Is an Internet blackout possible?

Tuesday November 26 2019

Last weekend Kenya experienced a fault in one of its four submarine cables that carry the bulk of the Eastern Africa’s Internet traffic to Europe and Asia.

Many decades ago, the satellite links used to carry internet traffic between continents but today, Internet traffic has moved onto the higher capacity, faster speeds, better quality service offered by the undersea fibre cables.

So Mombasa is basically a huge and strategic internet hub for traffic originating from upstream capitals of Nairobi, Kampala, Kigali and Bujumbura. If one of the submarine links in Mombasa sneezes, the rest of the region will definitely catch a cold.

And it was a major cold indeed – as witnessed even by major players like Safaricom and Zuku experiencing intermittent levels of service.

One of the submarine cable operators was undertaking scheduled maintenance services and had to shift its traffic onto the other three submarine cable operators; hence the congestion.

While it was highly inconveniencing, it could have been worse.


Imagine a situation where we had only one submarine cable to carry our internet traffic and then it goes down for whatever reason – maintenance or sabotage.

Whereas we might still have the option of switching traffic back to the over 30-year-old satellite stations in Naivasha, it is unlikely that they can carry even a tenth of our current internet bandwidth requirements.

We will basically be officially off the internet grid, up to and until the submarine cables in Mombasa come back online.

However, there will be a few actors – like US or European embassies - who can afford to lease their own expensive satellite links for as long as it takes to get back the submarine cables back on line.


This is however Internet downtime due to maintenance or unforeseen disasters.

What of Internet downtime due to malicious actors? Can someone deliberately shutdown the Kenyan or even the whole of the global Internet?

Theoretically, yes. Practically, it is very difficult to execute.

Over the years, the Internet core infrastructure has built redundancies across continents and countries such that even a total disconnect in Mombasa, may not translate to a total blackout of internet services.

For example, one of the key Internet component is known as the Root Server system. The root server acts as the navigation system, guiding Internet requests, to their destinations.

Each time you type in a website address in your browser, you are requesting for an Internet resource and in the background, the root server, through its so called domain name system, takes over and delivers your request.

So one way to shut down Internet services at a global scale would be to attack and shut down its navigation root-server system. However, there are multiple root servers scattered across the globe, acting as back up to each other.

When one goes down, the other continues delivering the service without internet users noticing a glitch.

Nevertheless, it is much easier to cause a localised internet shutdown than a globalised one and several African governments have been perfecting this notorious habit over the years.


If Kenya had an authoritarian government, they would simply call the Mombasa submarine station and instruct the technicians to pull the power supply and everyone in Kenya will technically experience the internet blackout.

Other governments don’t even bother to call. They simply send their special forces to pull the power plug at their submarine stations.

Other softer practices include ‘brown-outs’ rather than absolute shutdowns. These are localised shutdowns, specific to the geographic zone that the security forces want to constrain. They have reportedly been used in Kenya on several occasions when high value, high target visitors like Presidents and Prime Ministers from certain countries visit.

Brownouts simply require the telco providers to randomly jam their transmission signal at designated locations such that customers in that geo-location do not enjoy quality or reliable services.

This approach can also be applied in situation of riots or breakdown of law and order. There are continuous debates as to the legality or otherwise of such deliberate denial of service attacks, but many governments around the globe continue to do it.

So next time you get online, do not take it for granted.

Spare a thought for the many others around the globe whose Internet access is not guaranteed and instead depends on the good mood or otherwise of their autocratic rulers.

Mr Walubengo is a lecturer at Multimedia University of Kenya, Faculty of Computing and IT.

Email: [email protected], Twitter: @Jwalu