When a router forwards data packets from one network to another, what does it do?

When a router forwards data packets from one network to another, it encapsulates the packet in a new frame and removes the old frame. This process is essential for ensuring that the data can be transmitted effectively over different network segments. Routers operate at the network layer, which means they deal with packets and their addressing, while different network types may require different frame formats.

In encapsulating the packet, the router takes the original packet, which contains the data and its layer 3 header, and wraps it in a new layer 2 frame suitable for the next segment of the network. This new frame contains the appropriate header information needed for forwarding the packet to the next hop, including the destination MAC address of the next device on the network. Removing the old frame is necessary because each network layer operates under specific protocols, and the original frame is no longer relevant once the packet is routed.

This process allows routers to facilitate communication across various network technologies and topologies, maintaining the integrity of the data being transferred.