Routing is the process of getting packets and messages from one location to another.
A router needs the following key information, as displayed in Figure 4-1:
Destination address: The destination (typically an IP address) of the information being sent. This includes the subnet address.
Possible routes: Likely routes to get from source to destination.
Best route: The best path to the intended destination.
Status of routes: Known paths to destinations.
Figure 4-1. Information Needed by Router for Routing
A router is constantly learning about routes in the network and storing this information in its routing ...