Routers act independently. That is, the process of routing a single packet requires a router to go through its own logic without help from any other router.
At the same time, routers act in concert with each other. One router after another forwards a packet so that, eventually, the packet reaches the correct destination host. Each router’s independent action forwards the packet over one hop of an end-to-end route to the destination host.
This next topic discusses what routers do to route packets—first as an independent process on one router, and then as an overall effect.
Compared to hosts, routers have a little more work to do to route IPv4 packets. While the host logic ...