Which device is commonly used to connect networks and forward packets based on IP addresses at Layer 3?

Which device is commonly used to connect networks and forward packets based on IP addresses at Layer 3?

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

Answer: (B)

The main idea here is routing at the network layer. A router is designed to connect separate networks and forward packets by examining the destination IP address, consulting its routing table to choose the next hop, and sending the packet toward the destination network. This L3 function—deciding where to send traffic based on IP addresses—is what allows different networks to communicate. In contrast, a modem mainly provides access to an Internet connection and doesn’t route between internal networks. A bridge operates at Layer 2 and forwards data based on MAC addresses within the same network. A switch typically forwards frames using MAC addresses within a local LAN, though some higher-end switches can perform Layer 3 routing, the standard device associated with inter-network routing is the router.

The main idea here is routing at the network layer. A router is designed to connect separate networks and forward packets by examining the destination IP address, consulting its routing table to choose the next hop, and sending the packet toward the destination network. This L3 function—deciding where to send traffic based on IP addresses—is what allows different networks to communicate.

In contrast, a modem mainly provides access to an Internet connection and doesn’t route between internal networks. A bridge operates at Layer 2 and forwards data based on MAC addresses within the same network. A switch typically forwards frames using MAC addresses within a local LAN, though some higher-end switches can perform Layer 3 routing, the standard device associated with inter-network routing is the router.