What information does a router use to make its packet forwarding decisions?

A router uses the routing table to make its packet forwarding decisions. The routing table is a crucial data structure that contains information about the network paths available to reach various destinations. Each entry in the table typically includes the destination network address, the next hop address, and the associated metrics that help determine the best path for forwarding packets.

When a router receives a packet, it examines the destination IP address contained within the packet's header. It then references its routing table to find the corresponding entry that matches or best matches the destination. Based on this information, the router identifies the next hop on the path toward the packet's destination and forwards the packet accordingly.

While the destination IP address is essential for the routing decision process, it is the routing table that ultimately guides how the packet will be forwarded based on its destination. Other options, such as the MAC address of the next hop, might be involved in the link-layer communication but are secondary to the overall routing decision based on the routing table. Similarly, the type of network protocol is not a determining factor for packet forwarding since the routing table itself contains the necessary protocol information.