<P> Administrative distance (AD) 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 . </P> <P> On Cisco routers, routes issued by OSPF have a lower default administrative distance than routes issued by the Routing Information Protocol . By default, OSPF has a default administrative distance of 110 and RIP has a default administrative of 120 . </P> <P> The administrative distance (AD) value is assigned by the router on a per - protocol basis . Routers, by design, should not install multiple routes into the routing table as this has the potential to cause routing loops . While a router may run multiple routing protocols on the same device, it is necessary for the router to implement a process to ensure that multiple routes, pointing to the same destination do not simultaneously exist in the routing table . Each process running on a router advertises its administrative distance value to the local router . The router uses this value to determine which route should be used . Once a route has been selected, the routing information database is updated . If two routes have the same administrative distance, the router uses its vendor - specific algorithm to determine which route should be installed . Cisco routers simply ignore the values and fall back to the default values, which are never the same . </P>

What is the default administrative distance assigned to all ospf routes