Which device forwards frames using a MAC address table to deliver them to the correct port?

Which device forwards frames using a MAC address table to deliver them to the correct port?

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

Answer: (D)

The key idea is learning and using a MAC address table to forward frames only to the correct port. A switch creates a table that maps each device’s MAC address to the port where that device is reachable. As frames arrive, the switch notes the source MAC and the port it came from, building and updating this table. When a frame needs to be sent, the switch looks up the destination MAC; if it already knows which port has that device, it forwards the frame only to that specific port. If the destination MAC isn’t in the table yet, the switch floods the frame to all ports (except the incoming one) to learn the location. This behavior makes switches efficient at delivering frames and reduces unnecessary traffic, while also segmenting collision domains. Hubs simply repeat signals to all ports without learning addresses, so they can’t deliver to a specific device. Routers operate at Layer 3 using IP addresses and route between networks, not based on a MAC table for local delivery. Bridges can perform MAC-based forwarding on smaller scales, but switches are the more capable, multi-port evolution that routinely uses a MAC address table to deliver to the right port.

The key idea is learning and using a MAC address table to forward frames only to the correct port. A switch creates a table that maps each device’s MAC address to the port where that device is reachable. As frames arrive, the switch notes the source MAC and the port it came from, building and updating this table. When a frame needs to be sent, the switch looks up the destination MAC; if it already knows which port has that device, it forwards the frame only to that specific port. If the destination MAC isn’t in the table yet, the switch floods the frame to all ports (except the incoming one) to learn the location.

This behavior makes switches efficient at delivering frames and reduces unnecessary traffic, while also segmenting collision domains. Hubs simply repeat signals to all ports without learning addresses, so they can’t deliver to a specific device. Routers operate at Layer 3 using IP addresses and route between networks, not based on a MAC table for local delivery. Bridges can perform MAC-based forwarding on smaller scales, but switches are the more capable, multi-port evolution that routinely uses a MAC address table to deliver to the right port.