Default Protocol Preference for OSPF Internal Routes

A

The default protocol preference for OSPF internal routes is 10.

Protocol preference is a value assigned to a particular routing protocol to indicate its preference over other routing protocols when multiple routes to a destination exist. OSPF (Open Shortest Path First) is a link-state routing protocol that uses Dijkstra's shortest path first (SPF) algorithm to calculate the shortest path to a destination.

In OSPF, protocol preference values range from 0 to 255. Lower values are more preferred than higher values, and the default protocol preference for OSPF internal routes is 10.

This means that if OSPF learns multiple routes to a destination from different sources, it will prefer the route with the lowest protocol preference value of 10 over other routes with higher preference values. If there are multiple routes with the same preference value, OSPF will use the metric or cost of the route to determine the best path.

It's worth noting that the protocol preference value for OSPF external routes is 150, which is significantly higher than the default value for internal routes. This is because OSPF external routes are learned from other routing domains or autonomous systems and are considered less trustworthy than internal routes.