Networking World

How Router Build its routing Table

1. For each route received from its interfaces, router verify the next hop. If it founds it invalid, then it discard the route.
2. If multiple routes, valid routes are advertised by a routing protocol, it choose with the lowest metric.
3. Routes are identical if they advertise the same prefix and mask, so 192.168.0.0/16 and 192.168.0.0/24 are separate paths and are each placed into the routing table.
4. If more than one specific valid route is advertised by different routing protocols, choose the path with the lowest AD.