If you want to run large network you'd better think about
tools to configure routers and maintain configurations.
In my practice more than 70% of non-link related problems in
corporate networks (and i've seen _lots_ of them) is due to
unnecessary dynamic routing. Just watch some luser turing on
RIP on his itty bitty terminal server or someting and causing
the entire corporation to go banana.
In public Internet, dynamic routing over tail links is downright
antisocial. I hope i don't need to explain _that_.
As an addendum to my remarks -- if you think you have complete
knowledge of how you dynamically routed network behaves in case
of various failures you're deceiving yourself.
The distributed algorithms too often behave counterintuitively,
and implementations often have subtle bugs.