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 ?


You're describing "network partition", whose severity depends on the smallness of the network segment you end up on.

If you're on a large segment, you'll be able to reach things like DNS, and be able to find the subset of sites in your partition. If you're in a small segment, you'll be missing things like NTP, DNS and the like, and your ISP will be running around like chicken with their head cut off, trying to capture whatever they have cached and bring up essential services.

If you're on a very small segment, such as within a company branch, all sorts of unexpected things will break in surprising ways, notably databases with fail-over mechanisms, which will appear to work, but in fact fill up with inconsistent data, doing bad things to the company.

  • NTP, DNS and the like / need more, so this is all about partition ?
    – zinking
    Feb 15 '14 at 8:51

Depends on the circumstances.

If it was shut down in order to prevent communication, then probably all the others would be shut down at the same time. Otherwise, what's the point.

If it was shut down due to legal or accounting reasons, then other companies would probably be assigned/sold the equipment and things would proceed as before.

There's a whole lot of other potential scenarios, each with its own nuance. There's really no general answer though because the circumstances dictate how the network will behave. It's all run by people, after all.

Important links go down all the time, though. You usually don't hear about it because companies maintain redundant routes for load balancing and reliability reasons.

Traffic gets a bit slower, sometimes a whole bunch of sites become inaccessible. Usually the situation is either remedied or routes are reconfigured accordingly within an hour or two. And there's usually lots of angry clients and a few days later, a post-mortem report written in serious tones and signed by the CTO.

But I would imagine that the report wouldn't be necessary if it was shut down by the Government.

  • I was actually concerning about the technical bits, say if US shutdown their internet part, is internet going to survive ? like DNS, T1 internet backbone etc... what are the concerning bits.
    – zinking
    Feb 14 '14 at 5:25
  • 1
    The Internet ALWAYS survives, even in pieces. Some things may be inaccessible, and some things won't be inaccessible. DNS roots are widely distributed, so that's not an issue. But certain TLDs might be cut off from certain people.
    – tylerl
    Feb 14 '14 at 6:12
  • this is what I am looking for, like are there other details will occur after backbone routers being shut down.
    – zinking
    Feb 14 '14 at 6:22
  • in the worst worst worst case, we would have smaller internets. Or huge intranets. Take this, almost every country has a war plan, where if some WW3 starts, they would shut down the internet and whole country would have one huge intranet. Right now, internet is so big, it is actually unmanageble. I forget who and why said this but someone once said something like "internet is the biggest thing that humankind created, yet still not sure about how it works" So yeah they can try to shut it down, they can slow it down or remove themselves from it, but they can not shut it down at all.
    – cengizUzun
    Feb 14 '14 at 8:32
  • The Internet is kind of like the system of roads. Every country every city every neighborhood has roads. They're all connected, and you can get from one place to another. If you dig up the road, you break a particular route, but the rest of the road still works on both sides. It's extraordinarily simple even though it's big.
    – tylerl
    Feb 14 '14 at 20:24

We've actually seen some indicators of what would happen. Primarily, you would lose access to some things for a while while the Internet tried to route around the damage and if your ISP was dependent on that backbone, you'd be cut off.

You can look at the Level 3 communications peering dispute from 2005 to see what happened when two major backbone providers stopped exchanging information due to a disagreement over who should pay who for data transferred over there network. The end result was that portions of the Internet disappeared if the existing routings went over the downed connection, but eventually started working again (I'll be it under heavier load and thus slower.) Those sites that were within the network segment were offline until the peering was restored though.


The same thing that happens when a major highway is closed.

Subsequent city streets become overcrowded/gridlocked due to commuters detouring. Traffic slows to a crawl.

Your 27 minute drive now takes an hour and 30 minutes.

Networks behaves in much the same way.

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