4-1Anyone familiar with my recent rants on the subject of Internet regulation may have noticed that I have been slightly obsessed with the subject of network centrality. The Internet is supposed to be a distributed architecture, designed to withstand large-scale attacks. The decentralised nature of the Web allows for systems to be taken out, while the whole still will operate by redirecting traffic through the remaining nodes.  This makes the Internet resilient to random attacks.

Or so the theory goes.

We are increasingly seeing a shift in the Web’s basic structure, from a decentralised network we are presented with more centralised services which compromise the Internet’s resilience. Syria and Egypt managed to remove their countries entirely from the rest of the world by pulling a few switches (the operation is of course more complicated than that, but for the sake of brevity we will consider it so). This was not supposed to be possible if we had kept with the original intentions of the decentralised, organic and self-organised system.

Now a ground-breaking study by employees at Renesys has shed light on just how vulnerable the Web has become at national levels. They have studied a country’s Internet infrastructure by looking both at the physical interconnections that exist throughout the world, and also at the logical network, and have produced a map of the world in which it is clear that some countries are more likely to be disconnected than other precisely because they are more centralised. They used the following parameters:

  • If you have only 1 or 2 companies at your international frontier, we classify your country as being at severe risk of Internet disconnection. Those 61 countries include places like Syria, Tunisia, Turkmenistan, Libya, Ethiopia, Uzbekistan, Myanmar, and Yemen.

  • If you have fewer than 10 service providers at your international frontier, your country is probably exposed to some significant risk of Internet disconnection. Ten providers also seems to be the threshold below which one finds significant additional risks from infrastructure sharing — there may be a single cable, or a single physical-layer provider who actually owns most of the infrastructure on which the various providers offer their services. In this category, we place 72 countries, including Oman, Benin, Botswana, Rwanda, Pakistan, Kyrgyzstan, Uganda, Armenia, and Iran. Disconnection wouldn’t be trivial, but it wouldn’t be all that difficult. Egypt falls into this category as well; it took the Mubarak government several days to hunt down and kill the last connections, but in the end, the blackout succeeded.

  • If you have at least 10 internationally-connected service providers, but no more than 40, your risk of disconnection is fairly low. Given a determined effort, it’s plausible that the Internet could be shut down over a period of days or weeks, but it would be hard to implement and even harder to maintain that state of blackout. There are 58 countries in this situation, ranging from Bahrain (at the small end) to Mexico (at the largest end). India, Israel, Ecuador, Chile, Vietnam, and (perhaps surprisingly) China are all in this category.

    So is Afghanistan, reminding us that sometimes national Internet diversity is the product of regional fragmentation and severe technical challenges. It’s true; the government in Kabul is powerless to turn off the national Internet, because it’s built out of diverse service from various satellite providers, as well as Uzbek, Iranian, and Pakistani terrestrial transit.

  • Finally, if you have more than 40 providers at your frontier, your country is likely to be extremely resistant to Internet disconnection. There are just too many paths into and out of the country, too many independent providers who would have to be coerced or damaged, to make a rapid countrywide shutdown plausible to execute. A government might significantly impair Internet connectivity by shutting down large providers, but there would still be a deep pool of persistent paths to the global Internet. In this category are the big Internet economies: Canada, the USA, the Netherlands, etc., about 32 countries in all.

The end result is a map that has a worrying amount of green, meaning more chance of disconnection.

Research like this must be applauded, and hopefully the issue of centrality will continue to receive more coverage in Internet regulation debates. We seem to be stuck with some non-issues, while sleepwalking into a more centralised and therefore a more controlled Internet.

Categories: Networks



Javier Pallero · February 21, 2013 at 2:35 am

Como siempre, excelente. Más razones para ITU para promover políticas de desarrollo de banda ancha que no dependan enteramente de privados.

Me pregunto cual es la mejor forma de lograr los desarrollos en infraestructura sin dependencia absoluta de los grandes jugadores. Neutralidad desde la planificación.

Oh sueños del mañana… Saludos desde Córdoba, Argentina.


    Andres · February 22, 2013 at 4:28 am

    Desgraciadamente, la campaña contra el ITU significa que esta institución va a ser afectada en el alcance de sus decisiones. Necesitamos un cuerpo internacional que pueda ver asuntos como este, tal vez el ISOC.


mlinksva · February 22, 2013 at 6:27 pm

I'm extremely sympathetic to your concluding paragraph, but does this report indicate more centralisation and control?

"most countries have gradually moved towards more diversity in their Internet infrastructure over the last decade … significant diversification in smaller markets with a strong incumbent can take a long, long time"

The report highlights a great risk, but the risk is increasing due to the centrality of the net to society increasing, not because of an actual decrease in diversity of international connections. And Syria and Egypt were able to pull the plug not because the net has moved from its original architecture, but because there simply weren't many connections to those jurisdictions, and there were probably even fewer whenever the golden age was. Am I missing something?

But I applaud the research and your blogging on centrality, which needs to become a central issue! 🙂


    Andres · February 27, 2013 at 11:50 am

    Hi Mike,

    The report only is looking at one issue of centrality, which is that of national provider diversity. While there is more diversity in many countries, there is also more centrality in others, particularly regimes with an interest in curbing free internet access.

    The other problem is the growing centralisation at the hosting and domain name levels, which is another issue altogether, and not the subject of this study. I'm actually working on this topic.


      mlinksva · March 3, 2013 at 6:24 am

      Agreed there is more centrality in some jurisdictions than others, and those with high political risk of censorship tend to have more centrality. But I don't see anything pointing to *increased* centrality in national frontier connectivity, nor the difference among jurisdictions having anything to do with changes in net infrastructure toward more centralization.

      Your post on hosting and naming centrality is another good example. I'm not sure there is any increased centrality in naming. There is in hosting, which makes risk from the existing centrality of DNS more alarming.


Martijn Lafeber · February 23, 2013 at 4:10 am

Benin should be dark green, because there's only one giant internet cable going into the ocean. If an anchor hits it, the entire country doesn't have internet for a day or so.


    Andres · February 27, 2013 at 11:47 am

    Apparently the makers of the study have been getting a lot of feedback, but to place countries in green. Nobody thinks their country is more resilient.

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