Which network device operates at the network layer to route packets between networks using IP addresses?

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

Answer: (D)

Routing between different networks relies on IP addressing, which is handled at the network layer. A router operates at this layer, using destination IP addresses and its routing table to decide the next hop toward the destination network. It can connect multiple networks and forward packets across network boundaries, making decisions about where to send each packet based on the destination IP.

A hub just repeats electrical signals at the physical layer, with no addressing or routing. A switch primarily forwards frames within a single local area network using MAC addresses at the data link layer. A bridge also works at the data link layer, segmenting a network and forwarding frames based on MAC addresses, typically within the same network.

So, the device that routes packets between networks using IP addresses is the router.