This article describes someone who is constantly repairing the physical infrastructure of the Internet because of underwater cable breaks:
The incidents reveal a surprising fact about the Internet: that it requires constant physical maintenance. Without people like Rennie patching cables, the entire network would gradually stop. First, traffic would slow to a crawl as more bits crammed into fewer and fewer cables. Then, after a while, isolated service failures like the ones in the Middle East would pop up. Eventually, as line after line went dark, U.S. businesses would be cut off from their outsourced functions abroad, international e-mail traffic would halt, and global financial transactions would cease. Pockets of connectivity would persist, but ultimately the Internet we rely on to stay in touch with the rest of the world would be reduced to the local-area network in your office.
Something that must be constantly maintained simply because of wear and tear and accidents could be attacked more effectively, in my view. If deliberate attacks can't be more effective than fishing net incidents, anchors dragging, and whatever else, I'd be shocked.
Don't get so caught up with cyber-warfare that you forget that a room full of enemy hackers can be killed very nicely with a 500 pound JDAM.
