Do you really understand Administrative Distance? Are you sure you know which route will be selected? Well, see if you an answer this quiz question! This is a practical demonstration using GNS3.
Cisco routers use Administrative to select the best path. But, it depends!
Administrative distance (AD) or route preference is a number of arbitrary unit assigned to dynamic routes, static routes and directly-connected routes. The value is used by vendor-specific routers to rank routes from most preferred (low administrative distance value) to least preferred (high administrative distance value). When multiple paths to the same destination are available in its routing table, the router uses the route with the lowest administrative distance. Router vendors typically design their routers to assign a default administrative distance to each kind of route that is used, however, this value can usually be adjusted manually by a network administrator.