what will happen if us government shutdown Tier-1 internet backbone?
Although Internet is designed to be quite resilient: Internet BackBone
The Internet, and consequently its backbone networks, do not rely on central control or coordinating facilities, nor do they implement any global network policies. The resilience of the Internet results from its principal architectural features, most notably the idea of placing as few network state and control functions as possible in the network elements, and instead relying on the endpoints of communication to handle most of the processing to ensure data integrity, reliability, and authentication. In addition, the high degree of redundancy of today's network links and sophisticated real-time routing protocols provide alternate paths of communications for load balancing and congestion avoidance.
but There only 6 Tier-1 backbone providers, most of them US commercials, what will happen if US government shutdown their backbones ?
In my understanding, the Internet won't be shut down, only sites on top of those backbones will be closed, sites within EU will still be reached. But there're other concerns like DNS, so what are the consequences ?