarding is what makes a switch the device that efficiently moves frames within a single LAN.

Hubs don’t filter at all; they broadcast every frame to all ports. Routers operate at the network layer and move traffic between different networks, not within the same LAN based on MACs. Bridges can forward based on MAC addresses too, but modern networks rely on switches for this function, and switches add VLAN functionality to segment networks.