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. --vadim