Refer to the exhibit.

A company would prefer all Internet-bound OSPF routed traffic to use ISP ABC with ISP DEF as a backup.
As the network consultant, what three configuration changes should you make? (Choose three.)
Correct Answer: B,D,F
Explanation/Reference:
Explanation
Routers B2 & B3 need to advertise a default route to the Internet for inside OSPF routers so we should use the default-information originate command with a default route (something like ip route 0.0.0.0 0.0.0.0 ) pointing to the ISP router.
If no metric is specified, OSPF puts a default value of 20 when redistributing routes from all protocols except BGP routes (BGP routes get a metric of 1). We use ISP DEF as a backup so its metric value should be set to a higher value than 20.
There are two types of external routes: external type 1 and external type 2. The difference between the two is in the way the cost (metric) of the route is being calculated:
+ The cost of a type 2 route is always the external cost, irrespective of the interior cost to reach that route.
+ Type 1 cost is the addition of the external cost and the internal cost used to reach that route.
-> We should configure the type 2 external route to make sure the ISP ABC is always referred over ISP DEF because internal routing does not determine the path. Note: E2 is the default external metric, but E1 is preferred over E2 if two equal-cost paths exist.