Which component is primarily responsible for examining data packets and deciding on their onward path?

The component that is primarily responsible for examining data packets and deciding on their onward path is the router. Routers are specialized networking devices that analyze incoming data packets to determine their destination. They use routing tables and protocols to make intelligent decisions on how to forward packets to ensure they reach their intended recipient.

Routers operate at the network layer of the OSI model, making them crucial for directing traffic between different networks. They facilitate communication between devices on separate networks, ensuring that data can travel across the internet or between different local area networks (LANs). The decision-making process involves evaluating the destination IP address of the packet and determining the most efficient route for it to take.

In contrast, other components like servers primarily provide resources and services over a network rather than route packets. Switches operate at the data link layer and are concerned with forwarding packets within the same network based on MAC addresses, while modems are used to convert digital data to analog for transmission over communication lines and vice versa, but do not make routing decisions. Therefore, the router's capability to examine and direct packets accurately makes it the correct answer.