Layer 2 forwarding within a local network

Layer 2 forwarding within a local network

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

Answer: (B)

Layer 2 forwarding uses MAC addresses to move frames within a local network. A switch is designed for this role: it builds a MAC address table by listening to each frame’s source address and the port it arrives on. With that knowledge, it forwards a frame destined for a known MAC only to the specific port where that device can be reached. If the destination MAC isn’t yet in the table, the switch sends the frame to all ports (except the source) so the destination can respond and the address can be learned. This targeted forwarding reduces unnecessary traffic and creates separate collision domains per port, improving efficiency compared to devices that don’t inspect MAC addresses. In contrast, a hub or a repeater operates at Layer 1 and simply repeats signals to all ports, keeping a single shared collision domain. A router works at Layer 3 and routes traffic between different networks using IP addresses, not for forwarding within a single LAN.

Layer 2 forwarding uses MAC addresses to move frames within a local network. A switch is designed for this role: it builds a MAC address table by listening to each frame’s source address and the port it arrives on. With that knowledge, it forwards a frame destined for a known MAC only to the specific port where that device can be reached. If the destination MAC isn’t yet in the table, the switch sends the frame to all ports (except the source) so the destination can respond and the address can be learned. This targeted forwarding reduces unnecessary traffic and creates separate collision domains per port, improving efficiency compared to devices that don’t inspect MAC addresses.

In contrast, a hub or a repeater operates at Layer 1 and simply repeats signals to all ports, keeping a single shared collision domain. A router works at Layer 3 and routes traffic between different networks using IP addresses, not for forwarding within a single LAN.