Rooter Goes Away - What's the Difference?

o s p f is a hundred and 50 pages, much more complex than b g p. It's very hard to make the difference between a roter going away and he link to a neighbouring roter going Away. Some things that would change the graft would be new roters added or an existing router aware of a change in its ability to access parts of the internet. But i'm not sure if that is something that is different in o p f.