Internet shut-down easier, in more countries, than you think

Very true

I agree with the article, having worked on call during the Taiwan 2006 earthquake. Lots of people rapidly discovered an awful lot of Asia's infrastructure passed close to Taiwan, despite the logical wavelengths supposedly being diverse: it's a bit like CDO's, wavelengths are merrily resold all over the place. The company I work for requires fiber maps for just this reason now.

Another country that's a little under estimated is Ireland: just one transatlantic link landing in Londonderry, and three others crossing the Irish Sea

Number of phone calls

Renesys describes the metric as a first approximation to the "the number of phone calls (or legal writs, or infrastructure attacks) that would have to be performed in order to decouple the domestic Internet from the global Internet."

Governments in developed countries have a fairly large capacity for making phone calls. If the government of, say, the Netherlands passed a law requiring a shutdown of international transit, I find it hard to believe that the need to make a few hundred phone calls would prevent its implementation. Major ISPs would prefer to shut down than face criminal charges, but even if they didn't, there are enough police in the Netherlands to visit every organisation with an AS number, if that proved necessary.

The Rensys article made the interesting point that the government of Afghanistan is effectively powerless to shut down the internet in that country. Perhaps a better metric could have been constructed by dividing the route diversity by some measure of government power.

Pulling the wrong thing

It all depends what the "puller"'s motivation is.

Given that a country (and here I mean specifically a western democracy or the UK) would feel the need to deny its citizens access to news and information to/from abroad, what would they have to do to achieve that?

The first thing would be to switch off the landline & mobile phone networks. I doubt that would be too difficult and wouldn't even need the use of (much) force - just a quiet word and a soft <click> in the right ears would be enough.

To do the same to the internet wouldn't be much harder. Forget all the stuff about routing and IP and resilience, the simplest way is to attack the physical layer. Half an hour's work with some cable cutters (remember: to get to this point, we're already well past the suspension of democracy and looking Martial Law in the eye) would do the trick.

All that would leave would be a few hardy souls with direct satellite feeds. Since you'd have to be desperate, cut off and completely isolated to even contemplate the cost/slowness and inconveinece of satellite internet, those few individuals probably have little idea of what's going on, anyway.

Blowing stuff up

Personally I'd leave all the hardware in place, who knows when your dictatorship might actually win its battle and need the Internet to announce this. A few well placed people pulling plugs at APNIC et al would conceal what was going on quite easily.