|  | 10.2 | Path Determination
| 10.2.1 | Path determination

Path determination occurs at Layer 3 (network layer). It enables a router to evaluate the available paths to a destination, and to establish the preferred handling of a packet. Routing services use network topology information when evaluating network paths. Path determination is the process that the router uses to choose the next hop in the path for the packet to travel to its destination. This process is also called routing the packet.

Path determination for a packet can be compared to a person driving a car from one side of a city to the other. The driver has a map that shows the streets that he/she needs to take to get to the destination. The drive from one intersection to another is a hop. Similarly, a router uses a map that shows the available paths to a destination.

Routers can also make their decisions based on the traffic density and the speed of the link (bandwidth), just as a driver may choose a faster path (a highway) or use less crowded back streets.

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