I am reading conflicting information on how OSPF RID is selected. They all agree it starts by choosing a specified RID, then failing that, the highest loopback IP. Then failing that...they all say highest IP but do not agree on if that includes interfaces that do or do not participate in OSPF. I'm reading BA materials plus CP's authorized self study as well as official guide.
SO...if you HAVE to go as far down as looking at interfaced to get the highest IP to use as RID...
Which is it selected from: ALL interfaces that are up or only those interfaces that are both up and participating in OSPF process?
Is the real life answer different from what is expected on test?