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Internet Blackout in Sudan

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Update (8:01 ET, 26 Sep):

A few hours ago, we observed a total Internet blackout in Sudan and, as we publish this blog, the Internet remains largely unavailable. By count of impacted networks, it is the largest national blackout since Egypt disconnected itself in January 2011. The massive outage came as the government began a violent crackdown on protests triggered by the government’s decision to end fuel subsidies. SD_outa_1380088800

Previous National Blackouts

National Internet blackouts in recent years have taken a variety of forms. For example, in the case of Egypt in January 2011, we observed all Egyptian routed networks withdrawn from the global routing table within a few minutes. During the revolution in Libya, the routes generally stayed up, but nearly all Libyan traffic was blocked at the border. Myanmar experienced a brief national outage last month in which all of its routes were withdrawn during a several week period of Internet disruptions. And as civil war rages in Syria, this country has experienced a number of national outages, starting in June 2011. These have often involved the withdrawal of routed networks, although Syria’s latest outage in Aleppo was only evident due to the loss of one of the state telecom’s international providers.

Today’s Outage in Sudan

In Sudan’s case today, we observe a combination of tactics used to shutdown the Internet. As shown to the right, Sudan connects to the global Internet through three international gateways: Sudatel (the Sudanese incumbent), Sudanese Mobile (Zain), and Canar Telecom. Sudan_Internet

We initially stated that Sudan’s outage began at 12:47 UTC because that was when virtually all Sudanese routed networks were withdrawn from the global routing table. However, once we plotted our active measurement data, we observed traffic into Sudan dropping off dramatically 2.5 hours earlier at 10:23 UTC — the same time as an earlier outage by Sudatel. This drop in traffic was independently confirmed by CDN provider Akamai. In the graphic below, we see the success rate of latency measurements into the networks of Zain and Sudatel drop off at 10:23 UTC, only to momentarily recover before ceasing entirely for Zain at 12:47 UTC (marked with the red arrow):

sudatel zain
Our active measurements also reveal that traffic stopped moving through Canar Telecom at 11:52 UTC and, unlike Sudatel and Zain, was restored at 15:19 UTC. At the time of this writing, Canar is the only international gateway connecting Sudan to the global Internet. SD-2.traces.ASedges.upstreamsof33788

Conclusion

Our plots of connectivity clearly show that Sudatel and Zain experienced identical outage timelines, while Canar’s total blackout followed a somewhat different schedule. This difference in timing implies that this event was not caused by a single catastrophic technical failure, but strongly suggests a coordinated action to remove Sudan from the Internet. As we close out this post, the primary provider into Sudan, the incumbent Sudatel, is still offline. Hopefully, full connectivity will soon be restored. Follow our twitter feed for the latest developments.


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Whois: Doug Madory

Doug Madory is a Director of Internet Analysis at Dyn where he works on Internet infrastructure analysis projects. Doug has a special interest in mapping the logical Internet to the physical lines that connect it together, with a focus on submarine cables.