[ClearCase_guy]

Good one! Actually, the internet can be brought down -- anything can be brought down. But the internet was designed by DARPA to survive nuclear war. It's constructed to find paths between points, even if some routes are blocked. You'd have more collisions and slower and more problematic connections, I suppose, but it would take a lot to really bring it down.

I would also say that the coordination on 9-11 was a rare feat. At this point, I'd be very surprised if 5 terrorist cells operating in the US could all work together to take out 5 hubs on the same day. And is 5 hubs enough? How many cells need to sabotage how many hubs? I don't see it happening.

[Naspino]

There are thirteen critical servers I believe. The most recent attack (largest in history) took down eight and another 1 partially. There was little or no visible impact on the internet; however they said if the attack had lasted longer than an hour it would have started to slow down users. I believe some are even located outside of the country and their location is a closely guarded secret.

[Chemist_Geek]

Good one! Actually, the internet can be brought down -- anything can be brought down. But the internet was designed by DARPA to survive nuclear war. It's constructed to find paths between points, even if some routes are blocked. You'd have more collisions and slower and more problematic connections, I suppose, but it would take a lot to really bring it down.

Not to mention the information denisty is somewhat lower nowadays - more bytes must be moved to communicate a loosely written or a fancily designed Web page than just plain text.