some practice questions revolving around ospf

q1: router-id


q1: router-id


what does router router1 use as its ospf router-id?

the answer is: the router-id is 172.16.15.10, the loopbacks address.

the reason is: the router-id gets set to the loopback address if it is manually set. if there is no loopback address created, it will take the highest ip address and use that instead.