Default Protocol Preference Values

AC

The default protocol preference values are used by a Junos router to determine the most preferred path to a destination network. The following are the correct statements regarding the default protocol preference values:

B. Direct, local, and static routes have the same preference value: The preference value for direct, local, and static routes is 0, which is the lowest preference value. These routes are considered to be more reliable and more specific than other routes. Therefore, they are always preferred over any other routes in the routing table.

D. OSPF has a single preference value for both internal and external routes: OSPF's preference value for all routes, whether internal or external, is 10 by default. The internal OSPF routes are learned within an autonomous system (AS), while external OSPF routes are learned from another AS. By default, OSPF prefers the internal routes over external routes. However, if there are multiple paths to a destination network, the router will select the path with the lowest metric value, regardless of whether it is internal or external.

A. RIP is preferred over OSPF external routes: This statement is incorrect. RIP has a higher preference value than OSPF, which means that RIP routes are preferred over OSPF routes. However, OSPF internal routes are always preferred over RIP routes, regardless of the preference value.

C. OSPF's preference value is lower than BGP: This statement is also incorrect. BGP has the highest preference value of all routing protocols, which is 170. Therefore, BGP routes are always preferred over routes learned from other protocols, including OSPF.

In summary, the correct statements regarding default protocol preference values are that direct, local, and static routes have the same preference value of 0, and OSPF has a single preference value of 10 for both internal and external routes.